Interior permanent-magnet (IPM) machines exhibit relatively large spatial harmonics in phase voltages and high nonlinearity in torque production due to both the presence of reluctance torque and the magnetic saturation in stator and rotor cores. To simulate the real electromagnetic behavior of IPM machines, this paper proposes a high-fidelity and computationally efficient machine model considering the magnetic saturation, the spatial harmonics, and the iron loss effect based on the inverse solution of the flux linkages extracted via finite-element analysis (FEA). Neither FEA nor a derivative computation is involved in the time-stepping simulation; thereby, the proposed model is computationally efficient and numerically robust. The high fidelity of the proposed machine model is validated by both the FEA and the experimental results.

This paper introduces a novel virtual signal injection-based control method for maximum torque per ampere (MTPA) operation of interior permanent magnet synchronous machine (IPMSM) drives. The proposed method injects a small virtual current angle signal mathematically for tracking the MTPA operating point and generating d-axis current command by utilizing the inherent characteristic of the MTPA operation. This method is parameter independent in tracking the MTPA points, and it does not inject any real signal to current or voltage command. Consequently, the problems associated with real high-frequency signal injection, such as increases in copper and iron loss can be avoided. Moreover, it is robust to current/voltage harmonics and motor torque disturbances. The proposed method is verified by simulations and experiments under various operating conditions on a prototype IPMSM drive system.

Due to parameter variations with stator currents, the derivatives of machine parameters with respect to current angle or d-axis current are not zero. However, these derivative terms are ignored by most of mathematical model based efficiency optimized control schemes. Therefore, even though the accurate machine parameters are known, these control schemes cannot calculate the accurate efficiency optimized operation points. In this paper, the influence of these derivative terms on maximum torque per ampere (MTPA) control is analyzed and a method to take into account these derivative terms for MTPA operation is proposed based on the recently reported virtual signal injection control (VSIC) method for interior permanent magnet synchronous machine (IPMSM) drives. The proposed control method is demonstrated by both simulations and experiments under various operating conditions on prototype IPMSM drive systems.

With the increasing automobiles in China, the parking difficulty has gradually spread over the city. Developing city-wide parking guidance systems (CPGS) has become urgent to many local governments of China nowadays. However, there haven’t been any effective systems available yet, because the economic investments on sensors and the time costs of negotiation with proprietors of parking lots are unaffordable from city-wide perspective. The lack of parking data is the most critical problem in development of CPGS. In this paper, we propose a new lightweight technical solution to implement CPGS by strengthening data mining and utilization under the current conditions. We start with mining the public information of parking lots, to quantify the service capability and pick out some of the most important as the samples. Next, we build a RGAN to generate data for those parking lots without data, patching them based on the samples with the similar surroundings. The technology of data generation will help us rebuild the city-wide parking data at low costs, both time and money. Finally, we design a model of recommendation based on the real-time driving data to implement intelligent parking guidance, featuring active recommendation and automatic adjustment with vehicle moving. The solution makes the best use of the existing data while reducing the reliance on sensors significantly. And we develop an experimental system in Shenzhen, achieving the rather satisfying guidance effect in practice. Hence, it’s a novel and effective exploration of CPGS, breaking through the dilemma of heavy dependence on sensors.

This paper presents a field-weakening control scheme to expand the speed operating region of the recently reported virtual signal injection control (VSIC) method for interior permanent-magnet synchronous machine (IPMSM) drives. Because of voltage saturation, the VSIC for IPMSM drives is not effective in the field-weakening region. A new control scheme is developed to guarantee that the torque can be controlled with minimum current amplitude. The proposed method realizes fast dynamic response and efficient operation of IPMSM drives in both constant torque and field-weakening regions by controlling the d-axis current through virtual signal injection and detection of the voltage saturation. The proposed method can track maximum torque per ampere (MTPA) points in the constant torque region and voltage-constrained MTPA points in the field-weakening region accurately without prior knowledge of accurate machine parameters. The proposed control method is demonstrated by both simulations and experiments under various operating conditions on a prototype IPMSM drive system.

Carrying on SiC devices, the air-cooled inverter of the electric vehicle (EV) can eliminate the traditional complicated liquid-cooling system in order to obtain a light and compact performance of the powertrain, which is considered as the trend of next-generation EV. However, the air-cooled SiC inverter lacks strategic design methodology and heterogeneous integration routine for critical components. In this paper, a stepwise design methodology is proposed for the air-cooled SiC inverter in the power module, dc-link capacitor, and heat sink levels. In the power module level, an electrical-thermal-mechanical multi-physics model is proposed. The multi-dimension stress distribution principles in a six-in-one SiC power module are demonstrated. An improved power module is presented and confirmed by using the observed multi-physics design principles. In the dc-link capacitor level, ripple modeling of the inverter and capacitor are created. Considering the trade-offs among ripple voltage, ripple current, and cost, optimal strategies to determine the material and minimize the capacitance of the dc-link capacitor are proposed. In the heat sink level, thermal resistance of air-cooled heat sink is modeled. Structure and material properties of the heat sink are optimally designed by using a comprehensive electro-thermal analysis. Based on the optimal design results, the prototypes of the customized SiC power module and heterogeneously integrated air-cooled inverter are fabricated. Experimental results are presented to demonstrate the feasibility of the designed and manufactured air-cooled SiC inverter.