With the increasing popularity of electric vehicles, most electric cars on the market today use AC motors. These AC motors are powered by the vehicle's onboard battery, which provides direct current (DC) to the vehicle. However, a normal electric motor requires AC power to function properly. Therefore, converting DC to AC power is crucial for the operation of electric vehicles.
3 main modules of motor controller
1. Electronic Controller: This is a collective term encompassing the hardware circuitry and corresponding control software. The hardware circuitry mainly includes a microprocessor and its minimum system, monitoring circuits for motor current, voltage, speed, temperature, and other states, various hardware protection circuits, and communication circuits for data exchange with external control units such as the vehicle controller and battery management system. The control software implements corresponding control algorithms based on the characteristics of different types of motors.
2. Driver: It can convert the microcontroller's control signals to the motor into drive signals for the power converter and isolate the power signals and control signals.
3. Power Converter: This module controls the motor current. Power devices commonly used in electric vehicles include high-power transistors, gate turn-off thyristors, power MOSFETs, insulated-gate bipolar transistors (IGBTs), and intelligent power modules.
There are many types of electric motors
Due to different research purposes, there are many classifications of electric motors. Currently, electric vehicles basically use AC motors, and the mainstream motors used in mainstream vehicles are permanent magnet AC motors, which have three characteristics: first, simple structure and safe and reliable operation; second, small size, light weight, low power consumption, and high efficiency; and third, flexible and diverse shape and size.
The motor controller is working.
During the operation of a car, the electric motor controller is responsible for activating the motor. The motor controller consists of two parts: an inverter and a controller. The inverter receives DC power from the battery and converts it into three-phase AC power to supply the car's electric motor. The controller receives signals such as motor speed and sends them back to the instrument panel. When braking or acceleration occurs, the controller adjusts the inverter's frequency to achieve acceleration or deceleration.
The future development of motor controllers will follow these principles.
First, high safety is the most basic requirement for motor controllers.
The increasing integration of functions means increasingly stringent safety requirements. Safety performance needs to be achieved through the combination of many chip architectures, such as SBC+MCU monitoring architecture, high-voltage backup power supply, safety-related driver chips, comprehensive diagnosis of IGBT faults, independent safety shutdown path, independent ADC channel resolver signal decoding, different high-voltage sampling circuits, and different three-phase current Hall sensors, etc.
Second, with the increasing power density, the physical size will become smaller as the packaging process progresses.
With the development of device technology and packaging technology, costs are expected to gradually decrease. From a packaging perspective, traditional easy-to-use modules are trending towards square, ultra-thin forms, and finally, bare DBC/chip formats. The form factor is shrinking as packaging technology advances, and by 2018 or in the future, it could reach 1/10 of the form factor of 2013.
From a chip perspective, motor controllers are evolving towards higher efficiency and higher operating junction temperatures. For example, the E3 chip has an operating junction temperature of 150°C, the EDT2 chip's junction temperature can be raised to 175°C, and the SiC (silicon carbide) chip's junction temperature can exceed 175°C. If the power loss of the E2 chip is 1, the power losses of the latter two are 0.8 and 0.3 to 0.5, respectively. Using SiC devices can significantly reduce switching losses, improve system efficiency, reduce dead time, and enhance system output capability.
Considering the battery pack and controller as a whole, the total cost decreases by 5%, and considering the entire vehicle, the driving range increases by 10%. Using SiC devices can improve overall efficiency.
III. High voltage is the fundamental trend in the future development of motor controllers.
GBTs are trending towards 650V, while IGBT designs are moving towards even higher voltages of 750V and 1200V. EMC standards will continue to rise, with Class 5 being the next step. Current second-generation products may achieve Class 3 or Class 4, but future EMC standards will need to reach Class 5, requiring miniaturization and lower costs. The core breakthrough in EMC innovation lies in achieving high-level EMC requirements with superior filtering solutions and lower-cost EMC devices.
The motor controller has reached a "five-in-one" level, with five major product categories.
Currently, in many cities, basic electric vehicle motor controllers have achieved a "five-in-one" level, divided into five main product categories:
1. Single main drive controller and auxiliary three-in-one controller (integrated: EHPS controller + ACM controller + DC-DC).
2. Five-in-one auxiliary controller (integrated: EHPS controller + ACM controller + DC-DC + PDU + dual-source EPS controller).
3. Passenger vehicle controller (integrated: main drive + DC-DC).
4. Logistics vehicle three-in-one controller (integrated: main drive + DC-DC + PDU).
5. Logistics vehicle five-in-one controller (integrated: main drive + EHPS controller + ACM controller + DC-DC + PDU).
