QC/T 1152-2021Specifications for DC/DC converters of electric motorcycles and electric mopeds (English PDF)

3.6 Rated power

Under the specified environmental conditions, rated voltage, continuous operation, the maximum power at which the DC/DC converter can work continuously, after reaching thermal stabilization under the temperature rise limit.

3.7 Peak power

The maximum power that the DC/DC converter can work continuously, under the specified environmental conditions and within the specified time.

3.8 Thermal equilibrium

The state under which the temperature rise of the heating part of the DC/DC converter casing does not change by more than 1 K within 0.5 h.

Note: Thermal equilibrium can be defined by a time-temperature rise diagram, that is, the connecting line -- between the start and end points of adjacent intervals of 0.5 h has a gradient of 1 K or less than 1 K every 0.5 h, OR a gradient of 2 K or less than 2 K every 1 h.

3.9 Ripple factor

Ratio -- of half the difference between the peak value and the valley value of the pulsating DC power TO the absolute value of the DC component.

3.10 Dynamic response time

The time it takes for the system to change from a stable working state to another stable working state, after being stimulated.

4.1 General

The model of the DC/DC converter shall be composed of two parts: product name code and performance parameter code.

The model nomenclature of the DC/DC converter is as shown in Figure 1:

Figure 1 -- Schematic diagram of model nomenclature

4.2 Product name code

DC/DC converter product name code is ZB; if necessary, an extended name code can be added, after the basic name code; the two are separated by the symbol "-". The extended name code is: G - Isolated type.

4.3 Performance parameter code

4.3.1 The performance parameter code includes four parts: rated power code, nominal input voltage code, rated output voltage code, one-way and two-way code. The voltage unit indicated in the model name is V; the power unit is W.

4.3.2 The rated power, nominal input voltage, rated output voltage in the performance parameter code are all integer digits, of which the nominal input voltage and rated output voltage are 3 integer digits, the rated power is 4 integer digits; 0 is added in front, if its digit is insufficient.

4.3.3 For DC/DC converters with multiple outputs, all rated output voltage values shall be marked and separated by "/".

4.3.4 For two-way DC/DC converters, all nominal input voltage values and rated output voltage values shall be identified and separated by "/".

4.4 Example of product model

Examples of product models are as follows:

Example 1: ZB 0120-072-012 A: Indicates a one-way non-isolated DC-DC converter, which has a rated power of 120 W, a nominal input voltage of 72 V, a rated output voltage of 12 V.

Example 2: ZB-G 1000-072-012/005 B: Indicates two-way isolated DC-DC converter, which has a rated power of 1000 W, a nominal input voltage of 72 V, a rated output voltage of 12 V/5 V, two-way, isolated.

5.4 Environmental adaptability

5.4.1 Low temperature

After the DC/DC converter is tested, according to the provisions of 6.5.1, under the environment of -25 °C ± 1 °C, the insulation resistance shall meet the requirements of Table 1; the electrical performance shall meet the requirements of 5.3.2 and 5.3.3.

5.4.2 High temperature

After the DC/DC converter is tested according to the provisions of 6.5.2, under the environment of 60 °C ± 1 °C, the insulation resistance shall meet the requirements of Table 1; the electrical performance shall meet the requirements of 5.3.2 and 5.3.3.

5.4.3 Combined temperature/humidity cycle

After the DC/DC converter is subjected to 2 cycles of combined temperature/humidity cycle test as specified in 6.5.3, the insulation resistance shall meet the requirements of Table 1; the electrical performance shall meet the requirements of 5.3.2 and 5.3.3.

5.4.4 Salt spray

The DC/DC converter shall be subjected to the salt spray test as specified in 6.5.4. After the test is completed and allowed to stand, the electrical performance shall meet the requirements of 5.3.2 and 5.3.3.

5.4.5 Vibration

The DC/DC converter shall be subjected to the vibration test, in accordance with the provisions of 6.5.5. The parts shall not be loose or damaged during the test. After the test, the electrical properties shall meet the requirements of 5.3.2 and 5.3.3.

5.4.6 Shock

The DC/DC converter shall be subjected to the shock test, in accordance with the provisions of 6.5.6. The parts shall not be loose or damaged during the test. After the test, the electrical performance shall meet the requirements of 5.3.2 and 5.3.3.

5.4.7 Degree of protection

The product's degree of protection of the DC/DC converter shall meet the requirements of IP55 in GB/T 4208.

5.5 Protection function

5.5.1 Output current limit protection

The DC/DC converter shall have the output current limiting protection function. When the output load increases to the current limiting state, which is specified in the technical documents of the enterprise, the converter shall be able to enter the protection state. The output current shall be limited to the current limiting value range, which is specified in the technical documents of the enterprise, AND no longer increase.

5.5.2 Input undervoltage protection

The DC/DC converter shall have the function of input under-voltage protection. When the input voltage is lower than the under-voltage protection value, which is specified in the technical documents of the enterprise, the converter shall be able to enter the protection state and no longer output. When the input voltage recovers from the under-voltage protection value to within the normal operating voltage range, which is specified in the enterprise's technical documents, the converter shall be able to automatically resume normal operation OR resume normal operation after restarting.

5.5.3 Output short circuit protection

The DC/DC converter shall have output short-circuit protection function. When the output is short-circuited, the converter shall stop the output immediately. After the fault is removed, the converter shall be able to automatically resume normal operation OR resume normal operation after restarting.

5.6 Enable control

For DC/DC converters, which are equipped with an enable switch, when the nominal input voltage is provided at the input, if turning on the enable switch, the converter shall start working; if turning off the enable switch, the converter shall enter the standby or off state.

5.7 Electromagnetic compatibility

The electromagnetic radiation emission limit of DC/DC converter shall meet the requirements for electrical/electronic components (ESA) in GB 34660.

The DC/DC converter is subjected to the electromagnetic radiation immunity test, according to the provisions of GB 34660, for the electrical/electronic components (ESA). The deviation of the rated output voltage before the test, during the test and after the test shall not exceed ±10%.

5.8 Service life

Carry out the test according to the method of 6.9. The fault-free working time of the DC/DC converter shall not be less than 1000 h.

a) The frequency of the alternating current is 50 Hz ~ 60 Hz; the waveform is an actual sine wave;

b) The capacity of the test equipment is not less than 0.5 kV·A;

c) The test voltage (effective value), for the highest working voltage below 48 V (including 48 V), is 500 V; the test voltage (effective value) of other DC/DC converters is 1000 V.

When mass-produced DC/DC converters are subjected to the dielectric strength test, the test voltage is allowed to be 120% of the above specified value; the test time is correspondingly shortened to 1 s.

6.4 Electrical performance

6.4.1 Rated power

Make the input voltage of the DC/DC converter equal to the nominal input voltage value on the nameplate. Adjust the load output current, to make it equal to the rated output current. Observe whether the output voltage is within the rated output voltage range. Calculate whether the product of the output voltage multiplying the output current reaches the rated power. After the DC/DC converter continues to operate until the enclosure reaches a thermally stable state, the DC/DC converter continues to operate for no less than 2 h. Then read the output power value.

6.4.2 Input voltage change test

The DC/DC converter outputs rated power within the input voltage range, which is specified by the enterprise. Adjust the input voltage, to gradually increase it to the upper limit of the input voltage, which is specified in the technical documents of the enterprise.

Observe whether the output voltage meets the rated output voltage, which is specified in the technical documents of the enterprise.

The DC/DC converter outputs rated power within the input voltage range, which is specified by the enterprise. Adjust the input voltage, to gradually reduce it to the lower limit of the input voltage, which is specified in the technical documents of the enterprise.

Observe whether the output voltage meets the rated output voltage, which is specified in the technical documents of the enterprise.

6.5.1 Low temperature

The low temperature test of the DC/DC converter is carried out, according to the relevant requirements of GB/T 2423.1. When the ambient temperature reaches the range of -25 °C ± 1 °C, the DC/DC converter is kept at this temperature for 2 hours. After that, the DC/DC converter shall be able to start normally AND continue to run for 2 hours, at the rated output power. After the test, carry out insulation resistance test, input voltage change test, no-load test, according to the methods specified in 6.3.1, 6.4.2, 6.4.3.

6.5.2 High temperature

The high-temperature test of the DC/DC converter is carried out, according to the relevant requirements of GB/T 2423.2. When the ambient temperature reaches the range of 60 °C ± 1 °C, the DC/DC converter is kept at this temperature, for 2 hours. After that, the DC/DC converter continues to run for 2 hours, at the rated output power. After the test, carry out insulation resistance test, input voltage change test, no-load test, according to the methods specified in 6.3.1, 6.4.2, 6.4.3.

6.5.3 Combined temperature/humidity cycle

The DC/DC converter is subjected to 2 cycles of combined temperature/humidity cycle test, in the range of -10 °C ~ 65 °C, according to the provisions of Figure 2 in GB/T 2423.34-2012; the time of each cycle shall be 24 h. After the test, carry out insulation resistance test, input voltage change test, no-load test, according to the methods specified in 6.3.1, 6.4.2, 6.4.3.

6.5.4 Salt spray

The salt spray test shall be carried out, in accordance with the relevant provisions in GB/T 2423.17. The DC/DC converter shall be in the normal installed state. The test duration is 16 h. At the end of the test, after the DC/DC converter has been restored for 2 hours, carry out the input voltage change test and no-load test, according to the methods specified in 6.4.2 and 6.4.3.

6.5.5 Vibration

Fix the DC/DC converter on the vibration test bench, in the normal installation position.

At the same time, install and fix the cables and other accessories, which are connected to the DC/DC converter. Conduct the test, according to the provisions of 4.4 in QC/T 680-2014. During the test, the DC/DC converter is in a non-working state.

After the test, carry out the input voltage change test and no-load test, according to the methods specified in 6.4.2 and 6.4.3.

6.5.6 Shock

Fix the DC/DC converter on the test bench. Carry out the test, according to the method specified in GB/T 2423.5. The peak acceleration, pulse duration, waveform, number of shocks are as specified in Table 4 in QC/T 792-2007. During the test, the DC/DC converter is in a non-working state.

After the test, carry out the input voltage change test and no-load test, according to the methods specified in 6.4.2 and 6.4.3.

6.5.7 Degree of protection

Carry out test, according to the method of IP55 in GB/T 4208.

6.6 Protection function

6.6.1 Output current limit protection

Under the nominal input voltage of the DC/DC converter, use a DC load or similar equipment, to gradually increase the output load of the DC/DC converter to the current limit value, which is specified in the technical documents of enterprise. Observe whether the output current of the converter is limited within the technical documents of enterprise AND not increase within the specified current limit value range.

6.6.2 Input undervoltage protection

The DC/DC converter first works under the nominal input voltage. When the input voltage of the DC/DC converter is gradually adjusted to the undervoltage protection value, which is specified in the technical documents of the enterprise, by a DC power supply or similar equipment, observe whether the converter enters the protection state AND no longer output. Gradually adjust the input voltage, to recover from the undervoltage protection value to the normal operating voltage range, which is specified by the enterprise; observe the working state of the DC/DC converter.

6.6.3 Output short-circuit protection

Short-circuit the output terminal for no more than 5 s. Observe whether the DC/DC converter stops output immediately. After the fault is removed, observe the working state of the DC/DC converter.

6.7 Enable control

Provide the nominal input voltage, at the input of the DC/DC converter. Turn on the enable switch. Observe the converter by the use of a digital meter/oscilloscope (or other instruments which have the same function and accuracy level); the converter shall be able to work at the rated output power and rated output voltage.

Provide the nominal input voltage, at the input of the DC/DC converter; close the enable switch. Observe the converter by the use of a digital meter/oscilloscope (or other instruments which have the same function and accuracy level); it shall stop working.