• Journal of Power Electronics
• /
• 제7권1호
• /
• pp.81-88
• /
• 2007

This paper presents a new approach to the automatic control of the turn-off angle used to excite the Switched Reluctance Motor (SRM) employed in electric vehicles (EV). The controller selects the turn-off angle that supports and improves the performance of the motor drive system. This control scheme consisting of classical current control and speed control depends on a lookup table to take the best result of the motor. The turn-on angle of the main switches of the inverter is fixed at $0^{\circ}C$ and the turn-off angle is variable depending on the reference speed. The motor, inverter and control system are modeled in Simulink to demonstrate the operation of the system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권7호
• /
• pp.356-363
• /
• 2001

A SRG (Switched Reluctance Generator) has many advantages such as high efficiency, low cost, high-speed capability and robustness compared with other of machine. But the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using the PID controller which only controls turn-off angles while keeping turn-on angles of SRG constant. In order to keep the output voltage constant, the turn-off angle for load variations is controlled by using linearity between the generated current and turn-off angle since the reference generated current can be led through the voltage errors between the reference and the actual voltage. The suggested control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and the speed sensors. The proposed method is verified by experiments.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.414-417
• /
• 2001

SRG (Switched Reluctance Generator) have many advantages such as high efficiency, low cost, high-speed capability and robustness compared with characteristics of other machines. However, the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using PID controller that only controls turn-off angles while keeping turn-on angles of SRG constant. The linear characteristics between the generated current and the turn-off angle can be used to control the turn-off angle for load variations. Since the reference current for generation can be produced from an error between the reference and the real voltage, it can be controlled to keep the output voltage constant. The proposed control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and speed sensors. The proposed method is verified by experimental results.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제1권4호
• /
• pp.477-482
• /
• 2012

This paper describes a new rotor position sensorless control method for SRM drives based on an improved simplified flux linkage method. In the traditional simplified flux linkage method, every phases take turns conduction and current chopping control method is used. Every phases take turns conduction means turning on the incoming working phase while turning off the working phase. This conduction mode causes coupling between turn-on and turn-off angles, which goes against optimal efficiency or torque ripple minimization with sensorless speed control. In the improved simplified flux linkage method, turn-off angle is calculated by flux loop, the turn-on angle can be given arbitrarily and has no relations with the turn-off angle, and the current chopping control method is used. The speed and rotor position can be estimated then. Finally, a sensorless SRM speed control system and an experiment platform with DSP are built and validity of this method is confirmed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.1616-1618
• /
• 2005

In this paper, A fuzzy logic based turn-off angle compensator for torque ripple reduction in a linear switched reluctance motor is proposed. The turn-off angle, as a complex function of motor speed and current, is automatically changed for a wide speed range to reduce torque ripple. Simulation results are presented that show ripple reduction when the him-off angle compensator is used.

• 전력전자학회논문지
• /
• 제3권4호
• /
• pp.418-425
• /
• 1998

본 논문에서는 위상각 제어에서 주어진 턴온 각에서 최대의 토크를 유지하기 위한 적절한 턴오프 각을 자기동조방식(self-tuning method)에 의해 결정하는 방식을 제안하였다. 엔코더에 의해 샘플링 시간(sampling time)동안 구해진 펄스 수는 바로 이전의 샘플링시간 동안 구해진 펄스 수와 비교하여 턴오프 각을 앞으로 또는 뒤로 이동한다. 이러한 과정을 되풀이함으로서 최대 토크를 발생하는 턴오프 각을 결정하게 된다. 실제 회로에서는 원 칩 마이크로프로세서에 의해 처리되었으며 실험을 통해 턴온 각이 변하더라도 자기동조방식에 의해 턴오프 각을 조정하면 빠른 속도가 유지됨을 보여 주었다.

• 전기의세계
• /
• 제17권2호
• /
• pp.6-10
• /
• 1968

The conversive limitation of electric energy for the thyristor inverter is analysed under the boundary conditions which the term of a negative inverse voltage is longer than that of the turn off time of the thyristor under commutation. It is clear that the maximum electric energy conversion is affected by the turn off time of the thyristor, the reactance of a commutation reactor, the capacity of a commutation condenser and the voltage of Direct current source. It is useful for design the thyrister invertor and the motor speed control to apply the above conclusion.

• Journal of Power Electronics
• /
• 제18권3호
• /
• pp.892-901
• /
• 2018

SiC MOSFETs have been used to improve system efficiency in high frequency converters due to their extremely high switching speed. However, this can result in undesirable parasitic oscillations in practical systems. In this paper, models of the key components are introduced first. Then, theoretical formulas are derived to calculate the switching oscillation frequencies after full turn-on and turn-off in clamped inductive circuits. Analysis indicates that the turn-on oscillation frequency depends on the power loop parasitic inductance and parasitic capacitances of the freewheeling diode and load inductor. On the other hand, the turn-off oscillation frequency is found to be determined by the output parasitic capacitance of the SiC MOSFET and power loop parasitic inductance. Moreover, the shifting regularity of the turn-off maximum peak voltage with a varying switching speed is investigated on the basis of time domain simulation. The distortion of the turn-on current is theoretically analyzed. Finally, experimental results verifying the above calculations and analyses are presented.

• International Journal of Precision Engineering and Manufacturing
• /
• 제2권1호
• /
• pp.33-42
• /
• 2001

In switched reluctance motor(SRM) deives, the turn-on and turn-off angles of each phase switch should be accurately controlled for accuracy and efficiency. The accuracy of the switching angles is mainly dependent upon the resolution of the encoder and the sampling period of the microprocessor, that are used to provide the information of the rotor position and to implement a control algorithm of the SRM, respectively. Thus, the higher the speed of the SRM is increased, the larger the amount of the switching angle deviations are from preset turn-on and turn-off angles. Consequently, the motor can not be driven stably high speed region. There fore, a simples and low cost encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using a simple digital logic circuit is also presented for a wide speed range operation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.232-234
• /
• 2005

In this paper, A fuzzy logic based turn-off angle compensator for torque ripple reduction in a linear switched reluctance motor is proposed. The turn-off angle, as a complex function of motor speed and current, is automatically changed for a wide speed range to reduce torque ripple. Simulation results are presented that show ripple reduction when the turn-off angle compensator is used.