In order to improve the communication efficiency and security of Vehicular Ad-hoc NETwork (VANET), this paper proposed an anonymous identity authentication and group key distribution scheme based on quantum key and blockchain. Anonymous credentials for vehicles were generated by a combination of random numbers on the vehicle side and random numbers in the cloud, which achieved privacy protection for the vehicle during authentication. The utilization of blockchain for secure distribution of group keys has been proposed, which reduced the computational overhead of the Quantum Secret Service platform and enabled vehicle revocation and traceability. A two-stage key generation method was devised to ensure the security and efficiency of group key distribution in various scenarios, as well as achieve forward and backward security. The signaling and computation overheads were calculated, the signaling overhead was reduced by nearly half. During the group key distribution process, the computational overhead at the vehicle was reduced by 44%, while the computational overhead at the roadside is approximately 20% of the overhead in the comparison scheme. The formal security analysis results proved the security and feasibility of this scheme.

In this research, a lightweight authentication scheme was designed based on the quantum communication architecture of the Internet of Vehicle (IoV) cloud network. The authentication process consists of 2 stages: registration and authentication, and 2 rounds of authentication between the vehicle and the IoV cloud platform to ensure the security of the scheme. Test results show that this scheme has computational overhead of only 0.179 ms, and communication overhead of 417 B, which is lower than other 4 schemes, had has high efficiency while ensuring security, therefore it has high applicability for most IoV equipment with low computational amount and low communication volume.

In order to realize identity authentication and key distribution in Internet of Vehicle (IOV) scenario, this paper proposed an enhanced identity authentication scheme for the IOVs based on extended quantum key distribution. The features of this scheme are: (1) Quantum key mobile distribution was completed through quantum security module and preset quantum key in wireless communication, online negotiation of quantum key was completed through Quantum Key Distribution (QKD) equipment in wired communication, to achieve extended quantum key distribution; (2) Basic identity authentication based on post-quantum cryptography encryption and signature algorithms was conducted, and enhanced authentication through preset quantum keys. Finally, through security analysis and performance testing, it is confirmed that this scheme has sufficient security and low computational overhead. The total computational overhead is 1.689 ms, and the performance improvement is 60.43%~70.72%.

To realize secure transmission of vehicular network related data and privacy protection, this article proposed a quantum key based identity authentication and data access control scheme for the vehicular networks. An identity authentication scheme and key agreement mechanism based on pre-charge quantum keys were designed, vehicle data access control scheme based on quantum random number generator was proposed to generate quantum encryption keys, allowing the vehicle owner to control access requests for vehicle networking data from external devices to prevent unauthorized access, malicious intrusion by high-privileged personnel and improper opening of vehicle privacy data. Finally, this article conducted security and performance analysis, analysis results show that this scheme has good security, with a computational cost of 0.395 ms and a communication cost of 420 B, which are lower than that of other schemes.

In order to solve the electromagnetic noise issues of Permanent Magnet Synchronous Motor (PMSM) on Electric Vehicle (EV), this paper, based on its electromagnetic noise generation mechanism, proposed a way of reducing electromagnetic radial force by means of test verification to optimize its electromagnetic noise. From the 2 aspects of structural hardware and control strategy, the optimization and improvement were carried out by the verification and comparison approaches such as rotor segmented skew pole optimization, structural stiffness optimization and coupling resonance improvement, current harmonic injection and gap flux density optimization, and each optimization approach was illustrated with practical development case. The result shows that each method has an attenuation of at least 3 dB(A) on electromagnetic noise of PMSM, which further demonstrates the effect and advantage of improving electromagnetic noise by optimizing electromagnetic radial force though experimental means.

To clarify the discharge breakdown characteristics of drive motor bearing (discharge voltage, discharge current, discharge energy, discharge current density, etc.) and its influencing factor, thus reduce electrical erosion damage, a common mode equivalent circuit with concentrated parameters of a drive motor was established to extract shaft voltage. This paper determined the threshold voltage under the minimum oil film thickness according to the theory of elastic flow lubrication, analyzed the discharge breakdown characteristics of the bearing in combination with the discharge breakdown model, and clarified the variation law of the discharge breakdown characteristics under different rotational speed, temperature and force. The results show that as the rotational speed decreases and the temperature and radial force increase, the discharge breakdown characteristics related characteristics gradually decrease, meanwhile the effect of speed and temperature on the breakdown characteristics of the bearing is significantly higher than that of radial force.

To study the lubrication characteristics of oil-cooled electric drive system, this article analyzed the splash lubrication characteristics of an oil cooled electric drive system and the phenomenon of poor low-speed lubrication under extreme attitudes, analyzed the forced lubrication and suction phenomenon of oil pump. The results show that the main characteristics of splash lubrication are poor lubrication at low flow rates and good lubrication at high flow rates; As the inclination angle increases, the flow rate shows a downward trend in uphill condition, while the flow rate in downhill conditions is just the opposite; The left tilt of 20° shows no lubrication effect and oil suction port is empty, while the right tilt of 20° shows poor oil stirring effect at low speed, while splash lubrication oil amount at left and right tilt is just the opposite. Forced lubrication can comprehensively consider the flow demand and proportion of the motor and reducer in the electric drive. The risk of empty suction of oil pumps will lead to forced lubrication failure. The solution of empty suction shall also consider the reduction of efficiency.

In order to improve the heat exchange efficiency of the oil passages and windings of oil-cooled motors, continuously spray oil to key positions of the motor, this paper, based on a high-voltage oil-cooled flat wire motor, used fluid mechanics and heat transfer theories as well as computer fluid mechanics (CFD) simulation tool for numerical simulation. The paper firstly conducted flow distribution simulation and estimation, then made local simulation, to analyze the cooling state of motor stator, then explored the principle, effect, advantages and disadvantages of the winding spray cooling method by quantifying the oil flow state.