Open Winding Configuration Research Articles

Torque Ripple Suppression in the 6/4 Variable Flux Reluctance Machine with Open Winding Configuration by Using Harmonic Injection

High torque ripple can be observed with a 6/4 variable flux reluctance machine (VFRM). In order to minimize the torque ripple in VFRMs, this paper presents a harmonic injection method for 6/4 VFRMs with an open-winding configuration. By analyzing the impact of harmonics on VFRMs, the method involves detecting the third harmonic using a first-order low-pass filter (FLPF). Subsequently, the extracted harmonics are controlled and shifted to counteract the voltage harmonics in both inverters without inducing phase imbalance or overvoltage. With the proposed method, the torque ripple can be significantly reduced by about 50% under load conditions. The effectiveness of the harmonic injection method is validated through a prototype VFRM.

Photovoltaic Power Conversion System Based on Cascaded Inverters with Synchronized Space-Vector Modulation

The paper presents results of investigation of dual-inverter-bases power conversion system with synchronized pulsewidth modulation (PWM) for photovoltaic application. This system topology includes two insulated strings of photovoltaic panels, feeding two standard three-phase inverters, connected to grid by a three-phase transformer with the open winding configuration on primary side. Algorithms of synchronized PWM provide in this case continuous voltage synchronization both in each inverter and in the load. Simulations show a behavior of the systems with low switching frequency, with both continuous and discontinuous versions of synchronized PWM.

Unity power factor control of permanent magnet synchronous motor by using open winding configuration

This paper presents the performance of open-winding permanent magnet synchronous motor (OW-PMSM). It mainly includes vector modulation technology considering the unity power factor control.And a topology structure is proposed to optimize the fault tolerance of inverter. Matlab software and Maxwell software collaborative simulation are supplied to obtain the reactive power, speed, terminal voltage, electromagnetic torque etc. under normal and fault status. Finally, the simulation results of an open-winding permanent magnet synchronous motor are verified by the experimental results.

Power factor improvement of permanent‐magnet linear vernier motor by using dual‐inverter with hybrid discontinuous PWM

A permanent-magnet linear vernier (PMLV) motor has the advantages of large force and low cost, but it suffers from a low-power factor. This study proposes an instantaneous power control algorithm by using a dual-inverter open-winding (OW) configuration to equivalently improve the PMLV motor power factor. In the proposed algorithm, the active and reactive powers for the motor operation are supplied by the main and compensation inverters, respectively. Therefore, the main inverter dc-link voltage is fully utilised to generate the active power, which is equivalent to the improvement of the motor power factor. Furthermore, a hybrid discontinuous pulse width modulation (HDPWM) scheme is proposed, which takes into consideration the power factor characteristics of the dual-inverter. Compared to the existing OW modulation ones, the proposed HDPWM technique can greatly reduce the dual-inverter loss. The experimental results are carried out to verify the proposed control strategy.

Design, Control, and Experimental Test of an Open-Winding IPM Synchronous Motor

A concentrated winding interior permanent-magnet synchronous motor (IPMSM) capable of being used in wide speed range applications is designed and introduced. The IPMSM in the study is capable of being operated either from a single supply or from two converters in an open winding configuration. In this study, the phase windings are open connected to two separate voltage source converters: a dc-supplied main bridge, capable or supply real and reactive power, and a floating bridge (FB), connected to a capacitor and only capable of supplying reactive power to the motor. Vector diagram analysis and two-dimensional finite-element analysis (FEA) are presented to illustrate the extension of the capabilities of the IPMSM compared to the usual Y connection. The open winding IPMSM is built and performance experimentally investigated over a wide range of speeds. The results demonstrate 10–15% higher power capability using an open winding and FB, compared to the single inverter drive by experiments.

Experimental verification of winding switching technique to enhance maximum speed operation of surface mounted permanent magnet machines

Flux weakening is an inevitable requirement in the operation of variable speed permanent magnet (PM) machines for high-speed applications due to inverter voltage limits. A new winding switching technique is experimentally validated in this study that can extend the speed range of such PM machines. A drive topology is proposed that utilises two current regulated voltage source inverters to control the machine in a dual inverter fed configuration before transitioning into an open winding configuration after winding switching. The proposed drive topology extends the constant torque region of the machine and boosts its maximum output power capability. Complete experimental results are provided to demonstrate the effectiveness of the proposed machine drive system for continuous operation over the entire speed range.

Zero-Sequence Current Suppression Strategy for Open Winding PMSG Fed by Semicontrolled Converter

The open winding permanent magnet synchronous generator (PMSG) fed by semicontrolled converter takes the advantages of lower expense, simplified driving circuit, and reliable control realization. With a single dc supply, the implementation of open winding configuration in practical application could be much convenient. However, the common dc bus supplied configuration provides a zero-sequence current circuit unavoidably. In order to reduce the harmonic distortion, a zero-sequence current suppression scheme is proposed. The space vector pulse width modulation (SVPWM) technique is adopted to modulate the desired voltage reference in the three-dimensional (3-D) coordinate system by distributing duty cycles for active and zero vectors. With a comprehensive investigation on the semicontrolled configuration, the achievable modulation region for αβ 0 voltage vector reference is analyzed. Finally, the zero-sequence current suppression method with 3-D-SVPWM technique is implemented in a 1 kW open winding PMSG experimental system.

Zero Sequence Current Suppression Strategy of Open Winding PMSG System with Common DC Bus based on Zero Vector Redistribution

The open-winding configuration with a common dc bus provides a zero-sequence current loop which allows the zero-sequence current flowing. With the application in permanent magnet synchronous generator (PMSG) systems, the existing zero-sequence current is inevitably caused by the common mode voltage generated by pulsewidth modulation (PWM) techniques and the third back EMF by the inherent flux harmonic component. With the mathematical modeling analysis, the zero-sequence equivalent circuit based on the PMSG system is proposed. Meanwhile, a zero-sequence current suppression controller is designed. In this paper, a zero vector redistribution PWM technique is proposed. With this technique, the dwell times of zero vectors (000) and (111) for both converters are determined. Meanwhile, it gives the zero-sequence component overmodulation analysis. Both the control method and improved PWM technique are implemented in a 1-kW open-winding PMSG experimental setup, and the experimental results are discussed.

Open-Winding Power Conversion Systems Fed by Half-Controlled Converters

An open-winding power conversion system with two conventional six-switch voltage-source converters (VSC) affords operation with a lower volt-ampere (VA) rating of each device for a given power rating, as well as a degree of fault tolerance. The disadvantages of such a configuration include a higher total device VA rating and increased conduction loss as compared to a single Y/Δ-connected VSC. In certain ac-dc applications, such as telecommunications, wind, and aerospace generator drives, it is desired to have regulated input currents and output voltage, but regenerative operation is either not required or prohibited. For such applications, an alternative open-winding power converter is proposed in this paper where half-controlled converter (HCC) is employed at each end of an open-winding structure. The resultant total switch count and total VA rating are reduced by half, compared to using full bridges. Besides, the basic advantages of an open-winding configuration, use of HCCs also guarantees immunity to dc-bus shootthrough and simplifies the gate drive circuit. The total VA rating of the proposed topology is found to be 42% less than a six-switch VSC. The operating principle, control method, and analysis with simulation and experimental results of the proposed topology in both a grid-tied rectifier application and a PM generator application are illustrated in this paper.