New optimal predictive current mode control technique for bilevel quantum series resonant convertors

A new optimal predictive current mode control technique is proposed to improve the performance of a bilevel quantum series resonant convertor. With this technique, the fast transient response with negligible overshoot and the minimised current ripple with reduced offset current can be available.<>     

DSP-based active power filter with predictive current control

This paper presents an active power filter based on a digital signal processing (DSP) controller with enhanced current control performance. A novel predictive current control method is introduced to compensate the phase error of harmonic components caused by discrete sampling and finite nonnegligible execution time delay. The concept of average current control is also introduced that is adequate for digital current control. With a close coordination between the reference current prediction, PWM pattern generation, and control timing, a high performance control is achieved. Experimental results show that the developed system gives satisfactory performance in harmonic and reactive power compensation     

Design and implementation of current mode circuit for digital modulation

This paper proposes a new current-mode digital modulation circuit. The proposed circuit is MOS only hence, easily integrable. It employs an Extra X Current Conveyor (EX-CCII), two MOS transistors as switches, and a two MOS transistor-based active resistor. The amplitude shift keying/phase shift keying/frequency shift keying (ASK/PSK/FSK) modulator is obtained by proper selection of carriers (I_C1, I_C2). This circuit provides the current output signal at high output impedance, which is favorable for cascading. Also, the circuit is employing only MOS transistors, so it can be monolithically IC implementable. The effects of non-idealities and parasitics of the active element on the circuit performance are also investigated in detail. The functionality of the proposed digital modulator is verified through the Cadence Virtuoso tool using 0.18 μm Generic Process Design Kits parameters with the ±0.9 V supply voltage. The total area of the layout is 968.75 μm². Also, the experimental results are verified by using the IC AD-844 and IC CD4007.     

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°. Digitally simulated performance results are provided. Selected experimental results demonstrating the SMR operation are also presented     

A new current mode control process and applications

A stability analysis of constant frequency current mode power converters is presented. A current mode control method that overcomes the limited duty cycle range of stability is introduced. The authors present the application of the control method to half bridge and full bridge converters, and describe an improved performance uninterruptible power supply (UPS) based on the method. The UPS has only one power transformer and one power transistor bridge. The authors present detailed experimental results which confirm the advantages of the circuits     

Improved digital current control methods in switched reluctancemotor drives

This paper proposes a method to avoid current feedback filters in fast digital-based current loops in switched reluctance drives. Symmetrical pulsewidth modulation (PWM) and synchronized sampling of the phase current allow a noise-free current sampling with no antialiasing filter. This paper also proposes more efficient methods to chop the two transistors in the asymmetric inverter used with switched reluctance drives. A fast field-programmable gate array (FPGA)-based test system is used for validation of the new methods. Test results show a significant improvement in dynamic and steady-state current loop control compared with traditional methods. The new chopping method is found to reduce the switching losses and increase the drive efficiency     

Estimative current mode control technique for DC-DC converters operating in discontinuous conduction mode

A new control technique for DC-DC converters is introduced and applied to a boost converter operating in discontinuous conduction mode (DCM). In contrast to conventional control methods, the principal idea of the proposed control scheme is to obtain samples of the required signals and estimate the required switch-on time. The proposed technique is applicable to any converter operating in DCM, including power factor correctors (PFC), however, this letter mainly focuses on boost topology. In this letter, the main mathematical concept of a new control algorithm is introduced, as well as the robustness investigation of the proposed method with simulation and experimental results.     

Switched optimal predictive current control technique for improved quantum boost SRC

A dynamic model and a switched optimal predictive current control technique for an improved quantum boost series resonant convertor (SRC) are proposed to overcome the inherent disadvantages of the quantum SRC. With this technique, the current ripple and the overshoot can be minimised and the buck-boost operation can also be achieved.<>     

Odd-harmonic digital repetitive control of a single-phase current active filter

Shunt active power filters have been proved as useful elements to correct distorted currents caused by nonlinear loads in power distribution systems. This work presents an all-digital approach, based on the repetitive control technique, for their control. In particular, a special digital repetitive plug-in controller for odd-harmonic discrete-time periodic references and disturbances is used. This approach does not introduce high gain at those frequencies for which it is not needed, and thus it improves robustness. Additionally, the necessary data memory capacity is lower than in traditional repetitive controllers. The design is performed for the particular case of single-phase shunt active filter with a full-bridge boost topology. Several experimental results are also presented to show the good behavior of the closed-loop system.     

A digital current control technique for voltage-fed induction motor drives

Precise control of stator current is essential to high performance field orientation controlled induction motor drives. Any current error degrades the performance of the drive in the same way as incorrect tuning of field orientation. Previous research has shown that accurate current control can be achieved with intelligent but complex control algorithms. This paper presents a new current control scheme which can achieve high accuracy and fast dynamic response but which is very simple for microprocessor implementation. The scheme was derived using the discrete state space modelling of the induction motor. The control law does not require knowledge of rotor flux and was independent of the field orientation control tuning. Good static and dynamic performances were obtained in both the simulation and experimental verifications. The results also show that the leakage inductance model error might cause a current ripple. However, this parameter can be tuned to its correct value easily by inspecting the current response.     

A single-inductor dual-output switching converter with average current mode control

are about 40 mV at an oscillator frequency of 600 kHz.     

一种平均电流模式控制的单电感双输出型开关电源转换器

An integrated single-inductor dual-output （SIDO） switching DC-DC converter is presented. The outputs are specified with 1.2 V/400 mA and 1.8 V/200 mA. A decoupling small signal model is proposed to analyze the multi-loop system and to design the on-chip compensators. An average current control mode is introduced with lossless, continuous current detection. The converter has been fabricated in a 0.25μm 2P4M CMOS process. The power efficiency is 86% at a total output power of 840 mW while the output ripples are about 40 mV at an oscillator frequency of 600 kHz.     

Digital control of induction motor current with deadbeat responseusing predictive state observer

For a high-power induction motor drive, the switching frequency of the inverter cannot become higher than one kilohertz, and such a switching frequency produces a large current ripple, which then produces torque ripple. To minimize the current ripple, a method based on deadbeat control theory for current regulation is proposed. The pulsewidth modulation (PWM) pattern is determined at every sampling instant based on stator current measurements, motor speed, current references, and rotor flux vector, which is predicted by a state observer with variable poles selection, so that the stator currents are controlled to be exactly equal to the reference currents at every sampling instant. The proposed method consists of two parts: (1) derivation of a deadbeat control and (2) construction of a state observer that predicts the rotor flux and the stator currents in the next sampling instant. This paper describes a theoretical analysis, computer simulations and experimental results     

Robust model predictive current control strategy for three-phase voltage source PWM rectifiers

Traditional model predictive control (MPC) strategy is highly dependent on the model and has poor robustness. To solve the problems, this paper proposes a robust model predictive current control strategy based on a disturbance observer. According to the current predictive model of three-phase voltage source PWM rectifiers (VSR), voltage vectors were selected by minimizing current errors in a fixed time interval. The operating procedure of the MPC scheme and the cause of errors were analysed when errors existed in the model. A disturbance observer was employed to eliminate the disturbance generated by model parameters mismatch via feed-forward compensation, which strengthened the robustness of the control system. To solve the problem caused by filter delay in MPC control, an improved compensation algorithm for the observer was presented. Simulation and experimental results indicate that the proposed robust model predictive current control scheme presents a better dynamic response and has stronger robustness compared with the traditional MPC.     

Optimal two-vector combination-based model predictive current control with compensation for PMSM drives

The duty-ratio-based model predictive control (D-MPC) is rapidly researched for permanent-magnet synchronous machine (PMSM) drives. Existing D-MPC methods produce large current ripple and distortion. To solve this issue and promote the system performance, an optimal two-vector combination MPC (OTC-MPC) is proposed for current control in this paper. The collection of the combination is firstly produced for the proposed OTC-MPC by combining the two vectors and corresponding duty-ratio, and then the optimal combination is selected among all feasible two-vector combinations, thus, the output vectors and duty-ratio are simultaneously optimised. The optimising process is simplified so that the proposed OTC-MPC can be easily implemented. Moreover, a simplified repetitive control with feed-forward compensation method is added to eliminate the predictive current errors of MPC, and also to improve the system robustness against external disturbances. Theoretical analysis, simulation and experimental results demonstrate that the proposed OTC-MPC effectively reduces current ripple and distortion while retaining fast dynamic response compared with the conventional D-MPC.     

A new digital zero average current error control algorithm for inverters

Inverter performance is typically measured against its ability to produce a high fidelity output sinusoidal waveform with narrow band switching frequency and good transient response. For this purpose, pulse-width modulation techniques are used to generate the required control signals for the inverter semiconductor switches. Current control voltage-source inverters can be realized using one of the recently proposed zero average current error (ZACE) techniques based on analogue technology. A new and improved algorithm that belongs to the family of ZACE methods suitable for digital technology is proposed in this paper. Advantages include a more robust algorithm with quicker computation allowing fast response and higher switching frequency from a digital signal processor. The effectiveness of the new current control algorithm is demonstrated through simulations first. Experimental results taken from a low power laboratory prototype are also presented to verify the theoretical considerations.     

A digital automatic current control system based on an optimumassumed model

In this paper, a new ACR (automatic current regulator) scheme is introduced for brushless DC motors. It consists of a model closely resembling the motor and PWM inverter, an assumed rising pattern of the current, and a parameter estimation. Using the control scheme, the mean value of the motor current is kept at the reference current, and the transient current of the motor is kept equal to the rising pattern. For the disturbance, because of DC-line voltage change, the proportional path from the error to the duty cycle of the PWM signal stabilizes the ACR. This ACR scheme can be realized with a microcomputer     

Primary side detection and peak current mode control in flyback converter

A new cycle-by-cycle control flyback converter with primary side detection and peak current mode control is proposed and its dynamic characteristics are analyzed.The flyback converter is verified by the OrCAD simulator.The main advantages of this converter over the conventional one are simplicity,small size,rapid regulating and no sensing control signals over the isolation barrier.The circuit is suitable for digital control implementations.     

A sliding mode current control scheme for PWM brushless DC motordrives

This paper proposes a sliding mode current control scheme for pulsewidth modulation (PWM) brushless DC motor drives. An improved “equivalent control” method is used in this scheme. A simple algorithm is proposed that differs from the original equivalent control method, which requires extensive calculation to estimate the load parameters. This algorithm can be implemented using logic circuits. Moreover, using autotuning, the proposed algorithm can be applied without load information. An operating principle for the power stage switching devices called single-side firing is also proposed. Single-side firing solves the dead-time problem, allowing the PWM frequency to be increased and the sampling rate to be raised. This paper explains the current control algorithm, single-side firing principle, and implementation of the proposed scheme in detail. Simulations and experimental results are given to show the validity of this scheme