- Drive & Control System
- Control System
- Inverter or VSD(Variable Speed Drive) is consists of Converter, DC Link circuit and Inverter unit.
At the input side, the converter consists of a rectifier which is supplied with a contant voltage and contant frequency from a three-phase supply.
The rectifier produces a constant DC voltage which is smoothed by the DC link capacitors.
The IGBT inverter unit on the output side converts the DC link voltage to a three-phase system with a variable voltage and variable frequency.
This process operates according to the principle of PWM modulation.
By varying the voltage and the frequency, it is possible to vary the motor speed of the connected three-phase motor continuously.
① Classification according to control DC link source : Voltage source and Current source Inverter
② Classification according to modulate DC link source : PWM and PAM Inverter
Voltage Source Inverter
The IGBT inverter unit converts DC link voltage smoothed by the DC link capacitors to a three-phase system with a variable voltage and variable frequency.
Current Source Inverter
The Thyristor rectifier produces a constant DC current which is smoothed by the DC link reactor. And then the Thyristor inverter unit converts DC link current to a three-phase system with a variable frequency.
PAM (Pulse Amplitued modulation)
The IGBT inverter unit converts the variable DC link voltage to a three-phase system with variable frequency.
PWM (Pulse Width Modulation)
The IGBT inverter unit converts the constant DC link voltage to three-phase system with a variable voltage and variable frequency.
|① No motor slip ring and commutator blush, it is easy and simple to maintain and repair.|
|② Easy opearation, excellent control characteristics, continuous operation in the whole speed range is possible.|
|③ Energy savings can be achieved by controlling the output according to the load variation.|
|④ Wide range of acceleration and deceleration settings can reduce electrical and mechanical impact.|