Features
Vienna Rectifier provide following features:
- Three phase three level three switch PWM rectifier with controlled output voltage.
- Three wire input, no connection to neutral.
- Ohmic mains behavior.
- Boost system (continuous input current).
- Unidirectional power flow.
- High power density.
- Low conducted common-mode EMI emissions,
- Simple control to stabilize the neutral point potential.
- Low complexity, low realization effort.
- Low switching losses.
- Reliable behavior (guaranteeing ohmic mains behavior) under heavily unbalances mains voltages and in case of mains failure.
Figure 1 Schematic Diagram of Three Phase Vienna Rectifier
Topology
The Vienna rectifier is a unidirectional three phase three switch three level Pulse width modulation (PWM) rectifier. It can be seen as a three phase diode bridge with an integrated boost converter.
Applications
The Vienna Rectifier is useful wherever six switch converters are used for achieving sinusoidal mains current and controlled output voltage, when no energy feedback from the load into the mains is available. In practice, use of the Vienna Rectifier is advantages when space is at sufficient premium to justify the additional hardware cost. There include:
- Telecommunications power supplies.
- Uninterruptible power supplies.
- Input stages of AC drive converter systems
Figure 1 shows the schematic diagram of 9.8 kW Vienna Rectifier sinusoidal input currents and controlled output voltage.
Current and Voltage waveforms
Figure 2 shows the system behavior, calculated the MATLAB simulator. Between the output voltage midpoint (0) and the mains midpoint (M) the common mode voltage u0M appears, as is characteristics in three phase converter systems.
Figure 2 Simulation Results (a) Input AC Voltage (b) Input AC Current (c) Inductor Voltage (d) DC output Voltage
Figure 3 Input Voltage THD
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Figure 4 Input Current THD
