This project belongs to the field of energy and environmental technology. Developing hybrid vehicles (including plug-in vehicles) is the main task of the country's seven strategic emerging industries. The hybrid power system is its heart, the core that determines the performance of the whole vehicle, and the most important feature that reflects the characteristics of the whole vehicle. A hybrid power system is a complex multi-source system composed of different power supplies such as power batteries and supercapacitors, and different power sources such as engines and motors, in accordance with different electromechanical coupling methods and under the control of an electronic control system. Internationally advanced hybrid power systems generally adopt electromechanical coupling structures based on AMT, A/T, and CVT technologies. Most of them have complex structural problems and technical problems that are not easy to be independently realized in our country (especially for heavy-duty hybrid vehicles). There are outstanding problems such as poor adaptability to road conditions, energy saving rates that need to be improved, and lack of functions in high-voltage power safety control. With the support of relevant projects such as the National 973 and 863, the Natural Science Foundation of China, and provincial and ministerial projects, this project has carried out research on the above issues, and has achieved original results in the entire path of "power system-comprehensive control-high-voltage electric safety-production application technology". The results have been applied on a large scale in urban buses. The main technical inventions are as follows:

1. The unique technical idea of "three-core coaxial direct drive, multi-mode hybrid" was put forward, and the electronic continuously variable transmission hybrid system shared by plug-in and conventional hybrid was invented, which solved the problem between energy saving rate and system complexity. The contradiction breaks through the constraints of technical problems encountered in the development of hybrid urban vehicles in my country. This system enables the energy saving rate of city buses in actual operation to reach 36% in power balance mode and more than 47% in plug-in mode, reaching the technical level of similar international leading products.
2. Invented a new generation of "three-in-one" hybrid electronic control system technology, and created an adaptive energy management method, power quality control and fault-tolerant control method for hybrid electric vehicles (including plug-in models) from global optimization to instantaneous approximation optimization. Control method, etc., solves the drivability, smoothness and reliability problems caused by control delays, mode switching, etc., as well as the problems of poor adaptability to different actual road operating conditions and low energy saving rate. The adaptability to system working conditions and energy saving rate have been improved by 7.6%, the longitudinal impact of the vehicle has been reduced by 61% year-on-year, and the test calibration workload has been 46%, reaching the international leading level.
3. The high-voltage electric safety control system technology for electric vehicles has been invented, which has overcome the problems of diagnosis, early warning and positioning of insulation faults and connection resistance faults, and adaptability to different vehicle models. It has realized layered monitoring and protection of high-voltage electric safety, automatic battery balancing, and avoided battery abuse and extended its service life. A new generation of high-voltage electric safety monitoring system has been developed to achieve insulation resistance detection errors of ≤2.8%, connection resistance detection errors of ≤6% and accurate early warning and positioning of faults. Filling the technical gap in similar products.
4. The method and device for configuring control module parameters were invented, which realized accurate configuration of control system parameters; the intelligent energy-saving management system was invented, which realized remote intelligent diagnosis and management of the system.
   The project was authorized for 12 invention patents, 18 utility model patents, 3 software copyrights, and 107 papers were published, including 83 SCI/EI papers. The product transformation of the project results has been completed, and a series of conventional hybrid and plug-in hybrid oil-electric and gas-electric hybrid city bus products have been developed, which have been applied on a large scale in 24 provinces and municipalities across the country. In the past three years, the direct new output value has been 1.896 billion yuan, the profit has been 169 million yuan, and the tax revenue has been 87 million yuan.
   The hybrid power system invented by the project was successfully demonstrated and put into operation at the 2010 Shanghai City World Expo. It is also widely used in other major bus companies in my country. The domestic market share of similar products is 49.4%. Assisting the company in breaking through the passive situation that my country's hybrid bus market was once occupied by foreign systems in one fell swoop, and had a huge impact on the development of my country's hybrid buses. The complete vehicle based on the invention has successively won various awards such as "China's Best New Energy Bus Innovation Award" and "China's Best New Energy Bus Award" in industry evaluations.