Hysteresis Current Control Technique Research Articles

A novel PWM scheme for single-phase three-level power-factor-correction circuit

This paper presents a control scheme for a single-phase AC-to-DC power converter with three-level pulsewidth modulation. A single-phase power-factor-correction circuit is proposed to improve the power quality. The hysteresis current control technique for a diode bridge, with two power switches is adopted to achieve a high power factor and low harmonic distortion. A control scheme is presented where the line current is driven to follow the reference sinusoidal current which is derived from the DC-link voltage regulator, the capacitor voltage balance compensator and the output power estimator. The blocking voltage of each power device is clamped to half of the DC-link voltage. The high power factor and low current total harmonic distortion are verified by computer simulations and hardware tests.

Single‐phase three‐level PWM rectifier with power‐factor correction

AbstractA novel control strategy for single‐phase unidirectional switching‐mode rectifier (SMR) that draws a sinusoidal line current in phase with the supply voltage is proposed and discussed in this paper. In the adopted circuit topology, two AC power switches are placed between the AC side of the SMR and the center‐tapped terminal of the DC‐link capacitors. The control schemes are based on the hysteresis current control (HCC) technique and the simple look‐up table. The control schemes, stored in a programmable array logic (PAL), are implemented such that the line current is driven to follow the current command. There are three voltage levels (uDC, uDC/2, 0) on the AC side of the rectifier in each half cycle. The blocking voltage of each AC power switch is clamping to half of the DC‐link voltage. Software simulations and experimental circuits are implemented and measured to verify the proposed control strategy.

Multilevel AC/DC/AC converter for AC drives

A novel pulse width modulation (PWM) scheme for a multilevel AC/DC/AC converter is proposed. A power factor corrector using the hysteresis current control technique is presented to improve the power quality at the rectifier side. The circuit configuration of the adopted five-level rectifier has two AC power switches and one diode bridge. The proposed control scheme of the five-level rectifier is based on a look-up table that is implemented by programmable array logic (PAL). According to the proposed control method, the line current will follow the reference current with unity power factor. The reference supply current is derived from a DC link voltage regulator and an output power estimator. A three-level diode clamped voltage source inverter is used to reduce the output voltage harmonics and blocking voltage of each power device in each leg. The high power factor and low current distortion at the input of the rectifier and the low total harmonic distortion at the output of the inverter are verified by the experimental results.

A new control scheme for single-phase PWM multilevel rectifier with power-factor correction

A new control scheme for a single-phase bridge rectifier with three-level pulsewidth modulation is proposed to achieve high power factor and low current distortion. The main circuit consists of a diode-bridge rectifier, a boost inductor, two AC power switches, and two capacitors. According to the proposed control scheme based on a voltage comparator and hysteresis current control technique, the output capacitor voltages are balanced and the line current will follow the supply current command. The supply current command is derived from a DC-link voltage regulator and an output power estimator. The major advantage of using a three-level rectifier is that the blocking voltage of each AC power device is clamping to half of the DC-link voltage and the generated harmonics of the three-level rectifier are less than those of the conventional two-level rectifier. There are five voltage levels (0, /spl plusmn/V/sub DC//2, /spl plusmn/V/sub DC/) on the AC side of the diode rectifier. The high power factor and low harmonic currents at the input of the rectifier are verified by software simulations and experimental tests.

A unity power factor converter using half-bridge boost topology

A single-phase high-efficiency near-unity power-factor (PF) half-bridge boost converter circuit, which has been proposed earlier by other researchers, is presented with detailed analysis. This converter is capable of operating under variable PF. However, the focus of this paper is in achieving unity PF operation only. The efficiency of this circuit is high because there is only one series semiconductor on-state voltage drop at any instant. The existence of an imbalance in the voltages of the two DC-link capacitors, which was noted before, is confirmed here. The cause for the imbalance is analyzed using appropriate models, and a control method to eliminate it is discussed in detail. Analysis and design considerations for the power circuit using the fixed-band hysteresis current control (HCC) technique are provided. The analytical results are verified through simulation using switched and averaged circuit models of the scheme and also through experimental work. At 90-V AC input and 300-W 300-V output, the experimental prototype demonstrates an efficiency of 96.23% and a PF of 0.998. This converter, with its relatively high DC-output voltage, is well suited for the 110-V utility supply system. A circuit modification for universal input voltage range operation is also suggested.

High power factor correction circuits with space vector and hysteresis control methods

This paper presents a new topology of the three-phase ac to dc converter. Only three ac switches are required to perform the power factor correction. The series connection of the two output capacitors is adapted to employ the high dc output voltage. A space vector modulation strategy is used to control two of the three ac switches at any time, hence the switching numbers can be reduced. The addition of a hysteresis current control technique can simplify the hardware circuit and reduce the cost. Furthermore the input current can be made to follow any desired waveform. Finally, simulation and experimental results are presented to verify the characteristics of unity power factor and sinusoidal input current.

Three-phase switch mode rectifier with hysteresis current control

A three-phase configuration of a switch mode rectifier (SMR) that makes use of continuous conduction waveform of the input supply current is suggested. Continuous conduction is achieved by the hysteresis current control (HCC) technique. This three-phase SMR operates at close to unity power factor and has reduced current stresses on the switching devices because of the continuous nature of input current. The conduction period considered for the rectifier diodes is 180/spl deg/. Digitally simulated performance results are provided. Selected experimental results demonstrating the SMR operation are also presented.

Simulation and analysis of brushless DC motor drives using hysteresis, ramp comparison and predictive current control techniques

The brushless DC motor with a permanent magnet rotor is considered for the present study. Because of the special structure of the motor, it produces a trapezoidal back electromotive force (EMF). The applied current waveform is rectangular-shaped. Non-ideal effects in the trapezoidal back EMF and motor currents generate a pulsating torque. The reduction of the torque ripple is important from a speed and position control point of view. In the present paper a brushless dc motor drive is simulated and analyzed using hysteresis, ramp comparison and predictive current control schemes. By comparing the results obtained using these techniques, advantages and disadvantages of each technique and its range of applications are discussed.

Digital adaptive hysteresis current control with clocked commutations and wide operating range

A new hysteresis current control technique for voltage source inverters is proposed, which uses digital calculation to predict the proper band amplitude in order to minimize the error and give a switching frequency synchronized with a clock. The technique is self-adapting to supply and load parameters, and is easily extended to three-phase systems using the decoupling approach already proposed by the same authors. The proposed technique exhibits both the advantages typical of the hysteresis methods, and those of the digital controls. The implementation of the control is done by means of a standard microcontroller and simple additional circuitry. Simulations and experimental tests confirmed the advantages and the excellent performance of the new modulation method. >

Automated adaptive hysteresis current control technique for a voltage-fed PWM inverter

An adaptive hysteresis current control technique where the hysteresis band is automatically modulated by the input voltage integrator without the load information to maintain the modulation frequency nearly constant is presented. The computer simulation for the proposed current controller has been done and the results show good static and dynamic performances.