Overview
This document contains information on:
General
Function requirements
Function
General
The power electronics control unit controls the electric machine.
It is connected to the vehicle's network architecture.
In vehicles with two electric machines, there is one power electronics control unit for each machine.
Function requirements
Circuit 30t ON
Function
The power electronics control unit consists of a power unit and a logic section. The power unit is a power inverter, which connect a 3phase alternating voltage on the side of the electric machine to a direct voltage on the side of the high-voltage on-board electrical system. The power inverter facilitates an energy transfer in both directions. Depending on the direction of the energy transfer, the electric machine is operated either as an engine or as a generator.
The logic section is responsible for communication with other control units and for actuation of the power inverter. Activating the power-electronics elements changes the logic section amount and direction of the energy transfer in the power inverter.
The power electronics control unit monitors the temperature and engine rpm of the electric machine and provides diagnoses and forecasts on the available torque in the CAN compound.
Interlock:
The interlock monitoring serves for the contact protection of persons against inadvertent contact with live parts in the high-voltage components. The interlock monitoring takes place in a model-dependent manner by means of the central monitoring (interlock circuit) or locally by the high voltage component itself. In the case of vehicle stillstand, a response of the interlock monitoring results in the deactivation of the high-voltage on-board electrical system.
The following applies for hybrid vehicles:
A DC/DC converter is integrated in a model-dependent manner in the power electronics control unit that allows for an energy exchange between the high-voltage on-board electrical system and 12 V on-board electrical system.
The power electronics control unit processes the following items of information:
Circuit status
Specified value for torque of electric machine
Torque limitation of electric machine
Direction of rotation of electric machine
Drive train operational
The power electronics control unit processes these input factors and sends, among others, the following information:
Actual torque of electric machine
Actual engine speed of electric machine
Available torque from electric machine
Status of electric machine