Search

Due to high power density, high efficiency, and accurate control performance, permanent magnet synchronous motors (PMSMs) have been widely adopted in equipment manufacturing and energy transformation fields. To expand the speed range under finite DC-bus voltage, extensive research on field weakening (FW) control strategies has been conducted. This paper summarizes the major FW control strategies of PMSMs, which are categorized into calculation-based methods, voltage closed-loop control methods, and model predictive control related methods. The existing strategies are analyzed and compared according to performance, robustness, and execution difficulty, which can facilitate the implementation of FW control.

The inverter dead time effect is non-negligible for the control performance of sensorless synchronous reluctance motor (SynRM) drives at low speeds. In this paper, a reduced-order observer-based sensorless control method for SynRM drives combined with the adaptive linear neurons (ADALINE)-based dead-time compensation is proposed. The reduced-order observer-based sensorless control method is presented, for which is parameter tuning is easy. On this basis, the dead-time compensation strategy using ADALINE filters is proposed to reduce the voltage harmonics effect on the estimation performance of the reduced-order observer. With ADALINE filters, the sixth current harmonic can be successfully filtered out by compensating the voltage directly or fitting the current to compensate the voltage. In this way, the low-speed estimation performance of the reduced-order observer is improved. The effectiveness of the proposed method is verified on a 3 kW SynRM experimental platform.

In electrolytic capacitorless permanent magnet synchronous motor (PMSM) drives, the DC-link voltage will fluctuate in a wide range due to the use of slim film capacitor. When the flux-weakening current is lower than −ψf/Ld during the high speed operation, the flux-weakening control loop will transform to a positive feedback mode, which means the reduction of flux-weakening current will lead to the acceleration of the voltage saturation, thus the whole system will be unstable. In order to solve this issue, this paper proposes a novel flux-weakening method for electrolytic capacitorless motor drives to maintain a negative feedback characteristic of the control loop during high speed operation. Based on the analysis of the instability mechanism in flux-weakening region, a quadrature voltage constrain mechanism is constructed to stabilize the system. Meanwhile, the parameters of the controller are theoretically designed for easier industrial application. The proposed algorithm is implemented on a 1.5kW electrolytic capacitorless PMSM drive to verify the effectiveness of the flux-weakening performance.

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.

Synchronous reluctance machines (SynRMs) have drawn increasing attention in recent years owing to their advantages such as low cost, simple structure, ease of manufacture, and high robustness. The main obstacle to the promotion of SynRMs is severe parameter nonlinearity, which deteriorates drive performance. Sensorless control methods for SynRMs are critical technologies that can broaden the industrial applications of SynRMs. Various methods of parameter identification and sensorless control strategies are reviewed and discussed, including self-commissioning, which is analyzed in detail. Furthermore, sensorless control strategies that can improve the industrial application of SynRMs are described. Finally, future research trends concerning SynRMs are analyzed and discussed.

In recent years, the application of sensorless AC motor drives is expanding in areas ranging from industrial applications to household electrical appliances. As is well known, the advantages of sensorless motor drives include lower cost, increased reliability, reduced hardware complexity, better noise immunity, and less maintenance requirements. With the development of modern industrial automation, more advanced sensorless control strategies are needed to meet the requirements of applications. For sensorless motor drives at low-and zero-speed operation, inverter nonlinearities and motor parameter variation have significant impact on the stability of control system. Meanwhile, high observer's bandwidth is required in high-speed region. This paper introduces the state of art of recent progress in sensorless AC motor drives. In addition, this paper presents the sensorless control strategies we investigated for practical industrial and household applications. Both advanced sensorless drives of induction motor (IM) and permanent magnet synchronous motor (PMSM) are presented in this paper.

Affine projection algorithm (APA) has been used to estimate the parameters of interior permanent magnet synchronous motor (IPMSM). However, there is not a strict guideline of choosing the stepsize of this algorithm to make sure that the results of parameter estimation are convergent. In order to solve such problem, self-adaptive stepsize affine projection algorithm for parameter estimation of IPMSM is proposed in this paper. Compared with traditional affine projection algorithm, this method can obtain the stepsize automatically based on the operation condition, which can ensure the convergence and celerity of the process of parameter estimation. Then, on the basis of self-adaptive stepsize affine projection algorithm, a novel parameter estimation method based on square-wave current injection is proposed. By this method, the error of estimated parameter caused by stator resistance, linkage magnetic flux and dead-time voltage can be reduced effectively. Finally, the proposed parameter estimation method is verified by experiments on a 2.2-kW IPMSM drive platform.