PWM rectifier

About: PWM rectifier is a research topic. Over the lifetime, 2254 publications have been published within this topic receiving 25614 citations.

Control of Unit Power Factor PWM Rectifier

Abstract: To solve the problem of harmonic pollution to the power grid that caused by traditional diode rectifier and phase controlled rectifier, the unit power factor PWM rectifier is designed. The topology structure of the rectifier circuit is introduced and the double closed-loop control strategy in three-phase stationary coordinate system is analyzed. For the deficiency of control strategy, the control strategy in two-phase synchronous rotating coordinate system is proposed. This makes the independent control of active current and reactive current to be realized. The simulation model of the PWM rectifier is built and the effectiveness of the control method proposed in this paper is verified by simulation.

Characteristics of New Current Controlled PWM Rectifier-Voltage Source Inverter without DC Link Components for Induction Motor Drive

Abstract: The voltage-source inverters are normally equipped with an electrolytic capacitor in their DC link. The electrolytic capacitor has several disadvantage such as increasing size, limitting converter life and reliability. Therefore, several approaches for removing the DC link capacitor have been studied. This paper proposes a new strategy of the voltage source inverter without DC link components. To restrain the current resonance caused by LC filter of AC source side, rectifier of this inverter is controlled by current closed loop with di/dt feedback (di/dt; differenciation of AC source current). To improve AC source current waveform, feedback gain of di/dt and LC parameters are investigated by calculation for a 0.75kW induction motor driven by this inverter. Both the calculated and measured waveforms of AC source currents maintain nearly sinusoidal waveforms with a unity power factor.

Compensation of control delay and discrete control error in predictive direct power control for three-level PWM rectifier

Abstract: In three-level pulse width modulation (PWM) rectifier, the performances of the conventional predictive direct power control (PDPC) method are seriously degraded by the one-control-period delay and the discrete error of control variables. This paper investigates the problem by evaluating the influences of the control delay and the discrete control error on the performances of the system, and proposes a novel three-level PDPC method with compensation of control delay and discrete control error. An instantaneous power predictor is designed to compensate the control delay. Optimized prediction and control equations are deduced considering the variations of grid voltages during one control period in order to improve the control precision. Simulation and experimental results prove that the proposed three-level PDPC strategy achieves excellent steady-state and dynamic performances.

Generalized Predictive DC-Link Voltage Control for Grid-Connected Converter

Abstract: The main function of the grid-connected converter in many applications is to control the DC-link voltage with high performance, i.e. strong disturbance rejection capability and good dynamic response. Take the grid connected PWM rectifier of a motor drive system as an example, good disturbance rejection capability is essential for the DC-link voltage control to address the varying loads on the motor side, and the dynamic process of the DC-link voltage control is preferred to be fast and overshoot-free, so as to adaptively adjust the DC-link voltage according to the motor speed and reduce the switching losses. However, the performance of the conventional PI-based DC-link voltage control is not always satisfying and can be further improved. In this paper, the generalized predictive control (GPC) method is applied to the DC-link voltage control of a grid-connected converter for the first time, which can provide both good disturbance rejection capability and satisfying dynamic performance. Moreover, stability analysis of the proposed GPC-based DC-link voltage control strategy is theoretically studied, and a parameter tuning guideline is provided. The effectiveness and advantages of the proposed method are validated with experimental results.

Simplified Input Voltage Sensorless Vector Control for PWM Rectifiers

Abstract: A conventional input-voltage sensor-based vector-controlled PWM rectifier is used in wide range of applications due to its well-known control structure, simple design, and good dynamic performance. Many existing input voltage sensorless methods have a control structure significantly different from that of conventional vector control, involving additional computational and design efforts. This article proposes a simplified input voltage sensorless control which has the same control structure as that of vector control and can utilize similar controller design procedure. The input voltage required for a phase-locked loop (PLL) is estimated from the current controller output using a simple algebraic equation. The sensorless PLL, so obtained, is mathematically modeled, and its frequency response is shown to be similar to that of a sensor-based PLL. The performance of the proposed method is compared with those of existing methods in terms of input power factor, response to distorted input voltage, sensitivity to system parameter, and computation time requirement through simulations and experiments. Apart from having the lowest computation requirement, the proposed method is shown to achieve the sensorless operation without any performance degradation, compared to the sensor-based operation, and with robustness to parameter variation. The proposed method includes a start-up procedure, which ensures low starting transient current.