3-5
Climate Class 6100i / 6000i / 8100i / 8000i
[3] IPM Drive Circuit
The IPM is used for compressor drive. The power supply for the IPM drive, the shunt resistance for over current detection, etc., are provided outside
the IPM (control PWB).
1. IPM drive power supply circuit
The power supply for the upper-phase IGBT (HU, HV, HW) drive employs a bootstrap system, and provides power to the upper-phase IC.
The 15-V power supply for the lower-phase IC is provided by the control printed wiring board (PWB).
1.1. Brief explanation of bootstrap system (single power drive system)
To supply power to the upper-phase IC, the microcomputer (IC1) turns ON the lower-phase IGBT (LU, LV, LW).
This results in a charging current that ows to the electrolytic capacitor of each upper-phase IC input and charges the bootstrap capacitor with a 15V
current.
The power supply for the subsequent stages is charged while the lower-phase IGBT is ON in ordinary compressor drive control.
1.2 DC over current detection circuit
When a current of about 20 A or higher ows through the shunt resistance on the control printed wiring board (PWB), the voltage at this resistance
is input to IPM CIN pin (15). Then, the gate voltage of the lower-phase IGBT (LU, LV, LW) inside the IPM turns OFF to cut off the over current. At the
same time, an L output of more than 20μs is generated from IPM from pin (14), and this results in an L input to over current detection input pin (45)
of the microcomputer (IC1) and turns OFF the PWM signal output (IC1 pins (37) through (39) and pins (42) through (44)) to the IGBT gate.
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