• Proceedings of the KIEE Conference
• /
• 1990.11a
• /
• pp.319-322
• /
• 1990

Self-controlled permanent magnet synchronous motor (PMSM) has similar operating characteristics as seperately excited dc motor. It is favored in servo applications due to its improvement of efficiency and maintenance. This paper presents completely digitalized controller using microprocessor and voltage fed inverter. The speed control system for PMSM is implemented. To control the motor speed, the control system regulates the magnitude of Inverter output voltage by regular-sampled PWM method to generate sinusoidal PWM wave with microprocessor. And to keep the range of inverter switching frequency, it varies the number of pulse train according to the speed.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.501-503
• /
• 1996

In this paper, a novel control strategy for PWM current source converter and inverter is proposed, applying a multivariable state feedback control. The PWM converter controls line current to be sinusoidal and make input power factor unity. In addition, the modulation index control of dc link current is carried out, which produces lower loss of switching devices. Since the voltage control of inverter output filter capacitor is performed a decoupling of the d-q current of the induction motor is well retained. With the proposed algorithm, both high dynamic responses and satisfactory static performance can obtained.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.476-478
• /
• 1996

This paper is on speed control of induction motor using space vector PWM. Indirect vector control which controls independantly flux and torque current component in order to drive induction motor, is applied for driving motor. Voltage sourced inverter with space vector PWM is used to generate the practically perfect sinusoidal flux density in induction motor. The appropriateness of speed control is proven by appling IP(Integral-proportional) controller which is known to have a good speed response and still to have less overshoot than the now used PI(Proportional-Integral) controller.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.5
• /
• pp.159-164
• /
• 1996

In this paper, a novel control strategy of curretn source PWM converter and inverter system for induction motor dirves is proposed. The PWM converter controls line current to be sinusoidal and makes input power factor unity. In the inverter part, a minor voltage control loop is incorporated in the current control looop in order to suppress unstale resonance between the filter capacitor and the motor leakage inductance and to keep the stator voltage under the rated value. In additon, the modulation index control of the inverter currents ripples and inverter loss. With the proposed algorithm, both high dynamic responses and satisfactory static performance can be obtained.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.415-419
• /
• 2004

The U filter has been generally used to filter the output voltage of PWM inverter to the sinusoidal waveform. The resonant voltage on the output voltage of PWM inverter may be generated due to LC filter. This paper proposed the algorithm to damp the resonant voltage using the virtual resistor without decreasing the efficiency by the power loss in the real resistor The method is appled to the vector controlled induction motor driven by the PWM inverter with the LC filter. The simulation results are carried out to verify the performances of the proposed algorithm.

• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2656-2658
• /
• 1999

This paper presents a control scheme for a three-phase PWM converter system without any voltage sensors. Two input currents and one load current are measured. In a general PWM converter system, the required AC input and DC output voltage values in order to control the converter are estimated using the differential equations of the converter from the measured input currents and load current values in the switch modes of the converter circuit. The PI controller is used as DC voltage controller and sinusoidal tracking controller which tracks directly AC input current is used as input current controller. The Proposed method is verified by simulations. This paper describes the estimation method and configuration of the controller, and discusses steady state and transient performances of the converter

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.426-428
• /
• 1997

This paper presents the linearized optimal PWM techniques for current source GTO converter. This proposed method is to linearize an optimal PWM modulation strategy so that the turn-on/off-periods of the GTO switches can be computed on-line in real-time for any modulation index. This allows the rapid and continuous regulation of the DC output current while producing the sinusoidal AC input current waveform and unit power factor.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.3
• /
• pp.125-132
• /
• 2002

This paper presents a single-phase 3-level PWM inverter to alleviate the harmonic components of output voltage and current under the conditions of identical supply DC voltage and switching frequency to the conventional inverter. Operational principles and analysis are performed, and the switching functions are derived. Deadbeat controller is also designed and implemented for the inverter to keep the output voltage being sinusoidal and to have the high dynamic performances even in the cases of load variations and the partial magnetization of filter inductor. The validity of proposed inverter is proved from the simulated and experimented results.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.28B no.12
• /
• pp.38-50
• /
• 1991

A current-controlled scheme of pulse width modulation voltage source inverter (PWM VSI) has attracted considerable attention due to its fast response with current limit and especially suitable for potentially high performance applications such as AC motor drives and UPS systems. These features yield near-sinusoidal currents in the load with reduced current peaks, lower inverter switching frequency and reduce inverter and load stresses. A high performance current-controlled inverter must have a quick response in transient state and low harmonic current in steady state. This paper compares and shows the controlled-characteristics with hysteresis controller(HC), ramp comparison controller(RCC) and predictive controller(PC) of PWM inverter to control actual current of VSI-IM.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.2
• /
• pp.489-500
• /
• 2014

This paper presents a simple modified unipolar carrier-based pulsewidth modulation (CB-PWM) strategy for the three-level neutral-point-clamped (NPC) voltage source inverter (VSI). Analytical expressions for the relationship between modulation reference signals and output voltages are derived. The proposed modulation technique for the three-level NPC VSI includes the maximum and minimum of the three-phase sinusoidal reference voltages with zero-sequence voltage injection concept. The proposed modified CB-PWM strategy incorporates a novel method that requires only of one triangular carrier wave for generate the gating pulses in three-level NPC VSI. It has the advantages of being simplifying the algorithm with no need of complex two/multi-carrier pulsewidth modulation or space vector modulation (SVM) and it's also simple to implement. The possibility of the proposed CB-PWM technique has been verified though computer simulation and experimental results.