For sensorless starting control of the brushless synchronous starter/generator (BSSG), signal injection is commonly adopted to estimate the initial rotor position of the main generator (MG). Due to the special structure of BSSG, signal transmission link between MG and the main exciter (ME) is a rotating rectifier that has a complicated operating principle. The lack of theoretical analysis of this complex transmission path leads to unreliability and inaccuracy for the methods based on it. In this paper, the transmission mechanism of injected signals from the field winding of MG to the stator windings of ME is clarified. According to this theory, a novel initial rotor position estimation method of MG is proposed. Both the simulation and experiment results show that this approach can provide initial rotor position of MG with reasonable accuracy.

This paper analyzes the torque performance of the flat wire motor, a potential winding form of a high-performance motor. The motor has continuous flat wire(CFW), so it has no solder joint in every branch, which improves the reliability. Besides, the axis length of end windings is shorter than that of the hairpin motor, so its power density is higher. However, the torque ripple and the cogging torque of the CFW motor are higher because of the larger slot opening. This paper compares the rotor skew and the stator chute, reduces the torque ripple and the cogging torque by the rotor skew.

Extended range fuel cell vehicles are developing towards full power fuel cell vehicles, which require fuel cells to undertake most of the vehicle's power demand. Thus, fuel cell output power will change dynamically in a wide range, which may result in local gas shortage. It is necessary to design the control algorithm of fuel cell air supply system to ensure the sufficient reaction gas of fuel cell. This paper focuses on the dynamic characteristics and control method of fuel cell engine air supply system. The model of fuel cell system is built. And a new double-input and double-output control algorithm for air supply system is designed. The simulation results verified that the control algorithm performs well. The actual flow can track the target flow accurately whether the current step is up or down. The rising time of cathode inlet pressure is 0.1s and the overshoot is 1.8% when the load is rising. The falling time of cathode inlet pressure is 0.1s and the overshoot is 1.3% when the load is falling.

Being a promising alternative to combustion engines, the polymer electrolyte fuel cell still suffers durability issues. Specifically, the Pt catalyst degrades dramatically during dynamic operating conditions. Here, a Pt degradation model is developed and used to study the effect of accelerated stress test, i.e. electrode potential cycles, on Pt degradation. For triangle wave potential cycles, the ECSA loss rate is independent of a high potential sweep rate. For trapezoidal wave potential cycles with the same cycle duration, the ECSA loss rate is accelerated by a high potential sweep rate. Comparing two types of wave cycles, the trapezoidal cycle better accelerates Pt degradation than the triangle cycle. The effect of trapezoidal cycle duration is also studied. The results show that the ECSA loss rate is independent of the cycle duration, while the Pt mass tends to transport from the catalyst layer to the membrane with a longer cycle duration.

Power density is one of the most significant bottlenecks of vehicular polymer electrolyte membrane (PEM) fuel cell systems. In order to be suitable for commercial vehicles in the future, high-power fuel cell engines need to be developed. This paper presents an experimental study on a domestic high-power fuel cell engine. The test system consists of a 100-kW class fuel cell stack, accessory subsystems, a DC/DC converter and an electronic load. A rated working condition test and a cycle condition test stipulated by national standard. Key parameters, e.g., system current, system voltage, temperature and pressure at the inlet and outlet, hydrogen consumption rate are measured. Results show that the rated output power of the fuel cell engine is about 80 kW, and the peak power exceeds 100 kW, reaching the international advanced level. This fuel cell engine will be used in heavy-duty buses with long driving distance in the severe cold environment in the future.

In this paper, we propose a multi-objective optimization problem of power components parameters for a pre-defined driving cycle and energy management algorithm regarding fuel economy, system durability, power components cost and battery volume. We eliminate the parameter vectors that can't meet the vehicle power demand. Then applying the algorithm to the model of a fuel cell city bus gives the opportunity to choose the best values for battery capacity Qbatand the maximal net output power of the FCS Pfcsmaxaccording to the contour diagram. Simulation results show that for a "New Europe Driving Cycle", a battery capacity of 96 Ah and an FCS maximal net output power of 100 kW are optimal for the fuel economy, system durability, power components cost and battery volume limitation of a fuel cell city bus.