PWM rectifier

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

Line-frequency rectifier dc-bus voltage instability analysis and mitigation

Abstract: Use of small dc bus capacitors is desirable in variable-speed drives and distributed power systems as it can reduce the size and improve reliability of the system. However, small dc bus capacitors may lead to instability of the dc bus voltage. Such voltage stability problem can occur when the bus is fed from a PWM rectifier or a line-frequency rectifier. This paper considers the case when a line-frequency rectifier is used and presents a method for the analysis of dc bus voltage instability in such systems. Small-signal input impedance of multipulse line-frequency rectifiers is used in conjunction with the ac source output impedance to detect possible instability on the dc bus. Stabilization of the dc bus voltage by a passive damping is presented and compared to other stabilization methods such as increasing dc bus capacitance or placing the damper at the ac input of the rectifier. Experimental results from a 12-pulse rectifier feeding an electronic load that is programmed to emulate constant-power load behavior typical of DPS and variable-speed drives are presented to validate the analysis and design approach.

Two-phase inverted power system and comprehensive control method

Abstract: The invention discloses a two-phase inverted power system and a control method. DC side voltage is obtained by adopting a three-phase power width modulation (PWM) rectifier to realize a high voltage factor of a power grid side and reduce energy loss. Simultaneously, a two-phase inverter only comprises four power switching tubes, and compared with a conventional two-phase inverted power supply, the two-phase inverted power system cancels a switch arm to make the structure of the two-phase power supply simpler, greatly reduce cost and improve system reliability. The three-phase PWM rectifier adopts a double-closed loop control strategy consisting of a voltage outer loop and a current inner loop to realize high-precision control over the voltage of a DC side and the high-power factor controlover the current of the power grid side. The double-closed loop control strategy consisting of voltage sharing outer loop control and output current inner loop control over two series-wound capacitors on the DC side realizes the rapid tracking of output current and the voltage sharing of the two capacitors on the DC side.

Study of low voltage stress space vector pwm control for current source pwm rectifier

Abstract: To lower the voltage stress on switches of three phase Current Source PWM Rectifier (CSR), a new low voltage-stress SVPWM control method is developed in this paper based on the detailed analysis of the commutating process of power switches. By exchanging the sequence of the vectors composition, the power switches, could operate in natural commutation state, so the voltage-stresses of power switches are reduced greatly. Owning to the fact that the SVPWM control is of higher DC current utility-rate, low switching-looses and better transient performance. This new low voltage-stress SVPWM especially fits for high power three phase converter systems. The experimental results verify the theoretical analysis.

Data-driven design of fault diagnosis for three-phase PWM rectifier using random forests technique with transient synthetic features

Abstract: A three-phase pulse-width modulation (PWM) rectifier can usually maintain operation when open-circuit faults occur in insulated-gate bipolar transistors (IGBTs), which will lead the system to be unstable and unsafe. Aiming at this problem, based on random forests with transient synthetic features, a data-driven online fault diagnosis method is proposed to locate the open-circuit faults of IGBTs timely and effectively in this study. Firstly, by analysing the open-circuit fault features of IGBTs in the three-phase PWM rectifier, it is found that the occurrence of the fault features is related to the fault location and time, and the fault features do not always appear immediately with the occurrence of the fault. Secondly, different data-driven fault diagnosis methods are compared and evaluated, the performance of random forests algorithm is better than that of support vector machine or artificial neural networks. Meanwhile, the accuracy of fault diagnosis classifier trained by transient synthetic features is higher than that trained by original features. Also, the random forests fault diagnosis classifier trained by multiplicative features is the best with fault diagnosis accuracy can reach 98.32%. Finally, the online fault diagnosis experiments are carried out and the results demonstrate the effectiveness of the proposed method, which can accurately locate the open-circuit faults in IGBTs while ensuring system safety.

A novel direct power control strategy based on energy interface concept for three-level PWM rectifier

Abstract: This paper investigates the energy interfaces in three-level pulse width modulation (PWM) rectifier and proposes a novel direct power control (DPC) strategy. An optimized three-level switching table with high power regulation intensities is constructed in order to improve the tracking capabilities of power loops. An energy regulator is designed based on the power equations of the energy interfaces to control the energy stored in the dc-link capacitors and to maintain the required output voltage. Compared with the conventional three-level DPC, the novel strategy achieves better performances. Simulation and experimental results have verified the validity and feasibility of the proposed method.