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This paper proposes a control algorithm for disturbance rejection that reduces the overcurrent generated in a single-phase Grid Connected Inverter (GCI) required in the Vehicle to Grid (V2G) function in case of an accident in the grid system. The proposed algorithm contains a grid current observer for grid voltage estimation and a feedforward control algorithm. To verify the control algorithm, the topology used a single-phase IGBT inverter and an LCL low pass filter were used to reduce the harmonics of the inverter output. The proposed grid current control algorithm is developed and verified via simulation and experiment.

This paper presents disturbance rejection control algorithm at stationary reference frame for a grid connected inverter (GCI) to reduce peak current during transient when grid fault occurs. The proposed control algorithm includes feedforward control, a grid current observer for grid voltage disturbance estimation. Also sinusoidal current vectors (α, β vectors at stationary reference frame) are controlled instead of a current vector at a synchronous reference frame. By doing this, phase estimation algorithm for grid voltage such as phase locked loop (PLL) and reference transformation can be avoided and an entire control system can be simplified. However, phase delay and steady state error are occurred by controlling sinusoidal signals. The drawbacks can be also compensated by applying the proposed algorithm. The proposed algorithm is verified via simulation and experiment.

A compensation algorithm targeting torque development from an interior permanent magnet synchronous machine (IPMSM) is presented in this paper. Maximum Torque per Ampere (MTPA) lookup table (LUT) applied for copper loss minimization uses the estimated permanent magnet flux linkage, and torque error occurs because of PM flux linkage variation. In this paper, proposed, a control algorithm is proposed to reduce torque error applying a stator flux linkage observer. Permanent magnet flux linkage estimated using the stator flux linkage observer is applied to the initially developed MTPA-LUT to reduce for the torque error.

A structure and layout of printed-circuit-board (PCB) have a considerable impact on the overall system efficiency and switching performance for high-frequency applications. The current distribution of the copper traces can be significantly distorted due to eddy and proximity effects as the switching frequency increases. Also, stray inductances are the main source of destructive switching ringing and electromagnetic interference (EMI). They both are often designed to be minimized, however, it is difficult to quantify and design the effects in the complex geometry of PCB layout. PCBs for power transfer has been often designed by a rule of thumb. The practical case of the printed circuit board for a resonant-type grid-tied switching converter is studied to reduce the stray inductances and effective resistances at switching frequency of several hundreds of kHz in this paper. Quantitative studies with the exact geometry of PCB from Gerber files are conducted using three-dimensional finite element analysis (FEA) tools. The overall process is integrated and linked by scripting glue language, Python. The suggested structure and layout show considerable improvement by rearranging patterns of copper traces and properly handling high-frequency effects.

A torque error reduction algorithm targeting for an interior permanent magnet synchronous machine (IPMSM) is presented in this paper. In an IPMSM drive, Maximum Torque per Ampere (MTPA) lookup table (LUT) is typically applied for the minimization of copper loss. Estimated permanent magnet (PM) flux linkage is used for MTPA-LUT development, and torque error occurs due to change of PM flux linkage. In this paper, an IPMSM control algorithm is proposed to compensate torque error using a stator flux linkage observer. PM flux linkage estimated through the stator flux linkage observer is applied to the MTPA LUT to compensate for the torque error.

This paper presents a control algorithm for a grid-tied voltage source inverter for improvement of dynamic stiffness performance. The proposed control algorithm includes state feedback decoupling, filter inductor current control, load current is measured by a current sensor and used as an input to a controller for disturbance input decoupling. In the proposed algorithm, sinusoidal voltage vectors (d, q voltage vectors at stationary reference frame) are controlled instead of a voltage vector at synchronous reference frame. By doing this, a position estimation process in such as phase locked loop (PLL) can be avoided and an entire control system can be simplified. The proposed algorithm is verified via simulation.

This paper presents an initial rotor position estimation algorithm of asymmetric air-gap single-phase permanent magnet synchronous motors without using a hall sensor. Generally, the common problem associated with the sensorless drive is the starting operation. Most sensorless control methods are based on back-EMF. However, when motor is at standstill or low speed, the back-EMF is too small to detect rotor position. Therefore, high frequency injection methods are widely used in the standstill or low speed region. In case of the SP-PMSM, when high frequency signal is injected to asymmetric air-gap single-phase PMSM motors, flux saturation is not occurred at air gap unlike 3-phase PMSM. Due to alternating magnetic field at the air-gap, initial rotor position of the SP-PMSM is hard to be estimated. As a result, in this paper, DC offset voltage is added to the high frequency injection signal to generate flux saturation at the air-gap of the SP-PMSM. The several experimental results show that the proposed algorithm is effectiveness and usefulness for SP-PMSM with non-uniform air-gap.

A compensation algorithm targeting for torque development from a surface mounted permanent magnet synchronous machine (SPMSM) including a low speed operation is presented in this paper. As known, PM flux linkage in SPMSM is varied by temperature. Because a Maximum Torque Per Ampere (MTPA) look up table (LUT), a control algorithm used for minimizing copper losses, is generated using calculated permanent magnet flux linkage, change of permanent magnet flux linkage yields torque error of a SPMSM drive. In the manuscript, estimated permanent magnet flux linkage is obtained using a stator flux observer. The torque error is corrected using the estimated permanent magnet flux linkage. The proposed algorithm is implemented and verified in simulation and experiment

This paper presents a torque error compensation algorithm for a surface mounted permanent magnet synchronous machine (SPMSM) through real time permanent magnet (PM) flux linkage estimation at various temperature conditions. As known, PM flux linkage in SPMSM is varied by thermal conditions. Since an Maximum Torque Per Ampere (MTPA) look up table (LUT), a control method used for copper loss minimization, is developed based on estimated PM flux linkage, variation of PM flux linkage results in undesired torque development of SPMSM drives. In this paper, PM flux linkage is estimated through a stator flux linkage observer and the torque error is compensated using the estimated PM flux linkage in real time. In this paper, the proposed torque error compensation algorithm is verified in simulation and experiment.

This paper presents an algorithm for speed ripple reduction of an oil cooler compressor. An oil cooler compressor is typically used for a machine tool to reduce thermal variation error at a processing area. However, mechanical vibration of a single rotary compressor should be reduced because it results in noise and stress on a pipe. Therefore, a real time ripple reduction algorithm is proposed to minimize speed ripple caused by a single rotary compressor. In the proposed algorithm, a proportional resonant (PR) controller is applied to detect and compensate the frequency component in speed ripple. The proposed algorithm is verified in simulation.

In single-phase grid-connected inverters, an offset error in measured phase current on grid side is occurred by a current sensor and unbalanced voltage and nonlinearity characteristics of analog components in a measurement device. When current containing offset error is used for current control, it results in DC offset and the second harmonic component of fundament frequency in phase current of a grid side. The DC offset and the second harmonic component yield reduction of inverter efficiency. This paper presents an offset error compensation algorithm for grid-connected single phase inverters using a proportional resonant (PR) controller. The proposed algorithm is verified in simulation and experiment.

This paper presents a compensation method of dead time effects in a grid-tied single-phase inverter. In general, output current of grid-tied inverter contains odd-numbered harmonics because of dead time and nonlinear characteristics of the switching devices. Thus, in this paper, effects of dead time in output voltage and current are analyzed in detail. Also, a new compensation algorithm using Second-order Generalized Integrator (SOGI) is proposed to reduce the dead time effect. Simulation and experimental results validate the effectiveness of proposed algorithm.

This paper presents fast torque control of wound field synchronous machines (WFSMs) at start up via single step optimization. Transient torque response of WFSMs is affected by both of armature current and field current. Since dynamic responses (or time constant) of armature and field current are different due to winding turn ratio between armature and field, optimization of fast transient torque response of WFSMs is not simple. In certain circumstance, such as start-up operation, fast torque response is required. In this paper, a single-step optimization method is proposed to achieve simple real time implementation and fast and stable transient dynamics of WFSM drives. Simulation results for the single- step optimization method for WFSM drive are presented.

This paper presents robustness evaluation of deadbeat-direct torque and flux control (DB-DTFC) of IPMSM drives with respect to machine parameter variation. For performance comparison, current vector control (CVC), one of the most widely used control methods, is also implemented under identical operating conditions as DB-DTFC. As the metrics to evaluate dynamic performance of DB-DTFC and CVC IPMSM drives, command tracking is used to investigate torque command tracking performance and dynamics stiffness is used to evaluate disturbance rejection performance. In addition, the torque estimation accuracy of DB-DTFC and CVC is investigated with respect to parameter variation. Simulation and experimental results of robustness evaluation of DB-DTFC and CVC are presented in this paper. Furthermore, the dynamic robustness of DB-DTFC and CVC drives are evaluated via eigenvalue (EV) migration. Since an IPMSM drive is a nonlinear system, an operating point model of an IPMSM drive is derived for linear analysis of EV migration. Finally, the US06 Supplemental Federal Test Procedure (SFTP) automotive driving cycle is applied to investigate the EV migration of a test IPMSM drive over a wide operating space.

This paper presents the voltage and current limited operation of an interior permanent magnet synchronous machine (IPMSM) using deadbeat, direct torque and flux control (DB-DTFC). A commanded air-gap torque and stator flux can be achieved by the end of each PWM period using DB-DTFC. However, it may take several PWM periods to achieve a desired air-gap torque that is physically infeasible in one step due to voltage limits. In that case, the torque and flux command trajectories operating over multiple periods can be developed to achieve deadbeat torque and flux response for every PWM period. The torque and flux command trajectories can be developed in different shapes depending on desired objectives. In this paper, a minimum time ramp trajectory method is proposed to achieve both simple real time implementation and fast and stable transient dynamics of IPMSM drives. Simulation and experimental results for the minimum time ramp trajectory method for an IPMSM drive are presented.

An ultra-wide impedance bandwidth antenna is presented in this paper. To enhance an impedance bandwidth of antenna, a novel dual-resonance feed structure composed of two branch capacitors and inductors is combined with a conventional planar inverted-F antenna (PIFA). The antenna possesses a very wide impedance bandwidth which fully covers the band of various wireless communication services. The impedance bandwidth of proposed antenna is from 675 to 988 MHz in the lower band and from 1710 to 2695 MHz in the higher frequency band with good efficiency, respectively

This paper discusses the performance of an interior permanent magnet synchronous machine by using deadbeat-direct torque flux control (DB-DTFC) in a hybrid power circuit structure, which consists of an indirect matrix converter (IMC) and a reactor free boost converter (RFBC). The first section of this paper documents the performance of DB-DTFC when carrier comparison PWM and space vector modulation (SVM) are used as modulation techniques. Corresponding Volt-sec solutions for each modulation technique are shown via simulation and experiments. The second section discusses DB-DTFC properties in the proposed IMC/RFBC circuit. The results demonstrate that DB-DTFC is capable of delivering fast dynamic torque response in one sample period even when (i) variable switching frequency is applied in the inverter of the IMC and (ii) DC offset current occurs in the output current of the IMC.

This paper presents time optimal control of an interior permanent magnet synchronous machine (IPMSM) in voltage- and current- limited conditions using deadbeat-direct torque and flux control (DB-DTFC). A commanded air-gap torque and flux can be achieved by the end of each PWM period using DB-DTFC. However, it may take several PWM periods to achieve a desired torque that is physically infeasible in one step when operating near the voltage limit. The large torque command can be shaped as a feasible trajectory so that the deadbeat torque and flux is achieved for every sample time instant (switching period) along the trajectory. In this paper, the feasible trajectory is dynamically optimized to achieve a large torque command in the shortest time during voltage- and current-limited operation. Loss minimizing stator flux linkage is used during steady state operation to reduce computational complexity of the dynamic optimization and to operate the IPMSM at the loss minimizing condition. The voltage- and current-limited operation of IPMSM drives is evaluated in both simulation and experiment in this paper.

This paper presents time optimal torque control in overmodulation and switching level loss minimization control of an induction machine (IM) and an interior permanent magnet synchronous machine (IPMSM) via deadbeat, direct torque and flux control (DB-DTFC). Using DB-DTFC, the stator flux linkage can be manipulated each PWM cycle to minimize losses during normal operation. Due to voltage limits during overmodulation it may take a sequence of incremental torque commands over several PWM periods to achieve a desired air-gap torque that is physically infeasible in one step. In that case, the DB control becomes finite settling step (FSS) control in which the steps may be optimized using time optimal strategies. In this paper, a time optimal FSS control using a DB-DTFC solution during overmodulation and a loss minimizing DB-DTFC solution over the full torque-speed operating space are proposed and evaluated for IM and IPMSM drives.

Most of controlling disaster management focus on how to rescue people from a disaster area. In this paper, we propose an emergency escape system that helps people escape by themselves effectively from a disaster area in which each person owns a mobile device. We define a scenario for the proposed system in which there are five system states; they are Idle, Discovery, Subscription/Publication, Execution, and Communication states. The system uses several technologies such as service-oriented architecture, GPS and Wi-Fi positioning systems, and some sensors. The proposed system utilizes users' information such as weighted distances, weighted directions and revisit counts. The system is implemented on a double-layered MANET to reduce traffic and to collaborate with each other. We have constructed a simulator to test the proposed system. The simulation results show that the proposed system outperforms other approaches in terms of the distance and the time, proving that the proposed system could be an effective life-saving rescue system.

This paper presents a discrete time deadbeat-direct torque and flux controller (DB-DTFC) for interior permanent magnet synchronous machines (IPMSMs). A Gopinath-style discrete time flux linkage observer is developed which contains two different flux estimation methods based on current and voltage models for flux linkage. This observer produces correctly estimated flux linkages needed for accurate DB-DTFC implementation. In order to eliminate the sampling delay due to a characteristic of digital control computation, a complex vector model-based rotor reference frame current observer is also developed. Combining the discrete time current and flux linkage observers, the correct single time step (deadbeat) air-gap torque and stator flux linkage control at the (constant) switching frequency is achieved and experimentally evaluated.