Precision rectifier

About: Precision rectifier is a research topic. Over the lifetime, 4952 publications have been published within this topic receiving 63668 citations. The topic is also known as: super diode.

A New Control Method for Input–Output Harmonic Elimination of the PWM Boost-Type Rectifier Under Extreme Unbalanced Operating Conditions

Abstract: Under severe fault conditions in the distribution system, not only input voltages but also input impedances must be considered as unbalanced. This paper presents a new control method for input-output harmonic elimination of the pulsewidth-modulation (PWM) boost-type rectifier under conditions of both unbalanced input voltages and unbalanced input impedances. The range of imbalance in both input voltages and input impedances, for which the proposed method is valid, is analyzed in detail. An analytical approach for complete harmonic elimination shows that PWM boost-type rectifier can operate at unity power factor under extremely unbalanced operating conditions resulting in a smooth (constant) power flow from AC to DC side. Based on the analyses in open-loop configuration, a feedforward control method is proposed. Elimination of harmonics at AC and DC side of the converter affects the cost of DC link capacitor and AC side filter. The proposed method is very useful when the PWM boost-type rectifier is subject to extreme imbalance due to severe fault conditions in the power system. In addition, by using the proposed method, the PWM boost-type rectifier can be operated from the single-phase supply in cases where three-phase source is not available. Simulation results show excellent response and stable operation of the PWM boost-type rectifier under the proposed control algorithm. Experimental and simulation results are in excellent agreement.

Synchronous power rectifier

Abstract: A synchronous power rectifier incorporating a bipolar power transistor operable in a switching mode to rectify the energy from a secondary winding of a power transformer. The synchronous rectifier reduces or eliminates the need of rectifier diodes, which provides power rectification without the power loss associated with the rectifier diode voltage drops. Moreover, the present invention includes further refinements of the circuit, including adjustment of the rectifier switching time to accommodate delayed turn-off times of bipolar power devices, and adjustment of the switching signal duration to provide output voltage regulation independent of the excitation of the transformer primary. The resulting embodiments of the present invention provide a modular switching power supply circuit of high efficiency, which may be operable together in combination to provide multiple output voltages.

Reduction of Input Current Harmonic Distortions and Balancing of Output Voltages of the Vienna Rectifier Under Supply Voltage Disturbances

Abstract: This paper proposes a modified proportional resonant (PR) based control scheme for a three-level Vienna rectifier that reduces the input current harmonic distortion [total harmonic distortion (THD)] for harmonic contaminated and unbalanced supply voltage conditions. Low-order current harmonics that are present in the source side currents can be selectively eliminated using this proposed control strategy. In addition, the complete control technique includes the proportional integral (PI) based voltage balancing technique to balance the output voltages of the Vienna rectifier. This method includes the advantages of both hysteresis-based current control (fast transient response) and PI-based vector control (fixed frequency operation) methods. Various computational blocks such as space vector modulation (SVM) block, current/voltage transformation blocks, etc., are not necessary to implement this control method. Therefore, this scheme is relatively easy to implement using inexpensive digital controllers. A 1-kW prototype of the rectifier is built and tested in the laboratory environment using the proposed control method. The converter provides a unity power factor operation with low-current THD at the input side, balances the capacitor voltages, and tracks the voltage reference at the output side.

A Three-Phase Delta Switch Rectifier for Use in Modern Aircraft

Abstract: In the course of the More Electric Aircraft program frequently active three-phase rectifiers in the power range of several kilowatts are required. It is shown that the three-phase -switch rectifier (comprising three -connected bidirectional switches) is well suited for this application. The system is analyzed using space vector calculus and a novel PWM current controller modulation concept is presented, where all three phases are controlled simultaneously; the analysis shows that the proposed concept yields optimal switching sequences. Analytical relationships for calculating the power components average and rms current ratings are derived to facilitate the rectifier design. A laboratory prototype with an output power of 5 kW is built and measurements taken from this prototype confirm the operation of the proposed current controller. Finally, initial EMI-measurements of the system are also presented.

New multilevel rectifier based on series connection of H-bridge cell

Abstract: A three-level pulse-width modulation (PWM) rectifier is proposed. The control scheme is based on general logic gates to generate a three-level voltage waveform. In comparison with the two-level PWM scheme, the three-level PWM scheme can reduce the electromagnetic interference, decrease voltage stress of power semiconductors, and increase the switching frequency. A capacitor voltage compensator is used to balance two DC bus voltages. Based on the proposed control algorithm, the current harmonics of the line meet the International Electrotechnical Commission 1000-3-2 limits. The power factor of the proposed rectifier is nearly unity. The control strategy of the proposed three-level rectifier illustrates its validity and effectiveness experimentally.