This paper presents a maximum torque per ampere (MTPA) control method for interior permanent magnet synchronous motor (IPMSM) drives. The proposed method employs a variable-equivalent-parameter MTPA control law to calculate the MTPA current references. Different from conventional MTPA control laws, this novel MTPA control law equivalently considers both the influence of the motor parameter values as well as the influence of the derivatives of motor parameters with respect to d- and q-axis currents on the MTPA control. Therefore, the proposed method can achieve accurate MTPA control under different load conditions. In addition, this novel MTPA control law avoids the computation of derivatives of motor parameters and the complicated computations that exist in conventional MTPA control laws. Thus, the proposed method can provide the MTPA current references easily and in real time, allowing for fast MTPA control to be achieved. Both simulation and experimental results confirm the effectiveness of the proposed MTPA method.

This paper presents a maximum torque per ampere (MTPA) control scheme for interior permanent magnet synchronous motor (IPMSM) drives. In this scheme, an enhanced signal injection technique is responsible for correcting the MTPA reference deviation due to motor parameter variations, and a derived MTPA control law is responsible for generating constant-parameter model-based MTPA current references to enhance the dynamic performance of the MTPA operation. Unlike previous signal injection techniques, the enhanced injection technique directly injects signals into the d- and q-axis currents and extracts the MTPA indicator from the reconstructed dc-link current. Hence, this enhanced injection technique avoids any transformations associated with polar coordinates, and it does not depend on a dc-link voltage sensor or a high-resolution speed sensor. The derived MTPA control law, unlike conventional MTPA control laws, can be realized in real time without mathematical approximations or lookup tables. With the combination of the enhanced signal injection technique and the derived MTPA control law, the proposed MTPA scheme can achieve an accurate and fast MTPA operation. Simulation and experimental results confirm the validity of the proposed MTPA scheme.

According to the recent study, most of the mathematical model based motor efficiency optimized control schemes ignore the derivative terms of machine parameters with respect to the current angle. Therefore, even though the accurate machine parameters are known, these control schemes cannot calculate the accurate efficiency optimized operation points. Due to the machine parameter nonlinearity and harmonics, these derivative terms are difficult to be obtained online, which cause great difficulties in achieving accurate maximum torque per ampere (MTPA) control. To solve the above issues, in this article, an extended virtual signal injection control scheme is proposed. The proposed control scheme can automatically compensate for the MTPA control errors caused by parameter variations and achieve accurate MTPA control online. The proposed control method is demonstrated by both simulations and experiments under various operating conditions on prototype interior permanent magnet synchronous machine drive systems.

Vehicle dynamic parameters are of vital importance to establish feasible vehicle models which are used to provide active controls and automated driving control. However, most vehicle dynamics parameters are difficult to obtain directly. In this paper, a new method, which requires only conventional sensors, is proposed to estimate vehicle dynamic parameters. The influence of vehicle dynamic parameters on vehicle dynamics often involves coupling. To solve the problem of coupling, a two-stage estimation method, consisting of multiple-models and the Unscented Kalman Filter, is proposed in this paper. During the first stage, the longitudinal vehicle dynamics model is used. Through vehicle acceleration/deceleration, this model can be used to estimate the distance between the vehicle centroid and vehicle front, the height of vehicle centroid and tire longitudinal stiffness. The estimated parameter can be used in the second stage. During the second stage, a single-track with roll dynamics vehicle model is adopted. By making vehicle continuous steering, this vehicle model can be used to estimate tire cornering stiffness, the vehicle moment of inertia around the yaw axis and the moment of inertia around the longitudinal axis. The simulation results show that the proposed method is effective and vehicle dynamic parameters can be well estimated.

Signal-injection-based methods are a kind of competitive maximum torque per ampere (MTPA) control schemes for interior permanent magnet synchronous motor drives, due to their motor parameter independence and satisfactory control performance. However, the high current spectrum peaks (CSPs) produced by the conventional fixed-frequency injected signals may cause negative effects. To deal with this problem, an MTPA control method based on pseudorandomly reversed fixed-frequency (PRRFF) sinusoidal signal injection is proposed in this article. The PRRFF sinusoidal signals are injected into the d - and q -axis currents via a specific current loop, and the MTPA operating points can be detected utilizing the resultant system response. Benefiting from the random characteristic of the injected signals, the proposed method can achieve far lower injection-induced CSPs than the conventional fixed-frequency injection methods. Moreover, benefiting from the fixed-frequency characteristic of the injected signals, the proposed method avoids the difficult matching of candidate injection frequencies that exists in the pseudorandom-frequency injection method. The validity of the proposed method is confirmed by experiments.

In order to improve the grid current quality of the small dc-link capacitance (SDC) motor drives fed by three-phase diode rectifier, a grid current control method based on regulation of the rectifier current sixth harmonic is proposed in this paper. Considering the 120° maximum conduction angle of the rectifier diodes, a 120° rectangular waveform with low total harmonic distortion (THD) is selected as the grid current reference. Based on the relationship between the grid current and the rectifier current, the proposed scheme shapes the grid current into the selected 120° rectangular waveform by regulating the rectifier current sixth harmonic. In this way, the grid current THD of the SDC system is significantly reduced. Since the regulation of the rectifier current harmonic is independent of the speed and motor current control loops, the proposed method avoids the complicated controller and the cumbersome parameter tuning in the grid current control process. The experimental results demonstrate the effectiveness of the proposed method.