With the support of major national science and technology projects, China’s electric vehicle industry has developed rapidly. Some new energy vehicles have been developed, such as hybrid electric vehicles, pure electric vehicles, hydrogen fuel cell vehicles and so on.
They have been put into trial operation in Beijing, Shanghai and other cities. At the same time, breakthroughs have also been made in the field of key parts of electric vehicles, and key parts industries such as power batteries, power motors and controllers have developed rapidly. At the same time, in order to meet the needs of test and verification of electric vehicles, test centers for batteries, motors and vehicles of electric vehicles have been set up, and a series of relevant standards for electric vehicles have been formulated to promote the development of the industry and technological progress.
Among them, motor and controller are one of the most important parts of electric vehicle. Starting from different types of power motor, this paper introduces the application of power motor, probes into the main items in the current national standard of motor and controller, and analyses the test equipment and test method on the basis of test. And sum up. Motor drive system is the core of electric vehicle, which is closely related to the power performance of the vehicle, and is one of the key technologies of electric vehicle. The motor drive system consists of motor and drive controller.
Motor is a device that converts electric energy into mechanical energy.
In order to meet the demand of vehicle power performance, it is required to have the characteristics of high instantaneous power, strong overload capacity, good acceleration performance, long service life, wide speed range, regenerative braking energy feedback, high efficiency and high reliability when decelerating. Driving controller is another kind of power conversion control device which can change the battery’s power into another kind suitable for motor operation. Through this transformation and control, the motor is in the best working state to meet the actual driving conditions of electric vehicles. The driving controller requires simple structure, high control accuracy, good dynamic response, high reliability and low cost. The performance of the driving motor and its controller directly determines the quality of the vehicle, so it is necessary to test correctly in the laboratory. At present, the commonly used dynamometers mainly include DC electric dynamometer, AC electric dynamometer, eddy current dynamometer and hydraulic dynamometer. DC power dynamometer: It is composed of DC motor, dynamometer and tachometer generator. The stator of DC motor is supported by independent bearing seat. It can swing freely in a certain angle range. The chassis is equipped with a dynamometer, which cooperates with the dynamometer to detect the torque of the stator. Torque on the spindle can be measured by the stator. Similar to DC motor, DC dynamometer has good speed regulation performance and simple control, but it is not suitable for high-speed operation because of commutator, and the large-power dynamometer is larger than other types. It is not suitable for power motor testing. AC electric dynamometer: It consists of a three-phase AC motor, dynamometer and tachometer generator. The principle of dynamometer is the same as that of DC dynamometer, but there is no commutation problem. It has simple structure and high reliability. At present, the dynamic and static performance of AC dynamometer has been greatly improved. Electric dynamometer can be used to test not only the electric performance, but also the feeding performance. By installing fixtures and coupling, the measured motor is connected with dynamometer, and the shaft-to-shaft alignment is adjusted appropriately to meet the test requirements. For individual ultra-high speed motors, in order to prevent bearing heating failure or motor damage caused by shaft vibration or inaccurate alignment in the test process, vibration transmission can be installed at appropriate locations. Sensors and temperature sensors, real-time monitoring of local conditions in the test process, once there are abnormalities immediately stop. According to the requirements of the standard, the rotational speed, torque and efficiency characteristics under rated and peak loads, as well as the feeding characteristics under rated loads are tested. Temperature rise test is also carried out on the bench to measure the temperature rise of motor windings and controller respectively. Electric motors and controllers are equipped with heat dissipation systems, or water-cooled or air-cooled. When the motor and the controller start to work from the cold state, thermostatic element the temperature will increase slowly. Under the condition of fixed load, the temperature will eventually stabilize. During this period, the change of temperature is the temperature rise. There are three methods in the standard: resistance method, embedded thermometer (ETD) method and thermometer method.
The test motor should not be disassembled. Therefore, the resistance method is suitable for calculating the temperature rise of motor under different working conditions by comparing the changes of ambient temperature, cooling water temperature and winding DC resistance before and after the test. The temperature rise of the controller can be measured by a thermometer. Temperature rise is tested according to the working system requirements of different products. The motors used in different types of systems should choose different working systems, such as pure electric vehicles, series, parallel and hybrid electric vehicles, PLUG-IN hybrid electric vehicles and other different types of applications. In this project, besides the requirement of temperature rise, there are also requirements for the highest temperature of the motor in the test process. According to the different insulation grades of the motor, the requirements are also different. Indoor test; Electric vehicle transmission test-bed introduction. Electric vehicle transmission test-bed is mainly composed of six parts: power supply module, motor and transducer module, inertia simulation module, eddy current loading module, various sensors and consoles. It can complete the experimental research of motor, motor controller, power battery, vehicle performance and other related contents.
The special test equipment for motor-controller of electric vehicle has good versatility and can meet the test of motor and controller of various types and specifications. It mainly consists of accompanying motor, high-power motor driver, high-performance embedded control system, intelligent working condition simulation system, energy system (battery system), system working parameters detection and acquisition system, etc.
It can display the working conditions of electric vehicles in different working conditions in an all-round way. Intelligent simulation of vehicle load system and motor control system linkage, simulation of different conditions of electric vehicle system (starting, idling, uniform speed, acceleration, deceleration, parking and climbing), and real-time, adaptive, intelligent adjustment of load size. The test equipment integrates the advantages of fast and flexible computer simulation and accurate and reliable road test to study the motor and controller of electric vehicle. Fig. 1 shows the block diagram of the special test equipment for electric vehicle motor and control, which is designed according to the test characteristics of electric vehicle motor and controller. Energy management module: realizes the energy management of the test system, and adopts a certain control strategy to achieve the optimal energy control of the test system.
With the deepening of the energy crisis and the aggravation of environmental pollution, the use of clean and environmentally friendly energy to replace petrochemical energy has become a hot issue that is urgently needed and being solved in the world. Because of its advantages of green environmental protection, diversification of energy sources and high efficiency of energy utilization, electric vehicles are actively studying and developing energy. Electric cars instead of traditional cars. Electric vehicles are the direction of sustainable development of automobiles. Hybrid and pure electric vehicles are developing rapidly. They will be listed in large quantities in the foreseeable future. The analysis of standards and test methods combined with tests will help to evaluate the performance of motors and controllers in detail and improve the overall quality level of the electric vehicle industry.
With the progress of technology, motor and controller are also developing continuously. Standard and test technology should reflect the current level of technology development and provide better test service for electric vehicle parts.