Chun-Hsin Chang

In this study, the authors propose a method for evaluating the influence of ambient temperature (T_a) on the optical characteristics and power consumption of a LED lamp used for the automotive headlamp, which helps the designer to figure out the acceptable range of the ambient temperature for the LED lamps to work well in the practical case. The LED lamp was fixed on the test holder and placed in a fixed position in the air circulation temperature control oven to measure the illuminance, spectrum in three different directions, and power consumption under various T_a. The experimental results indicate that T_a has little effect on the correlated color temperature (CCT), chromaticity coordinates, and angular distribution of the emitting light. In contrast, T_a has a significant effect on the lamp’s resistance, thus affecting illuminance and power consumption. When the T_a increased from 30 °C to 60 °C, the illuminance of the low beam and high beam decreased on average by 16.6% and 21.7%, respectively, while the power consumption of the low beam and high beam decreased on average by 21.4% and 22.2%, respectively. The drop in the luminous flux output indicates the probability of originally qualified automotive LED headlamps becoming unqualified in high T_a.

The application of the high gain boost DC-DC converter is gaining more attention due to an increasingly wide range of applications for sustainable green energy solutions, as well as other high voltage applications. In this study, a modified high gain quadratic boost converter is proposed using a single switch. The proposed topology is a member of the family of the non-isolated category with a common ground feature and can operate in a wide range of duty ratios, and is able to provide the required voltage gain. In this proposed circuit configuration, a dual voltage boost cell was formed by incorporating two capacitors in series with two inductors of a conventional quadratic boost converter. Additionally, a capacitor was integrated with a second voltage boost cell. This special configuration increases the voltage gain as well as reduces the voltage stress across the switch. To show its feasibility, a 200-W prototype setup with 48 V input and 400 V output was designed, and the required PWM signal was fed from the microcontroller unit. A detailed analysis of the design parameters and losses are formulated and are shown in this paper. The simulation was performed in SIMPLIS software, and the experimental results agreed with the obtained output voltage gain. The proposed topology showed a peak efficiency of 94.5% at 150-W output power after considering the power losses in all the components of the PCB.

Graphene heat-dissipating coating (GNHC) of 0.6 wt % GN concentration is utilized to promote the cooling performance of automotive light-emitting diode (LED) lamps. Three cases are studied as follows: Case 0 is the original automotive LED lamp as the baseline. Case 1 is to apply GNHC to reduce the thermal resistance of the junction surfaces between the components of automotive LED lamps. The aluminum fin radiator of Case 1 is further coated with GNHC on the surface that becomes Case 2. The spectrum, illuminance, power consumption, and surface temperature are measured at different ambient temperatures (T_a) to fully evaluate the feasibility of applying GNHC to improve cooling performance and the impacts on the related characteristics of automotive LED lamps. The results show that the maximum illuminance efficacy of Case 1 and Case 2 with high beam, irradiation angle of 0 degrees, and T_a of 80 °C is 11.03% and 8.70% higher than that of Case 0, respectively. The minimum temperature difference of heat dissipation path of Case 1 and Case 2 with high beam, irradiation angle of 90 degrees, and T_a of 80 °C is 6.41% and 5.33% lower than that of Case 0, respectively, indicating GNHC as a promising coating material for improving the cooling performance of automotive LED lamps.

This study developed a mechatronics platform for a seven-mode vehicle-oriented powertrain system. The innovative “all-in-one” concept was used for flexibly arranging various power or energy sources to be combined for various hybrid powertrains. Hence, it significantly reduces the cost and human resources for evaluating new-type power systems or developed vehicle control strategies on the same experimental platform. In this study, three power sources were chosen for providing hybrid power. The first source is a 125 c.c. spark ignition (SI) engine, where a controllable throttle valve governs the output torque, while a fuel meter measures the consumed fuel. The second one is a 1.5kW hub motor, where a motor control unit (MCU) and a 48V lithium battery pack properly provide the required electric power. The third source is an air engine, where a 220V air compressor and other components provide the pneumatic power. For the experimental platform, a developed Matlab/Simulink package receives the measured signals and sends the control commands to actuators. Through the on/off state control of three controllable e-clutches, three single-source modes, three dual-source modes, and one three-source mode (3+3+1) can be conducted. A 1.1kW/24V magnetic powder brake emulates the road load. The results show that three dual-source modes and a three-source mode were successfully operated. The efficiencies, torques and speeds, mass flow rates, etc. have been measured and calculated. This platform is aimed for the research fields of green energies, advanced powertrains, and power flow management.