A ZVS Grid-Connected
Three-Phase Inverter
ABSTRACT:
A six-switch three-phase inverter is widely used in a
high-power grid-connected system. However, the anti parallel diodes in the topology
operate in the hard-switching state under the traditional control method
causing severe switch loss and high electromagnetic interference problems. In
order to solve the problem, this paper proposes a topology of the traditional
six-switch three-phase inverter but with an additional switch and gave a new space
vector modulation (SVM) scheme. In this way, the inverter can realize
zero-voltage switching (ZVS) operation in all switching devices and suppress
the reverse recovery current in all anti parallel diodes very well. And all the
switches can operate at a fixed frequency with the new SVM scheme and have the
same voltage stress as the dc-link voltage. In grid-connected application, the
inverter can achieve ZVS in all the switches under the load with unity power
factor or less. The aforementioned theory is verified in a 30-kW inverter
prototype.
KEYWORDS:
1.
Grid connected
2.
soft switching
3.
space vector modulation (SVM)
4.
three-phase inverter
5.
zero-voltage switching (ZVS)
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1.Soft-switching three-phase
inverter topology: (a) dc-side topology and (b) ac-side topology.
CONCLUSION:
The
analysis and experimentation presented verify that the SVM-controlled
three-phase soft-switching grid-connected inverter can realize ZVS operation
for all switching devices, and the reverse recovery current in the antiparallel
diodes of all switching devices is suppressed well. SVM can be realized at the
fixed switching frequency. And the switching voltage stress across all the
power switch devices is the same as the dc-link voltage. The ZVS can be
achieved in the grid-connected ZVS inverters under the load with unity power
factor or less. The reduced switching loss increases its efficiency and makes
it suitable for practical applications.
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[3]
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[5]
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