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Electric vehicle drive motor system reliability test methods

1 scope of

standard specifies the the electric vehicle motor drive system generally Reliability Test Method gantry, wherein the reliability test comprises a load specification and the reliability evaluation method.

This standard applies to the final power output of the motor drive or motor and an engine combined with an electric vehicle driven by a drive motor system.

2 Normative References documents

The following  for the application of this document is essential. For dated reference documents, all subsequent amendments (excluding corrections) or revisions do not apply to this section, however, encouraged to whether the latest versions of these documents are part of the parties to this agreement . For undated reference documents, the latest versions apply to this document.

And electric vehicle motor controller: technical conditions

for electric vehicle motor and controller: Test method for

an electric automobile term

reliability, maintainability term

electric vehicle drive motor is determined and fault classification system

3 Terms and definitions

GB / T2900.13 , GB / T18488.1, GB / T18488.2and QC / Txxx-xxxx established terms and definitions apply to this standard.

4Test conditions

4.1 General

4.1.1when no special instructions, test conditions should meet the requirements GB / T 18488.2-2006 of.

4.1.2 test is complete the motor drive system 1 sets comply with the manufacturer’s technical conditions; motor drive system of visual inspection, should meet the requirements of the product standards.


4.2.1 test, the test power supply is provided by a DC power supply, or (energy) provided by the system of devices and other energy storage power direct current power source; S250V test work DC voltage power supply, the voltage accuracy satisfies ^ ± 2.5V; test voltage DC power supply operating> 250V, the voltage accuracy which satisfies ^ ± 1% operating dc voltage is again driven motor system.

4.2.2 Test subjects were able to meet the power driven motor system power requirements, and can operate in the state of rated voltage, the maximum operating voltage state, the minimum operating voltage or other status of the working voltage state.

4.3the cooling

cooling apparatus or cooling conditions of during the test should meet the following requirements:

– the motor or the controller for the air, with air during the test time of actual loading motor;



GB / T X X X X X -200X

– for natural cooling of the motor or controller, may be applied to the blower motor controller or blowing;

– or a controller for a liquid-cooled motor, the coolant should be used specified by the manufacturer;

– cooling conditions should be met Requirement specifications or the manufacturer’s instructions product, and indicate in the test report.

5 Experimental procedure

5.1 Experimental Preparations

5.1.1 motor system should be firmly mounted on a stand, all fasteners should be tightened to a predetermined value, the connecting line between the controller and the motor and the actual vehicle should be consistent, while the monitoring system installed . To ensure the system is operating properly, the signal does not respond to the installation parts or simulation masked by other means, the controller should have the over-voltage, over current, over-temperature protection in real time.

5.1.2 power supply, the test stand and the state of the monitoring system should be working properly.

5.1.3 develop appropriate integrated test conditions and test record documentation in accordance with the method of 6, to develop the appropriate troubleshooting measures.

performance measurement the test before the


Performance measurement before test in accordance with the requirements of GB / T 18488.1 and GB / T 18488.2 is, measurements are shown in Table A1. The measured properties should meet the requirements of the test product technical conditions and as measured during the test and the test performance at the end of a baseline for comparison.

5.3 Reliability Test

tested in accordance with Chapter 6.

5.4 5.2 repeat performance retest.

6 Reliability test specification

reliability test categories according to the vehicle driving motor system, and the duty cycle with reference to FIGS. 1 Table 1. Each cycle lasted 30 minutes, and 800 cycles were run, the running time is 400 hours.

Motor drive system status bus voltage change in accordance with the following requirements, first load cycle is operating in a nominal rated operating voltage of 320 hours, and then load the 40-hour work cycle the maximum operating voltage, the load speed n in the above two cycles 1.1 times the rated speed is maintained. Finally, for 40 hours, and the minimum operating voltage is applied to the load cycle, load cycle the rotational speed ns to  reduceis set according to a ratio between the linear and the minimum operating voltage of the rated voltage. Namely:

when the maximum operating voltage and rated working voltage Status: n1.1ns =N;





FIG:ns          skin test motor speed setpoint during the test


(r / min); Tpp n    is the rated motor speed test (r / min);

Tn    is the nominal torque of the motor driving test system (Nm);

Tpp– a drive motor system is again operating torque at peak power rated speed (Nm) ‘table

1 driving an electric vehicle motor system reliability test cycle specification




load torque Operating time (min)
electric ISG parallel (or hybrid
1 rated torque
type) Tgl) 22 10 16.5 2 T transition to Tpp (T2) lEto powerrated05 0.5
3 peak torque T pp (T3) 2 0.5 0.5
 torque to – T n (T4) 1.5 1.5
reserved rated torque – T n (T5) 3 16.5
N transition to Tn (T6) 1 1 1
the accumulated time 3,030,307






inspection and maintenance

inspection and maintenance in accordance with the following requirements, but its contents and can make the appropriate changes in period, check the result where and should maintain a detailed record. Recording the respective fault see appendix A2,maintenance records see appendix A3.

7.1 at any time to check

the use of fault diagnostics, instrumentation and computer monitoring and other operational data at any time, exceed the limits, an alarm or emergency stop, according to the severity of the failure, for processing. If it is a motor drive system failure, the failure count stop. Record trouble parking time, causes and circumstances.

Monitor the drive motor abnormal sound operation of the system and take measures if necessary.

7.2 per hour inspection

The 1 timely recording  motor output torque and speed over hour, the DC bus voltage and current input the motor controller, the motor surface temperature and the temperature and flow rate of the coolant, if necessary, further examination motor working temperature controller of the power element. If the motor is mounted with thermistor temperature sensors also check the operating temperature of the motor winding, and draw the operating time to(h)onas the abscissa of the curve supervision.

7.3checked every 48 hours

7.3.1 ADW 1, test equipment inspection and check fasteners, mechanical pipe connections and, in particular  check the connection cables,

hose,and interface  only the principle of the examination table itself.

7.3.2 Check the coolant liquid level in the cooling system if there drip and other conditions, if necessary, supplemental cooling fluid.

7.3.3 stop to check the time no more than 1h.

7.4 Stop process faults and

Recording each operation content and the cause of the downtime.

When a failure occurs, failure analysis should be carried out, troubleshooting, and recorded.

Interrupted loading cycles are not included in the motor drive system reliability hours. If the stop time exceeds 1h,then restarted after the cycle 2cycles time is not counted for reliability driving motor system, from the thirdcycle starts.


8 test results

8.1 based on”QC / TXXX-XXXXwereelectric vehicle drive motor system fault classification and judgment” record, providing photographs if necessary, carry out sophisticated analysis.

8.2 motor drive system based on actual continuous operation time (h) and recorded during operation, to be assessed in accordance with Chapter 9.

9 Reliability Evaluation Method

9.1motor drive system should be not lower than the actual running time of 400h.

9.2 Reliability Test failure first failure time, number of stops and failures mean time between failure to assess the average.

The average first failure time MTTFF


= Z T Tj+  – (Nn)Te

J = 1

Mttff       wherein:– average first failure time point estimate (h);

n– amount of the first motor drive system fault occurs;

T– time between failures Total work (h);

T– j-th motor system first failure time (h), excluding minor fault; n; Number of test system

Te    – censoring time, 400h.

The average time between failures

                    (MTBF) MTBF = T (3




Mtbf        where:– the point estimate of the mean time between failures (h);

r      total failure time T, contain minor fault;

K number of test suspension system;

T total working time(h);

T– j-th time the test was stopped motor system (H), excluding minor fault;

unilateral interval estimation the lower limit is calculated as

Where in follows:(& BF1– mean time between failures lower confidence limit

(h); [2 (r           degrees of freedom 2 (r + 1), confidence level a’s? Distribution value; recommended as a 0.1;

9.3 Comparison of the first test and retest performance curves and parameters, performance parameters should meet the requirements GB / T 18488.1 and GB / T 18488.2 of.

9.4 Conclusions and recommendations

described mode of failure, type, quantity.

Description average first failure time and mean time between failures.

If necessary, based on the reliability of the test results, make recommendations for improvements and additions test.

10 Test report The


test report should at least include:

  1. Introduction: explain the source of test tasks;
  2. experimental basis;
  3. testing purposes;
  4. Subjects: Indicate the main parameters of the test drive motor system, and additional graphics, photos and necessary instructions;
  5. and test equipment instrument: should indicate the name of the main equipment and instrumentation, manufacturer, model, accuracy, date of calibration and measurement site;
  6. differs from the standard test conditions, he shall be described;
  7. test results: the
  • original test data are collated, as a curve said that important data can be a list;
  • reliability evaluation results;
  • failure, maintenance statistics;
  • during the test adjustments replacement record
  • performance test results;
  1. conclusions and recommendations;
  2. test date