Switch-mode Rectifier Research Articles

A Flyback Rectifier With Spread Harmonic Spectrum

This paper presents a flyback switch-mode rectifier (SMR) with spread harmonic spectrum. The SMR switching control is conducted by a charge-regulated pulsewidth modulation (PWM) scheme with constant turn-on period. The inherently stable discontinuous conduction mode operation is preserved to yield good line drawn power quality. In voltage loop, a quantitatively designed PI feedback controller is augmented with a robust error cancellation control scheme. Further improved dc output voltage regulation and input power quality performances are achieved under varied operating conditions. In spread harmonic spectrum control, the harmonic spectral properties of the developed flyback SMR are first analyzed. Then, the dedicated random switching scheme is developed to let its switch current harmonic spectrum be dispersedly distributed. In the proposed random switching scheme, the PWM turn-off period is modulated using 1-b binary sequence, pseudo random binary sequence, and 4-b binary sequences. Under randomized harmonic spectrum, the SMR control performances are not sacrificed.

An Integrated Driving/Charging Switched Reluctance Motor Drive Using Three-Phase Power Module

This paper develops an integrated driving/charging switched reluctance motor (SRM) drive for electric vehicles using off-the-shelf three-phase intelligent power modules (IPMs). Five legs of two IPMs are employed to construct the four-phase SRM modified Miller converter. Moreover, its front-end dc/dc boost converter is formed by the remaining one leg to boost the dc-link voltage from a battery. Proper current and speed control schemes are designed to yield satisfactory driving performance. In particular, the performance under higher speed is enhanced by the boosted dc-link voltage and the advanced shift of commutation instant. In idle case, some imbedded IPM power devices and SRM windings are arranged to form a buck-boost type or a buck-type switch-mode rectifier (SMR) for charging the battery from a utility with good charging control characteristics and a line drawn power quality. The rating derivations, performance analyses, and controller designs for these two SMRs are performed in detail. All constituted circuit components of the charger are naturally placed onboard; only the insertion of a power cable to the ac source socket is needed. A common digital signal processor is used to realize all control schemes fully digitally, and their control performances are demonstrated experimentally.

Modified Single-Loop Current Sensorless Control for Single-Phase Boost-Type SMR With Distorted Input Voltage

The first single-loop current sensorless control (SLCSC) for single-phase boost-type switching-mode-rectifier (SMR) had been proposed in the prior paper. SLCSC with sinusoidal input voltage possesses good performance, but its performance with distorted input voltage should be improved. In this paper, a modified SLCSC is proposed and implemented in a field-programmable gate array (FPGA)-based system to obtain better performance than SLCSC. Instead of the phase-shift signal in SLCSC, the inductor voltage amplitude signal becomes the output of proportional-plus-integral (PI)-type voltage controller in the modified SLCSC. The provided simulation and experiment results demonstrate the modified SLCSC.

Design and Evaluation of a 42-V Automotive Alternator With Integrated Switched-Mode Rectifier

This paper presents techniques for the design of high-power Lundell alternators with integrated switched-mode rectifiers. A multisection stator winding and interleaved rectifier arrangement is introduced that enables high power levels to be achieved using small semiconductor devices, and which greatly reduces the output filter capacitor requirements. We also demonstrate control methods suited for this interleaved system. In addition to accurate closed-loop output voltage control, we introduce methods to provide (partial) synchronous rectification for reduced loss, and to provide tight load-dump transient control. The proposed technology is validated in the design and experimental evaluation of a 42-V, 3.4-kW alternator with fully integrated power electronics and controls. The prototype alternator achieves approximately a factor of 2.1 increase in power and 1.6 increase in power density as compared to a conventional diode-rectified alternator.

A High Performance Three-Phase Telecom Supply Incorporating a HF Switched Mode Rectifier with a Phase Shifted PWM Controller

Telecom supplies need to conform to low Total Harmonic Distortion (THD) and high Power Factor (PF) as per IEC 61000-3-2 and IEEE 519-1992 standards. These high rating power supplies use a three phase utility in which low THD and high PF are realized via various passive and active wave shaping schemes. In this paper, a new design for three phase telecom power supplies is presented with circuit parameter values optimized for high performance in terms of a low THD, high PF, low ripple and high line and load regulation using a suitable combination of various strategies. The performance of the power supply is validated by extensive simulations.

On the Switched-Reluctance Motor Drive With Three-Phase Single-Switch Switch-Mode Rectifier Front-End

This paper presents a switched reluctance motor (SRM) drive powered by a three-phase single-switch (3P1SW) switch-mode rectifier (SMR). The digital controls of both power stages are realized in a common DSP. In the front-end SMR, a robust current harmonic cancellation scheme and a robust voltage control scheme are developed. The undesired line current and output voltage ripples are regarded as disturbances and they are reduced via the proposed robust controls. In voltage control, a feedback controller is augmented with a simple robust error canceller. The robust cancellation weighting factor is automatically tuned according to load level to yield compromised voltage and power quality control performances. The chaotic phenomena can be automatically avoided and better SMR operating performance is obtained simultaneously. With boostable and regulated dc-link voltage, the current and speed dynamic responses of the followed SRM drive are enhanced, and the vibration and speed ripple are also lessened. As to the SRM drive, a random-band hysteresis current-controlled pulsewidth modulation (CCPWM) scheme (RB-HCCPWM) with harmonic spectrum shaping is developed and applied for its winding excitation control. The winding current harmonic spectrum is more dispersedly distributed to yield reduced stator vibration and speed ripple. Moreover, the commutation advanced shift is applied to yield further performance improvement of SRM drive.

Reduction of speed ripple and vibration for switched reluctance motor drive via intelligent current profiling

This study presents the speed ripple and vibration reductions for a switch-mode rectifier (SMR) fed switched reluctance motor (SRM) drive via intelligent current profiling approach. Firstly, the SRM drive with a boost-type SMR front-end is established, which possesses well-regulated DC-link voltage and good AC line drawn power quality. Secondly, the speed ripple generating process of a SRM is explored. Accordingly, a robust and intelligent speed ripple reduction approach is proposed, wherein the leading edge of winding current command is modified by adding a compensating component, which is automatically generated from the DC-link negative stroke spikes caused by non-ideal commutation. Thirdly, a robust current error cancellation control scheme is designed to yield closer current waveform tracking response, and thus the smoother motor developed torque. In outer loop, a robust speed ripple cancellation control scheme is employed to directly reduce the speed ripple. Finally, the commutation shift is applied to further improve the torque sharing characteristics between phases during commutation period and thus reduce the speed ripple and vibration. In addition, the commutation shift also leads to the improved torque per ampere capability of a SRM. Validity of all the proposed control approaches is demonstrated experimentally.

Modeling and control of soft‐switching mode rectifiers with power factor correction

The small‐signal modeling and quantitative controller design of a soft‐switching mode rectifier (SSMR) is presented in this paper. First, a single‐phase boost‐type SSMR is formed from the traditional boost‐type switching mode rectifier (SMR) with auxiliary resonant branch to achieve zero‐voltage‐transition (ZVT) soft switching for the main and auxiliary switches. For the current‐controlled pulse width modulation (PWM) scheme, the small signal model of the current control loop is obtained using a statespace averaging method and the parameters of the controller are found based on a frequency response approach. As for the voltage control loop design, the dynamic model of the proposed SSMR is first derived using averaging method for two‐time‐scale (AMTTS) and averaged power method. Then, a quantitative procedure is proposed to find the parameters of the voltage controller according to the prescribed control performance. The accuracy of the derived SSMR dynamic model and the effectiveness of the proposed controller are demonstrated by some simulation and experimental results.

Modeling and Small-Signal Analysis of a Switch-Mode Rectifier With Single-Loop Current Sensorless Control

The conventional multiloop control with one inner current loop and one outer voltage loop is often applied to a single-phase boost-type switch-mode rectifier where the output of the voltage loop is a current amplitude signal. In the duty phase control (DPC) proposed recently, the output of the voltage loop is a phase signal used to generate the switching signals without current loop and sensing current. To improve the clamped current waveform of DPC, a single-loop current sensorless control (SLCSC) with some nominal parameters had also been proposed to compensate for the voltage drops across the switch, diodes, and inductor resistance. In this paper, the effect of the differences between nominal and real circuit parameters on the input current waveforms of SLCSC are addressed in detail. The results are helpful in the design of SLCSC. From the simulated and experimental results, we can find that the output voltage is well regulated by the only voltage loop and the input current harmonics are significantly improved.

Development of a Compact Switched-Reluctance Motor Drive for EV Propulsion With Voltage-Boosting and PFC Charging Capabilities

This paper presents a compact battery-powered switched-reluctance motor (SRM) drive for an electric vehicle with voltage-boosting and on-board power-factor-corrected-charging capabilities. Although the boost-type front-end DC/DC converter is externally equipped, the on-board charger is formed by the embedded components of SRM windings and converter. In the driving mode, the DC/DC boost converter is controlled to establish boostable well-regulated DC-link voltage for the SRM drive from the battery. During demagnetization of each stroke, the winding stored energy is automatically recovered back to the battery. Moreover, the regenerative braking is achieved by properly setting the SRM in the regenerating mode. The controls of two power stages are properly designed and digitally realized using a common digital signal processor. Good winding current and speed dynamic responses of the SRM drive are obtained. In addition, the static operation characteristics are also improved. In the charging mode, the power devices that were embedded in the SRM converter and the three motor-phase windings are used to form a buck-boost switch-mode rectifier to charge the battery from utility with good power quality. All constituted circuit components of the charger are placed on board, and only the insertion of power cords is needed.

Phase Feedforward Control for Single-Phase Boost-Type SMR

In this letter, a phase feedforward control (PFFC) for a single-phase boost-type switching-mode rectifier is addressed. In the conventional input voltage feedforward loop, the feedforward signal is fixed regardless of the load level. The proposed phase feedforward signal adjusts according to the load level without sensing the load current. The simulated and experimental results also demonstrate the effectiveness of proposed PFFC. Compared to a conventional feedforward signal, relatively small proportional gain can be used in the proposed PFFC without loss of current tracking performance, which would also increase the overall system immunity against noise.

Development of a Switched-Reluctance Motor Drive With PFC Front End

In this paper, the development and control for a switched-reluctance motor (SRM) drive with front-end switch-mode rectifier (SMR) are presented, and good motor driving performance and line drawn power quality are obtained. In the SMR, the dc-link voltage spikes caused by periodic pulse-type motor currents are eliminated using high-frequency small capacitor. And the bulky capacitor is designed according to the specified double-frequency voltage ripple. Then, the robust voltage and current schemes are developed to yield excellent and robust SMR control performance. Having well-regulated and adjustable dc-link voltage source, the performance enhancements of the SRM in vibration as well as current and speed dynamic responses are performed and evaluated. The robust current and speed control schemes are designed to yield improved driving performance. In addition to voltage boosting, the commutation advanced shift is proposed to further the improve current and speed dynamic responses, the torque-generating capability, and the vibration of SRM.

Design and Control for a Charge-Regulated Flyback Switch-Mode Rectifier

This paper presents the design and control of a single-stage charge-regulated varying-frequency flyback switch-mode rectifier (SMR). First, the ratings of key constituted circuit components are derived, and accordingly, the power circuit is designed and implemented. Then, a novel charge-regulated, varying-frequency, current-controlled pulsewidth modulation (CCPWM) switching scheme is developed. In the proposed control scheme, the switch turn-on time is fixed, and the turn-off time interval is determined by the comparison result between the low-pass filtered switch current and its current command. The proposed switching scheme possesses the features of without slope compensation, having more dispersedly distributed harmonic spectrum, robust current tracking control, and ease of implementation using off-the-shelf integrated circuits. Finally, the quantitative and robust voltage regulation controls considering nonlinear behavior are made. Good dc output voltage regulation and ac input power quality control performances under wide load range are obtained. Some simulated and measured results are provided to demonstrate the performance of the developed SMR.

Single-Loop Current Sensorless Control for Single-Phase Boost-Type SMR

In this paper, the first single-loop current sensorless control (SLCSC) in continuous current mode (CCM) for single-phase boost-type switching-mode rectifiers (SMRs) is developed and digitally implemented in a DSP-based system. Compared to the conventional multiloop control with one inner current loop and one outer voltage loop, there is only one voltage loop in the proposed SLCSC, where the voltage loop's output is used to shift the nominal duty ratio pattern generated from the sensed input and output voltages. Because of no current loop, the efforts of sampling and tracking inductor current can be saved. It implies that the proposed SLCSC is simple and very adaptable to the implementation with mixed-signal ICs. First, the effects of shifting nominal duty ratio pattern on the input current waveform are analyzed and modeled by considering the inductor resistance and conduction voltages. The result of analysis shows that the pure sinusoidal current can be inherently generated by the nominal duty ratio pattern where the current amplitude is roughly proportional to the controllable phase of nominal duty ratio pattern. Then, a voltage controller is included to regulate the DC output voltage by tuning this controllable phase. Finally, some simulated and experimental results have been given to demonstrate the performance of the proposed SLCSC.

Duty Phase Control for Single-Phase Boost-Type SMR

In this paper, a novel duty phase control (DPC) for single-phase boost-type switching-mode-rectifier (SMR) is developed and digitally implemented in DSP-based system. Compared to the conventional multiloop control structure with inner current loop and outer voltage loop, it is noted that there is only one voltage loop tuning the phase of predefined duty pattern (i.e. duty phase) in the proposed DPC. Due to no current loop, sampling inductor current and tracking current are unnecessary when SMRs are operated to shape the current waveform and regulate the output voltage. It implies that the single-loop DPC is simple and adaptable to the implementation with digital and analog integrated circuits. In this paper, first, the effect of the duty phase on the input current is analyzed and modeled. It shows that the sinusoidal current waveform can be naturally generated by the predefined duty pattern and the current amplitude is roughly proportional to the controllable duty phase. Then, a voltage controller is designed to regulate the dc output voltage by tuning this duty phase. Finally, some simulated and experimental results have been given to illustrate the performances of the proposed DPC.

On the Front-End Converter and Its Control for a Battery Powered Switched-Reluctance Motor Drive

This paper presents the development of a front-end converter and its control for a battery powered switched-reluctance motor (SRM) drive. In motoring mode, the converter is operated as a dc-dc boost converter to establish dynamically boostable and well-regulated dc-link voltage from battery. The digital control schemes of boost converter and motor drive are implemented using a common digital signal processor. A proper voltage boosting feedback controller is designed to effectively enhance the SRM winding current and speed dynamic responses. Then the robust speed control performance is achieved by the proposed control scheme consisting of robust disturbance feedforward control and variable-structure system control. In addition, an effective regenerative braking control scheme for SRM is developed. In idle charging mode, the proposed front-end converter is arranged to act as a buck-type switch-mode rectifier (SMR) for charging the battery with good line power quality. Four diodes embedded in the SRM converter and the two motor phase winding inductances are employed to form the necessary constituted components of the SMR. The circuit and controller designs are presented, and good charging power conditioning performance is demonstrated experimentally.

On Acoustic-Noise-Reduction Control Using Random Switching Technique for Switch-Mode Rectifiers in PMSM Drive

This paper presents an acoustic-noise-reduction control using a random switching technique for front-end switch-mode rectifiers (SMRs) of a permanent-magnet synchronous-motor (PMSM) drive. First, the PMSM drive and its front-end ac-switch-based SMR are established. The proper controls are conducted to let the motor drive possess good driving characteristics. In the acoustic-noise-reduction control for a low-frequency SMR under a voltage closed-loop control, the important audible vibration modes of the SMR inductor are first identified from the measurements. Then, the controls for eliminating one specific vibration mode and two vibration modes simultaneously via deterministic and stochastic approaches are studied. Specifically, a novel random three-stage excitation scheme is devised. As to the high-frequency SMRs, the random switching frequency ramp-comparison current-controlled pulse-width modulation (CCPWM) scheme and the randomly varying band hysteresis CCPWM scheme are developed. Theoretical bases of all the proposed control approaches are derived, and their comparative performances are evaluated experimentally.

A Control Strategy for Output Maximisation of a PMSG-Based Variable-Speed Wind Turbine

This paper presents a control strategy for output maximisation of a direct drive permanent magnet synchronous generator (PMSG)-based small-scale variable-speed wind turbine. The control topology uses a single switch three-phase switch-mode rectifier and the generator torque, and power is controlled by controlling the switch duty cycle of the switch. To extract maximum power from the wind, the torque reference of the PMSG is calculated from generator speed and wind turbine characteristics. From this torque reference, a current reference is calculated using measured DC link voltage and generator speed. The current error is then used to control the duty cycle of the switch-mode rectifier and thereby torque of the generator is regulated through a proportionalintegral regulator. The operational characteristics of the generating system are investigated under varying wind speed through extensive simulations and the results confirm that the proposed control strategy can maximise the output power under fluctuating wind speeds.

Robust control of switch-mode rectifier considering nonlinear behaviour

This work presents the disturbance observer-based robust current and voltage controls for a digital signal processor (DSP)-based boost-type switch-mode rectifier (SMR) considering nonlinear behaviour. First, a robust current control scheme is developed to let the SMR inductor current waveform closely track its command around zero-crossing points, and hence the SMR possesses improved line drawn power quality. Then a robust voltage two-degrees-of-freedom control (2DOFC) scheme and its systematic design approach are proposed. In determining the power circuit components and the key parameters of the proposed robust control schemes, the compromise between the desired performance and the nonlinear behaviours is considered. Specifically, the adaptation of voltage robust compensation control is made according to the observed nonlinear phenomena. Experimental results confirm that robust and good voltage tracking and regulation responses are obtained by the developed SMR. Furthermore, the developed SMR is successfully applied to serve as a front-end converter of a switched reluctance motor drive, and its effectiveness in vibration reduction and power quality improvement is demonstrated experimentally.

Investigation of inverterless control of interior permanent-magnet alternators

This paper investigates the performance and control of a low-cost 6-kW concept demonstrator of an inverterless automotive alternator. This is based on a switched-mode rectifier (SMR) combined with a high-flux interior permanent-magnet (PM) machine. Duty cycle control of the SMR is described and the theoretical predictions are compared with open-loop experimental results. The efficiency of the concept demonstrator is examined as a function of speed and load. Control issues regarding automotive operation are discussed.