Inverter rear stage power

What is a three-phase inverter module?

This module has a three-phase diode based rectifier input stage, a three-phase IGBT based inverter output stage, an IGBT based brake chopper and an NTC thermistor integrated inside the module. In this design the rectifier stage is unused and provision is given to power the three-phase inverter stage directly with a DC power supply.

What are the losses in the inverter stage?

Figure 51 shows the losses in the inverter stage as a function of inverter output current. As the current increases the switching losses become less dominant and the conduction losses become more dominant. It is observed that the loss is ≈ 92 W at 130 A for 8-kHz switching and ≈ 100 W at 10-kHz RMS switching frequency.

How much power does an inverter have?

The inverter is powered from a 48-VDC lead acid battery. It is designed to deliver 5 kW of output power from the motor and can handle continuous motor currents of up to 130 ARMS with a suitable cooling setup. Its high current rating is achieved by using multiple MOSFETs (CSD19536) in parallel, mounted onto a thermal clad PCB.

How does a three-phase AC inverter drive work?

In the three-phase AC inverter drive, the output phase current flows complementarily between the high-side switch and the low-side switch. During the positive half cycle of the motor phase current, the high-side switch conducts and the low-side switch freewheels and vice versa during the negative half cycle.

What is the efficiency of a 5 kW inverter?

Using the loss at 130 ARMS, for 5-kW motor output power and 0.8 power factor the efficiency of the inverter can be estimated to be around ≈ 98% for a 8-kHz switching frequency. Note that during the test, 130 A RMS is pumped into the motor by overloading the reactance part of the motor load and not the real part because of test setup limitations.

How much power does a traction inverter have?

The typical battery voltages are 24, 36, and 48 VDC, and the traction inverters are rated up to 8 kW. This necessitates using multiple MOSFETs in parallel to achieve the required current and power rating.