Electric vehicle is becoming more and more popular because of its environmental protection. For electric vehicle manufacturers, it is a very important task to choose the power matching motor controller. The following is a detailed introduction of the electric vehicle controller’s software and hardware, and how to choose the power matching motor controller.
In general, when communicating with the vehicle manufacturer, they will give the wiring harness drawings and functional requirements drawings of the controller. The function requirements include the related functions of the controller and the wiring harness assembly, and the technical requirements are generally such as low level / high level anti-theft, cruise, over voltage, average current and so on. As shown in Figure 1.
Motor controller customer input technical requirements
Figure 1 motor controller customer input technical requirements
For example, figure 1 requires the controller to be 60/72V compatible, dual voltage controller. The limiting current value of the controller is 40 + 1A and the under voltage range is 52.5 + 0.5V and 63 + 0.5V respectively. These parameters basically determine the maximum output power of the controller. It is easy to think that the maximum output power of the control is the product of the input voltage and the current limiting value. Considering that the voltage range of 60V lead-acid battery is generally 52~70V and the voltage range of 72V lead-acid battery is 63~80V, the maximum output power of the controller is 2.8KW, and 3.2KW (the maximum output power discussed here).
However, the motor samples sent to us by the manufacturer generally identify 60V 800W motors and 72V 800W motors instead of 60V2.4KW motors and 72V 2.88KW motors. It may be doubting that the motor nominal power is the power that the motor works in the wide efficiency platform, long distance, high torque and so on in the process of using the motor. The following is a 72V 40A controller that matches the 72V 800W motor, as shown in the following figure.
Controller with 60V 800W motor
Figure 2 60V/40A controller with 60V 800W motor
Dynamometer curve data table
Figure 3 data table of dynamometer curve
Figure 2 shows the relationship between controller output power, efficiency, average current and speed under various loads. It can be seen from the diagram that when the load reaches 821W, the average current control is 13.48A, the motor efficiency is about 84.2%, and the output torque is 21.2 Nm. This working condition is the best working condition of the controller in ensuring the mileage, efficiency and torque.
After understanding the above problem, let’s talk about how to choose a suitable controller when choosing a controller in the future.
(1) select the type of controller that matches the type of motor. For example, DC brush, DC brushless, square wave or sine wave, Holzer, no Holzer and so on.
(2) before choosing the controller, see whether the motor power is rated or maximum power. If the rated power is rated power, the matching motor controller can be selected according to the 2~3 times of the rated power. For example, the nominal rated power of the motor is 650W and the voltage is 48V, then the rated voltage 48V is selected and the maximum output power is 1.3KW~2KW motor controller. If the motor indicates the maximum working power, it is possible to match the motor with a smaller motor power.
(3) match the parameters of the motor. Taking brushless DC motor as an example, Holzer and Holzer do not usually need to match special parameters for square wave controller. If there is a Holzer sine wave controller, if the speed output is needed, the parameters such as the pole number and speed of the motor must be required. In order to match the program without Holzer sine wave, parameters such as phase inductance, phase resistance, polar logarithm and maximum speed of motor must be solved.
After knowing how to choose the controller that matches the motor, let’s talk about the effect of the controller if the power is too small or too large.
First, it is said that the power of the controller is small. For example, the maximum output power of 60V motor is 2KW, and the maximum output power of 60V controller is only 800W.
For example, the maximum average current of the controller of 60V 800W is 13.3A. The average current of the phase current protection value of the phase current is 3 times that of the motor when the motor is blocked, and the protection value of the phase current is 40A. The maximum average current of the 60V 2KW motor is 33.3, assuming that the current protection value of the matching motor controller phase is also set to 3 times the average current, which is 100A. If the control of the 800W is matched with the motor of the 2KW, the controller is equivalent to the small Mara, and the controller will cause the control of the power pipe to be damaged by the power pipe and heat dissipation. If the controller software does not contain phase current and current limiting protection, the damage rate of the controller will be even higher.
Finally, if the power of the selected controller is too large, the output current of the motor will be greater than that of the motor under the condition of large load. Short time light load does not normally cause damage to the motor, but if long load work will cause serious heat, damage the Holzer sensor inside the motor and even burn out the stator winding of the motor.
If there are any mistakes, readers will be criticized. About motor control problems, you can ask me in the comment area, thank you for your attention!
Shenzhen yaoertai technology is a high-tech enterprise specializing in (RF) wireless controller, wireless transmitter module, wireless receiver module, wireless remote control, wireless receiver, infrared detector, gate magnetic, smoke detector, gas alarm, burglar alarm and other related products. Wireless controller supporting products are widely used in remote control electric doors and windows, telescopic doors, garage doors, remote control lights, switches, communications and security and other fields. Professional matching garage door factory, GPS plant, security plant, electric control lock factory, automobile factory, electric doors and windows, gates, industrial control, etc. Welcome everyone to come to consult!
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