Three-Phase Boost-Type PFC Rectifier (AC/DC)

Vienna Rectifier 1 - Overview

Characteristics and Advantages of the Vienna Rectifier 1 (as compared to the two-level six-switch boost-type PWM rectifier)

Three-phase three-level three-switch PWM rectifier with controlled output voltage; three-wire input, i.e. no connection to the neutral required
Sinusoidal input currents, in principle no low-frequency harmonics, unity power factor operation, i.e. ohmic fundamental mains behavior
Boost-type system, i.e. continuous input current
Unidirectional power flow
Power circuit of low complexity with only three active switches and/or three gate drive circuits, a control failure does not result in a short circuit of the DC output voltage, guaranteeing in high reliability and low costs
High power density; the three-level characteristic does reduce input-current ripple and/or input inductor volume for given ripple
Stability of neutral point potential is guaranteed by a simple control
Three-level characteristic does reduce the blocking voltage stress on all power semiconductor components by a factor of 2
Low conducted common-mode EMI emission due to switching of always only half the output voltage
Straightforward control scheme, low complexity, low realization effort
Switching losses reduced
- by a factor of 2 according to reduced turn-off voltage
- by a factor of about 2 according to possibility of using ultra fast recovery free-wheeling diodes
- by a factor of about 1.5 according to reduced switching frequency due to the three-level characteristics
Total reduction of switching losses theoretically by a factor of 6 result in reduction of the total losses of about 40% for a typical switching frequency (48kHz) - the efficiency at rated output power has been verified experimentally to be 97.5% for a 10kW system operating at 400Vrms line-to-line input voltage (output voltage is 800V DC).
Operation at heavily unbalanced mains voltages and/or in case of a mains failure (two-phase operation) possible, the proposed control schemes do guarantee an ohmic mains behavior also in this case
Ongoing development, e.g. 2U-unit with 12kW rated power and wide input voltage range (320V...530V) system footprint: 16cm x 25cm
Development of a 1U-unit of same rating under way (switching frequency of 500kHz, SiC technology)
Fully documented mixed signal control board (analog current control and digital voltage control, start-up management, failure management etc.) available as evaluation board from the Power Electronic Systems Laboratory/ETH Zurich
Fully documented power circuit hardware 10kW/400V input, 800V DC output available from the Power Electronic Systems Laboratory/ETH Zurich
Fully digital control under development

Possible fields of applications of the Vienna Rectifier are

Telecommunications power supply
Uninterruptable Power Supply (UPS)
Input stage of AC drive converter systems
Industrial process technology (input stage of electronic welding current sources, plasma power supplies, laser power supplies etc.)
Basically all areas where six-switch converters are used for achieving sinusoidal mains current and controlled output voltage but no energy feedback from the load into the mains is required.