Comparison between VSI and CSI
Comparisons between voltage source inverters and current source inverters are as follows.
- In voltage source inverters, the input voltage is maintained constant and the amplitude of output voltage does not depend on the load. However, the waveform of load current, as well as its magnitude, depends upon the nature of load impedance. In current source inverters (CSI), the input current is constant but adjustable. The amplitude of output current from CSI is freelance of the load. However, the magnitude of output voltage and its undulation output from CSI depends upon the character of load resistivity.
- A CSI does not require any feedback diodes, whereas these are required in a VSI.
- Power semiconductor devices such as GTOS, power transistors, and power MOSFETs cannot be used in a CSI, but in VSI these devices can be used.
- CSI is more reliable and rugged than VSI.
- CSI is a wave suitable for low leakage impedance, a high leakage impedance produces voltage spikes which can dangerous for the device.
Application of current source inverter
(1) Speed control of ac motors.
(2) Induction heating.
(3) Lagging VAR compensation.
(4) Synchronous motor starting.