Performance investigation of modified hysteresis current controller with the permanent magnet synchronous motor drive A.N. Tiwari1 P. Agarwal2 S.P. Srivastava2; IET Electr. Power Appl., 2010, Vol. 4, Iss. 2, pp. 101– doi: /iet-epa 指導教授：王明賢 學生班級：四電資四甲 學生編號： 學生姓名：林炳宏

Outline I.INTRODUCTION II.REVIEW OF THE TRADITIONAL SENSORLESS METHOD III.PROPOSED ARITHMETIC FOR SENSORLESS BLDC DRIVES IV.EXPERIMENTAL RESULTS V.CONCLUSION VI.REFERENCES

I.INTRODUCTION(1/2) The PMSM drives are most suitable for high performance adjustable speed as well as position servo applications. These drives are used to realise servomechanisms for CNC machine tools, industrial robots and aerospace actuators.

I.INTRODUCTION(2/2) In the machine tool industry the transfer of rotor losses of drives in the form of heat to the machine tools and work pieces affects the machining operation. Thus, because of negligible rotor losses compared to other servo drives like dc motor and induction motor drives, there is wide scope of PMSM drives in the machining operations. The advantages of PMSM drives over other drives are high power factor operation, high torque to inertia ratio and high efficiency [1].

II. PMSM drive scheme(1/2) The PMSM drive scheme with modified hysteresis current controller is shown in Fig. 1. Three-phase PWM rectifier draws almost sinusoidal input current at unity power factor from the three-phase supply. It also has regenerative capability to make the drive operate in all four quadrants.

II. PMSM drive scheme(2/2) Fig. 1. PMSM drive scheme with modified hysteresis current controller

III. Mathematical model (1/2) The mathematical model of a PMSM is similar to that of wound rotor synchronous motor. The rotor of synchronous motor is replaced with high resistivity permanent magnet material; hence, induced current in the rotor is negligible. The permanent magnets on the rotor are shaped in such a way as to produce sinusoidal back EMF in stator windings [8, 9].

III. Mathematical model (2/2)

III. Mathematical model (3/2)

III. Mathematical model (4/2)

III. Mathematical model (5/2)

III. Mathematical model (6/2)

IV. Speed controller design (1/2) The speed control scheme of the PMSM drive is shown in Fig. 2. The speed controller of the drive is operated on a digital computer and the current controller work on the analogue system. To design the transfer function of the drive scheme, the theory of sampled data control system is applied.

IV. Speed controller design (2/2) Figure 2 Speed control system of the PMSM drive

IV. Speed controller design (3/2)

IV. Speed controller design (4/2)

IV. Speed controller design (5/2) Figure 3 Variations in stability regions with sampling period

V. Modified hysteresis current control scheme(1/3) In CHCC, actual three-phase currents are compared with their respective reference currents and error signals are sent to the hysteresis controller. Each phase current errors are compared with upper and lower hysteresis band. If current error of one of the phase of the motor is crossing upper hysteresis band, the lower switching device of respective inverter leg will turn-off and the upper switching device of the leg will turn-on. If the current error crosses lower hysteresis band, the lower device is turned-on and the upper device is turned-off. A lock-out delay is mandatory to avoid short circuit of DC link voltage.

V. Modified hysteresis current control scheme(2/3) Figure 4 Modified hysteresis current control scheme

Figure 5 Comparative waveforms at full-load of phase ‘a’ reference current, actual current, and switching pulses of corresponding upper (T1) and lower (T4) switching devices of the phase ‘a’

VI. Simulation and experimental results(1/5) A MATALAB/SIMULINK model for the proposed PMSM drive scheme is developed to perform the digital simulation. The experimental implementation of the scheme is performed with outer speed loop PI controller on digital computer and inner loop hysteresis current controller with analogue circuits. The sampling period for the outer speed control loop is kept 10 ms. The simulation and experimental study is performed with both the CHCC and MHCC, keeping drive and controller gains and hysteresis band-width same with both the current controllers. The drive and controller parameters in actual values are given in Appendix. The inverter is operated with hysteresis band of 0.05 pu of motor phase current for both CHCC and MHCC.

VI. Simulation and experimental results(2/5)

VI. Simulation and experimental results(3/5) Figure 7 Harmonics spectrum of motor phase current

VI. Simulation and experimental results(4/5)

VI. Simulation and experimental results(5/5) Figure 8 Waveforms of speed response

VII. 7 Conclusion(1/1) The MHCC and CHCC-based PMSM drive is simulated and implemented experimentally. Both the simulation and experimental investigations show that the MHCC provides more sinusoidal motor current than that with the CHCC. Further, the MHCC scheme renders advantages over CHCC such as less THD in motor current, smaller number of switching per cycle, smaller steady-state error inspeed, less torque ripples and hence, less losses making the drive more efficient.

VIII. References(1/3)

VIII. References(2/3)

VIII. References(3/3)