- The voltage source inverter is one in which output voltage remains constant and it does not depends upon type of load.
- The voltage across load is kept constant by connecting large capacitor at the input side of the inverter.
- The current source inverter is one in which output current remains constant with respect to type of load.
- An inductor of suitable value is placed in series with DC voltage source.
- The DC input voltage in the current source inverter is supplied through rectifier bridge/controlled rectifier bridge or DC chopper.
- The LC filter is connected at the input in order to get ripple free current.
- The function of the inductor L is to decrease the ripple current whereas the capacitor C is to reduce source impedance.
- The power flow from supply to load and vice versa is possible at different power factor due to low impedance of DC supply.
- The current source inverter is either load commutated or force commutated.
- The current source inverter is load commutated if the load power factor is leading whereas it must be force commutated if the load power factor is lagging.
- The current source inverter can be used for the speed control of induction motor in which variation of load torque occurs.
- There is additional diode requires for feeding the reactive power back to the supply when inductive load is used.
Advantages
- There are converter grade thyristor used in the current source inverter which has reverse blocking voltage capability.
- The converter grade thyristor should have withstand capacity of high voltage spike during commutation.
Disadvantages
- The commutation capability depends upon the load current and this will limit the operating frequency.
- Sluggish performance and stability problem at light load and high frequency
Applications
- Induction heating
- Speed control of AC motor
- Starting of synchronous motor
- To compensate lagging reactive power
Advantages
- There are converter grade thyristor used in the current source inverter which has reverse blocking voltage capability.
- The converter grade thyristor should have withstand capacity of high voltage spike during commutation.
Disadvantages
- The commutation capability depends upon the load current and this will limit the operating frequency.
- Sluggish performance and stability problem at light load and high frequency
Applications
- Induction heating
- Speed control of AC motor
- Starting of synchronous motor
- To compensate lagging reactive power
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