Technical analysis of electric motor controller
1 motor controller basic application
1.1 Motor Controller Integration Form
The integrated form includes:
Single main drive controller, auxiliary three-in-one controller (integrated: EHPS controller + ACM controller + DCDC), auxiliary five-in-one controller (integration: EHPS controller + ACM controller + DCDC + PDU + dual source EPS controller), passenger car controller (integration: main drive + DCDC), logistics car three-in-one controller (integration: main drive + DCDC + PDU), logistics car five-in-one controller (integration: main drive + EHPS controller + ACM controller + DCDC + PDU).
1.2 Basic principle of motor controller
The basic function of the motor controller: the inverter is modulated by the inverter bridge to output the imaginary wave, and the all-in-one controller includes
Distribution circuit: Provides power distribution for each part of the integrated controller, such as TM contactor, fuse, electric air conditioning loop power supply, electric defrost circuit power supply, etc.
IGBT drive circuit: receiving control signals, driving IGBTs and feedback status, providing voltage isolation and protection;
Auxiliary power supply: Provides power to the control circuit and provides isolated power to the drive circuit;
DSP circuit: receiving the vehicle control command, and providing feedback information, detecting the sensor information of the motor system, and transmitting the motor control signal according to the command;
Structure and cooling system: Provides heat dissipation for the motor controller, provides controller installation support, and provides controller security protection.
Motor controller thermal design
The actual operating environment of the vehicle is complex and the working conditions are relatively harsh, which puts high demands on the thermal design:
Simulation experiments require multiple levels:
System level (mainly focused on controller system level heat including waterway design rationality and control level internal ring temperature simulation, system level simulation including module level model)
Module level (key component model capacitance, bronze simulation, simulation of capacitor temperature by density, heat flux density)
The board level (simulated board ambient temperature, heat dissipation of key parts on the board, the purpose is to accurately dissipate heat from a key component of the board, such as the board put some key resistors. If the board is simulated in the previous stage, you can Quick design of the design above)
Chip level (IGBT, main power module simulation, IGBT is the core of the module controller, how to maximize the IGBT capability, depending on the accuracy of the IGBT chip level simulation)
The test needs to meet high precision: carry out multiple rounds of test and test simulation closed loop, heat sink deviation ± 3 ° C
Complex working condition simulation: rated, overload typical working condition simulation, stalling special working condition simulation, periodic load, non-linear load determining the maximum capacity of the controller.
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