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A GaN high‐electron‐mobility transistor (HEMT) with a wide‐bandwidth operational amplifier was employed to implement and develop a two‐mode‐operation transconductance regulator (TMOTR). Using the proposed TMOTR, the laser diode can be operated in either the continuous constant‐current mode to fulfill a continuous‐wave laser or pulse‐width modulation (PWM) to achieve a narrow‐pulsed laser. When the laser diode is operated in PWM mode and at high frequency, the parasitic elements of the GaN HEMT, laser diodes, printed circuit board, and power wires must be considered, because these parasitic elements can influence the rising‐edge slope of the laser diode driving current resulting in narrow‐pulsed duty cycle diminution. This study applied equivalent circuit models of a GaN HEMT and laser diode to determine the parasitic parameters in accordance with device packages; therefore, the simulation circuit of the TMOTR with its parasitic element could be implemented to obtain the critical simulation waveform. The parasitic element parameters of the laser diode and GaN HEMT were calculated in detail and used simulation software to verify the TMOTR's characteristics. Finally, the TMOTR prototype was implemented, and the experimental waveforms were measured to confirm simulations, equivalent circuits, and dynamic responses; the GaN HEMT and MOSFET were experimented to compare their differences.

In this paper, a dynamic operational linear regulator (DOLR) based on a GaN high-electron-mobility transistor (HEMT) and wide-bandwidth operational amplifier was developed and implemented. The driving current could be regulated and controlled by the DOLR for 632 nm laser diodes. The constant-current mode for the continuous-wave laser and the pulse-width modulation (PWM) mode for the short-pulsed laser were realizable using this DOLR. This study focused on the rising-edge time change on the laser driving current when the DOLR was operated under the high-frequency PWM mode, because the parasitic components on the GaN HEMT, laser diodes, printed circuit board, and power wires could influence the current’s dynamic behavior. Therefore, the equivalent circuit models of the laser diode and GaN HEMT were applied to establish a DOLR simulation circuit in order to observe the rising-edge time change on the laser driving current. A DOLR prototype was achieved, and so experimental waveform measurements could be implemented to verify the DOLR simulation and operation.

A high-power laser diode driving controller (HPLDDC), which incorporates the power converter with the feedback controller, was developed and implemented in this paper. The synchronous buck–boost converter (SBBC) was the topology of the power converter; the SBBC could be operated in step-up or step-down mode in accordance with variable on-board battery voltage inputs into the HPLDDC. Moreover, the feedback controllers were equipped with a current-loop controller (CLC) and a voltage-loop controller (VLC); the VLC was employed to regulate the SBBC output voltage to drive and start-up the high-power laser diode (HPLD). The CLC was used to regulate the SBBC output current to supply a constant-current driving the HPLDs. During the start-up transient phase, when the SBBC output mode is changed from the constant-voltage to the constant-current, a start-up current spike occurs that can destroy the semiconductor material of the laser diode. However, few studies have discussed methods of coping with this problem. Therefore, this study proposed a proportional-integral associating proportional (PIAP) control technology, which can be applied to the CLC for the start-up current spike mitigation. Complete designs and analyses are presented in this paper. Simulations and experiments validate that the PIAP control method is effectual to solve the start-up current spike.

This study developed and implemented a LiFePO4 battery pack (LBP) rapid charger. Using the three-terminal switch and partnership for a new generation of vehicles (PNGV) battery models, this study could obtain a small-signal system matrix to derive transfer functions and further analyze frequency responses for the charge voltage and current loops; therefore, both voltage and current feedback controllers could be designed to fulfill the constant-voltage (CV) and constant-current (CC) charges. To address practical applications, the proposed equivalent model also considered the wire resistance-inductance of the power cable. According to the derived high-order transfer function, the pole-zero break frequency in the Bode plot was observed that approximated the practical measurement; therefore, the pole-zero compensation could be accomplished for both charge loop requirements. Moreover, the design features for implementing the CV and CC charges are presented in detail herein, and the current overshoot during the start-up phase could be mitigated using the method of zero break frequency shifting and a novel proportional shifting proportional-integral control. The LBP parameter estimations, model construction processes, and frequency response analyses are also presented. The feedback compensation design based on the proposed model was validated through simulations and experiments. The results were determined to be in excellent agreement with theoretical derivations.

Summary In this study, a laser headlight driving controller (LHDC) using the controller area network (CAN)‐bus communication system was developed and implemented for vehicle headlight applications. To observe temperature variations that influence the forward‐bias voltage and optical power of laser diodes, the laser diode was placed in an ambient temperature‐testing chamber to measure the electro‐optic characteristics and calculate the electro‐optic conversion efficiencies. The optical power and conversion efficiency values obtained at different temperatures (from negative to positive temperatures) when optical power adjustment was executed using analog and pulse‐width modulation technologies were compared. Moreover, a human‐machine operating interface was developed using the LabVIEW software. Therefore, the LHDC and laser optical power can be controlled using a computer through the CAN‐bus communication system to control the LHDC and monitor it.

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This study aims to implement a single-stage differential boost inverter (SSDBI) applied in a single-stage battery energy storage system (BESS) topology that can supply power from a lower-voltage battery module to an alternating current (AC) load. Compared with the common two-stage topology, which has a two-stage converter and higher-voltage battery module array, the single-stage topology can reduce the number of cells and components and improve the power density. In addition, a modified sinusoidal pulse-width modulation (SPWM) control was proposed to reduce the control complexity of the SSDBI while improving the total harmonic distortion (THD) of the inverter. The modified SPWM control can reduce the duty ratio of the SSDBI and the stress on the components in order to improve the AC voltage output waveform and reduce the THD.