The core components of new energy vehicles (NEVs) primarily consist of three parts: the motor drive system, battery system, and vehicle control system, revolutionizing the traditional automotive development model.
The motor drive system, which directly converts electrical energy into mechanical energy, determines the core performance indicators of electric vehicles. Compared to industrial motors, motors designed specifically for the driving characteristics of electric vehicles have the following special performance requirements:
Durability: High demands for dynamic performance in frequent start/stop, acceleration/deceleration, and torque control.
High Torque: To reduce overall vehicle weight, multi-stage transmissions are often omitted, necessitating high torque capability with 4-5 times overload capacity.
High Efficiency: Wide speed regulation range with maintained high operational efficiency across the entire range.
High Rotational Speed: High-speed motors are compact, contributing to lighter electric vehicle weight (preferably with aluminum alloy housings).
Braking Energy Recovery: Regenerative braking should recover 10%-20% of the total energy.
Reliability: Motors for electric vehicles must exhibit exceptional reliability and environmental adaptability due to more complex and harsh operating conditions.
Integration: The three-in-one electric drive assembly solution is becoming mainstream.
Comparison of Testing Standards and Methods between NEVs and Traditional Vehicles
Compared to traditional vehicles, NEVs operate in significantly different environments, and the electrical and mechanical loads specified in traditional testing standards differ considerably from those of NEVs.
When designing motors, controllers, and reducers as individual components, domestic manufacturers typically adhere to relevant standards such as GB/T 18488.1-2015 “Electric Vehicle Drive Motor Systems – Part 1: Technical Conditions,” GB/T 29307-2012 “Reliability Test Methods for Electric Vehicle Drive Motor Systems,” and QC/T 1022-2015 “Technical Conditions for Reducer Assemblies Used in Pure Electric Passenger Vehicles.”
Integration of Individual Component Testing Standards with Vehicle Testing Standards
A new challenge facing the NEV industry is unifying individual component testing standards with vehicle testing standards. For instance, the national standard for endurance testing of motor system components specifies a total test duration of 402 hours, which considers the characteristics of the electric vehicle’s power supply unit. The motor and control system operate under floating voltage conditions, first at the rated voltage for 320 hours, then at maximum and minimum voltages for 40 hours each, and finally at rated operating voltage and power for 2 hours.
While this endurance testing method is prevalent among domestic motor manufacturers, its application to NEVs has limitations:
- It does not incorporate temperature cycling conditions during actual vehicle operation.
- It lacks specifications for critical cooling system parameters of motors and controllers.
- It overlooks practical scenarios such as repeated start/stops, reversing, and cold starts.
Various automakers adopt different testing methods to more thoroughly verify the reliability of individual components and the entire vehicle. Using the above endurance test as an example, some automakers complete component testing before proceeding with other endurance tests for the entire vehicle, while others forego the 402-hour component test and directly perform endurance tests under other conditions.
Thus, defining the electrical loads of NEV on-board electronics, calculating suitable endurance profiles for electric drive systems, and determining acceleration factors for equivalent life are essential research priorities in the field of NEV drive system environmental and reliability testing.
GRGTEST has invested significant technical personnel and equipment in the field of NEV drive motors. We can complete drive system testing based on different testing strategies of automakers and provide suggestions grounded in our extensive project experience to assist them in conducting more thorough and scientific experiments.
Post time: Sep-13-2024
