What are the test items for vehicle power supply and how to test it?

On-board power supply usually refers to the equipment used in the on-board power supply system to deal with transient voltage shocks and ensure power supply stability, such as on-board batteries, power converters, DC-DC converters, etc. It covers electrical performance, safety, environmental adaptability, electromagnetic compatibility and reliability.

On-board power supply test

Electrical performance test

1. Basic input and output characteristics

Test items: input voltage range, output voltage/current stability, rated power, efficiency, voltage regulation, load regulation.

Test method:

Use a DC power supply or a power grid simulator to provide input voltage, simulate load changes through an electronic load, and use a multimeter and power meter to record input and output parameters.

Efficiency calculation: output power/input power ×100%.

2. Transient response characteristics

Test items: voltage overshoot and recovery time when the load changes suddenly; output stability when the input voltage changes suddenly.

Test method:

Use an oscilloscope to monitor the output voltage waveform, trigger a load mutation through an electronic load or a signal generator, and record the voltage fluctuation amplitude and recovery time.

Vehicle power supply test method

3. Protection function test

Test items: overload protection, short circuit protection, overvoltage protection, undervoltage protection, overtemperature protection.

Test method:

Gradually increase the load to the overload threshold to verify whether the protection is triggered and automatically restored;

Artificially short-circuit the output end to check whether the output is immediately cut off;

Simulate the input/output voltage to exceed the rated range, or trigger overtemperature through the heating module to observe whether the protection mechanism is effective.

4. Ripple and noise

Test items: output voltage ripple, low-frequency fluctuations.

Test method:

Use an oscilloscope to connect a high-frequency capacitor in parallel with the output end to measure the peak-to-peak ripple voltage.

Vehicle power supply test items

Safety test

1. Insulation resistance and withstand voltage test

Test items: insulation resistance of input/output to the shell and between terminals; high-voltage isolation withstand voltage capability.

Test method:

Insulation resistance: measured with an insulation withstand voltage tester;

Withstand voltage test: apply rated voltage with a withstand voltage tester for 1 minute, leakage current ≤ specified value.

2. Ground continuity

Test item: On-resistance between the ground terminal of the housing and the ground path.

Test method: Measure with a low resistance tester.

Power supply high and low temperature test

Environmental adaptability test

Test items: high temperature operation, low temperature operation, temperature cycle.

Test method:

Place the sample in the high and low temperature test chamber, apply the rated load, and monitor the working status;

Electromagnetic compatibility test

1. Electromagnetic radiation

Test items: conducted emission, radiated emission.

Test method:

Conducted emission: connect the input power line with LISN and measure with a spectrum analyzer;

Radiated emission: in an anechoic chamber, use an antenna to receive the sample radiation signal.

2. Electromagnetic immunity

Test items: electrostatic discharge, radio frequency radiation immunity, electrical fast transient pulse group, surge impact.

Test method:

Use special equipment to apply interference according to standards such as static electricity, radio frequency, transient pulses, etc., and monitor whether the power supply malfunctions or fails.

Electromagnetic compatibility test

Reliability and life test

1. Aging test

Test items: long-term full-load operation life.

Test method: Continuous operation in the aging room, regular detection of output parameters, and evaluation of performance degradation.

2. Fatigue test

Test items: Number of power-on and power-off cycles.

Test method: Automatically control the on-off of the input power supply and check the durability of the contacts or semiconductor switches.

3. Special battery test

Test items: capacity degradation, cycle life, overcharge/over-discharge protection, battery management system function.

Test method:

Battery charge and discharge tester for cycle testing;

Simulate abnormal battery status to verify whether the BMS responds in time.

Through the above tests, the stability, safety and reliability of the vehicle power supply in a complex vehicle environment can be fully evaluated to ensure that it meets the stringent requirements of automotive electronics.