Shinn-Ming Sue

A linear maximum torque per ampere control for IPMSM drives over full-speed range

In this paper, a linear torque control strategy is first proposed for interior permanent magnet synchronous motor drives to fully utilize the reluctance torque and simplify the controller design. The proposed linear torque control strategy also extends the existing maximum torque per ampere control in the constant torque limit region up to the entire field-weakening region. It is found that in an intermediate speed region, called partial field-weakening region, the existing maximum torque per ampere control can still be applied under lighter load condition. In addition, the proposed control can also achieve the objective of minimum copper loss (i.e., maximum torque per ampere) for the entire speed range. Sound theoretical basis is given in the context. Moreover, an adaptive limiter is proposed for efficiently implementing the proposed control strategy over the entire speed range. Finally, a prototype is also constructed by using a fixed-point DSP TMS320F240 and some experimental results are given to verify the validity of the proposed control strategy.

Voltage-Constraint-Tracking-Based Field-Weakening Control of IPM Synchronous Motor Drives

In this paper, first, the effect of the interior permanent-magnet synchronous-motor (IPMSM) stator resistance to the maximum available motoring or regenerative braking torque is clarified. Then, a drive operating point is interpreted geometrically as the intersecting point of the torque-demand curve with either the maximum torque per ampere (MTPA) trajectory or the voltage-constraint curve inherently imposed by the motor and inverter under different control modes. Based on this principle, a novel voltage-constraint-tracking (VCT) field-weakening control scheme for IPMSM drives is proposed. The proposed method can automatically determine the desired MTPA or field-weakening control modes and provide a smooth transition between these two modes. No machine parameters are required in the field-weakening control mode, and no dc-link voltage sensor is used, rendering the proposed scheme rather robust. In addition, the minimum copper-loss operation can be preserved in the VCT-based control to achieve high efficiency. The proposed control method has a simple structure so that it can easily be implemented by modifying a conventional vector-controlled drive system for practical applications. Finally, a DSP-based prototype drive is constructed to verify the feasibility of the proposed scheme, and some experimental results are provided to demonstrate the satisfactory features.

A phase advanced commutation scheme for IPM-BLDC motor drives

This paper presents a phase advanced commutation scheme for IPM-BLDC motor drives. In order to utilize the torque capability of an IPM-BLDC motor as much as possible for a low cost and information limited drive, the inverter gating time is advanced such that the phase angle of the stator current can lead that of the corresponding back-emf. Hence the reluctance torque of an IPM-BLDC can be developed properly. The motor electric parameters, rotor speed as well as the inverter switching duty cycle are used to determine the advanced angle instead of look up table method or complicated evaluation scheme. Experimental results show that the proposed scheme can achieve higher efficiency and more extended speed range than the conventional control scheme does.

A Hall-sensor-based IPM traction motor drive

Due to the sinusoidal air gap flux waveform of interior permanent magnet (IPM) motors, an expensive encoder is usually required for the drive. In this paper, a robust and low cost hall-sensor-based rotor position signal synthesizer is first proposed for traction motor drives. Then, a double-band hysteresis current controller is adopted for the inverter to further reduce switching loss. Also, a digital signal processor, namely TI TMS320F240 is used to implement the speed controller. Experimental results show that, for common traction motor applications, the proposed IPM traction motor drive can satisfy the desired performance without using an expensive and delicate encoder.

A new integrated interior permanent-magnet synchronous motor drive with wide-range output voltage inverter

The aim of this paper is to propose a new integrated interior permanent magnet synchronous motor (IPMSM) drive to improve performances for the whole speed range. Conventionally, in the field-weakening operation of the IPMSM (or PMSM) drives, there are three common drawbacks, which are high copper loss, serious current chattering phenomena, and poor current transient performance. The proposed control strategy can achieve two different levels of variable dc-link voltage and near zero transient voltage dynamics simultaneously. Hence, it can achieve a new high-speed operation mode that is different from that of the conventional field-weakening control strategies. The merits of the proposed motor drive include achieving the maximum torque per ampere control in the full speed range and having more versatile selection for DC link voltage.

A new MTPA control strategy for sensorless V/f controlled PMSM drives

This paper presents a new maximum torque per ampere (MTPA) control strategy for sensorless V/f controlled PMSM drives. The proposed theoretical basis can be applied to both surface permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) drives to obtain high efficiency. Two closed loops are required in the proposed drive. First, by using the oscillatory active power information, a load angle compensation component is generated to adjust the load angle to stabilize the system. Second, the drive imaginary power is regulated to follow the imaginary power of MTPA performance such that the drive can operate under the minimum copper loss condition in the steady state. The imaginary power controller can generate a voltage compensation component to properly adjust the drive voltage. Hence, the demanded MTPA performance is obtained. The provided simulation results show the performance and validity of the proposed strategy. The hardware implementation of the proposed control is now undertaking and the experimental results will soon be shown in the near publication.

A New Field-Weakening Control Scheme for Surface Mounted Permanent-Magnet Synchronous Motor Drives

This paper presents a new field-weakening control scheme for surface-mounted permanent-magnet synchronous motor (SMPMSM) drives. The proposed method can determine either the constant torque limit control mode or the field-weakening control mode which should be applied to the drive under different operation conditions and variations of system parameters. In addition, the minimum copper loss operation can be preserved to achieve high efficiency and the smooth transition between these two control modes can be obtained by the proposed control. Hence, the proposed scheme is quite suitable for the application of wide speed range operation and/or battery powered SMPMSM drives such as electric vehicles. A digital signal processor (DSP) controlled prototype is built and some experimental results are provided to show the promising features of the drive by using the proposed scheme.

Design and Implementation of a Dynamic Voltage Boosting Drive for Permanent Magnet Synchronous Motors

This paper presents an integration of the interleaved bi-directional DC/DC converter with a vector controlled permanent magnet synchronous motor (PMSM) drive to give the motor operating in high speed with minimum copper loss control. The interleaved DC/DC converter is designed in the discontinuous conduction mode (DCM) such that the controller design becomes straightforward. The large signal perturbation usually makes the controller saturation and the inductor over current. Hence, the anti-windup and current limit considerations are also discussed in the paper. The modified vector controlled scheme of the PMSM drive is developed by considering dynamic DC link voltage boosting such that the motor can always have minimum copper loss performance in high speed. Finally, several experimental results are provided to show the performances of the integrated drive.

Exactly analysis of ZVS behavior for class E inverter with resonant components varying

Class E resonant power amplifier (or inverter) is often applied to design a high frequency switching power converter. The zero voltage switching (ZVS) or zero current switching (ZCS) operation leads the converter to high converting efficiency even the converter works at high frequency. Theoretically, with a high speed power transistor, the class E amplifier can work from several megahertzes to dozen of megahertzes. While the resonant components of class E inverter are varying, the ZVS operation will be shifting around the dominant operating point. In this paper, an exact circuit model is proposed to analyze the circuit behavior for the class E inverter. Unnecessarily mathematical assumption and complicated numerical iteration, the proposed model is easy to analyze the class E circuits in frequency domain. Through this model, a close form formula is proposed to solve the load current and drain-source end voltage of MOSFET at switching instants for steady state without a complicated numerical iterating. By this formula, the optimal and suboptimal conditions for the ZVS operation are expressed in terms of the shifting angle of load current with respect to drain-source voltage. Also, some practical design examples are given to demonstrate the formula calculating results that are good agreement with the numerical iterating results.

A linear maximum torque per ampere control for IPMSM drives considering magnetic saturation

In this paper, a new maximum torque per ampere control is proposed for an interior permanent magnet synchronous motor (IPMSM) drive to achieve a linear control law with respect to the input in the outer loop. Not only the reluctance torque can be fully exploited but also the magnetic saturation effect is also considered. The theoretical basis of the proposed control is detailed and a prototype is also implemented with a fully digital controller by using a fixed point DSP TMS320F240 to simplify the hardware circuits. Some experimental results are also provided to verify the validity of the proposed control strategy. It is seen that the proposed control can indeed provide improved performances as compared with that of the conventional linear torque control.