Vlatko Vlatkovic

Input filter design for power factor correction circuits

The issues involved in the design of power factor correction circuit input filters are significantly different from those involved in the design of input filters for DC-DC power converters. In many cases, the EMI and power factor requirements are impossible to meet using the existing filtering technology. This paper proposes the use of high-order elliptic filters to achieve the required EMI attenuation and power factor. The new input filter technology provides a significant filter size reduction over the standard filter designs, minimizes the filter-power converter interaction, and maintains a good converter power factor. New active and passive filter damping methods that guarantee optimal filter pole damping, while virtually eliminating damping resistor power dissipation, are proposed. The filter design procedure that makes possible a simple and fast design of filters with an arbitrary number of stages is also presented.

A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation

A new control algorithm for the three-phase buck rectifier with an input filter is developed. The algorithm employs a separate control loop for compensation of the input current displacement factor in steady-state, in addition to the standard output voltage regulation loop. The algorithm allows separate design of the input filter and of closed loop output voltage control. The design procedure is explained and illustrated on an example. The algorithm is verified experimentally on an 1-kW, 100-kHz, three-phase isolated buck power converter. >

Space vector modulated, zero-voltage transition three-phase to DC bidirectional converter

Operation and implementation of the novel, space vector modulated, zero-voltage transition, three phase voltage source inverter/boost rectifier is presented. The converter is intended for high performance, medium power applications requiring bidirectional power flow. The proposed modified space-vector modulation allows all switches to be operated with soft-switching and constant frequency. The modulation algorithm also eliminates any low frequency distortion caused by the zero-voltage transitions and can be applied to any soft switching PWM three-phase converters. A simple, digital signal processor based implementation of the modulator and current regulators, operating with 30 /spl mu/s sampling time, is described. Measured efficiency of the 30 kHz, IGBT prototype is around 95%, and distortion of the three-phase currents is extremely small.<<ETX>>

A new zero-voltage transition, three-phase PWM rectifier/inverter circuit

A switching rectifier/inverter technique that combines the conventional three-phase, six-stepped pulse-width modulated (PWM) rectifier/inverter with a simple commutation circuit to provide zero-voltage turn-on for the switches and soft turn-off for the diodes is presented. The commutation circuit is active only during a short period of the switching cycle, thus it consumes minimum power and does not impair the normal constant frequency PWM control. The addition of the commutation circuit does not result in increased component current and voltage stresses compared to the conventional PWM converter.<<ETX>>

A zero-voltage switched, three-phase isolated PWM buck rectifier

A novel three-phase, single-stage, isolated PWM rectifier is proposed, which is capable of achieving unity power factor, and low harmonic distortion of input currents, and at the same time realizing zero-voltage switching for all power semiconductor devices. Operation of the proposed circuit is thoroughly analyzed. Design equations and trade-offs are provided. The performance of the proposed circuit is demonstrated through a 2 kW, 100 kHz, digital signal processor controlled prototype. The conversion efficiency is around 93%. >

Digital-signal-processor-based control of three-phase space vector modulated converters

The paper presents the implementation of a DSP-based controller for three-phase, space-vector modulated converters. The implementation is illustrated for the control of a 2 kW, ZVS matrix power converter-based three-phase PWM rectifier. The controller features very high data processing speed (converter switching frequency of 100 kHz), and provides high-quality, low-distortion power converter input currents and output voltages. The controller can be implemented using only a few standard integrated circuits, providing high reliability and low cost. >

Analysis and design of a zero-voltage switched, three-phase PWM rectifier with power factor correction

A three-phase, single-stage, isolated PWM rectifier capable of power factor correction and low harmonic current distortion and at the same time realizing zero voltage switching for all power semiconductor devices is proposed. The circuit is thoroughly analyzed. Design equations and tradeoffs are provided. The performance of the circuit is demonstrated through the implementation of a 2 kW, 91 kHz, digital signal processor controlled prototype. The isolated DC output voltage is regulated at 50 V. The conversion efficiency is around 93%.<<ETX>>

Soft-transition three-phase PWM conversion technology

By recognizing common topological properties of PWM converters and of available semiconductor switches, a new generalized soft-switching principle (soft-transition (ST) principle) is developed for the elementary PWM switching cell. Application of the ST principle opens a way of implementing many different new soft-switching PWM topologies. Its application is especially valuable in three-phase converters where the circuit complexity and presence of AC variables can often obscure possible ways of applying the ST technique. The generalized ST principle was successfully used for the development of two novel ZVT rectifier topologies.<<ETX>>