The "five major" principles of the composition schematic diagram and test of the switching power supply
Test instruction
Short-circuit the output of the module under various input and output states, the module should be able to realize protection or retraction, repeat the short-circuit many times, and the module should be able to automatically resume normal operation after the fault is eliminated.
Test Methods
No-load to short-circuit: In the full range of input voltage, when the module is from no-load to short-circuit, the module should be able to achieve output current limiting or retract normally. After the short-circuit is removed, the module should be able to resume normal operation. Let the module work repeatedly from no-load to short-circuit, the short-circuit time is 1s, the release time is 1s, and the duration is 2 hours. After that, release the short circuit and judge whether the module can work normally.
Full load to short circuit: In the full range of input voltage, when the module is fully loaded to short circuit, the module should be able to achieve output current limiting or retract normally, and the module should be able to resume normal operation after the short circuit is removed. Let the module go from full load to short circuit and then keep short circuit for 2 hours. Then release the short circuit to judge whether the module can work normally.
Short-circuit start-up: Short-circuit the output of the module first, then power on the market, and then power on within the input voltage range of the module. The module should be able to achieve normal current limiting or retraction. After the short-circuit fault is eliminated, the module should be able to resume normal work. Repeat the above steps After 10 tests, release the short circuit and judge whether the module can work normally.
judgement standard
After the above test, the power module can work normally when it is turned on; check the circuit board and other parts if there is no abnormal phenomenon (such as whether the input relay is electric shocked during the short-circuit process, etc.), it is qualified; otherwise it is unqualified.
Repeated switch test
Test instruction
When the output of the power module is under the maximum load, the input voltage is 220v, (input overvoltage point -5v) and (input undervoltage point +5v), and the input is switched on and off repeatedly to test the performance of the power module on and off repeatedly.
Test Methods
The input voltage is 220v, the power module is fast with the maximum load, use the contactor to control the voltage input, close for 15s, disconnect for 5s (or simulate with ac source), and run continuously for 2 hours, the power module should work normally.
The input voltage is overvoltage point -5v, the power module has the maximum load, use a contactor to control the voltage input, close for 15s, disconnect for 5s (or simulate with ac source), and run continuously for 2 hours, the power module should work normally.
The input voltage is under-voltage point -5v, the power module has the maximum load, use a contactor to control the voltage input, close for 15s, disconnect for 5s (or simulate with ac source), and run continuously for 2 hours, the power module should work normally.
judgement standard
In the above tests, the power module works normally, and the power module can work normally after the test, and the performance has no obvious change, which is qualified; otherwise, it is unqualified.
Input low pressure point cycle test
Test instruction
The setting hysteresis of the input undervoltage point protection of the primary power module often occurs in the following situations: the input voltage is low, the primary power module is close to the undervoltage point, and the primary power module is turned off. After falling, the voltage will rise, which may cause the primary power module to be in a state of repeated development at low voltage.
Test Methods
The power module runs with full load, the input voltage changes slowly from (input undervoltage point-3v) to (input undervoltage point+3v), the time is set at 5 to 8 minutes, and the power module should be able to work normally and stably, continuously Run for at least 0.5 hours, and the performance of the power module does not change significantly.
judgement standard
The primary power module operates normally and continuously, and the performance does not change significantly after at least 0.5 hours, which is qualified; otherwise, it is unqualified.
Input transient high voltage test
Test instruction
The pfc circuit uses an average value circuit for overvoltage and undervoltage protection. Therefore, when a transient high voltage is input, the pfc circuit may quickly realize protection and cause damage. Test the stable operation capability of the power module under transient conditions to evaluate reliability .
Test Methods
Rated voltage input, use a dual-trace oscilloscope to test the input voltage waveform and overvoltage protection signal, the input voltage jumps from the power limit point plus 5v to 300v, read the number n of 300v cycles before the overvoltage protection from the oscilloscope, as the following test in accordance with.
Rated input voltage, the power module operates with full load, and a voltage jump of 300v is superimposed on the input, the number of superimposed cycles is (n-1), the superimposed frequency is 1 time/30s, and the total operation is 3 hours.
judgement standard
If the primary power supply module can run stably under the above conditions without damage or other abnormal phenomena, it is qualified; otherwise, it is unqualified.
Input low voltage drop and output dynamic load
Test instruction
During the actual use of the primary module, when the input voltage drops, the limit situation of sudden load on the power module may occur. At this time, the power devices and magnetic components work at the maximum transient current state. The test can verify the control sequence and current limit Rationality of protection circuit and software design.
Test Methods
Adjust the input voltage to jump between undervoltage point +5v (duration 5s) and overvoltage point -5v (duration 5s), and adjust the output at the maximum load (maximum rated capacity, duration 500ms), Jump between no-load (duration 500ms), run for 1 hour;
Adjust the input voltage to jump between undervoltage point +5v (duration of 5s) and overvoltage point -5v (duration of 5s), and adjust the output at the maximum load (maximum rated capacity, duration of 1s), empty load (500ms duration) and run for 1 hour.
judgement standard
Under the above conditions, it should be able to run stably without damage or other abnormal phenomena, and it is qualified; otherwise, it is unqualified. If damage occurs, record the fault problem to provide a basis for analyzing the cause of the damage.
