Transcript Position Sensorless Control Based on Coordinate Transformation

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. 101–108 101
doi: 10.1049/iet-epa.2009.0022
指導教授：王明賢
學生班級：四電資四甲
學生編號：49728017
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)