A brief discussion on electric vehicle controllers at home and abroad-EEWORLD

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1. Introduction of foreign products

(1) Toyota vehicle controller

The schematic diagram of Toyota's vehicle controller is shown below:

The car is rear-wheel drive, with the left and right rear wheels driven by two wheel hub motors respectively.

Its vehicle controller receives the driver's operation signals and the car's motion sensor signals, where the driver's operation signals include accelerator pedal signals, brake pedal signals, shift position signals and steering angle signals, and the car's motion sensor signals include yaw angular velocity signals, longitudinal acceleration signals, lateral acceleration signals and speed signals of the four wheels.

The vehicle controller calculates these signals through the control strategy and drives the left and right rear wheels respectively through two sets of left and right motor controllers and inverters.

(2) Hitachi Vehicle Controller

The schematic diagram of Hitachi's pure electric vehicle controller is shown in the figure below.

The electric car in the figure has a four-wheel drive structure, in which the front wheels are driven by a low-speed permanent magnet synchronous motor through a differential, and the rear wheels are driven by a high-speed induction motor through a differential.

The control strategy of the vehicle controller is to use different motors to drive the electric vehicle under different working conditions, or to use two motors together to drive the electric vehicle according to a certain torque distribution ratio to maximize the system power transmission efficiency.

When the electric vehicle starts or climbs a slope, the front wheels are driven by a low-speed, high-torque permanent magnet synchronous motor. When the electric vehicle is traveling at high speed, the rear wheels are driven by a high-speed induction motor.

(3) Nissan vehicle controller

Nissan LEAF is a 5-door, 5-seater pure electric car equipped with lithium-ion batteries and a driving range of 160km. Using 200V household AC, it takes about 8 hours to fully charge the battery; fast charging takes 10 minutes and can provide power for 50km of driving.

The schematic diagram of the vehicle controller of Nissan LEAF is shown in the figure below. It receives electronic signals from the vehicle speed sensor and accelerator pedal position sensor of the instrument cluster, and controls the DC voltage converter DC/DC, headlights, defrost system, air conditioning, motor, generator, power battery, solar cell, and regenerative braking system through sub-controllers.

(4) Infineon New Energy Vehicle VCU & HCU Solutions

The controller is compatible with both 12V and 24V power supply environments and can be used in new energy passenger cars and commercial vehicle electronic control systems as a vehicle controller or hybrid power controller. The controller manages, coordinates and monitors each link of the new energy vehicle power chain to improve the energy efficiency of the vehicle and ensure safety and reliability.

The vehicle controller collects the driver's driving signals, obtains the relevant information of the motor and battery system through the CAN bus, performs analysis and calculation, and gives motor control and battery management instructions through the CAN bus to realize vehicle drive control, energy optimization control and brake feedback control. It has complete fault diagnosis and processing functions.

In addition, the controller also uses a dedicated 16-bit processor unit to implement safety monitoring of the main processor and control of Safety IO.

Performance indicators:

Main controller: Infineon 32-bit TC1782

Safety controller: Infineon 16/32bit XC2000

Working voltage range: 9～32V;

Working temperature range: -40～105;

Communication interface: 3-chn *CAN; 1-chn *LIN;

Digital input: 26-chn

Analog input: 6-chn*10-bit@0～5V; 7-chn*12-bit@0～12V;

Low-side driver: >14-chn;

High-side driver: >7-chn;

Sensor power supply:>1-chn@ Vbat;4-chn@5V;

2. Domestic Products

The vehicle controllers in the domestic market are mainly developed by some universities and research institutions. The technical solution is to write control software code through the embedded structure of the microprocessor to achieve the function of efficiently driving pure electric vehicles. It generally collects signals such as the accelerator pedal, brake pedal, shift position, vehicle speed, etc., and uses the CAN bus to communicate with the motor controller and battery management system to achieve management and control of the entire vehicle.

(1) Tianjin Qingyuan Electric Vehicle Co., Ltd. and FAW Tianjin Xiali Co., Ltd. took the lead, and more than a dozen units including China Automotive Technology Research Center, Tianjin University, Tianjin Peace Bay Company and Tianjin Blue Sky Hi-Tech Company jointly developed the XL2000 pure electric car. Its control system is shown in the figure below.

The electric vehicle adopts a centralized motor drive mode and uses the CAN communication bus to connect various control nodes. The vehicle controller comprehensively processes the collected analog quantities, switch quantities and data fed back by other control units, determines the vehicle driving conditions, controls the motor and other components to coordinate work, and ensures the normal driving of the pure electric vehicle.

(2) Zotye Vehicle Controller

Zotye 2008EV is the first pure electric SUV developed by Zotye Automobile Group in China, and participated in the Shanghai Auto Show in March 2009. In July 2010, Zotye 5008EV was sold to an individual customer in Hangzhou for 100,800 yuan, becoming the first pure electric vehicle to be put on the road in China.

Zotye 5008EV uses lithium-ion power batteries and is equipped with an onboard charger, which can be charged in household power or fast charging mode. The maximum power is 27 kW, the maximum speed can reach 110km/h, the driving range after full charge is 300 km, and the power consumption per 100 kilometers is only 12kW·h.

At present, the price of Zotye 5008EV is 100,800 yuan after enjoying the national subsidy of 60,000 yuan and the local subsidy of Hangzhou. The schematic diagram of the vehicle control unit (VCU) of Zotye 2008EV is shown in the figure below.

It connects the accelerator pedal, control motor controller, battery management system, DC/DC converter, electric power steering system EPS, vacuum assist system, air conditioning system, and instrument cluster. The vehicle controller can count the power consumption of all electrical equipment in the vehicle, compare the power that the power battery can provide, and output the controller command signal to the motor controller based on the power model calculation results. The motor controller adjusts the torque value of the traction motor.

When the vehicle controller receives the power demand information input by the accelerator pedal, it conducts a comprehensive analysis based on the power distribution of all electrical equipment in the vehicle and the voltage, current and other information of the power supply battery input by the battery management system, and reasonably adjusts the torque output of the traction motor to ensure that it has sufficient traction.

3. A detailed introduction to the vehicle controller of a domestic company

1. Description:

The vehicle controller is the core control device of pure electric vehicles. Its main functions are to collect vehicle information and driver intentions, control vehicle operation, diagnose vehicle faults, etc.

Vehicle component topology:

Main functions: VCU completes the monitoring and communication of various modules of the vehicle and is the "brain" of the entire vehicle.

(1) Vehicle driving: Collecting the driver’s driving needs and managing vehicle power distribution;

(2) Network management: monitoring communication networks, information scheduling, information aggregation, and gateways;

(3) Auxiliary drive of instrument;

(4) Fault diagnosis and processing: diagnose faults of sensors, actuators and other system components and perform corresponding fault processing, and store fault codes in a standard format. Standard fault code display;

(5) Online configuration and maintenance: Control parameter modification, matching calibration, function configuration, monitoring, and debugging capabilities based on standard interfaces can be performed through the vehicle standard CAN port;

(6) Energy management: by coordinating and managing the onboard energy consumption systems of electric vehicles (such as air conditioning, electric pumps, etc.) to achieve optimal energy utilization;

(7) Power distribution: By integrating vehicle information, battery and motor information to calculate the motor power distribution, the vehicle's drive control and brake energy feedback control are performed to achieve the best driving performance within the system's allowable range;

(8) Control and fault diagnosis of vacuum booster pump, and electric brake assist control when vacuum pump fails;

(9) Hill-hold parking assist control;

(10) Control to prevent backward sliding when starting on a slope.

VCU performance parameters——Hardware performance parameters:

(1) Working characteristic parameters

Working voltage range: 9~18V

Power consumption: ≤50W

Storage temperature: -40℃～90℃

Working environment temperature: -40℃～85℃

Working humidity: ≤90%, no condensation

Instruction execution speed: ≥20MIPS

(2) I/O function indicators