Yigeng Huangfu

Robust buck converter design with a high-order sliding mode differentiator

This paper aims to focus on the smooth output of Buck converters under the input perturbations and load disturbances using the high-order sliding mode controller with a differentiator (HOSMD) based on the only measurement of output voltage. Theoretical analysis and design procedures of the controller designed by prescribed control law, one of the high-order sliding modes, are presented in detail. As well as the differentiator with the super-twisting. Comparison of numerical simulation results between traditional sliding mode control (SMC) and HOSMD under steady state, input voltage perturbations, output load disturbances have been presented. And it validates the effectiveness and robustness of the method proposed in this paper, which would reduce the hard-ware cost and increase the superiority.

Stability Analysis and Active Stabilization of On-board DC Power Converter System with Input Filter

As it has changed gradually from more electric aircraft (MEA) to all electric aircraft, the stabilization of the on-board dc power system is a hot research topic in recent years. In such an application, small and light systems are required, and thus, the optimization of passive LC filter is a significant issue. It is known that reduction of the LC filter capacitor will cause instability when the constant power load is employed. There is always a compromise between stability margin and system size. A practical method using the current perturbation was proposed in order to stabilize the on-board power system. The main objective is to suppress the instability and improve the stability margin, while keeping the benefits of the low weight and volume. The mathematical model of the system is analyzed, and the simulations and experimentations are performed to confirm the validity and effectiveness of the proposed method.

A novel static fault diagnosis approach for three-phase full-bridge inverter

This paper presents a novel fault diagnosis approach for three-phase full-bridge inverter, which is the most popular used in the brushless DC motor (BLDCM) system and the permanent magnet synchronous motor (PMSM) system. The short or open circuit fault diagnosis of the six power switches of the inverter is accomplished by only four simple resistor divider networks and one sampling resistor. By comparing the divided voltages with the reference voltage, the faults are detected and identified under a set of special judgment rules. The proposed method is designed to be used before system running. Compared with the existed methods, the proposed approach works with only weak current passing, which is more safe. Finally, the effectiveness is verified by simulation.

Energy optimization of a PEM fuel cell system by minimizing the parasitic consumption generated by the compressor

Air compressor which is employed to supply the oxygen to the cathode is a key component in the fuel cell system. It is also the main parasitic consumption, which consumes up to 15% of fuel cell generated power. How to find out the most efficiency operating point, thereby reduce the compressor consumption, is the research topic of this paper. Oxygen excess ratio connected both to the stack output power and compressor consumption is deemed as a adjustable parameter to optimize the net power. A optimal seeking approach is proposed to obtain the maximum output power. Compared with the lookup table method the proposed approach has the advantage of robustness eliminating affection by the working condition variations. The validity of this approach is proved by simulation results.

A novel wide stability control strategy of cascade dc power system for PEM fuel cell

The electric vehicle technology has been adopting PEM fuel cells for hybrid applications over the past decades. Fuel cell systems are often low voltage systems. The key requirements of a boost converter for such application are need of high-voltage. The second-order low-pass filter is often used to filter the high frequency current ripple. It is known that the interaction between the poorly damped filter with the converter leads to degradation of dynamic performance and instability of the system. This paper addresses a novel wide stability control strategy to solve this problem without increasing the weight and size. In this paper, the mathematical model of the system is built. The dynamic stability of the system is investigated based on root locus and Lyapunov first method. The simulation results are reported to verify the effectiveness of the proposed method.

A Buck-Boost converter based on robust avoidance chattering sliding mode control for PEM fuel cell

In the process of power generation by hydrogen energy, the randomness of hydrogen, oxygen input and power output often appear, which puts forward higher requirements for the robust design of power converters. The inevitable chattering phenomenon do exist in the power converter based on traditional sliding mode due to its discrete control law. In order to conquer the above problems, this paper presents a novel avoidance chattering converter based on the super-twisting sliding modes. To remove the intermittent disturbance in the new energy power generation, especially in PEM fuel cell system, this paper compares the effect of the converter controlled by super-twisting sliding mode controller with the classic PI controller in a typical Buck - Boost power converter as an example. The simulation results show that: under the condition of large disturbances in input and output, the converter controlled by super-twisting sliding mode has stronger robustness.

Cathode partial pressures estimation of a proton exchange membrane fuel cell for transportation applications

Cathode partial pressures, such as the oxygen partial pressure and nitrogen partial pressure, are important performance parameters of the proton exchange membrane fuel cell. Oxygen partial pressure has a direct influence to the fuel cell output voltage. And the cathode total pressure, mainly composed of oxygen partial pressure, nitrogen partial pressure and vapor partial pressure, has to be kept at the optimal value to ensure the high efficiency of the fuel cell. Therefore, partial pressures are crucial variables which need to be appropriately controlled. However, those parameters are usually not measurable. In this paper, an extended state observer, which can effective deal with the nonlinearity and disturbance of the system is proposed. The simulation results show that this observer can accurately estimate the partial pressures.

Hardware-in-the-loop validation of an air supply method for vehicular fuel cell applications

This paper presents hardware-in-the-loop (HIL) validation of an air supply method for the fuel cell in automotive applications. A 12 kW proton exchange membrane fuel cell (PEMFC) model is developed and implemented in dSPACE. The performances of the fuel cell stack and compressor during a classic European Driving Cycle are tested. The experimental results show that the compressor consumes up to 25 % of the fuel cell generated power in the worst operating point, whereas only 4.2 % on average.