Flux Linkage Vector Research Articles

Синхронный многофазный электропривод с управлением по многоканальному принципу

A promising way to improve the technical and economic characteristics of an AC electric drive is to design it based on an executive synchronous motor with an increased number of phases of the stator winding. However, the specific nature of the m-phase (m > 3) synchronous motor is determined by the energy transfer by the whole spectrum of spatial harmonics of the field. Thus, the task is to design an electromechanical system that takes this feature into account. The author has used the method to study the adjustment characteristics of an m-phase synchronous motor based on spectral vectors of electromagnetic parameters reduced to spatial harmonics of the field. A multichannel principle of realization of an m-phase synchronous electric drive is proposed. It ensures the targeted formation of the electromagnetic state of a synchronous motor through all its energy channels as a control object. Various ways of its implementation are considered. The realization of the multiphase synchronous motor can be carried out based on of the forced mutual orientation of the flux linkage vectors and the stator current for higher spatial harmonics, which ensures the creation of additional constant components of the electromagnetic torque. This design of electric drives is advisable, in particular, for mobile installations with low-voltage (autonomous) power sources.

ЕЛЕКТРОМАГНІТНІ МОМЕНТИ УПРАВЛІННЯ ПРЕЦЕСІЙНИМ РУХОМ ТРИСТУПЕНЕВОЇ ЕЛЕКТРИЧНОЇ МАШИНИ

The main known structures and principles of functioning of electric machines with three degrees of freedom of rotational motion of the rotor are considered. The type of such machines in which it is possible to realize a high frequency of the rotor rotation is highlighted, which gives it the property of gyro-stabilization. The structure of the magnetic system of the machine of this type is presented and a hypothesis is put forward about the adequacy of the expressions of the classical analytical mathematical model, but the need for accurate calculation of the concentrated parameters that make up it. The distribution of magnetic flux density is analyzed based on a numerical mathematical model of a three-dimensional mag-netic field. The dependences of electromagnetic torque components and flux linkages on the rotor axis orientation and the angle of its rotation are calculated. It was concluded that the classical analytical mathematical model are adequate pro-vided that the calculating of its coefficients is based on the results of the modeling of three-dimensional magnetic field in the machine active volume and the surrounding space. It is underlined that, the amplitude of the flux linkage vector of the control winding and the fluctuations of the vector components to use in lumped parameter model must be calculated from the corresponding values of the electromagnetic torque components. Taking into account the results of the analysis of the three-dimensional field demonstrates a significant decrease in the speed of controlled precession and an increase in the amplitude of nutation. References 9, figures 10, tables 2.

Three Voltage Vector Duty Cycle Optimization Strategy of the Permanent Magnet Synchronous Motor Driving System for New Energy Electric Vehicles Based on Finite Set Model Predictive Control

Faced with the increasingly serious energy crisis and environmental pollution problems, traditional internal combustion engine vehicles are receiving more and more resistance, which has rapidly promoted the development of new energy electric vehicles. Permanent magnet synchronous motors are widely used in new energy electric vehicles and in other fields because of their simple structure, light weight, small size, and high power density. With the continuous advancement of production technology, the requirements of accuracy, rapidity, and stability in permanent magnet synchronous motor systems have gradually increased. Among many advanced control technologies, this paper proposes an optimized model predictive torque control strategy based on voltage vector expansion. This strategy involves the construction of a reference stator flux linkage vector based on the analytical relationship between electromagnetic torque, reference stator flux linkage amplitude, and rotor flux linkage and the transfer of the separate control of electromagnetic torque and flux linkage amplitude into flux linkage vector control. At the same time, the optimal duty cycle corresponding to the two adjacent extended voltage vectors and the zero vector is calculated according to geometric relationships so as to realize the three voltage vector duty cycle optimization control. Experimental results show the effectiveness and superiority of the proposed strategy.

Синхронный многофазный электропривод с управлением по основному энергетическому каналу

One of the options to improve the technical and economic characteristics of a synchronous electric drive is to design it based on an actuating motor with an increased number of phases. However, the characteristics of m-phase (m > 3) synchronous motor associated with the transfer of electromagnetic energy by a whole spectrum of spatial harmonic fields sets the task to develop an automatic control system that considers these features. The method to calculate the characteristics of an m-phase synchronous motor in quasi-stationary modes based on the use of spectral vectors of electromagnetic parameters for its individual substructures as a control object is used. The authors have proposed an approach to study and calculate energy characteristics of m-phase synchronous motor for different control laws implemented on the basis of equations of its design equivalent circuit. The results of the study of the main energy characteristics of the engine for various control laws along the main energy channel are presented. To implement the advantages of a multiphase synchronous motor, it is necessary to force the required mutual arrangement of the flux linkage vectors and stator current for higher spatial harmonics. It can be implemented based on the multi-channel principle of control system design.

State estimation accuracy analysis of an induction electric drive by the algorithms of Luenberger and Kalman

In complex electromechanical objects containing electric drives with induction motors, it is often difficult or impossible to install sensors of output variables. In this case, to determine the output coordinates of the motor, it is necessary to introduce state observers into the control system of the electric drive. The main problems of creating observers are the presence of noise and interference in the measuring circuits of the control system which affect the accuracy of the estimation of immeasurable state variables. The paper presents a comparison of the accuracy of estimates obtained as a result of the work of the observer algorithms based on the Kalman filter and the observer of the Luenberger in the induction electric drive system, with vector control at the noise level of the current measurement channels in the stator windings of the induction motor. To synthesize algorithms for state observers, methods of identification theory and quasi-linearization of nonlinear models of the control object under consideration were used. The simulation model of an induction motor is based on a classical vector field-oriented control system where an estimate of the angular speed of the motor shaft is used as a feedback signal. The model implements the following blocks: a mathematical model of an induction motor in a two-phase fixed coordinate system α–β; the structure of the observer algorithm; the procedure for converting the basis of the current vector and the control voltage from stationary to rotating and vice versa; proportional-integral regulators of current, flux linkage and angular speed. The S-shaped intensity setter forms a speed setting curve. The input signals for observers are the stator voltages and currents of the reference model of an induction motor. The adaptation coefficients for the Luenberger observer were selected experimentally from the condition of obtaining the average minimum value of the difference modulus of the estimated values. The covariance matrices for the observer based on the Kalman filter are configured on the basis of the experiment, ensuring a minimum of the average value of the absolute error. The time dependences of the transients of the angular speed of the shaft, the modulus of the flux linkage vectors of the rotor and stator currents are obtained. The dependencies were evaluated when starting an induction motor with nominal values and values of frequency and voltage amounting to 10 % of the nominal values. The work of estimation algorithms in the presence of a noise component, as well as when changing the parameters of the induction motor replacement circuit by ± 10 %, is investigated. The results of modeling the operation of the electric drive in starting modes with a mechanical load equal to the nominal value at a supply voltage frequency of 50 Hz and at 10 % of the nominal value for a voltage of 1 Hz are obtained. It is shown that the greatest relative estimation errors occur in the starting mode of the electric drive, and the maximum accuracy is achieved in the case of using a nonlinear Kalman filter. The results of the work can be used in the development of automatic control systems for sensorless electric drives and frequency-controlled electric drive of centrifugal pumping units for oil production.

OBSERVER OF SPEED AND FLUX LINKAGE IN THE SYSTEM OF VECTOR CONTROL OF ASYNCHRONOUS ELECTRIC DRIVE

The use of physical sensors in electric drive control systems requires taking into account their additional dynamics in the model of the control object, which can cause problems with the synthesis of regulators due to an excessive increase in the order of the control object model. The use of observers makes it possible to recover state variables that are not available for direct measurement and to exclude additional sensors, which contributes to the improvement of operational and cost indicators of control systems. The structure of the observer in asynchronous electric drives must contain such an adaptation function that ensures the asymptotic convergence of the observer to the reference model, which is a real object of control.
 The article presents a synthesis of the speed observer and flux linkage of the rotor of an asynchronous machine in a sensorless field-oriented control system. Equations of electromagnetic processes in an asynchronous machine, formulas of coordinate converters and equations of a PI controller are used as the initial mathematical model. By transforming the differential equations of the asynchronous machine, the structure of the adaptation function is determined, which adjusts the observer model in such a way that the deviations of the stator currents from their calculated values ​​go to zero. In this way, the adaptation function, which uses the vector product of the rotor flux linkage vectors and the stator current, ensures the stability of the movement of the speed identifier.
 In the proposed observer of the speed of an asynchronous machine, which uses stator currents to ensure the asymptotic stability of the observer, in the process of research on mathematical models, self-oscillations of the speed estimate were not found, in contrast to the well-known observer, which uses deviations of the flux links. It is possible to avoid self-oscillations not only by selecting the gain factors of the PI controller, but also due to the fact that there are no integrators not covered by negative feedback in the structure of the observer's electromagnetic circuits.

A Deadbeat Current and Flux Vector Control for IPMSM Drive with High Dynamic Performance

In this paper, a new deadbeat stator current and flux linkage vector control (DB-CFVC) scheme for interior permanent magnet synchronous machines (IPMSM) is proposed. The control structure is simplified by implementing the proposed flux linkage vector control method in the α-β stationary coordinate. Unlike conventional deadbeat methods, the dynamic performance of the proposed DB-CFVC can be enhanced while voltage command saturation and over output current are avoided. This is achieved with a “reinforced” phase angle reference of stator flux linkage vector by considering rotor speed error and maximum voltage to properly enhance the quality of the calculated flux phase angle command. By predicting stator flux linkage and current in the stationary coordinate, the deadbeat direct flux linkage vector control based on the one-step delay compensation strategy becomes straightforward and exhibits low sensitivity to motor parameters compared to conventional methods performed in the rotating frame. Then, by developing a practical and robust hybrid flux linkage observer, the proposed DB-CFVC method can work more reliably and effectively than conventional methods. Simulations and experiments are conducted in a drive system for an IPMSM to evaluate the effectiveness and reliability of the proposed method.

Modeling and Evaluation of Mutual Coupling Effect in Conventional Switched Reluctance Machines Using Space Vector Representation

This paper presents a non-linear model for conventional switched reluctance machines (CSRMs) that considers the mutual coupling between phases. Although CSRMs are based on single-phase excitation, there is usually an overlapping between the excited phases. During this overlapping, the CSRM is at 2-phase excitation and the single-phase representation of motor dynamics is not accurate. Hence, a dynamic model is presented in this paper that that accounts for the the mutual coupling between phases in addition to the effects of saturation and spatial harmonics. The proposed method is based on modeling the resultant current vector due to 2-phase excitation in space. The relationship between the resultant current and flux linkage vectors is obtained at different rotor positions using finite element method (FEM). This relationship is saved as a 3D lookup table (LUT). These 3D LUTs are reduced into 2D LUTs independent of rotor position by representing the phase currents as vectors instead of instantaneous values. Similarly, the relationship between the resultant current vector and the electromagnetic torque is obtained and saved as a 3D lookup table. The proposed method is compared with a conventional model where the mutual coupling is not considered. This comparison is conducted using FEM on two different motors; the first motor is 12/8 3-phase 2kW CSRM and the second motor is 24/16 3-phase 75kW CSRM. FEM results show that the mutual coupling is significant for high power motors. The proposed dynamic model is compared with experimental results using the 12/8 3-phase 2kW CSRM.

Direct Torque Control for a Bearingless Induction Motor Based on Model prediction

Purpose The purpose of this paper is to address the large stator flux linkage ripple and electromagnetic torque ripple caused by the hysteresis comparator in traditional direct torque control for a bearingless induction motor (BIM). Design/methodology/approach Model predictive direct torque control (MPDTC) strategy is adopted. On the basis of the mathematical model of BIM, the stator current and stator flux observational values are obtained, and the electromagnetic torque and stator flux at the next moment are predicted. Then, based on the relationship between the stator flux and the electromagnetic torque, the predicted stator flux can be transformed into an equivalent flux linkage vector, which eliminates the weighting coefficients problem among multiple variables in traditional objective functions. The objective function and torque PI controller will output the optimal stator flux linkage and the increments of the torque phase angle. Through the phase angle increments, the space voltage vector can be obtained by the reference flux linkage controller instead of the stator flux linkage and the torque hysteresis controller. Findings The proposed MPDTC method can effectively improve the stator flux linkage and the torque ripple. It can implement the stable suspension of the rotor and improve the dynamic performance and steady-state accuracy of the BIM system. Originality/value A MPDTC strategy is proposed to reduce the ripple of stator flux and electromagnetic torque. The phase angle increment angle of stator flux linkage and electromagnetic torque is optimized by model prediction, and the optimal space voltage vector is obtained by designing the reference flux controller.

KINETICS OF EXCITATION OF A MAGNETIC FIELD IN ASYNCHRONOUS VALVE CASCADE

The essence of the physical processes of vector control of an asynchronous valve cascade (AVC), in particular the processes of excitation of a rotating magnetic flux, becomes clearer if this field is considered as an independent object. The nonlinearity of the system of differential equations of AVC prevents the separation and consideration of a rotating magnetic field as an independent physical object. For AVC, when the stator of asynchronous machine (AM) is powered from the network, and the rotor circuit – from the frequency converter, the problem of studying the process of creating a magnetic field was not considered. It is possible to substantiate the possibility of considering the dynamics of the magnetic flux isolated from the reaction of the active power channel, provided that the rotor is held stationary by the control system and the reactive current of the rotor is stabilized by its regulator at a certain level.
 The process of magnetization of AM in the circuit AVC is mainly due to the voltage of the supply network, which significantly limits the possibility of actively influencing the formation of the reference vector of the stator flux linkage with the help of the regulator of the reactive component of the rotor current. It becomes impossible to qualitatively control the electromagnetic torque AM at the initial stage of start-up, when the stator flux linkage takes on a steady-state value after prolonged oscillations. This phenomenon leads to the need to supply a reference signal to the speed control channel when the stator flux linkage vector reaches a steady-state value when the rotor is stationary and there is no load torque on the shaft. In the article, the task is to investigate the process of excitation of the magnetic field of the AVC and the influence of the current regulator on this process at its different structures in the reactive power channel. An original method of studying the statics and dynamics of excitation of the magnetic field of the AVC is applied, the results of which allow us to conclude that to increase the stability margin of the reactive power circuit of the AVC, it is necessary to regulate the magnetizing current in the control system of this circuit instead of the reactive component of the rotor current.

Rapid Torque Rising of PMSM by Directly Chasing Rotating Flux Linkage Vector

The principle of permanent magnet synchronous motor (PMSM) torque control could be seen as driving the stator flux linkage vector to chase a rotating reference by the voltage vectors. An increase in the magnitude of the stator flux linkage vector limits the ability of the voltage vector to vary the torque angle and the torque. In most control strategies, simultaneously increasing that magnitude and the torque angle slows down the PMSM torque response. In this article, a new method to quicken the PMSM torque rising is proposed. The key idea is to predict an almost static flux linkage vector as the target and find a shortcut consisting of the voltage vector sequence during torque tracking to catch up with the rotating reference rapidly. Then, the torque rising can be accelerated by first shortening the stator flux linkage vector to quickly rotate it and then lengthening it. A set of comparative experimental results are presented to confirm the validity of this method.

THE APPLICATION OF VIBRATIONAL-ROTATIONAL OPERATION MODE IN VIBRATORY DRIVE

In this paper an analysis of the resultant flux linkage vector ψ0 of double-way feed motor (DFM) in the vibrational-rotational mode is shown. It is used for vibration-based diagnostics of various equipment with AC drives. In the case of using DFM in the vibrational-rotational mode the accuracy of motion law implementation is higher than using the standart induction motor. The results of research obtained with the help of a mathematical model of the DFM that allows to explore the special operating modes such as oscillating, polyharmonical, vibrational-rotational and creeping speed ones. The urgency of DFM operational mode and its practical significance as a method of control for vibration-based diagnostics systems are also given herein. The influence of the load parameters on the dynamic parameters of the executive vibratory drive is shown. Keywords: vibrational-rotational operation mode, vibration-based diagnostic, double-way feed motor, resultant flux linkage vector, damping torque, transient time

SPEED OBSERVER FOR SENSORLESS ENERGY GENERATION SYSTEMS BASED ON FIELD ORIENTED INDUCTION GENERATOR

The paper presents a novel adaptive speed – rotor flux linkage observer for sensorless field oriented control of induction generators. The proposed solution is based on Matsuse observer structure to- gether with specially designed correction terms and utilize current measurement and calculated stator volt- ages for real-time flux and speed reconstruction. A special coordinate transformation is used to avoid non- linear parametrization in the right side of flux linkages differential equations. Adaptive observer is designed in two steps: at the first step nonadaptive flux linkage observer is designed under condition of speed meas- urement; at the second step adaptive to rotor speed version of the flux linkage observer is designed. Infor- mation about rotor speed for adaptive flux observer is calculated by developed speed observer. A second Lyapunov’s method together with adaptive control theory are utilized for observer’s correction terms synthe- sis and stability proof. Designed adaptive observer under persistence of excitation conditions guarantees local exponential estimation of constant rotor speed and flux linkage vector components of induction ma- chine. From the practical point of view persistency excitation conditions are met if rotor flux linkages are nonzero. Proposed solution investigated by simulations. It is shown, that developed adaptive speed observer provides asymptotic estimation of induction motor currents, speed and flux linkage components under con- stant speed conditions. For varying speed proposed observer provides estimation of required variables with a small dynamic error. Proposed observer can be used in energy generation systems based on induction generators as well as in sensorless induction motor-based drive systems with constant or slowly varying ro- tor speed.

Stator Flux Based Model Reference Adaptive Observers for Sensorless Vector Control and Direct Voltage Control of Doubly-Fed Induction Generator

A position sensorless operation of a doubly-fed induction generator (DFIG) is desired from considerations of cost, maintenance, cabling, and reliability. This article proposes two stator flux based model reference adaptive observers (SF-MRAOs) for the estimation of the rotor speed and position in a stand-alone DFIG. The cross product of the reference and estimated stator flux linkage vectors is fed as controller input in the existing method, thereby, making the observer model nonlinear. The first proposed method, which is based on notch filtering, offers a performance comparable to that of the existing method while reducing the number of voltage and current sensors required. The second proposed method linearizes the error input to the controller, making the controller design straight forward, and also leading to superior performance than the existing methods. The linearized SF-MRAO is shown to work successfully with good dynamic performance in vector control of a stand-alone DFIG. This article also shows that the proposed linearized SF-MRAO can be employed for obtaining the rotor current angle in direct voltage control of a stand-alone DFIG. Simulation and experimental results are presented from a laboratory prototype of a 10-hp DFIG coupled to a squirrel-cage induction motor. The sensitivity of the performance of the proposed linearized SF-MRAO to variations in machine parameters is also studied theoretically and experimentally.

Induction Machine Control for a Wide Range of Drive Requirements

In this paper, a method for induction machine (IM) torque/speed tracking control derived from the 3-D non-holonomic integrator including drift terms is proposed. The proposition builds on a previous result derived in the form of a single loop non-linear state controller providing implicit rotor flux linkage vector tracking. This concept was appropriate only for piecewise constant references and assured minimal norm of the stator current vector during steady-states. The extended proposition introduces a second control loop for the rotor flux linkage vector magnitude that can be either constant, programmed, or optimized to achieve either maximum torque per amp ratio or high dynamic response. It should be emphasized that the same structure of the controller can be used either for torque control or for speed control. Additionally, it turns out that the proposed controller can be easily adapted to meet different objectives posed on the drive system. The introduced control concept assures stability of the closed loop system and significantly improves tracking performance for bounded but arbitrary torque/speed references. Moreover, the singularity problem near zero rotor flux linkage vector length is easily avoided. The presented analyses include nonlinear effects due to magnetic saturation. The overall IM control scheme includes cascaded high-gain current controllers based on measured electrical and mechanical quantities together with a rotor flux linkage vector estimator. Simulation and experimental results illustrate the main characteristics of the proposed control.

Disturbance Compensation-Based Model Predictive Flux Control of SPMSM With Optimal Duty Cycle

Finite control set model predictive torque control (FCS-MPTC) is receiving more attention for electric drives, due to its intuitive idea, flexibility to incorporate constrains, and fast torque dynamic response. However, traditional FCS-MPTC requires heavy computation effort and has high torque ripple at steady state. The weighting factors of the cost function are hard to optimize to obtain desired performances. Moreover, torque tracking error exists because FCS-MPTC belongs to the open-loop control strategy. This paper proposes disturbance compensation-based model predictive flux control (DCB-MPFC) with optimal duty cycle (ODC) of surface permanent magnet synchronous motor (SPMSM). This paper first proves the uniformity of MPTC, MPFC, and model predictive voltage control (MPVC). The cost function based on the stator flux linkage vector can be converted to the equivalent cost function based on voltage vector. The role of the equivalent cost function is to compare the deadbeat vector with three pairs of vectors, which can reduce computation effort and torque ripple. In addition, the disturbance compensation strategy is proposed to eliminate torque tracking error. The proposed DCB-MPFC is verified effectively by experiments that are compared with traditional algorithm, proportional-integral speed loop-based mode predictive torque control (PI-MPTC).

Speed Estimation Technique Using Modified Stator Current Error-Based MRAS for Direct Torque Controlled Induction Motor Drives

This paper uses a stator current error-based model reference adaptive system (MRAS) to estimate the speed of an induction motor drive. Usually, speed error signal uses the cross product of stator current error vector and flux linkage vector for the estimation of speed. However, this speed error signal has limitations, such as speed tracking error and instability (at regenerative mode) under loaded conditions at low speeds. To mitigate these issues, a modified MRAS speed estimation algorithm is proposed in this paper. In the proposed method, the adaptive model state variables are formulated in terms of flux linkages (stator and rotor) in order to alleviate the impact of current noise in the flux linkage estimation. Moreover, a compensator is added to reduce the speed error tracking in the reference model. Furthermore, the stability of the drive is kept by using the dot product of stator current error vector and the rotor flux linkage vector during the regenerative mode of operation. The analysis of the proposed algorithm is presented and validated experimentally on the laboratory setup with direct torque control-space vector modulation technique for a wide operating range including the dynamic performance.

Third Harmonic Current Injection in Fault-Tolerant Five-Phase Permanent-Magnet Motor Drive

This paper presents a third harmonic current injection method for a five-phase permanent-magnet (PM) motor with trapezoidal back electromotive force (EMF) under postfault field oriented control (FOC). The key of the proposed method is the third harmonic current online calculation and injection under postfault FOC. The postfault FOC lies in the fundamental decoupled model based on the concept of maintaining spatial circular rotation of fundamental PM flux linkage vector and magnetic motive force under open-circuit fault. Based on the mathematical model of torque pulsations caused by third harmonics of air-gap flux, the injected third harmonic current can be calculated by the radio of the amplitude of third harmonic EMF and fundamental EMF easily. The presented fault-tolerant control strategy can achieve the real time optimal current reference generation and third harmonic current injection under postfault FOC while reducing the torque pulsations. The effectiveness of the proposed method is verified by experimental results under various operation conditions.

Sensorless Direct Flux Vector Control of Synchronous Reluctance Motors Including Standstill, MTPA, and Flux Weakening

This paper proposes a sensorless direct flux vector control scheme for synchronous reluctance motor drives. Torque is controlled at constant switching frequency, via the closed loop regulation of the stator flux linkage vector and of the current component in quadrature with it, using the stator flux oriented reference frame. A hybrid flux and position observer combines back-electromotive force (EMF) integration with pulsating voltage injection around zero speed. Around zero speed, the position observer takes advantage of injected pulsating voltage. Instead of the commonly used current demodulation, the position error feedback is extracted here at the output of the observer's flux maps, thus resulting in immunity toward the cross-saturation position error. The maximum torque per ampere (MTPA) strategy is used. A detailed analysis puts in evidence the key advantages and disadvantages related to the use of the MTPA in the sensorless control of the synchronous reluctance machine, for both the saliency-based and the back-EMF based sensorless methods. Extensive experimental results are reported for a 2.2 kW synchronous reluctance motor prototype, showing the feasibility of the proposed method. These include speed response to step and sinusoidal load disturbances at standstill, up to 121% of rated torque, and speed response tests covering the flux weakening speed region.

Improved model‐predictive‐flux‐control strategy for three‐phase four‐switch inverter‐fed flux‐reversal permanent magnet machine drives

In this study, an improved model-predictive-flux-control (MPFC) is developed and implemented based on a three-phase flux-reversal permanent magnet (FRPM) machine drives fed by three-phase four-switch voltage-source-inverter (TPFS-VSI) with fewer switches and lower costs. The voltage variations and offsets across the two DC-link capacitors in this kind of inverter topology are suppressed by deriving an analytical expression of the DC-link capacitor voltages to reveal the inherent relationship between capacitor voltages and phase currents. In addition, the calculation process of the stator flux-linkage vector reference is simplified by adopting the dq-axes frame, and consequently, a precise predictive model is constructed for the stator flux-linkage vector control. Then, both the steady and dynamic performances of the TPFS-VSI-fed FRPM machine under the developed MPFC are evaluated by simulations and experiments. Meanwhile, the inverter and machine losses of the FRPM machine driven system of TPFS- and TPSS-VSI are measured for efficiency evaluation. The simulated and experimental results indicate that the developed MPFC not only offers the convergence of the DC-link voltages fed by the TPFS-VSI, but also improves the performance of the TPFS-VSI-fed FRPM machine drive in the low to medium speed applications.