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Interior Permanent Magnet Synchronous Motors (IPMSMs) offer excellent features, however, the dynamic complexity of these motors has always caused a challenge to control them. In addition, Field Oriented Control (FOC) method developed using Proportional–Integral (PI) regulators, which is the most implemented approach to control the IPMSM, is associated with slow dynamic response and saturation in the controller. This paper presents a novel control algorithm based on State Feedback (SF) regulator for IPMSM drives. The focus of the paper is on simplifying the dynamic of the IPMSM using nonlinear analysis methods and enhancing the response of the designed control approach. The development of the control system starts with linearizing the dynamics of the IPMSM. A linearization approach based on Quadratic Linearization Method (QLM) is proposed and then the linear model is used for designing a state feedback controller optimized by Linear Quadratic Regulator (LQR) method. Applying control constraints is a challenge in systems controlled by state feedback theory. Hence, the proposed control method offers a novel solution based on hysteresis control theory. The proposed hysteresis technique offers several advantages such as lowering overshoot in speed step response in addition to applying constraints and it eliminates all drawbacks of hysteresis controllers. To control the IPMSM in the whole speed range (constant torque and constant power regions), the proposed approach adopts Maximum Torque per Ampere (MTPA) and Voltage Constraint Tracking (VCT) control strategies. Finally, simulations are carried out in MATLAB/SIMULINK environment to compare the performance of the proposed controller with the conventional FOC method. • Quadratic linearization creates a singularity-free linearization for IPMSM. • Quadratic Linearization is an exact linearization method for second-order systems. • State feedback control is used to eliminate problems associated with PI controller. • A reference reforming-based technique is proposed to apply control constraints. • The defects of hysteresis controllers do not exist in hysteresis reference reformer. [ABSTRACT FROM AUTHOR]

Appropriate position estimation of electric actuator is one of the most important stages in the control and automation processes. Considering various applications including robotics and automotive systems, Brushless DC (BLDC) motors sensor-less positioning is substantial in two major aspects. Electric commutation on the electric side should be performed precisely as well as motion control on the mechanical side. The mathematical models which befit precise applications are inherently nonlinear and require specific control techniques to deal with. Nonlinear Kalman filtering methods are considered as suitable solutions to estimation problems where uncertainty and noise exist. Three major and basic algorithms are Extended (EKF), Unscented (UKF) and Cubature Kalman filtering (CKF). In this paper, the application of these methods in estimation of rotor angular position with emphasis on low speed state is presented. Performance measures are compared using experimental setup. A typical 3-phase low voltage BLDC motor is implemented in the setup so that system noise could deteriorate quality of Back-EMF signal in low speed mode. It is shown that UKF and CKF techniques yield better results and performance in comparison to EKF according to measures. Estimated model states diagrams indicate the superior performance of Unscented and Cubature types regarding both accuracy and convergence. [ABSTRACT FROM AUTHOR]

Dynamic behavior of DC–DC converters plays a crucial role in stability of renewable energy exploitation systems. This paper presents small signal modeling of an input/output magnetically coupled interleaved buck–boost converter for fuel-cell applications to help the designers with the better understanding of converter dynamics. Aiming to have a continuous converter transfer function for a smooth transition between the operation modes and an improved inner dynamics, a damping network and an input/output coupling have been added to the interleaved structure of well-known cascaded buck–boost converter. Having the same step-up/step-down voltage transfer ratio, smooth transition and improved inner dynamics make this converter quite suitable for renewable energy applications. The paper presents a small signal ac equivalent circuit model of the proposed converter based on state space averaging (SSA) method. Simulation results show remarkable improvements in converter dynamic behavior in both time and frequency domains. Prototype setup of 360 W and 36 V output voltage for a fuel cell with a brand of “FCgen 1020ACS” Ballard Power Systems, Inc. was implemented. Experimental results are presented to verify the theoretical model and its expected merits. [ABSTRACT FROM AUTHOR]

Efficiency and dynamics of DC-DC converters play a major role in proficiency of renewable energy exploitation. This paper presents a novel DC-DC interleaved buck-boost converter for fuel-cell applications. While keeping the same step-up/step-down voltage transfer ratio, the proposed converter exhibits non-pulsating I/O currents using interleave technique. A damping network is also added to improve the inner dynamics of converter. Besides the steady state operation based on state space averaging (SSA) method, design considerations of converter are thoroughly elaborated. MATLAB/SIMULINK environment is used for simulating the steady state operation of proposed converter, and the experimental results are presented, to verify the theoretical expected merits of the converter including high efficiency, non-pulsating I/O currents and low voltage oscillation. Prototype setup of 360 W and 36 V output voltage for a fuel cell with a brand of "FCgen 1020ACS" Ballard Power Systems, Inc was implemented. Experimental results including efficiency and time domain responses in the steady state show impressive benefits of the proposed converter. [ABSTRACT FROM AUTHOR]

Abstract: Three leg inverters for photovoltaic systems have a lot of disadvantages, especially when the load is unbalanced. These disadvantages are for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the four-leg inverter. Consequently, generation of balanced voltage with sinusoidal waveform is necessary for these inverters. The power stage model of the 4-leg inverter in rotating coordinates dqo is highly coupled. Consequently, controller design procedure is very difficult and complex. On the other hand, adaptive control for 4-leg inverters has not yet been discussed in the literature. This paper proposes the state feedback approach to decouple the system and convert it to a second-order system which has two poles equal to zero. Then, it suggests a compensator to cancel poles of the closed-loop system and to convert the final system to a desired second-order system. Thanks to use of this strategy the transient performance of the system, such as overshoot and speed of response, becomes greatly adjustable. In addition, an STR (Self-Tuner Regulator) is introduced to tune the state feedback matrix and to guarantee the adaptive performance of the system. Simulation results validate that, by using proposed control strategy, the 4-leg inverter generates balanced voltage, with perfect sinusoidal waveform, in spite of the presence RL time-variant loads. [Copyright &y& Elsevier]

Abstract: Three-leg inverters for photovoltaic systems have many disadvantages, especially when the load is unbalanced. These disadvantages are, for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the 4-leg inverter. Most papers dealing with 4-leg inverters suggest classic controllers, such as PI controller, for the system. However, the transient performance of the closed-loop system does not become acceptable. On the other hand, adaptive control of 4-leg inverters has not yet been discussed in the literature. This paper proposes pole-placement control strategy, via state feedback, for 4-leg voltage-source inverters to adjust the transient performance of the closed-loop system. In addition, a STR (self-tuner regulator) is introduced to guarantee the adaptive performance of the controller in the presence of time-variant RL loads. Simulation results validate the theoretical results and proposed control strategy. [Copyright &y& Elsevier]

Abstract: Three leg inverters for photovoltaic systems have a lot of disadvantages, especially when the load is unbalanced. These disadvantages are for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the 4-leg inverter. Most papers dealing with 4-leg inverters ignore the effect of digital delays in control loop and suggest classic controllers, such as PI controller. However, the transient performance of the system does not become adjustable by applying classic control techniques. Additionally, adaptive control techniques have not yet been discussed for 4-leg inverters. This paper proposes the pole-placement control strategy via state feedback with integral state, which is a modern control technique, to control the system. Consequently, resulted system becomes highly robust. In addition, it suggests a Self-Tuner Regulator to guarantee the adaptive performance of the final system. Moreover, it proposes a novel model, considering digital delays, for 4-leg inverters. Simulation results show that transient performance of the system becomes accurately adjustable and the 4-leg inverter generates balanced voltage, with sinusoidal waveform, in spite of the presence of RL time variant loads. [ABSTRACT FROM AUTHOR]

Abstract: Three leg inverters for photovoltaic systems have a lot of disadvantages, especially when the load is unbalanced. These disadvantages are for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the four-leg inverter. Most papers dealing with 4-leg inverters ignore the effect of digital delays in control loop and suggest classic controllers, such as PI controller. However, the transient performance of the closed-loop system does not become, accurately, adjustable and acceptable, in most cases. This paper proposes a novel model, considering digital delays, for 4-leg inverters. Then, it applies pole-placement control strategy, via state feedback, to adjust the transient performance of the closed-loop system to a desired second-order system. Simulation results validate theoretical results and proposed control strategy. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes an average model of indirect matrix converter (IMC) with an output LC filter in stationary and rotating reference frames. The developed model is non-linear and should be linearized in order to design linear controllers. Transient performance of the IMC is compared with that of conventional inverter in classic AC/DC/AC system. In order to make the IMC applicable for power conditioner applications a synchronous controller is designed. A power conditioner acts in one or more ways to deliver a voltage of the proper level and characteristics to enable load equipment to function properly. In order to afford the power conditioner requirements the controller has two segments. One segment controls the IMC with balanced input supply voltage and the other controls the system with unbalanced input supply voltage. The system can provide balanced output voltages with slight distortion of line side currents. Theory analyses, the model validation and simulation results are presented to verify the effectiveness of this control method. [Copyright &y& Elsevier]