• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.5
• /
• pp.442-449
• /
• 2003

This paper discusses how to generate the reference compensation voltages in Dynamic Voltage Restorers (DVR) by use of PQR instantaneous power theory. Sensed three-phase terminal voltages are transformed to PQR coordinates without time delay. Since the reference voltage in PQR coordinates is a single dc value, the voltage controller for DVRs is simple and easy to design. Proposed control method can be implemented by feedforward controllers or by feedback controllers. This paper verified the theory by a feedforward controller of a DVR with simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.12
• /
• pp.751-758
• /
• 2004

This paper presents a new method to compensate the non-linearity for matrix converter drives using PQR instantaneous Power theory. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled by PQR power theory and compensated using a reference current control scheme. The proposed method does not need any additional hardware and off-line experimental measurements. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system without a speed sensor. Simulation and experimental results show the proposed method using PQR power theory Provides good compensating characteristic.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.404-409
• /
• 2003

This paper discusses how to generate the reference compensation voltages in Dynamic Voltage Restorers (DVR) by use of PQR power theory Sensed three-phase terminal voltages are transformed to PQR coordinates without time delay. Since the reference voltages in PQR coordinates are do values, the voltage controller for DVRs is simple and easy to design. Proposed control method can be implemented by feedforward controllers or by feedback controllers. This paper verified the theory in the feedforward controller of a DVR by experiments.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.3
• /
• pp.524-530
• /
• 2007

This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and on-state switching device voltage drop are modelled using PQR transformation and compensated using a reference power control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.5
• /
• pp.420-429
• /
• 2004

This paper proposes a novel current control strategy on active power filters using PQR instantaneous power theory which can compensate the line current harmonics and the neutral line current under the unbalanced and/or distorted source conditions in three-phase four-wire systems. The characteristics of the inverter ac filters are analyzed and a novel digital controller are proposed to overcome the inherent time delay problem in digital controllers with designed control gain in this paper. The proposed current control method is based on a sinusoidal PWM for fully-digital implementation compared with a conventional hysteresis PWM. PSiM simulation results verify the good performance of the proposed current control strategy on shunt type APFs.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.5
• /
• pp.435-441
• /
• 2003

Dynamic Voltage Restorers (DVR)s are known as the best effective and economic means to compensate for voltage sags and swells. This paper proposes a novel method to generate reference voltages synchronized with the grid whether the line voltages are distorted by a fault or not. The proposed reference wave generator (RWG) looks for the original wave forms from the corrupted line voltages and synthesizes the expected positive sequence reference waves for DVRs. There is no transient problem on the generated reference waves when the line voltages are distorted by the fault.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.398-403
• /
• 2003

Dynamic Voltage Restorers (DVR)s are known as the best effective and economic means to compensate for voltage sags and swells [1]-[11]. This paper proposes a novel method to generate reference voltages synchronized with the grid whether the line voltages are distorted by a fault or not. The proposed reference wave generator (RWC) looks for the original wave forms from the corrupted line voltages and synthesizes the expected positive sequence reference waves for DVRs. There is no transient problem on the generated reference waves when the line voltages are distorted by the fault.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.504-506
• /
• 2005

This paper proposes a new neutral current reduction method using PQR instantaneous power theory on the active power filter, unbalanced nonlinear load condition in three-phase four-wire systems. For reduction of neutral line current, the single phase active power filter is used and its performance is same with the three-phase four-wire active power filter. For fully-digital implementation, ramp comparison PWM method was adopted. Simulation results verify good performance of the proposed current control strategy on the shunt APFs.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1489-1491
• /
• 2005

This paper proposes a design method using PQR instantaneous power theory on the active power filter, unbalanced nonlinear load condition and unbalanced source voltage condition in three-phase four-wire systems. For reduction of current harmonics and neutral current, the control structure including repetitive controller is proposed and controller gain is designed. For fully-digital implementation, ramp comparison PWM method was adopted. Simulation results verify good performance of the proposed current control strategy on the shunt APFs.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.1
• /
• pp.113-123
• /
• 2006

In this paper, an improved direct torque control (DTC) method for sensorless matrix converter drives is proposed which enables to minimize torque ripple, to obtain unity input power factor, and to achieve good sensorless speed-control performance in the low speed operation, while maintaining constant switching frequency and fast torque dynamics. It is possible to combine the advantages of matrix converters with the advantages of the DTC strategy using space vector modulation and a flux deadbeat controller. To overcome the phase current distortion by the non-linearity of a matrix converter drive, the simple non-linearity compensation method using PQR power theory are presented in the proposed scheme. Experimental results are shown to illustrate the feasibility of the proposed strategy.