Goodrive3000 Pwm Rectifier; Description Of The Pwm Rectifier - INVT Goodrive3000 Series Operation Manual

Goodrive3000 series medium voltage VFD

5 Goodrive3000 PWM rectifier

Note: This chapter is only for the rectifier of the four-quadrant VFD.

5.1 Description of the PWM rectifier

The main circuit of PWM rectifier unit includes the LCL filter circuit, main contactor, buffer contactor,
buffer resistor, IGBT power modules and bus capacitors. Dual closed-loop control structure is also
applied. The outer loop is the bus voltage loop and the inner loop is the current loop. The reactive current
component of the input grid current can be controlled by the voltage phase detection and coordinate
transformation and regulation of PI regulator. When the controlled reactive current is 0, the power factor
of the rectifier can be close to 1 and the energy can flow in both directions.
Q1
3PH 1140VAC
Note: Q1 is the isolating changeover switch; the LCL filter consists of L1, C and L2; R0 is the power buffer
resistor; KM1 is the main contactor; KM2 is the buffer contactor and L3 is the output reactor.
PWM rectifier and inverter can be combined into the four-quadrant VFD. The PWM rectifier can be used
for potential loads, such as hoists, locomotive traction, oil pumping units and centrifugal machines. In
some large power applications, the four-quadrant VFDs are needed to reduce harmonic pollution to the
grid. The VFD with PWM rectifier has the functions of four-quadrant operation, meeting the requirements
of speed regulation of various potential loads. It can transform the regenerative energy of the motor into
electric energy back to the grid and achieve high-efficiency energy saving in energy feedback braking.
After the conversion of PWM rectifier, 3-phase AC current can be provided as DC current into the DC bus
and the DC circuit provides power to the motor. PWM rectifier monitors the control power before AC
power overvoltage, phase loss fault, IGBT module overtemperature, overcurrent, overload and
pre-charging. Rectifier unit will lock the pulse and send a fault single which can be reset after repowering
if fault occurs.
L1 L2 KM1
C KM2
R0
Figure 5.1 PWM rectifier
Goodrive3000 PWM rectifier
Rectifier
Current Bus voltage
IGBT drive
sampling sampling
Control part
Phase
detection
-23-
Converter
L3
M