Kai-Wei Hu

An EV SRM Drive Powered by Battery/Supercapacitor With G2V and V2H/V2G Capabilities

This paper develops an electric vehicle switched-reluctance motor (SRM) drive powered by a battery/supercapacitor having grid-to-vehicle (G2V) and vehicle-to-home (V2H)/vehicle-to-grid (V2G) functions. The power circuit of the motor drive is formed by a bidirectional two-quadrant front-end dc/dc converter and an SRM asymmetric bridge converter. Through proper control and setting of key parameters, good acceleration/deceleration, reversible driving, and braking characteristics are obtained. In idle condition, the proposed motor drive schematic can be rearranged to construct the integrated power converter to perform the following functions: 1) G2V charging mode: a single-phase two-stage switch-mode rectifier based charger is formed with power factor correction capability; 2) autonomous V2H discharging mode: the 60-Hz 220-V/110-V ac sources are generated by the developed single-phase three-wire inverter to power home appliances. Through the developed differential mode and common mode control schemes, well-regulated output voltages are achieved; 3) grid-connected V2G discharging mode: the programmed real power can be sent back to the utility grid.

A Reversible Position Sensorless Controlled Switched-Reluctance Motor Drive With Adaptive and Intuitive Commutation Tunings

This paper presents a reversible position sensorless switched reluctance motor (SRM) drive with adaptive and intuitive commutation instant tunings. The narrow voltage pulses are injected into an unenergized phase winding via the PWM channel. The resulted amplitude modulated winding currents are sensed and signal processed to yield the observed Hall signal. No external injection circuit and the motor parameters are required. The estimated rotor speed is obtained from the observed Hall signal. The motor is first started in stepping motor mode, and then it is changed to the sensorless SRM mode as the speed is raised to a suited value. The smooth and fast starting as well as reversible operations are yielded. To improve the torque generating capability, an adaptive commutation tuning control scheme with the identified winding inductance is developed to set the commutation shift angle according to the observed speed, the winding current command, and observed inductance. Moreover, the static intuitive commutation tuning is further conducted in static period to pursuit maximum torque-per-ampere characteristics. Experimental evaluation shows that the developed position sensorless SRM drive possesses very smooth reversible operation and driving performance within a wide speed range, even higher than rated speed.

Development of a Wind Interior Permanent-Magnet Synchronous Generator-Based Microgrid and Its Operation Control

This paper presents the development of a wind interior permanent-magnet synchronous generator (IPMSG)-based dc microgrid and its operation control. First, the derated characteristics of PMSG systems with various ac/dc converters and operation controls are comparatively analyzed. Then, the IPMSG followed by a three-phase Vienna switch-mode rectifier is developed to establish the common dc bus of dc microgrid. Good developed power and voltage regulation characteristics are achieved via the proposed commutation tuning, robust current, and voltage controls. Second, a single-phase three-wire inverter is constructed to serve as the test load. Good ac 220 V/110 V output voltage waveforms under unknown and nonlinear loads are preserved by the developed robust waveform tracking control scheme. Third, a battery energy storage system is established, and the fast energy storage support response is obtained via the proposed droop control approach with adaptive predictive current control method. In addition, a chopped dump load is equipped to enhance the energy balance control flexibility.

On a Bidirectional Adapter With G2B Charging and B2X Emergency Discharging Functions

This paper presents a bidirectional adapter having the functions of charging and discharging, providing 110 V/60 Hz emergency output from the battery embedded in a laptop computer, in electric vehicles, in an uninterruptible power supply, or in other possible appliances. The developed adapter possesses the grid-to-battery and battery to any emergency need (B2X) capabilities. In discharging mode, a front-end dc/dc converter is equipped to establish boosted dc-link voltage from battery for the followed inverter. Then, an H-bridge single-phase inverter is established to yield 110 V/60 Hz emergency source for critical appliances. The two power stages are implemented using an intelligent power module (IPM) with three legs. Good output ac sinusoidal voltage waveforms under unknown and nonlinear loads are obtained by the proposed model following the control scheme, with its tracking error regulation via proportional-plus-integral control and resonant control. Further improvement in waveform quality is achieved by robust control. Conversely, in charging mode, a buck switch-mode rectifier based charger is formed using the same IPM. The performance and rating analyses as well as the design for its power circuit components are derived in detail simultaneously. Satisfactory charging control performance and line drawn power quality are obtained.

Incorporated Operation Control of DC Microgrid and Electric Vehicle

This paper presents the establishment and operation control of a dc microgrid incorporating with electric vehicle (EV) as movable energy storage. The developed microgrid consists of a wind permanent-magnet synchronous generator ac source and a dc source, a battery/supercapacitor (SC)/flywheel hybrid energy storage system, and a grid-connected bidirectional single-phase three-wire (1P3W) load inverter. Various harvested ac and dc sources can be plugged into the microgrid via the developed interfaced power converters. In addition to good microgrid operation performance, the microgrid-to-grid and grid-to-microgrid operations can be successfully conducted with good power quality. As to the developed EV interior permanent-magnet synchronous motor drive, the SC auxiliary storage is equipped to assist the main battery source in intermittent energy conversion. Satisfactory acceleration/deceleration/reversible and regenerative braking operation characteristics are obtained via the developed power stages and control schemes. Moreover, the successful microgrid-to-vehicle and vehicle-to-microgrid interconnected operations of EV and microgrid are achieved. In addition, the vehicle-to-grid/grid-to-vehicle operations can be also performed via the developed 1P3W inverter.

A Switched-Reluctance Generator With Interleaved Interface DC–DC Converter

This paper presents the development of a wind switched-reluctance generator (SRG) with interleaved interface dc-dc converter. First, the power circuit and control scheme of the SRG are properly designed. The hysteresis current-controlled pulse width modulation (PWM) scheme is designed to achieve good winding current tracking control, and the robust voltage control scheme is developed to yield well-regulated dc output voltage under varying prime mover driving speed and load conditions. Moreover, the voltage regulation and the developed power performances of SRG are further enhanced using the proposed commutation shift approach. Next, an interleaved current-fed push-pull interface dc-dc converter with two modules is developed to establish the boosted common dc bus voltage of a dc microgrid from the SRG output having fault-tolerant capability. The rating analysis and circuit component design are conducted in detail. Similarly, well-regulated voltage with lower ripples is also yielded via the properly designed schematic and control scheme.

On an Auxiliary Power Unit With Emergency AC Power Output and Its Robust Controls

The development of an auxiliary power unit (APU) with 110 V/60 Hz output from conventional battery, laptop computer battery pack, or other available dc sources and its robust controls are presented in this paper. First, a front-end current-fed push-pull dc/dc converter is designed and implemented. It is used to establish the boosted and well-regulated dc-link voltage for the followed inverter. The quantitative designed feedback controller is augmented with a novel robust tracking error cancellation scheme (RECC) to achieve the desired regulation performance. Then, a full-bridge single-phase pulse-width modulated inverter is established to yield 110 V/60 Hz source for emergency use. In treating the inverter waveform control, the causes of waveform distortion under nonlinear loads are explored. Then a novel robust model following control scheme is proposed accordingly. In the proposed control scheme, the simple model following controller is augmented with a RECC. Theoretic bases of all the proposed control schemes are derived thoroughly. The simulation and experimental evaluations indicate that the developed APU possesses good output voltage waveform under unknown and nonlinear loads.

A Current Control Scheme With Back EMF Cancellation and Tracking Error Adapted Commutation Shift for Switched-Reluctance Motor Drive

In this paper, an improved winding current control scheme for switched-reluctance motor drive is developed and evaluated. The current feedback controller (CFBC) is augmented with an observed back electromotive force (EMF) current feedforward controller (CFFC) and a current tracking error adapted dynamic commutation shift controller (DCSC). In the proposed DCSC, the rising winding current tracking errors of all phases are extracted, synthesized, and processed to generate the suitable advanced commutation shift angle. The effects of motor back EMF and nonlinear winding inductance can be reduced to yield improved winding current tracking waveforms under a wide operation range. The gradual improvements in current responses and efficiencies by augmenting the CFBC with the CFFC and then the DCSC are verified experimentally. Then, the robust speed control scheme is properly designed to achieve good acceleration/deceleration, reversible running, and dynamic characteristics.

On a battery/supercapacitor powered SRM drive for EV with integrated on-board charger

This paper develops a battery/supercapacitor powered switched-reluctance motor (SRM) drive for electric vehicle (EV) propulsion. Its on-board integrated charger is formed using the embedded motor drive components. The boosted motor drive DC-link voltage is established by an interleaved DC/DC boost converter from the battery. The super-capacitor (SC) is interfaced to the DC-link via a DC/DC buck converter. And it is connected to the battery bank by a diode to assist the battery in acceleration and deceleration. Good driving and regenerative braking performances are achieved by proper control. In idle condition, the grid-to-vehicle (G2V) battery charging can be conducted by the formed on-board integrated charger with good line drawn power quality. The established charger consists of a full-bridge boost switch-mode rectifier (SMR) and a buck DC/DC converter based charger.

On the PFC AC-DC converter fed SRM drives with reversible and regenerative braking capabilities

This paper presents the development of two types of power factor corrected (PFC) AC-DC converter fed switched-reluctance motor (SRM) drives, both possess reversible and regenerative braking capabilities. First, a three-phase six-switch four-quadrant boost switch-mode rectifier (SMR) fed SRM drive is established. The DC-link voltage of the SRM drive is adjustable and well regulated for effectively enhancing the SRM driving performance under higher speeds. Moreover, the recovery of regenerative braking energy back to the mains is achievable. Next, a new PFC front-end consisting of a diode rectifier and an anti-paralleled active power filter (APF) is proposed. It allows the use of IGBT module with lower rating to achieve the regenerative braking and PFC functions. However, the DC-link voltage boosting and regulating abilities are sacrificed. Some measured results are provided to comparatively evaluate the performances of the SRM drives powered by the two AC-DC front-end converters.