1. Repeated short-circuit test
◆ Test instructions
The output of the module is short-circuited in various input and output states, the module should be able to achieve protection or retraction, repeated short-circuits, and after troubleshooting, the module should be able to automatically resume normal operation.
◆ Test Method
a. No-load to short-circuit: In the full range of input voltage, the module should be able to achieve output current limiting or retraction normally, and the module should be able to resume normal operation after the short-circuit is eliminated. Let the module work continuously from no-load to short-circuit repeatedly, the short-circuit time is 1s, the release time is 1s, and the duration is 2 hours. After that, the short circuit is released to determine whether the module can work normally.
b. Full load to short circuit: In the full range of input voltage, the module should be able to achieve output current limiting or retraction normally, and the module should be able to resume normal operation after the short circuit is eliminated. Let the module go from full load to short circuit and then keep it short for 2 hours. Then the short circuit is released to determine whether the module can work normally.
c. Short-circuit start-up: the output of the module is short-circuited first, then powered on, and then powered on within the input voltage range of the module, the module should be able to achieve normal current limiting or retraction, after short-circuit troubleshooting, the module should be able to resume normal operation, repeat the above test 10 times, let the short circuit go, and judge whether the module can work normally.
◆ Judgment criteria
After the above test, the power module can work normally when it is turned on; Open the casing to check, there is no abnormal phenomenon in the circuit board and other parts (such as whether the input relay is electrocuted in the process of short circuit, etc.), qualified; Otherwise, it is not qualified.
2. Repeated on/off tests
◆ Test instructions
When the output of the power module has the maximum load, the input voltage is 220V, (input overvoltage point - 5V) and (input undervoltage point +5V) respectively, and the input is switched on and off repeatedly to test the performance of the power module repeatedly on and off.
◆ Test Method
a. The input voltage is 220V, the power module is fast with the maximum load, the voltage input is controlled by the contactor, it is closed for 15s, disconnected for 5s (or it can be simulated with AC source), and the power module should be able to work normally after continuous operation for 2 hours;
b. The input voltage is the overvoltage point - 5V, the power module has the maximum load, the voltage input is controlled by the contactor, it is closed for 15s, disconnected for 5s (or it can be simulated with AC source), and the power module should be able to work normally after continuous operation for 2 hours;
c. The input voltage is the undervoltage point - 5V, the power module has the maximum load, the voltage input is controlled by the contactor, it is closed for 15s, and it is disconnected for 5s (or it can be simulated with AC source), and the power module should be able to work normally after continuous operation for 2 hours.
◆ Judgment criteria
In the above test, the power module works normally, and the power module can work normally after the test, and there is no obvious change in performance, which is qualified; Otherwise, it is not qualified.
3. Enter the low pressure point cyclic test
◆ Test instructions
The following situations often occur when the input undervoltage point protection of the primary power supply module is set back: the input voltage is low, close to the undervoltage point of the primary power supply module is turned off, the undervoltage is underloaded when it is loaded, and after it is broken, due to the internal resistance of the power supply, the voltage will rise after the load is removed, which may cause the primary power supply module to be in a state of repeated development at low voltage.
◆ Test Method
The power module is running at full load, the input voltage changes slowly from (input undervoltage point - 3V) to (input undervoltage point +3V), the time is set to 5 - 8 minutes, and the power module should be able to work normally and stably, with at least 0.5 hours of continuous operation, and there is no obvious change in the performance of the power module.
◆ Judgment criteria
The primary power supply module runs normally and continuously, and there is no obvious change in performance after at least 0.5 hours, and it is qualified;
4. Input transient high voltage test
◆ Test instructions
The PFC circuit uses an average circuit for over- and under-voltage protection, so when transient high voltage is input, the PFC circuit may quickly achieve protection, resulting in damage, and the ability of the primary power module to operate stably under transient conditions is tested to evaluate reliability.
◆ Test Method
a. Rated voltage input, use a double 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, and the number of cycles N before 300V is read out from the oscilloscope, which is used as the basis for the following tests.
b. Rated input voltage, the power module is running at full load, and the voltage jump of 300V is superimposed on the input, the number of cycles superimposed is (n-1), the superposition frequency is 1 time/30s, and the total operation is 3 hours.
◆ Judgment criteria
The primary power supply module can operate stably under the above conditions, without damage or other abnormal phenomena, and is qualified; Otherwise, it is not qualified.
5. Input voltage drop and output dynamic load
◆ Test instructions
During the actual use of the primary module, when the input voltage drops, the limit of the sudden load of the power module
In this case, the power device and magnetic components work in the maximum transient current state, and the test can verify the rationality of the circuit and software design such as control timing and current limit protection.
◆ Test Method
a. Adjust the input voltage to jump between the undervoltage point +5V (duration of 5s) and the overvoltage point - 5V (duration of 5s), and the output adjustment jumps between the maximum load (maximum rated capacity, duration of 500ms) and no-load (duration of 500ms), and runs for 1 hour;
b. Adjust the input voltage to jump between the undervoltage point +5V (duration is 5s) and the overvoltage point - 5V (duration is 5s), and the output adjustment jumps between the maximum load (maximum rated capacity, duration is 1s) and no load (duration is 500ms), and runs for 1 hour.
◆ Judgment criteria
Under the above conditions, it should be able to operate stably, without damage or other abnormal phenomena, and be qualified; Otherwise, it is not qualified. In the event of damage, the fault problem is recorded to provide a basis for analyzing the cause of the damage.
6. High-pressure no-load, low-pressure flow-limiting operation test
◆ Test instructions
High-voltage no-load operation is the loss of the test module, especially the module with soft switching technology, in the case of no load, the soft switch becomes a hard switch, and the loss of the module increases accordingly. Low-voltage full-load operation is the loss of the module when the maximum input current of the test module, under normal conditions, the module has the lowest efficiency when it is low-voltage input and full-load output, and the heating of the module is the most serious at this time.
◆ Test Method
a. Adjust the input voltage of the module to the input overvoltage protection point - 3V, the output of the module is the lowest output voltage, no-load operation, at this time, the duty cycle of the module is the minimum, continuous operation for 2 hours, the module should not be damaged;
b. Adjust the input voltage of the module to the undervoltage point +3V, and the output of the module is the inflection point state of the highest output voltage, at this time, the duty cycle of the module is the maximum, and the module should not be damaged after continuous operation for 2 hours;
c. Adjust the input voltage of the module to the input voltage at the lowest point of efficiency, and the output of the module is the inflection point state of the highest output voltage, and the module should not be damaged after continuous operation for 2 hours;
d. Adjust the input voltage of the module to the overvoltage point - 3V, and the output of the module is the inflection point state of the highest output voltage, at this time, the duty cycle of the module is the maximum, and the module should not be damaged after continuous operation for 2 hours;
e. Adjust the input voltage of the module to the input voltage at the lowest point of efficiency, and the output of the module is the inflection point state of the highest output voltage, and the module should not be damaged after continuous operation for 2 hours.
Note: The above tests must be performed at the maximum operating temperature specified in the datasheet.
◆ Judgment criteria
Working under the above conditions, the module is not damaged and qualified; Otherwise, it is not qualified.
7. Special waveform test of power supply
◆ Test instructions
Check the stable operation ability of the power module under the condition of sharp edges, burrs and harmonics that may be formed by the waveform distortion of the power grid. The following waveforms must be entered for experimentation:
(1) Glitch input test waveform
The glitch of the power grid is the most common waveform in the power grid, and there is no limit to the size and amplitude of the burr, under normal circumstances, through the oscillating wave input test and the ringing input waveform, the glitch input in the power grid can be basically simulated, but the following glitch input test needs to be done.
Features: The power grid tip is overshoot and will fall to 0V, the overshoot and drop pulse width is very narrow, generally not greater than 100ms, and the overshoot amplitude is generally not more than 100V. The phase of the drop is not limited to the peak point, it can occur at any phase. This waveform is common in the real grid and can be caused by any switch turned on.
(2) Voltage clipping waveform input
This waveform is also very common in power grids, characterized by a sudden drop from an indefinite phase to 0V and then not recovering until the start of the next half wave. In IEC1004-4-11, the drop of the waveform starts from more than half a cycle, but there are still many similar waveforms in the actual power grid with a drop time of less than half a cycle. During the test, the input voltage waveform is required to drop from 90 degrees, drop for 1/4 cycle, and work for 2 hours for a long time.
(3) Half of the wave head of the power grid rises sharply to double the voltage, this waveform is mainly used to simulate the resonant overvoltage that will suddenly appear in the actual power grid, and in this case, the input overvoltage protection line of the module does not work, and this impact is dangerous for the circuit with PFC. Test content: a. In the case that the input voltage is 180V and the output is fully loaded, the waveform is simulated with AC source, which requires 180V to work for 3 minutes, and then the voltage suddenly increases to 380V, lasts for 100ms, and then returns to 180V, so that the module can work for 1 hour for a long time in this case, and should not be damaged; b. Set the AC source so that the input voltage is 0V for 5 minutes, then the voltage suddenly increases to 380V for 100ms, and then returns to 0V, so that the module can work for 1 hour for a long time in this case, and should not be damaged.
◆ Test Method
AC source is used to supply power to the module, and the module is output at full load; The AC Source simulates the spikes, glitches, and harmonic voltage inputs, each of which operates for 2 hours, and measures the input and output voltages. The module should be able to operate stably, and pay attention to other possible problems such as x capacitance, auxiliary power supply, soft start resistor, etc.
Determination method:
In practice, it can operate stably without damage and pass under the situation that sharp edges, burrs and harmonic voltages may occur; Otherwise, it is not qualified.
8. Active PFC performance test
◆ Test instructions
Power modules with active PFCs are sensitive to grid spikes, glitches, and harmonics and should be thoroughly and carefully tested.
◆ Test Method
The AC source is used as the input voltage source, and the output is half-load and full-load respectively, the input current waveform and voltage waveform are tested, and the voltage after PFC is monitored at the same time. Test the phase and amplitude relationship of input voltage and current in the grid under the condition of sharp edges, glitches and harmonics; Measure the current and voltage of PFC switches to verify the safety of switches and other power devices and the ability of current to track voltage changes in the full voltage range and under the conditions of glitches, spikes, harmonics, etc.
◆ Judgment criteria
PFC testing can be used as a reliability reference and should be addressed in a timely manner when serious problems occur.
9. Operating voltage test
◆ Test instructions
There are a variety of operating overvoltages in the power grid, among which the most common is the overvoltage of the no-load line closing, which is also a great threat to the module, and this test is to verify the ability of the module to resist the operating overvoltage.
◆ Test Method
The simulation of an overvoltage line is very simple and works as follows:
The parameters of the inductance are 10mh (for reference: in the module test method of EES, there is no ground capacitance, the input resistance is connected in series with the inductor, the resistance value is 0 ohm, the inductance is 8mh, the resistance is 79 ohms, and the inductance is 10mh), the capacitance is 16.7uf, and the test waveform is as follows (not drawn).
The device to be tested is connected to both ends of the capacitor, and at the moment of K closing, an overvoltage will be generated at both ends of the capacitor, which is used to simulate the damage of the overvoltage to the device during the power-on process. As the limit test item, the input is connected to L and N wires, and the tested equipment is connected to both ends of the capacitor, and the machine is turned on and off frequently, and the repetition rate is 1 time/5 minutes, and the continuous test is 5 hours. For three-phase input equipment, the input is connected to the L and L lines, and the tested equipment is connected to both ends of the capacitor, and the repetition rate is 1 time/5 minutes, and the continuous test is 2 hours.
◆ Judgment criteria
If there is a short-term functional degradation or performance deterioration during the test, but it can be automatically recovered, it is qualified; However, if there is permanent deterioration of performance or manual intervention is required to recover, it is not qualified.
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