“Abstract: In the design of Electronic equipment products, the quality of power products will directly affect their technical performance, work safety and reliability. When there is a problem with the power supply, the entire product will be paralyzed, and the comprehensive testing of the power supply product is particularly important.
Abstract: In the design of electronic equipment products, the quality of power products will directly affect their technical performance, work safety and reliability. When there is a problem with the power supply, the entire product will be paralyzed, and the comprehensive testing of the power supply product is particularly important.
Let’s take an electric motorcycle charger as an example. As one of the four major components of an electric motorcycle (controller, charger, battery, and motor), the charger is an important part of the electric motorcycle and directly affects the safety of the electric motorcycle. . Inferior chargers may cause serious consequences of electric shock, fire or even explosion. Therefore, the charger will undergo rigorous testing and certification in the stages of R&D, production, and certification. Figure 1 shows the complete test solution provided by ZHIYUAN Electronics.
Figure 1 Test scheme diagram
An important circuit component of the charger is the switching power supply, as shown in Figure 2. When the power supply runs for a long time, the problem of unstable voltage and current will occur, and even overvoltage, undervoltage, overload, overheating, etc. may cause equipment damage. Therefore, it is necessary to strictly carry out all-round tests on the input, output, abnormal working conditions, switching devices, etc. of the power supply, and conduct durability tests to verify the stability of the product. Today, I will focus on introducing two testing tools for you – PA power analyzer and ZDL oscilloscope recorder.
Figure 2 Switching power supply circuit topology
1. Test equipment – PA power analyzer
The PA power analyzer can accurately measure the output voltage, current, power, harmonics and conversion efficiency of the power supply and other parameters. The PA5000H power analyzer of ZHIYUAN has a power measurement accuracy of 0.05%, a 5MHz bandwidth and a wide range of harmonic measurement functions. Research and development and testing of power products.
1. Power analyzer – electrical parameter test
The power analyzer focuses on the steady-state test. The power analyzer can test AC input and DC output at the same time, perform synchronous analysis on the overall energy efficiency and electrical parameters, test the input and output voltage, current, test voltage, current RMS, power factor, efficiency, harmonics, etc., as shown in Figure 3.
Figure 3 Electrical parameter test
2. Power Analyzer – Efficiency and Power Factor Test
The power analyzer tests the AC input power and DC output power, and sets the electronic load from no load to full load. Using the XY Display mode of the power analyzer, you can directly test the efficiency and power factor curve from no load to full load.
Figure 4 Efficiency Curve
Figure 5 Power factor graph
3. Power Analyzer – IEC Harmonic Test
Electrical products will be tested for harmonics according to IEC61000-3-2 and IEC61000-3-11 standards to verify whether they meet the standard requirements. The PA power analyzer can measure up to 500 harmonics, and there are multiple combined Display methods to simultaneously Displays the harmonic content of each order.
Figure 6 IEC Harmonic Test
4. PA Power Analyzer – Impulse Current Test
Usually, a large current will be generated at the moment when the load is energized. Excessive current will affect the normal operation of the equipment. Using the PSA programmable AC power supply can simulate the voltage situation when the output start-up phase is at 0°, 90° and 270°, and use the PA power analyzer to test the start-up inrush current of electronic products.
Figure 7 Inrush current test
2. Test equipment – ZDL oscilloscope recorder
The ZDL6000 oscilloscope recorder comes standard with 8 card slots, and each input channel is isolated from each other, which can save a lot of high-voltage differential probes for power users, and can provide various input cards such as voltage, current, temperature, etc. Up to 128CH, it provides the best solution for customers to observe waveform timing and find abnormal signals.
1. Scope recorder – drive timing test
The general method to test the drive timing is to use an oscilloscope to add a differential probe to test the Vgs and Vds of the MOS, and use a current probe to test the Inductor current. The corresponding drive signal quality and inductor current working mode can be observed. If an oscilloscope recorder is used for testing, Then a differential probe is not needed, and the test is more accurate and convenient, as shown in Figure 8.
Figure 8 Drive timing test
2. Oscilloscope Recorder – Anomaly Capture and Durability Test
Abnormal capture: When the power supply product is running for a long time, it is not known what problems will occur. The oscilloscope cannot set trigger conditions, and it is not easy to capture the abnormality. After the waveform is recorded by the oscilloscope recorder, it can be reviewed and the abnormal waveform can be effectively captured;
Durability test: Power products require frequent on/off experiments, and there may be only one failure for thousands of times, so a recorder is required to record and analyze the stable performance of the product for a long time.
Figure 9 Multi-channel synchronization endurance test
3. Component temperature rise test
Abnormal temperatures in key parts of the equipment can cause equipment performance degradation or even damage. Therefore, the temperature rise test is an indispensable item in the product development process. Using the ZDL6000, you can flexibly combine voltage acquisition cards, 16-channel cards, temperature acquisition cards and other boards for simultaneous measurement. For example, in the temperature rise test, a 100M card and a temperature card can be assembled to simultaneously test the working voltage, current and temperature rise of key parts of the device.
Figure 10 Component temperature rise test
In order to ensure the stability of the power supply for a long time, it is necessary to conduct a comprehensive test and analysis of the power supply. There will be dozens of test items. It is necessary to choose a suitable test instrument according to the test item to give full play to the maximum performance of the instrument. Power analyzers are used in energy efficiency and harmonic testing, and oscilloscope recorders are used in isolation testing, multi-channel synchronous analysis, durability testing, and abnormal capture.