High Frequency Voltage Injection Research Articles

Sensorless Capability Expansion for SPMSM Based on Inductance Parameter Identification

Pulsating high-frequency voltage injection can be used for the sensorless control of a surface-mounted permanent magnet synchronous motor (SPMSM) at zero- and low-speed ranges. However, the sensorless capability still faces challenges to the requirements of industrial application, especially at heavy load status. Aiming at this issue, this article proposes a sensorless capability expansion method for an SPMSM based on inductance parameter identification. Firstly, incremental inductances at the d-q-axis and cross-coupling inductance are identified offline by three steps combining the rotating high-frequency voltage injection and pulsating high-frequency voltage injection. Using a polynomial curve fitting algorithm, apparent inductances are calculated. Secondly, positive DC current injection at the d-axis is proposed to enhance the saliency ratio based on the analysis of parameter identification results. Compared with the conventional id = 0 or id < 0 method, the saliency ratio is enhanced obviously when a positive DC current is injected at the d-axis. Then, the convergence region of the sensorless control method at heavy load status is expanded and the accuracy of rotor position estimation is improved using the proposed method. Finally, the experimental results validate that the sensorless capability of the SPMSM is expanded.

Variable-Angle Random High-Frequency Voltage Injection Strategy with Cross-Saturation Effect Compensation for Sensorless Synchronous Reluctance Motor Drives

There are usually noise problems when the position sensorless control of a synchronous reluctance motor (SynRM) is carried out by high-frequency (HF) signal injection method. Due to the special structure, the cross-saturation effect of the SynRM is particularly serious, resulting in reduced position observation accuracy. In this paper, a variable-angle random HF voltage injection strategy with cross-saturation effect compensation is proposed for position sensorless SynRM drives. Random number generation based on the chaotic mapping method is used to generate random HF voltage signals with different frequencies for injection; the current power spectral density (PSD) distribution is extended and the HF noise can be reduced. A control strategy based on variable-angle square-wave injection is proposed to suppress the cross-saturation effect. By measuring the position error curves of different loads off-line and polynomial fitting the curves, the position error is achieved by combining with the corresponding signal demodulation algorithm. The proposed method does not require additional hardware resources and can maintain high control accuracy and robustness. Finally, the effectiveness of the proposed sensorless control strategy is verified on a 3 kW SynRM experimental platform.

Sensorless control of submersible permanent magnet synchronous motor under long-line cable model

In the process of oil production, the submerged oil motor works 1-3 km downhole and is connected to the inverter by a long-wire cable, which generates overvoltage at the motor end due to the problem of matching the impedance of the motor with the impedance of the power cable. The downhole environment is not suitable for the installation of precision devices, such as position sensors. To solve these problems, a sensorless control method of submerged oil motors based on a high-frequency voltage injection method is proposed. A motor terminal voltage and current observer under a long-wire cable model is designed to estimate the actual values of motor terminal voltage and current by collecting the voltage and current at the inverter terminal. A three-level inverter is used to provide energy to the submersible oil electric pump through the long-wire cable, which can effectively suppress the motor terminal overvoltage compared to the two-level inverter. The control algorithm is verified by modeling the whole system using simulation software.

Early Fault Detection of Stator Inter-Turn Short Circuit of Asynchronous Motor Based on Rotating High Frequency Voltage Injection

Early Fault Detection of Stator Inter-Turn Short Circuit of Asynchronous Motor Based on Rotating High Frequency Voltage Injection

Sensorless Control Strategy for Interior Permanent Magnet Synchronous Motors in the Full-Speed Section

Along with the advancement of modern control technology, electric vehicles have gradually become the leading force in the development of the automobile industry. Interior permanent magnet synchronous motors (IPMSMs) have gradually become a mainstream electric vehicle drive component due to their high power density and excellent controllability. This type of motor can form a high-precision closed-loop control system with position sensors, which improves the overall performance. However, the operating conditions are complicated, and position sensor failure can easily occur, which reduces the stability of the motor system. For the fault-tolerant control problem of position sensor failure, pulse high-frequency voltage injection and an improved sliding mode observer (SMO) are employed to achieve the sensorless control of both the low-speed and medium-high-speed sections of the electric motor. Combining the advantages of high-frequency voltage injection in the low-speed section with a high accuracy of position estimation and the advantages of improved SMO in the high-speed section with low computational volume, the composite sensorless control strategy is proposed for IPMSM in the full-speed section. Secondly, an improved SMO using a segmented composite function as the control function is proposed to improve the robustness of the system. It is proposed to address the issue of the smooth transition between the low-speed section and the medium- and high-speed section by using linear weighting. Finally, in order to validate the accuracy of the sensorless control technology, a rapid control prototype of IPMSMs based on Speedgoat is constructed by using a semi-physical simulation system. The efficacy of the control algorithms in the low-speed section, high-speed section and transition interval is verified.

A Unified Wide-Speed Range Sensorless Control Method for Switched Reluctance Machines Based on Unsaturated Reluctance

A unified unsaturated-reluctance-based wide speed range sensorless control method for switched reluctance machines (SRMs) is proposed in this paper. Firstly, the sensitivity analysis of the estimated position to the possible reluctance calculation error is analyzed. This analysis reveals the feasible regions with low sensitivity and low risk of entering saturation. Then, the unsaturated reluctance in these feasible regions is obtained and modeled. A simple second-order rational expression is proposed to fit the highly nonlinear unsaturated reluctance curve. With this simple model, the rotor position can be analytically calculated only by solving a simple quadratic problem. Based on the above-presented analysis, a wide-speed range sensorless control is developed. The rotor position is universally estimated from the real-time reluctance value and the proposed analytical model. The high-frequency voltage injection and normal conduction phase are combined to calculate the phase reluctance over the wide-speed range. The concerns of calculating reluctance at the low-speed range are also discussed. A 5.1 kW four-phase 8/6 SRM is used to verify the proposed method. Various steady state and transient state experimental results prove the effectiveness of the proposed sensorless control method.

Sensorless Control of IPMSM Drives Using High-Frequency Pulse Voltage Injection With Random Pulse Sequence for Audible Noise Reduction

Saliency tracking based sensorless control schemes of interior permanent magnet synchronous motor (IPMSM) are generally troubled by the audible noise induced by high-frequency (HF) signal injection and the estimation error caused by voltage distortions. Aiming at that, a novel sensorless control strategy of IPMSM drives using HF pulse voltage injection with random pulse sequence (HFPVI-RPS) is proposed. Firstly, the conventional HFPVI method could restrain the impact of voltage distortions, and its mechanism is briefly reviewed. Then, based on that, a novel injected form that injecting HF pulse signals with random pulse sequence into the estimated d-axis is designed to eliminate discrete harmonics in the current power spectra density (PSD) and broaden the current PSD to a wide range. The audible noise can be reduced as much as possible. Further, a signal demodulation scheme matched with the injected form of HFPVI-RPS is proposed for the accurate extraction of rotor position. The PSD analysis of the HFPVI and proposed HFPVI-RPS methods is carried out, and the PSD comparison between reported methods and HFPVI-RPS method is given. Eventually, the effectiveness of the proposed sensorless control strategy is verified on a 750W IPMSM drive platform.

Motor Current Reconstruction Method Using Single Shunt Resistance by High-Frequency Voltage Injection

Motor Current Reconstruction Method Using Single Shunt Resistance by High-Frequency Voltage Injection

An Improved High-Frequency Voltage Injection Method for Interturn Short-Circuit Fault Detection in PMSMs

The inter-turn short-circuit fault (ITSCF) is a common incipient fault for the permanent magnet synchronous machine (PMSM) drive system. In recent years, the high-resolution ITSCF detection method that combines the high frequency (HF) signal injection and zero-sequence voltage measurement has been put forward. However, for the traditional HF signal injection technique, nonnegligible voltage distortion may occur when the injection frequency is close to the PWM carrier-frequency. In addition, the injected voltage varies with the operating conditions of the PMSM. These drawbacks of the traditional HF signal injection technique greatly limit the ITSCF detection performance using HF signal injection. To further improve the ITSCF detection performance, an improved HF injection scheme is proposed in this paper. In the proposed method, the six active voltage vectors are injected into the PMSM in certain orders to realize a rotating voltage injection, and the injection frequency is up to five-sixth of the PWM carrier-frequency. By employing the proposed injection method, the ITSCF detection sensitivity can be much improved. And the ITSCF detection performance is not affected by the operation conditions of the PMSMs. Finally, the simulations and experiments are carried out to verify the proposed method.

A variable frequency injection method for modular multilevel converters in variable speed drives

Modular multilevel converter (MMC) is a novel circuit that has appeared in the last few decades, and has been extensively applied to medium/high voltage scenarios, especially in motor drive owing to its scalability and easy to supply a higher number of output voltage levels. As theoretical analysis shows, the sub-module (SM) capacitor voltage magnitude is positively related to the converter output current amplitude and conversely connected to the fundamental frequency. Therefore, the prime challenge of applying MMC to variable speed drives is that there is a huge voltage oscillation in SM capacitor voltage during low-speed working. An innovative high-frequency voltage injection modality to diminish the fluctuation of the capacitor voltage in variable speed drives is proposed in this paper, in which the frequency of the injected component can be changed with the operating frequency of the converter and the low frequency component of power can be converted into high frequency component. The discussed measure not only significantly reduces the voltage float in capacitor, but also avoids the overmodulation of arm voltage modulation waveform caused by high frequency of injection component when converter works in low frequency. With the improved method, the performance of motor at low frequency is enhanced. Finally, the feasibility and effectiveness of the proposed improved high-frequency voltage injection method are verified by simulation and experiment.

Application Research of Pulse Vibration High-Frequency Voltage Injection Method Without Speed Sensor in New Energy Vehicles

The high-frequency voltage injection method of pulse vibration in the range of zero/low speed to medium-high speed has to be demonstrated for new energy vehicles., because it is very necessary and necessary to control the safety performance of the whole vehicle without speed sensor. The permanent magnet synchronous motor starts slowly to circle when the clean - energy vehicle cranked, and the correctness of the rotor’s startup position identification is significant. In order to achieve high-performance control of permanent magnet synchronous motor without speed sensor, this paper focuses mainly on how to estimate the rotor position of permanent magnet synchronous motor by amplifying the mathematical model of the motor. The high-frequency mathematical model of the permanent magnet synchronous motor’s voltage parameters are attained in the process of maintaining the motor’s preoperational position to address the problem of self-adaptability between the injected voltage and the likely phase current. The initial position identification of the rotor of a permanent magnet synchronous motor can be achieved by optimizing the adaptive method, and the pulse vibration highfrequency voltage anesthetic method also shows better efficiency and safety when the motor achieves a stable start and has sound output torque. The struggling to retain adaptive measurement device vibration high frequency voltage injection approaches is used by the light-duty low-speed new energy vehicle, which may minimize the mechanical speed sensor after becoming damaged, save the cost and improve the compactness of the electric vehicle space design, which is conducive to solving the situation of energy shortage in my country and alleviating environmental pollution. This is in line with the future development concept of society.

Rotor Position Estimation Strategy Based on Rotating High-Frequency Voltage Injection Using Synchronous Frequency Filter

In order to improve the performance of motor drive systems, this paper introduces a sensorless control method for interior permanent magnet synchronous motors (IPMSM) based on the rotating high-frequency voltage injection method. The demodulation method using a synchronous frequency filter (SFF) instead of a bandpass filter (BPF) and a high pass filter (HPF) is proposed. The structure and transfer function of SFFs are introduced, and their characteristics are simulated and analyzed. Therefore, the center frequency of SFFs can be adaptively adjusted according to the estimated rotational speed, which is convenient for frequency setting. Finally, according to the proposed rotating high-frequency voltage injection method, the simulation model is built. The experimental results verify that the control strategy can maintain good position estimation accuracy, better speed tracking performance and anti-load disturbance performance.

A Sensorless Control Strategy of Injecting HF Voltage Into d-Axis for IPMSM in Full Speed Range

This article presents a sensorless control strategy by injecting high-frequency (HF) voltage into the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis for the interior permanent magnet synchronous motor (IPMSM) in the full speed range. The defined quadratic virtual back electromotive force model can be adopted in the full speed range, and thus, there is no need to design a transition algorithm from the zero–low speed to the medium–high speed. Besides, the accurate model of IPMSM is applied to eliminate the error caused by ignoring the stator resistance. Furthermore, the estimation error caused by the filter and system delay during demodulating the HF current in the conventional HF voltage injection method is avoided. Compared with the method of injecting HF voltage into the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis, the proposed method has smaller torque ripple and smaller injected voltage. The effectiveness of the proposed method is verified by experimental results.

Hybrid Pulse High-Frequency Voltage Injection Control Algorithm of Sensorless IPMSM for Vehicles

A hybrid pulse vibration high-frequency voltage signal injection method is proposed to solve the problems that the conventional sensorless control algorithm of vehicle IPMSM may generate a large estimated rotor position error and opposite directions in identifying the polarity of magnetic poles under zero-speed and high-torque starting and low-speed operation. The magnetic pole polarity is identified by the saturation effect of the flux chain by injecting a high-frequency sinusoidal voltage signal and opposite pulse voltage signal into the axis of the assumed coordinate system simultaneously. Subsequently, the position relationship between the assumed axis and the actual d axis is studied in accordance with the amplitude of response current to acquire the rotor position and speed information. The simulation and experimental results suggest that the algorithm is capable of accurately identifying the magnetic pole polarity and estimating the rotor position at zero speed and low speeds, starting the motor smoothly at zero speed, and then operating the motor stably at low speeds.

Sensorless Control of Permanent Magnet Synchronous Motor in Full Speed Range

Aiming at resolving the limitation of the speed regulation range of sensorless control technology, a new composite sensorless control strategy is proposed to realize a control method for a permanent magnet synchronous motor (PMSM) in full speed range. In the medium- and high-speed range, the improved new sliding mode observer method is used to estimate the motor speed and rotor position information. In the zero and low speed range, in order to avoid the defects of the sliding mode method, the rotating high-frequency voltage signal injection method is used. When switching between low, medium, and high speed, the fuzzy control algorithm is adopted to achieve smooth transitions. The simulation experiment results show that the hybrid mode combining the sliding mode observer and rotating high-frequency voltage injection methods, can effectively reduce the jitter in the algorithm switching process, and realize the smooth control of a PMSM in full speed range.

Improved Cross-coupling Effect Compensation Method for Sensorless Control of IPMSM With High Frequency Voltage Injection

In this paper, the conventional cross-coupling effect compensation method that uses offline measured cross-coupling factor by current compensation in high frequency pulsating voltage injection based sensorless control is firstly extended for use in high frequency rotating voltage injection based sensorless control by angle compensation. Compared with the current compensation method, the angle compensation method has better dynamic performance as confirmed by experiments. To enable direct angle compensation, a novel method for offline measuring the cross-coupling induced errors is proposed by injecting HF voltages in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis, respectively. The measured errors can be used for online cross-coupling effect angle compensation irrespective of the injected signal that is used for position estimation. Experiments have verified the effectiveness of the proposed methods. In addition, stability and convergence of sensorless operation with the proposed cross-coupling effect compensation methods at highly saturated conditions are also analyzed and experimentally evaluated.

Research on Position Sensorless Vector Control of Synchronous Reluctance Motor Based on High Frequency Injection Method

In order to achieve the high-performance control position sensorless vector control of synchronous reluctance motor (SynRM), this paper investigated its running-up performance and capability at zero or low speed range. The contribution of this paper mainly includes two parts. Firstly, it takes cross-saturation effect into consideration, Secondly, the paper improves the control stiffness and reliability under low-speed sensorless operation condition by adopting the pulsating sinusoidal high frequency voltage injection snesorless method. By injecting high-frequency voltage excitation signal, the rotor position is estimated from the high-frequency response current. The simulation results verified the feasibility of the control algorithm, and fulfilled the running-up of the SynRM at zero speed, the capability of stability is evaluated via simulation results.

Position and Cross-Coupling Factors Estimation for Sliding Mode Current Control Based Position-Sensorless Control of IPMSM

This paper presents a control method with an estimation method of cross-coupling factors of Interior Permanent Magnet Synchronous Motors (IPMSM) inductance for position-sensorless servo drive systems. The cross-coupling factors are from dq-axis mutual inductance. Conventionally, the cross-coupling factors have been ignored in the IPMSM model and deteriorate control performance. That has caused decreasing robustness and velocity vibration in the low-speed range. Since the cross-coupling factors vary with the rotor position and the current, it is hard to measure them. Therefore, the proposed method utilizes a high-frequency voltage injection method to estimate the cross-coupling factors online. In addition, the proposed current control method utilizes a sliding mode control and voltage disturbance observer based on the voltage equation, including the dq-axis mutual inductance model. The estimated cross-coupling factors are reflected in the proposed current controller instantaneously. Experimental results show that the proposed method considering cross-coupling factors increases the robustness to the disturbance force and reduces the velocity vibration.

Low speed sensorless control method of brushless DC motor based on pulse high frequency voltage injection

A low speed sensorless position control method for brushless DC motor based on pulse pulse high frequency voltage injection is proposed according to the characteristic that the brushless DC motor (BLDCM) which is produced at present makes the counter electromotive force waveform show sinusoidal waveform in view of the problem that it is difficult to accurately obtain the rotor position and speed of the brushless DC motor at zero and low speed. Its principle is to inject high frequency sinusoidal voltage signal on the estimated direct axis of the synchronous rotating coordinate system so that the motor can generate saturated salient effect, obtain the estimation error containing the rotor position information, and by detecting the output current of PI regulator of quadrature axis current loop, and then estimate the initial position of the rotor and judges the magnetic pole, realize the determination of the actual rotor position, finally, realize the non-position static low speed control of BLDCM by adding current and speed rings. According to the simulation test, it shows that this method can detect the position and speed of the motor rotor well at both zero speed and low speed.

Estimated Position Error Compensation Method Considering Impact of Speed and Load in Permanent Magnet Synchronous Motor Position Sensorless Control Based on High-Frequency Voltage Injection

Estimated Position Error Compensation Method Considering Impact of Speed and Load in Permanent Magnet Synchronous Motor Position Sensorless Control Based on High-Frequency Voltage Injection