Deadbeat controlled PWM inverter with parameter estimation usingonly voltage sensor

A technique based on deadbeat control theory is proposed to obtain a nearly sinusoidal PWM (pulsewidth-modulated) inverter output voltage using only a voltage sensor. The closed loop sampled-data feedback scheme inherently results in very fast response to load disturbance and nonlinear load, producing low total harmonic distortion. Parameter estimation of the plant provides a type of self-tuning of the proposed controller. A theoretical analysis, simulation, and experimental results are presented for a single-phase PWM inverter controlled by an Intel 8086 microprocessor     

Discrete sliding-mode control of a PWM inverter for sinusoidaloutput waveform synthesis with optimal sliding curve

This paper presents a discrete sliding-mode control scheme with feedforward compensation for the closed-loop regulation of the pulse-width modulated (PWM) inverter used in an uninterruptible power supply (UPS). The proposed feedforward controller can effectively improve the tracking performance of the PWM inverter. In designing the sliding-mode controller, we have taken load disturbance into consideration to enhance the robustness of the PWM inverter. Moreover, the upper bound of the load disturbance under which the sliding condition can be maintained has also been derived. The sliding curve of the sliding-mode controller is designed such that the behavior of the controlled PWM inverter is optimal subject to the selected cost function. Due to the coordinate transformation proposed in this paper, only the output voltage needs to be measured as feedback for the purpose of closed-loop regulation. Simulation and experimental results are given to show the effectiveness of the proposed control scheme     

Vector current controlled voltage source converter-deadbeat controland saturation strategies

This paper presents a voltage source converter connected to a grid with software specially designed for limited control voltage. The voltage source converter uses a deadbeat vector current controller. The paper deals with limiting reference voltage, integrator windup and delay time compensation. Simulations and experimental verifications of the proposed controller are included     

Computer-based controller design for quantum boost series resonant rectifier

To obtain a stable output voltage from a recently-developed rectification circuit called a quantum boost series resonant rectifier (QBSRR), two control schemes, digital PI (proportional-integral) control and deadbeat control, are derived for a computer-based system. Since the output voltage regulation loop has a sampling time corresponding to the zero crossing point of the AC line voltage, the output voltage can be controlled regardless of the 120 Hz ripple component. By deriving a simple and exact model for the current program loop (open loop) of a QBSRR and using the pole-assignmenl technique, the controller gains can be systematically designed in the digital PI control scheme. The deadbeat control scheme is also developed to maintain fast dynamic performance in the presence of any load variations. In this control scheme, the controller gain is adjusted in accordance with the load information using a load estimation method. Simulation and experimental results are presented to verify the usefulness of these two control schemes.     

A discretized current control technique with delayed input voltagefeedback for a voltage-fed PWM inverter

A current control technique for a voltage-fed PWM inverter is presented. The discretized state equation of an inverter and a load independent of operating conditions with the delayed input voltage feedback has been derived using the averaging concept. The discretized current controller is proposed to reduce the current error as fast as possible using the deadbeat control strategy and to stabilize the closed loop system asymptotically when the variations of load parameters are given in the predetermined stabilized region. This proposed control scheme is realized by the symmetrical uniform sampling method and is easily implemented using a microprocessor-based system. Computer simulation for the proposed controller has been carried out and the results show good static and dynamic performances     

A new single-phase five-level PWM inverter employing a deadbeat control scheme

A single-phase five-level PWM inverter is presented to alleviate harmonic components of the output voltage and the load current. Operational principles with switching functions are analyzed. To keep the output voltage sinusoidal and to have the high dynamic performances even in the cases of load variations and the partial magnetization in filter inductor, the deadbeat controller is designed and implemented on a prototype. The validity of the proposed inverter is verified through simulation and experiments. To assess the proposed inverter, it is compared with the conventional single-phase three-level PWM inverter under the conditions of identical supply DC voltage and switching frequency. In addition, it is compared with the five-level cascaded PWM inverter.     

逆变器无差拍性能控制方案的分析与设计

分析了两种单电压环的无差拍控制方案。通过分析,比较了两者的异同,指出单纯保证输出电压无差拍控制方案的劣势。并详细分析了能够同时实现两个状态无差拍控制的单电压环控制方案。该方案利用输出电压反馈进行极点配置,实现系统对给定无差拍跟踪;利用负载电流进行前馈控制,实现系统对扰动的抑制。并针对控制策略进行了仿真,验证了方案的可行性。     

A Control Scheme for PWM Voltage-Source Distributed-Generation Inverters for Fast Load-Voltage Regulation and Effective Mitigation of Unbalanced Voltage Disturbances

This paper presents a control scheme for grid-connected pulsewidth-modulated voltage-source inverters (VSIs) featuring fast load-voltage regulation and effective mitigation of unbalanced voltage disturbances. To ensure perfect regulation of the voltage at the point of common coupling (PCC) and provide means for rejecting fast and dynamic voltage disturbances, the frequency modes of the disturbances to be eliminated should be included in the stable closed-loop system. Toward this, a hybrid voltage controller combining a linear with variable-structure control element is proposed for an inverter-based distributed-generation interface to regulate the voltage at the PCC. The proposed voltage controller can embed a wide band of frequency modes through an equivalent internal model. Subsequently, a wide range of voltage perturbations, including capacitor-switching disturbances, can be rejected. To account for unbalanced voltage disturbances, a dual-sequence voltage controller is proposed. To provide accurate and robust tracking of the generated active and reactive current trajectories, a newly designed deadbeat current control algorithm is proposed. The controller is designed under the practical considerations of inherent plant delays, which are associated with the digital implementation of the control algorithm, and the uncertain nature of the current dynamics. Theoretical analysis and comparative evaluation tests are presented to demonstrate the effectiveness of the proposed control scheme.     

Adaptive repetitive control of PWM inverters for very low THDAC-voltage regulation with unknown loads

An adaptive repetitive control scheme is proposed and applied to the control of a pulsewidth-modulated (PWM) inverter used in a high-performance AC power supply. The proposed control scheme can adaptively eliminate periodic distortions caused by unknown periodic load disturbances in an AC power supply. The proposed adaptive repetitive controller consists of a voltage regulator using state feedback control, a repetitive controller with tuning parameters and an adaptive controller with a recursive least-squares estimator (LSE). This adaptive repetitive controller designed for AC voltage regulation has been realized using a single-chip digital signal processor (DSP) TMS320C14 from Texas Instruments. Experimental verification has been carried out on a 2 kVA PWM inverter. Simulation and experimental results show that the DSP-based adaptive repetitive controller can achieve both good dynamic response and low total harmonic distortion (THD) under large-load disturbances and uncertainties     

Dual closed-loops current controller for a 4-leg shunt APF based on repetitive control

ABSTRACT

Current repetitive control strategy for a 4-leg APF is usually of a poor speed in responding to the drastic changes in load harmonic profile. In this paper, a dual closed-loop current controller composed of a repetitive control-based outer loop and a PI-based inner loop is proposed to improve the performance of a 4-leg APF, with a focus on response speed and harmonic current compensation gain. The principle of the dual loop controller is explained in detail, and the stability of the system is analysed thoroughly. To further decrease the inherent time delay associated with the PWM strategy, a zero-sequence-voltage-based PWM strategy is proposed to solve the complexity in the implementation of 3D-SVPWM methods. By formulating the relationship between the duty ratio of the neutral leg control pulse and the zero-sequence-component of the reference voltages, the duty ratios of the other three legs can be calculated conveniently. The simulation and lab experiment results are provided to verify the correctness and effectiveness of the proposed dual closed-loop current controller and the zero-sequence-voltage-based PWM strategy.     

High-performance programmable AC power source with low harmonicdistortion using DSP-based repetitive control technique

This paper proposes a new control scheme based on a two-layer control structure to improve both the transient and steady-state responses of a closed-loop regulated pulse-width-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation. The proposed two-layer controller consists of a tracking controller and a repetitive controller. Pole assignment with state feedback has been employed in designing the tracking controller for transient response improvement, and a repetitive control scheme was developed in synthesizing the repetitive controller for steady-state response improvement. A design procedure is given for synthesizing the repetitive controller for PWM inverters to minimize periodic errors induced by rectifier-type nonlinear loads. The proposed control scheme has been realized using a single-chip digital signal processor (DSP) TMS320C14 from Texas Instruments. A 2-kVA PWM inverter has been constructed to verify the proposed control scheme. Total harmonic distortion (THD) below 1.4% for a 60-Hz output voltage under a bridge-rectifier RC load with a current crest factor of 3 has been obtained. Simulation and experimental results show that the DSP-based fully digital-controlled PWM inverter can achieve both good dynamic response and low harmonics distortion     

A Hybrid-Type Variable-Structure Instantaneous Torque Control With a Robust Adaptive Torque Observer for a High-Performance Direct-Drive PMSM

This paper describes a novel instantaneous torque control scheme for a high-performance direct-drive permanent-magnet synchronous motor. The scheme consists of a robust adaptive instantaneous torque observer and a hybrid-type variable-structure instantaneous torque controller. First, to robustly obtain the instantaneous electromagnetic torque information, a robust adaptive torque observer is designed by considering all possible current model uncertainties. The observation gains and uncertainties prediction rules are derived in the sense of Lyapunov theory so that the stability of the proposed estimation scheme is fulfilled. Second, to ensure perfect tracking of the output torque and providing means in eliminating torque ripples, the frequency modes of the disturbances to be eliminated should be included in the stable closed-loop system. To achieve this objective, a hybrid-type variable-structure controller with internal model, for the flux harmonics and system uncertainties, is adopted. The hybrid controller shows better disturbance rejection without control chattering. Comparative evaluation results are presented to demonstrate the validity and effectiveness of the proposed instantaneous torque control scheme.     

自适应开启时间的Buck型DC-DC控制器设计实现

设计了一种基于自适应开启时间(adaptive on-time, AOT)控制的Buck型DC-DC控制器电路,利用输入电压前馈和输出电压反馈技术来获得开启时间,并提出了一种充电电流补偿和充电时间超前电路,校正了开启时间的线性度.AOT控制保证了转换器在无需内部振荡器的条件下,工作于固定频率脉冲宽度调制模式,并改善了输出电压的纹波特性.AOT控制使系统在负载阶跃时能够连续开启最小关断时间的开关周期或连续关断,从而快速调节电感电流,极大地提高了系统的瞬态响应速度.自动跳跃式脉冲频率调制模式,有效地改善了轻负载下的转换效率.芯片采用UMC 0.6μm BCD工艺投片验证,并出了详细的测试结果.     

Ultra Fast Fixed-Frequency Hysteretic Buck Converter With Maximum Charging Current Control and Adaptive Delay Compensation for DVS Applications

An integrated DC-DC hysteretic buck converter with ultrafast adaptive output transient response for reference tracking is presented. To achieve the fastest up-tracking speed, the maximum charging current control is introduced to charge up the output voltage with the maximum designed current. For down-tracking, the output is discharged by the load only to save energy. Although the converter works with hysteretic voltage mode control, an adaptive delay compensation scheme is employed to keep the switching frequency constant at 850 kHz to within plusmn2.5% across the whole operation range. The integrated buck converter was fabricated using a 0.35 mum CMOS process. With an input voltage of 3 V, the output voltage can be regulated between 0.5 and 2.5 V. With a load resistor of 10 Omega, the up-tracking speed of the maximum reference step (0.5 to 2.5 V) is 12.5 mus/V. All design features are verified by extensive measurements.     

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.     

Paralleled DSP-based soft switching-mode rectifiers with robust voltage regulation control

This paper presents the current sharing and robust voltage regulation controls for paralleled digital signal processor-based soft switching-mode rectifiers (SSMRs). First, the design and implementation of single-module SSMRs are made. In dealing with the current control loop design of each SSMR module, the small-signal model is derived and used to design the current-controlled pulse-width modulation (PWM) scheme. As to the common voltage control loop, its dynamic model is estimated from measurements. Then, a quantitative design procedure is developed to find the parameters of the voltage controller according to the prescribed control specifications. As the changes of parallel number and operating condition occur, the robust control is added to reduce the voltage regulation control performance degradation. The proposed multimodule operation control scheme consists of a master controller and N slave controllers. The former further consists of a common voltage controller and a current distribution unit, and the latter are the current-controlled PWM schemes of all SSMRs. Each slave controller receives the weighted sinusoidal current command from the master controller and regulates the feedback current of SSMR. The results confirm that the designed parallel SSMR system possesses good line drawn current power quality, module current sharing and voltage regulation control performances.     

基于DSP的三相PWM整流器控制系统设计

结合三相电压型PWM整流器的数学模型，引入三相电源电压前馈补偿，提出三相电流解耦的双闭环PI调节控制方法。根据控制系统响应速度快、保护功能强的要求，设计了以TMs320LF2407A为核心的控制系统，给出具体硬件电路和详细软件流程。实验结果验证了控制方法和控制系统的有效性。     

应用于PWM降压DC-DC变换器的高性能误差放大器

提出了一种应用于PWM降压型DC-DC变换器的高性能误差放大器。该误差放大器采用反馈结构,具有较大的动态范围,并可消除噪声影响,从而显著减小了DC-DC电源的纹波电压。另外,采用该误差放大器还有效地减小了电源启动时间。文中提出的误差放大器电路及PWM控制芯片的其他电路模块采用2.0μmBipolar工艺实现。仿真结果表明,误差放大器的开环和闭环增益分别为61dB和33dB,GBW为200MHz,SR为0.64V/μs。芯片测试结果表明,在输出电压为3.3V,负载电流为0.2A时,输出纹波电压的峰-峰值小于25mV。     

Lagrangian modeling and passivity-based control of three-phase AC/DC voltage-source converters

In this paper, we investigate the dc-bus voltage regulation problem for a three-phase boost-type pulsewidth-modulated (PWM) ac/dc converter using passivity-based control theory of Euler-Lagrange (EL) systems. The three-phase PWM ac/dc converters modeled in the a-b-c reference frame are first shown to be EL systems whose EL parameters are explicitly identified. The energy-dissipative properties of this model are fully retained under the d-q-axis transformation. Based on the transformed d-q EL model, passivity-based controllers are then synthesized using the techniques of energy shaping and damping injection. Two possible passivity-based feedback designs are discussed, leading to a feasible dynamic current-loop controller. Motivated from the usual power electronics control schemes and the study of Lee, the internal dc-bus voltage dynamics are regulated via an outer loop proportional plus integral (PI) controller cascaded to the d-axis current loop. Nonlinear PI control results of Desoer and Lin are applied to theoretically validate the proposed outer loop control scheme. The PWM ac/dc converter controlled by the proposed passivity-based current control scheme with outer loop PI compensation has the features of enhanced robustness under model uncertainties, decoupled current-loop dynamics, guaranteed zero steady-state error, and asymptotic rejection of constant load disturbance. Experimental results on a 1.5-kVA PC-based controlled prototype provide verification of these salient features. The experimental responses of a classical linear PI scheme are also included for comparative study.     

基于数字PID补偿的降压型DC-DC控制器

设计了一个基于数字PID控制,可为低压系统提供稳定电源的多相位降压型DC-DC控制电路,包括flash ADC、数字PID控制器;并设计了一种新的基于延时单元/计数器的数字PWM电路,实现了一个降压型控制器。电路使用3.3 V CMOS工艺设计,芯片面积为0.16 mm2,输入电压3 V,输出电压1.25 V,负载电流最大800 mA,纹波小于10 mV,开关频率1 MHz,效率最高达到90%。