Single Phase Circuit Diagram Explanation
1. Circuit Overview
The single-phase inverter circuit converts the incoming 230 V AC supply into a high-voltage DC supply and then uses the Integrated Power Module (IPM) to create the controlled three-phase output required by the DC compressor.
| 230 V AC Power Supply | → | Filter PCB | → | Diode Bridge | → | ACTPM + Choke Coil | → | Capacitor Board | → | IPM → Compressor |
2. Power Circuit Stages
2.1 AC power supply
Single-phase mains power enters the outdoor unit as Active (L) and Neutral (N). The supply feeds the filter PCB before continuing into the main power-conversion circuit.
2.2 Filter PCB
The Filter PCB is the first stage after the incoming supply. From the diagram, it provides AC power onward to the diode bridge and also provides an AC supply path to the Main PCB.
| Input | L / N - approximately 230 V AC |
| Output path | AC supply to the diode bridge and Main PCB |
| Associated component | Posistor shown connected with the filter/main-control section |
2.3 Diode bridge - AC to DC conversion
The diode bridge rectifies the incoming AC waveform into DC. The diagram identifies the voltage after this stage as approximately 200-230 V DC.
AC power from Filter PCB → Diode Bridge → approximately 200-230 V DC
2.4 ACTPM and choke coil - power-factor correction and DC boost
The ACTPM works with the L1 choke coil. According to the supplied diagram, this stage improves power factor and boosts the rectified DC voltage.
| Point | Function / voltage |
|---|---|
| Input to ACTPM stage | Approximately 200-230 V DC from the diode bridge |
| Choke coil | Connected through the ACTPM power-factor-correction circuit |
| Output from ACTPM stage | Approximately 330-370 V DC |
| Negative path | Shown passing directly to N in the supplied diagram |
2.5 Capacitor board - DC smoothing
The capacitor board is connected across the high-voltage DC bus. Its purpose is to smooth the DC voltage before it is used by the inverter power module.
2.6 Integrated Power Module (IPM)
The IPM receives the high-voltage DC supply and electronically switches it to produce the controlled output required by the compressor.
| DC input | Positive (+) and negative (-) high-voltage DC bus |
| Compressor output | U, V and W outputs to the DC compressor |
| Control | Controlled by the Main PCB according to compressor speed/load requirements |
3. Main PCB and Control Circuit
The Main PCB supervises the inverter power circuit. The supplied diagram shows control harnesses linking the Main PCB with the Filter PCB, ACTPM and IPM transistor/power circuit.
| Main PCB supply / connection | Shown in diagram |
|---|---|
| AC supply | Approximately 230 V AC via the Filter PCB |
| High-voltage DC | Approximately 330-370 V DC associated with the IPM transistor/power circuit |
| Control harnesses | Filter PCB, ACTPM and IPM transistor/power circuit to Main PCB |
4. Service Interpretation and Test Points
When troubleshooting a no-run, compressor or inverter-related fault, follow the power path in sequence. A missing voltage at one stage will prevent the following stage from operating correctly.
| Step | Check | Expected from supplied diagram |
|---|---|---|
| 1 | Incoming supply at L and N | Approximately 230 V AC |
| 2 | AC supply leaving Filter PCB / feeding diode bridge | Approximately 230 V AC |
| 3 | DC output from diode bridge | Approximately 200-230 V DC |
| 4 | DC bus after ACTPM boost stage | Approximately 330-370 V DC |
| 5 | Capacitor board / DC bus | Stable smoothed high-voltage DC supply |
| 6 | IPM output to compressor | Controlled U/V/W inverter output when the compressor is commanded to operate |