The DC-DC converter for fuel cell vehicles should be characterized by high-gain, low voltage stress, small size and high-efficiency. However, conventional two-level, three-level and cascaded boost converters cannot meet the requirements. A new non-isolated DC-DC converter with switched-capacitor and switched-inductor is proposed in this paper, which can obtain high-gain, wide input voltage range, low voltage stresses across components and common ground structure. In this paper, the operating principle, component parameters design, and comparisons with other high-gain converters are analyzed. Moreover, the state-space averaging method and small-signal modeling method are adopted to obtain the dynamic model of converter. Finally, simulation and experimental results verify the effectiveness of the proposed topology. The input voltage of the experimental prototype ranges from 25V to 80V. The rated output voltage is 200V and rated power is 100W. The maximum efficiency is 93.1% under rated state. The proposed converter is suitable for fuel cell vehicles.

The DC–DC converter for fuel cell vehicles requires high gain and wide voltage input range to boost the voltage of the fuel cell. However, with the traditional boost converter, it is difficult to meet the requirements of the fuel cell vehicle power system. Based on a quasi-Z-source network DC–DC converter, this paper proposes a composite controller, which includes a feedforward compensation network and feedback control to meet the control robustness requirement of the fuel cell vehicle power system. The dynamic model of the converter is obtained by using the state space averaging method and the small-signal dynamic modeling method. The input voltage and load disturbance experiments are performed on the DC–DC converter. Moreover, the converter is tested under the worldwide harmonised light vehicle test procedure (WLTP) to validate the effectiveness of the proposed composite controller. The simulation and experiment results show that the proposed composite controller effectively enhances the converter’s ability to resist input and load disturbance, and improves the dynamic response performance of the DC–DC converter for fuel cell vehicles.

This article presents an effort to develop an effective method for the robust design optimization of a hairpin winding permanent magnet motor. The comprehensive influence of variable uncertainties due to PM property inconsistency and manufacturing uncertainties is considered. During the implementation of robust design optimization of the hairpin winding permanent magnet motor by using an evolution-based multi-objective optimization algorithm, one major obstacle is the huge computation cost, especially for the robust analysis process. Therefore, a two-level solution strategy, an adaptive least square support vector regression model, and a novel dominant judging condition are skillfully employed to realize the tradeoff between the computation cost and accuracy of the robust design optimization algorithm. To verify the effectiveness of the proposed method, the fluctuation and distribution of electromagnetic performance of the robust motor design are analyzed and compared with those of a deterministic motor design. Finally, a prototype of the hairpin winding permanent magnet motor is manufactured and tested to further confirm the validity of the proposed method.

The silicon carbide (SiC) inverter brings great advantages to the motor drive systems of new energy vehicles; however, severe challenges to the bearings also happen. The high dc bus voltage and switching frequency of SiC inverter can increase the discharge frequency and energy when the bearing grease film collapses. As a result, the bearing suffers severe electric corrosion, and the service life of the motor drive system can be shortened. In this paper, the characteristics of common-mode voltage and bearing voltage are analyzed, firstly under space vector pulse width modulation (SVPWM). After that, the common-mode equivalent circuit model of the motor drive system is established. The frequency characteristics of bearing voltage are revealed, and the safe working area is determined. Then, the frequency characteristics of bearing voltage and current are verified based on IGBT and SiC inverters in experiments. After that, by designing a common-mode filter, the bearing voltage and current are significantly attenuated. Furthermore, the active zero state PWM (AZSPWM) is adopted to reduce the common-mode voltage from the inverter. At the same time, combined with the common-mode filter, the bearing voltage and current are further reduced. The experimental results show that the switching frequency has a decisive effect on the amplitude of bearing voltage and current. The bearing voltage can be attenuated to around half of the reference bearing voltage by using the common-mode filter and AZSPWM strategy, respectively. The combination of the common-mode filter and AZSPWM strategy can reduce the bearing voltage to around one-fourth of the reference bearing voltage, which can effectively reduce the breakdown time and discharge energy of the grease oil film.

The Pulse Width Modulation (PWM) technology is widely used in the industrial motor drive field because of its excellent control performance and high efficiency. However, the common-mode voltage of the PWM inverter can aggravate the bearing electric corrosion problem and shorten the bearing life. In this paper, the generation mechanism and coupling path of bearing voltage were studied. After that, the active mitigation method of bearing voltage in motor drive system was proposed, which included software and hardware suppression measures. The Active Zero State Pulse Width Modulation (AZSPWM) strategy was used to suppress the amplitude of common-mode voltage at the inverter output. Then, an Active Common-Mode Voltage Eliminator (ACMVE) installed between the motor and the inverter was proposed to further cancel the residual common-mode voltage. Finally, the mitigation effect of proposed method for the bearing voltage was verified by simulation.