The motor drive system of new energy vehicle includes power electronic converter and corresponding controller. Power electronic converter is composed of solid-state devices, and its main function is to transfer a lot of energy from power supply to motor input.
A controller is usually composed of a microcontroller or a digital signal processor and related small-signal electronic circuits. Its main function is to process information and generate switching signals required by the semiconductor switching devices of the power converter. The relationship between the main components of motor drive system, energy storage device and motor.
The block diagram of motor drive system of power converter in new energy vehicle includes DC converter and AC converter, DC converter is used to drive DC motor and DC converter is used to drive AC motor. The power converter is composed of high-power and fast-response semiconductor devices. The solid-state devices in the power electronic circuit of the motor drive system are used as on-off electronic switches to convert constant voltage into variable frequency and voltage power supply.
All power devices have a control input gate (or gate or base), and the power devices are turned on or off according to the control signal output by the controller. In recent 20 years, with the rapid development of power semiconductor technology, DC and AC motor drive systems have developed rapidly in the direction of miniaturization, high efficiency and reliability. IGBT is the most commonly used power device in the motor drive system of pure electric vehicles and hybrid electric vehicles. The voltage, current range and switching frequency of IGBT fully meet the requirements of electric drive system.
The function of DC/DC and DC/ AC converter The controller of the new energy vehicle drive system manages and processes the system information to control the power flow direction of the electric drive system. The controller acts according to the driver's input instructions and follows the control algorithm of the motor. After decades of development, there are many control algorithms for various motors. Among these control algorithms, some are used in high-performance drive systems, and some are used in speed-regulating drive systems with lower requirements.
The electric drive system for electric traction needs fast response and high efficiency, so it is classified as a high-performance drive system. These control algorithms of motor drive system need a large amount of calculation, and need a fast processor and a considerable number of feedback signal interfaces. The current processors are basically digital signal processors, replacing the original analog signal processors.
Compared with analog signal processor, digital signal processor can not only reduce drift and error, but also greatly improve the performance of dealing with complex algorithms in a short time. In fact, the controller is an embedded system, in which the microprocessor and the digital signal processor perform signal processing through the peripheral interface electronic module.
(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)