Modulated Hysteresis Current Controller Research Articles

A modified hysteresis current controller with DFCEA for current harmonic mitigation using PV-SHAPF

ABSTRACT A Modified Hysteresis Current Controller (MHCC) with Dual Fundamental Component Extraction Algorithm (DFCEA) is presented in this paper. Its purpose is to improve the current harmonics mitigation performance of a three-level T-type inverter-based Shunt Active Power Filter (SHAPF) while operating under non-sinusoidal voltage conditions. The DFCEA is responsible for isolating the fundamental voltage and current components that are necessary for synchronizing each phase and producing the reference current. The existing dual fundamental component extraction technique is updated in order to create the optimized reference currents that are required by the proposed PV-linked T-Type inverter-based Shunt Active Power Filter (PV-SHAPF). This was done in order to meet the requirements of the PV-SHAPF. It is also anticipated that it is excellent at extracting reference currents even under situations of voltage that are not optimum. To maintain the dc-link capacitor voltage at 600 V, a control algorithm of the dc-link capacitor known as the ‘DC link voltage controller’ is used. Both control algorithms are tested in a three-phase T-Type inverter-based PV-SHAPF by simulating them in a MATLAB/Simulink environment. The performance of the MHCC-DFCEA that was designed to mitigate current harmonics was proven by the findings that were gathered.

Adaptive Dead-Time and Partial-ZVS Regulation for GaN-Based Active Clamp Flyback Converter With Predictive Hysteresis Current Mode Control

Active clamp flyback (ACF) converter is regarded as a good candidate in high-frequency small-size adapters. With adaptive dead-time optimization method, there is no reverse conduction loss and switching-on loss in power switches, then ACF can realize optimum full-ZVS control at every operating conditions. However, the other losses such as the conduction loss of clamp switch, the primary winding loss of transformer may be increased to counteract this efficiency advantage, but which has not been outlined. Therefore, this paper proposes a higher-efficiency predicted hysteresis current mode (PHCM) control strategy with adaptive dead-time and partial-ZVS regulation for GaN-based ACF converter for the first time. Firstly, the accurate analytical model by considering above losses is derived. Secondly, the optimal valley current is calculated by the minimum loss, to determine the conduction time of clamp switch and the dead time of main switch. Finally, a digital controlled GaN-based ACF converter is designed to verify the method. The computation speed of needed analytical equations and the magnetizing inductance offset are considered in implementation process. The experimental results show the proposed method can improve efficiency by 0.4% than existing method, which also show a fast dynamic response since the cycle-by-cycle variable-frequency control concept.

An ultra‐low quiescent current tri‐mode DC–DC boost converter with 95.6% peak efficiency for internet of things application

AbstractAn ultra‐low quiescent current tri‐mode DC–DC boost converter is proposed in this paper, which can efficiently handle loads from 1 μA to 300 mA, providing 5‐V output from 3 to 4.2‐V input. Hysteresis current mode control is adopted to realize seamless mode switching between continuous conduction mode (CCM) and discontinuous conduction mode (DCM). In order to deal with the light load situation, this paper proposes a quasi burst mode (QBM). In this mode, most of the modules are turned off and only the QBM controller, low‐power current bias and sample and hold circuit are retained, which significantly reduces the static current of the converter, and thus improves the light load efficiency. Meanwhile, the average current of error amplifier and comparator are reduced significantly by dynamic biasing. Finally, the efficiency of the converter is greatly improved and kept at a reasonable output ripple. The proposed converter is implemented in a 0.13‐μm BCD process design and manufacturing. The test results show that the quiescent current of the converter is only 780 nA, which can achieve a peak efficiency of 95.6%, and ensure that the efficiency is maintained above 80% in the load range of 10 μA to 300 mA.

Performance Improvement of Shunt Active Power Filter using Modified Hysteresis Current Controller

Performance Improvement of Shunt Active Power Filter using Modified Hysteresis Current Controller

Modified hysteresis current controller for cascadedH‐Bridgeinverter–basedSTATCOM

Modified hysteresis current controller for cascaded<scp>H‐Bridge</scp>inverter–based<scp>STATCOM</scp>

Modified hysteresis current control of multilevel converter for grid connected battery storage system

Due to active power demand in the distributed power system, the large voltage deviation appears in the grid network. The battery energy storage system is optimal solution to support the active power when it is needed, which improves the voltage stability. To maintain the accuracy in the active power injection, the modified hysteresis current control of multilevel converter for grid connected battery storage system is proposed in this paper. It supplies accurate active power by estimating the exact reference current from the grid voltage at every sampling period. This novel control mechanism ensures that there will not be any mismatch in the active power requirement and supply; thereby it enhances the quality of grid under nay situation. The detailed control block diagram is addressed to generate the required PWM signals. And also, the detailed operating waveforms are discussed in this paper. The equivalent circuit of power transfer to grid is also reported in this paper. Mathematically it gives that the proposed approach can inject the actual active power needed by the system. To validate the proposed modified hysteresis current control scheme of multi-level converter, the entire simulation study has been developed and carried out in PSCAD/EMDTC software. The measured results observed and presented in this paper and also it confirms that the proposed has practical feasibilities to implement in the real system.

Analysis of Current Error Space Phasor for a Space Vector-Modulated Indirect Matrix Converter

AC motor drives fed from current-controlled power electronic converters are popular on account of their superior steady-state and transient performance. Hysteresis control is a popular current control technique, which needs modifications to compensate for its demerits. Appraisal of current error as a space phasor for implementing the hysteresis controller is one such modification. Current error space phasor (CESP)-based hysteresis controller for voltage source inverters-fed motor drives are capable of achieving superior dynamic performance. With the modified hysteresis current controller, the drive operates at a constant switching frequency and ensures an optimal switching vector selection. This article presents the analysis of CESP for a space vector-modulated indirect matrix converter (IMC). The modified algorithm for space vector modulation of IMC accommodates for the variations in dc-link voltage since CESP is input voltage dependent. The boundary for the hysteresis current controller is calculated from the computed values of CESP. The time-varying nature of the hysteresis boundary ensures a constant switching frequency operation for IMC. Thus, a CESP-based hysteresis controller is proposed for the vector control of the IMC-fed permanent magnet synchronous machine (PMSM) drive. Experimental results are presented for validating the performance of the proposed controller.

Investigations on STATCOM using current error space phasor based modified hysteresis current controller

Investigations on STATCOM using current error space phasor based modified hysteresis current controller

Variable Frequency Average Current Mode Control for ZVS Symmetrical Dual-Buck H-Bridge All-GaN Inverter

The quasi-square-wave (QSW) zero-voltage-switching (ZVS) symmetrical dual-buck H-bridge (DBHB) all-GaN inverter has been proven to have high efficiency and high density in Google's Little Box Challenge. This variable frequency QSW ZVS inverter is drawing more and more interest in the industry and academia. However, the ac current control with cycle-by-cycle variable frequency ZVS operation is a basic challenge for this inverter. The conventional control methods for this QSW ZVS inverter, such as the hysteresis current mode control and the variable on-time control, require high-speed current sensing or zero-crossing detection (ZCD) circuits, which are very sensitive to noises. In this article, achieving variable frequency average current mode control with variable frequency pulsewidth modulation (VFPWM) is discussed and implemented for this QSW ZVS inverter to eliminate high-speed current sensing or ZCD circuits. For any synchronous half-bridge type converter, the voltage conversion ratio is dependent only on the duty-cycle in either continuous conduction mode (CCM) or QSW ZVS mode. The frequency of the PWM triangular carrier is another degree of freedom. In this control method, the averaged inductor current is sensed and regulated by the average current mode feedback controller and the duty-cycle is generated by the average current controller. The frequency of the PWM carrier is variable and directly calculated based on the duty-cycle signal and the sensed and filtered voltage and current signals. Since all the sensed signals for this current controller are low speed and filtered signals, this current control is highly immune to noises. The reliability of ZVS for this inverter is improved. The complexity of the controller is also reduced. A detailed analysis of the QSW ZVS conditions for the full range operation of the symmetrical DBHB inverter is done in this article. More negative currents can be introduced to reduce the switching frequency and increase the reliability of ZVS. A frequency limiter helps limit the frequency when the current is close to zero or under light load conditions. A frequency updating method with a constant and low interrupt frequency in a digital controller is also discussed. Finally, to verify this control method, a 1-kW all-GaN DBHB inverter prototype is developed and tested in this article.

Comparative Study between Shunt Active Filter and Hybrid Filter

This paper presents an comparative study between shunt active filter and shunt hybrid filter based on configuration system and harmonic isolation. The harmonic isolator isbased on Self Tuning Filters (STF) (it can be tuned at any frequency). The study of the active filter control is divided in two parts. The first part deals with the harmonic isolator which generates the harmonic reference currents. The second part focuses on the generation of the switching pattern of the IGBTs of the inverter by the modulated hysteresis current controller. The studied hybrid active filter consists of an active filter and three phase tuned LC filters for 7th harmonic frequency. The nonlinear load is a diode rectifier feeding a (R, C) parallel load. The use of STF's simplifies the control scheme by reducing the number of extraction filters. The use of STFs instead of classical extraction filters allows extracting directly the voltage and current fundamental components. The effectiveness of this study has been verified by computer simulation and comparing the results.

Improved bacterial foraging optimization for grid connected wind energy conversion system based PMSG with matrix converter

Abstract This paper proposes an improved fast dynamic system for controlling Matrix Converter (MC) based on modified hysteresis current controller using optimal tuning PI controller. An improved Bacterial Foraging Optimization (BFO) technique is employed for controlling the active and reactive current components of the Permanent Magnet Synchronous Generator (PMSG) to extract the maximum power from the wind. This proposed controller has the ability to supply the grid by both active and reactive power at normal and fault conditions. Dynamic limiter is employed with the proposed improved BFO controller to control the injected reactive power to the grid during Low Voltage Ride Through (LVRT) at a range limited by MC rated current to improve the system stability. The pitch angle controller with rate limiter was implemented in the proposed controller to protect WECS from mechanical damage. The simulation results prove the validity of the proposed controller under any conditions.

New Method to Harmonic Isolation Based on High Selectivity Filter to Control of Shunt Active Filter with Experimental Validation Using DSPACE System

This paper presents a new control method of a parallel active power filters based on improved harmonic isolation with hardware implementation. The harmonic isolator is based on High Selectivity Filters (it can be tuned at any frequency) and the current control technique consists in a modulated hysteresis current controller. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load. The study of the active filter control is divided in two parts. The first part deals with the harmonic isolator which generates the harmonic reference currents and is implemented into a DSPACE DS1104 prototyping card. The second part focuses on the generation of the switching pattern of the IGBTs of the inverter by the modulated hysteresis current controller, implemented into an analogue card. The use of High Selectivity Filters instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the α-β axis at high performances. The effectiveness of the new proposed method is verified by computer simulation and by experimental study.

Comparative Study of Three Phase Four Wire Shunt Active Power Filter Topologies based Fuzzy Logic DC Bus Voltage Control

In this paper, a comparative study based fuzzy logic DC bus voltage control for three phase four wire shunt active power filter for two different inverter topologies, three-leg splitcapacitor topology (TLSC) and four-leg inverter (FLFB) are proposed. Identification of reference currents will be developed by classical extraction filters based on pq theory in the first section of the paper. DC-bus voltage control in three-phase four-wire shunt active filter is treated by a fuzzy logic control. A comparison of the proposed method against the conventional proportional integral is illustrated with two different inverter topologies through simulation results and a clear advantage of the fuzzy logic control can be observed. Moreover, the switching pattern of the inverter is generated by a modulated hysteresis current controller. All simulations have been realized in the same conditions so results can be compared with each other. The effectiveness of the proposed method is verified by MATLAB software.

Adaptive Modified Hysteresis Current Control for Reduction of Switching Losses in Grid Connected Solar Inverters

Current Control logic plays an important role in the performance of Grid connected inverters. In the present work Adaptive Modified Hysteresis controller has been used for generation of switching pulses to the minimally switched grid connected inverter. Different from the previous works the new control logic helps in maintaining the instantaneous switching frequency low and nearly constant with reduction of switching losses to one-third of that of the conventional type. Considerable reduction in Total harmonic distortion of supply current, better DC bus voltage stabilization, good reactive power compensation, satisfactory performance under unbalanced source and load conditions and good dynamic response is also achieved. The experimental verification is done using SIMULINK/REALTIME WINDOWS TARGET. Present control logic is compared with conventional hysteresis controller with and without adaptive control to prove the effectiveness.

Enhanced PLL based SRF control method for UPQC with fault protection under unbalanced load conditions

This paper presents novel control strategy of a three-phase four-wire unified power quality conditioner (UPQC). It is used to improve power quality in distribution system. The UPQC is realized by the integration of series and parallel active power filter (SAPF and PAPF) sharing a common dc bus capacitor. The realization of parallel APF and series APF are carried out using a three-phase, three legs voltage source inverter (VSI) with split capacitor. In both APFs the fundamental source voltages and currents are extracted by synchronous reference frame technique. SAPF connected with the supply by series transformer. The secondary of series transformer is affected by load side short circuits. This paper also explains the control circuit for protection of series transformer against over voltage and over current. PAPF connected with the system by series inductance. The performance of the applied control algorithm of shunt active filter with series active filter is evaluated in terms of power-factor correction, load balancing, and mitigation of voltage and current harmonics in a three-phase four-wire distribution system for non-linear load, unbalanced supply and load conditions . Sinusoidal PWM current controller, modulated hysteresis current controller are used for generation of switching pulses to series and parallel APFs. The two control algorithm is simulated by use of MATLAB/Simulink-based environment and the obtained results validated through experimental study with the UPQC hardware prototype.

PI and Fuzzy Hysteresis Current Controlled Inverter for PMSM Based EVs Drives

This paper presents a modified hysteresis current control using fuzzy tuned PI current control technique for field oriented control (IFOC) of permanent magnet synchronous motor (PMSM) based Electrical vehicle (EV) drives. In fact, a comparative study of three IFOC drives of PMSM using different current control schemes: the first with conventional hysteresis current control, the second with conventional PI-hysteresis current control and the third with fuzzy tuning PI- hysteresis current control. The simulation was carried out using these current control techniques to study the performance of the PMSM drive. This study proves the high current and torque ripple reduction of the fuzzy tuning PI-hysteresis current control technique comparing to the others current control techniques.

Modeling and Analysis of Projected Cross Point Control—A New Current-Mode-Control Approach

This paper features the projected cross point control (PCPC) approach which is a recent current-mode control (CMC) technique. PCPC benefits from several advantages including fixed switching frequency, wide stability range, high current loop gain, improved audio susceptibility, and simpler design procedure. An introduction of its principles of operation is followed by detailed discussions about its stability and dynamic response. This paper then describes the development of the small-signal model of PCPC and derives transfer functions, such as current loop gain, audio susceptibility, and output impedance. Finally, simulations and experimental results are presented. Peak, average, and hysteresis CMC schemes are used for comparison.

Low cost single stage micro-inverter with MPPT for grid connected applications

This paper presents a novel control and modulation technique applied to a low cost single stage solar micro-inverter. Multiple modulation strategies are analysed and finally an optimal one is proposed and implemented in order to obtain a low total harmonic distortion factor and a power factor close to unity of the current supplied to the grid. The luminosity step time response of the system is improved using two analog control loops: a hysteresis current mode control loop and a voltage loop on the input solar panel voltage. A MPPT power loop is also implemented in order to harvest maximum energy from the solar panel. The simulation times of the entire system is improved by implementing an average model for the inverter. In this way multiple control strategies and MPPT algorithms can be tested and compared in a shorter time. The experimental results validate the theoretical and simulated ones.

Performance investigation of modified hysteresis current controller with the permanent magnet synchronous motor drive

This study presents complete permanent magnet synchronous motor (PMSM) drive scheme along with mathematical model of motor and inverter. Speed proportional integral (PI) controller parameters are designed in discrete time domain. Stability of the speed controller is observed with respect to motor-load parameters. A modified hysteresis current control scheme is implemented for the drive and a detailed comparative study is done with conventional hysteresis current control scheme. Merits of the modified hysteresis current controller over conventional hysteresis current controller are investigated with both simulation and experimental results.

New digital reference current generation for shunt active power filter under distorted voltage conditions

In this paper, a new reference current computation method suitable for shunt active power filter control under distorted voltage conditions is proposed. The active power filter control is based on the use of self-tuning filters (STF) for the reference current generation and on a modulated hysteresis current controller. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load under distorted voltage conditions. The study of the active filter control is divided in two parts. The first one deals with the harmonic isolator which generates the harmonic reference currents and is experimentally implemented in a DS1104 card of a DSPACE prototyping system. The second part focuses on the generation of the switching pattern of the inverter by using a modulated hysteresis current controller, implemented in an analogue card. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the α–β axis without phase locked loop (PLL). The performances are good even under distorted voltage conditions. First, the effectiveness of the new proposed method is mathematically studied and verified by computer simulation. Then, experimental results are presented using a DSPACE system associated with the analogue current controller for a real shunt active power filter.