Repeated short-circuit test The test shows that the output of the module is short-circuited under various input and output states. The module should be able to protect or retract. After repeated short-circuits, the module should automatically resume normal operation after troubleshooting.
testing 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 retract from no-load to short-circuit. After the short-circuit is removed, the module should be able to resume normal operation. Let the module work continuously from no-load to short-circuit, the short-circuit time is 1s, the release time is 1s, and the duration is 2 hours. After this, 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, when the module is loaded from full 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 go from full load to short circuit and then keep the short circuit state for 2 hours. Then release the short circuit to determine whether the module can work normally.
c. Short-circuit startup: first short-circuit the output of the module, and 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 retract, and the module should be able to resume normal operation after the short-circuit fault is removed. After repeating the above test 10 times, let the short circuit be released and judge whether the module can work normally.
Judgment criteria After the above-mentioned test, the power module can work normally after booting; check the boot shell, the circuit board and other parts have no abnormal phenomena (such as whether the input relay is stuck in the process of short-circuiting, etc.), and it is qualified; otherwise, it is not qualified.
Repeated power-on and power-off test test instructions When the output of the power supply module is under the maximum load, the input voltage is 220v, (input overvoltage point -5v) and (input undervoltage point +5v), the input is switched on and off repeatedly, and the power module is tested repeatedly on and off Machine performance.
testing method
a. The input voltage is 220v, the power module will quickly bring the maximum load, use a contactor to control the voltage input, close for 15s, disconnect for 5s (or you can use ac source for simulation), run continuously for 2 hours, the power module should be able to work normally;
b. The input voltage is overvoltage point -5v, and the power module has the maximum load. Use a contactor to control the voltage input, close for 15s, disconnect for 5s (or you can use ac source for simulation), run continuously for 2 hours, the power module should be normal jobs;
c. The input voltage is under-voltage point -5v, and the power module has the maximum load. Use a contactor to control the voltage input, close for 15s, disconnect for 5s (or you can use ac source for simulation), run continuously for 2 hours, the power module should be normal jobs.
In the test above the judgment standard, the power module works normally, and the power module can work normally after the test, with no obvious change in performance, and it is qualified; otherwise it is not qualified.
The input low-voltage point cycle test test shows that the input under-voltage point protection of the primary power module is set to hysteresis. The following situations often occur: the input voltage is low, and the power module is close to the under-voltage point of the primary power module. Due to the internal resistance of the power supply, the voltage will rise after the load is removed, which may cause the primary power module to be in a state of repeated development at low voltage.
Test method The power supply module runs with full load, the input voltage changes slowly from (input undervoltage point -3v) to (input undervoltage point +3v), and the time is set to 5-8 minutes. Repeatedly cycle operation, the power supply module should be able to work normally and stably , Continuous operation for at least 0.5 hours, the performance of the power module has no obvious change.
Judgment standard Once the power module runs normally and continuously, there is no obvious change in performance after at least 0.5 hours, and it is qualified; otherwise, it is not qualified.
Input transient high voltage test The test shows that the pfc circuit uses an average circuit for over-voltage protection. Therefore, when the transient high voltage is input, the pfc circuit may quickly achieve protection, which may cause damage. Test the power module in a transient condition. Stable operation capability to evaluate reliability.
testing method
a. 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 to 5v to 300v, read the number of cycles n of 300v before overvoltage protection from the oscilloscope, as the following The basis of the test.
b. Rated input voltage, the power module runs at full load, 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 it runs for a total of 3 hours.
Judgment standard The primary power module can operate stably under the above conditions without damage or other abnormal phenomena, and it is qualified; otherwise it is not qualified.
The input voltage drop and output dynamic load test shows that in the actual use of a module, when the input voltage drops, the limit condition of the power module sudden load is likely to occur. At this time, the power devices and magnetic components are working at the maximum transient current state. , The test can verify the rationality of the circuit and software design such as control timing, current-limiting protection, etc.
testing method
a. Adjust the input voltage to jump between undervoltage point +5v (duration 5s) and overvoltage point -5v (duration 5s), and the output is adjusted to the maximum load (maximum rated capacity, duration is 500ms) ), no-load (duration is 500ms) jump between, run for 1 hour;
b. Adjust the input voltage to undervoltage point +5v (duration time is 5s), overvoltage point -5v (duration time is 5s), and the output is adjusted to the maximum load (maximum rated capacity, duration time is 1s) , Jump between no-load (duration of 500ms), and run for 1 hour.
Judgment criteria: Under the above conditions, it should be able to operate stably, without damage or other abnormal phenomena, and qualified; otherwise, it should be unqualified. In the event of damage, record the failure problem to provide a basis for analyzing the cause of the damage.
High-voltage no-load, low-voltage current-limiting operation test test shows that high-voltage no-load operation is the loss of the test module, especially the module with soft switching technology. Under no-load, the soft switch becomes the hard switch, and the loss of the module increases accordingly. Big. Low-voltage full-load operation is to test the loss of the module when the module is at the maximum input current. Normally, when the module is at low-voltage input and full-load output, the efficiency is the lowest. At this time, the module generates the most serious heat.
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, and run at no load. At this time, the duty cycle of the module is the smallest, and the module should not be used for 2 hours of continuous operation. damage;
b. Adjust the input voltage of the module to the undervoltage point +3v, and the output of the module is in the inflection point state of the highest output voltage. At this time, the duty cycle of the module is at its maximum. After continuous operation for 2 hours, the module should not be damaged;
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 at the inflection point of the highest output voltage. After continuous operation for 2 hours, the module should not be damaged;
d. Adjust the input voltage of the module to an overvoltage point of -3v, and the output of the module is in the inflection point state of the highest output voltage. At this time, the duty cycle of the module is at its maximum. After continuous operation for 2 hours, the module should not be damaged;
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 at the inflection point of the highest output voltage. After continuous operation for 2 hours, the module should not be damaged.
Note: The above test must be carried out at the highest operating temperature specified in the specification.
The judgment standard works under the above conditions, and the module is not damaged, and it is qualified; otherwise, it is not qualified.
Power supply special waveform test Test instructions test the power supply module's ability to operate stably under the conditions of spikes, burrs and harmonics that may be formed by the distortion of the grid waveform. The following types of waveforms must be input for testing:
(1) Glitch input test waveform
The burr of the power grid is the most common waveform in the power grid. The size and amplitude of the burr are not limited. Generally, through the oscillation wave input test and the ringing input waveform, the burr input in the power grid can basically be simulated, but it still needs Do the following glitch input test characteristics: the grid spike has overshoot and will drop to 0v, the pulse width of overshoot and drop is very narrow, generally not greater than 100ms, and the amplitude of overshoot generally does not exceed 100v. The falling phase is not limited to the peak point, it can happen at any phase. This kind of waveform is very common in actual power grids, and turning on any switch will cause this phenomenon.
(2) Voltage clipping waveform input
This kind of waveform is also very common in the power grid. The characteristic is that the power grid suddenly drops to 0v from an indeterminate phase, and then does not recover until the beginning 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 with a drop time of less than half a cycle in the actual power grid. During the test, it is required that the input voltage waveform drop from 90 degrees, drop for 1/4 cycle, and work for 2 hours for a long time.
(3) The half wave 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 circuit of the module does not work , This kind of impact is dangerous for circuits with pfc. Test content: a. When the input voltage is 180v and the output is full, use ac source to simulate the waveform. It requires 180v to work for 3 minutes, and then the voltage suddenly increases to 380v for 100ms, and then restores to 180v. Let the module stay in this way If it works for 1 hour for a long time, it 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 restores to 0v, so that the module will be longer in this case Work for 1 hour and should not be damaged.
The test method uses ac source to supply power to the module, and the module is fully loaded with output; ac source is used to simulate spike, burr and harmonic voltage input. Each special voltage input works for 2 hours, and the input current and output voltage are measured. The module should be able to operate stably. Pay attention to the x-capacitor, auxiliary power supply, soft-start resistance and other possible problems during the test.
The judgment method can operate stably under the situation of sharp spikes, burrs, and harmonic voltages in practice, without damage, and qualified; otherwise, it is unqualified.
Active pfc performance test Test instructions The power supply module with source pfc is more sensitive to grid spikes, burrs and harmonics, and should be thoroughly and carefully tested.
The test method uses ac source as the input voltage source, and the output is with 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; the input voltage of the test grid under spikes, burrs, and harmonics Current phase and amplitude relationship; measure the current and voltage of the pfc switch tube to verify the safety of the switch tube and other power devices and the ability of current to track voltage changes in the full voltage range and burrs, spikes, harmonics, etc.
The determination standard pfc test can be used as a reference for reliability, and when serious problems occur, they should be resolved in time.
The operating voltage test test shows that there are many operating overvoltages in the power grid, the most common of which is the time no-load circuit closing overvoltage, which is also a greater threat to the module. This test is to verify the ability of the module to resist operating overvoltages .
The simulation of the test method over-voltage circuit is very simple, and the principle is as follows:
The parameter of the inductance is 10mh (for reference: in the module test method of ees, there is no grounding capacitance, the input resistance is connected in series with the inductance, the resistance value is 0 ohms, 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 shown).
Connect the device under test to both ends of the capacitor. At the moment of closing k, an overvoltage will be generated at both ends of the capacitor, which is used to simulate the degree of damage to the device by the overvoltage during the power-on process. As a limit test item, the input is connected to the l and n wires, the device under test is connected to both ends of the capacitor, and the machine is turned on and off frequently, the repetition frequency is 1 time/5 minutes, and the test is continuous for 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. The repetition frequency is 1 time/5 minutes, and the test is continuous for 2 hours.
Judgment criteria In the test process, there is a short-term functional decline or performance degradation, but it can be automatically restored, and it is qualified; but the performance is permanently deteriorated or requires manual intervention to recover, it is unqualified.
