Advantages and weaknesses of electric vehicle controllers, common faults and maintenance methods

As one of the most popular means of transportation today, electric vehicles have already taken a part in life. A common electric vehicle is a vehicle that uses a battery as an energy source and controls the current to change its speed through an electric vehicle controller. In physical research, it is called converting electrical energy into mechanical energy. The advent of the first electric vehicle in 1834 represented the upgrade of people's mobility tools. The electric vehicle controller is the electric vehicle controller. The electric vehicle controller is used to control the start, run, advance and retreat, speed, stop and electric of the electric motor. The core control device of other electronic devices of the car is like the brain of an electric car. It is an important component of the electric car. It mainly controls the rotation speed of the motor and has various protection functions such as undervoltage protection and current limiting protection. Brake power off, etc.

Pros and cons of the controller of electric vehicle

1. Work

Good controller work is not the same, we first observe with the naked eye, the appearance is not the wave soldered product, the appearance is exquisite, the wire is thick; the radiator is heavy and so on.

2. Contrast temperature rise

Use the newly sent controller and the original controller to carry out the blocking heat transfer test under the same conditions. Both controllers remove the radiator, use a car, prop up the foot, first turn the turn to reach the highest speed, immediately Brake, do not brake, lest the controller enter the stall protection, maintain it at very low speed for 5 seconds, release the brake, quickly reach the highest speed, brake again, repeat the same operation, such as 30 times, check the maximum temperature of the radiator point.

Take the data comparison of the two controllers, the lower the temperature, the better, the experimental conditions of the two cars are the same. At the end of the test, the tightness of the screws of the fixed MOS should be checked. The more loose the insulation, the worse the temperature resistance of the insulating plastic particles is. The long-term use can easily cause the MOS to be damaged due to heat in advance.

3. Observe the ability of back pressure control

Select an electric car with a large power, unplug the battery and supply it with a charger, and connect the E-ABS enable terminal to ensure that the brake switch is in good contact. Slowly turn the handle (too fast, the charger can't output a large current, it will cause undervoltage), let the motor reach the highest speed, fast brake repeated many times, there should be no MOS damage. This test can also be carried out during a fast downhill trip and brakes when the car reaches its maximum speed.

4. Current control capability

Connect the battery with a large capacity, first let the motor reach the highest speed, then select the two motor output lines for short circuit, repeat, 30 times or more, there should be no MOS damage; let the motor reach the highest speed, use the battery positive and any The selected one motor line is short-circuited and repeated 30 times. This is more severe than the above test. There is one internal resistance of the MOS in the loop, and the instantaneous short-circuit current is larger, which tests the controller's current fast control capability. If damage occurs, you can compare the number of times the two controllers successfully withstand a short circuit, the less the worse.

5. Test controller efficiency

Turn off the overspeed function and test the highest speed reached by different controllers under the same load of the same car. The higher the speed, the higher the efficiency and the higher the cruising range.

Common faults and maintenance methods for electric vehicle controllers

One: When the electric vehicle has a brush controller without output

1. Set the multimeter in the +20 (DC) position, first measure the high and low potential of the output signal of the brake.

2. If the brake lever has a potential change of more than 4V when the brake is applied, the brake will be eliminated.

3. Then, according to the commonly used function table of the brush controller, the circuit analysis is performed with the measured voltage value of the main control channel logic chip, and the values of the peripheral devices (resistors, capacitors, diodes) of each chip are checked. The marking of the surface is consistent.

4. Finally, check the peripheral device or the integrated circuit is faulty. We can eliminate the fault by replacing the same type of device.

Two: When the electric vehicle brushless controller has no output at all

1. Refer to the main phase check measurement diagram of the brushless motor controller, and use the multimeter DC voltage +50V file to detect whether the gate voltage of the 6-way MOS transistor is corresponding to the rotation angle of the turntable.

2. If not it means that the PWM circuit or MOS tube drive circuit in the controller is faulty.

3. Refer to the main phase check chart of the brushless controller to measure whether the voltage of the input/output pin of the chip has a corresponding relationship with the rotation angle of the turntable. It can judge which chips are faulty, and replace the same type of chip to eliminate the fault.

Three: When the power supply of the electric vehicle brush controller control unit is abnormal

1. The internal power supply of the electric vehicle controller generally adopts a three-terminal voltage-stabilized integrated circuit, generally using 7805, 7806, 7812, 7815 three-terminal voltage regulator integrated circuits, and their output voltages are 5V, 6V, 12V, 15V respectively.

2. Set the multimeter to the DC voltage +20V (DC) position, and place the multimeter black and red pens on the black and red lines of the switch respectively to observe whether the multimeter readings match the nominal voltage, and their upper and lower voltage differences Should not exceed 0.2V.

3. Otherwise, the internal power supply of the controller is faulty. Generally, the brush controller can eliminate the fault by replacing the three-terminal voltage regulator integrated circuit.

Four: When the electric vehicle brushless controller is out of phase

The fault of the brushless controller power supply and the brake lever of the electric vehicle can be ruled out by referring to the troubleshooting method of the brush controller. For the brushless controller, there are also special fault phenomena such as phase loss. The phase loss phenomenon of the electric vehicle brushless controller can be divided into two cases: main phase phase loss and Hall phase loss.

1. The detection method of the main phase phase loss can refer to the electric vehicle brush controller flying vehicle fault elimination method to detect whether the MOS tube breaks down. The brushless controller MOS tube breakdown is generally a pair of upper and lower MOS tubes of a certain phase. At the same time, it is required to be replaced at the same time. Check the measurement points.

2. The Hall phase of the electric vehicle brushless controller shows that the controller cannot recognize the motor Hall signal.

The page contains the contents of the machine translation.