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The single-phase dual active bridge (DAB) DC/DC converter is a vital component in modern power electronics systems, facilitating efficient bidirectional power transfer between various energy sources and loads. One of the critical aspects in the design of such converters is the selection of an appropriate leakage inductance, as it significantly affects the circulating power within the converter. This study investigates the influence of inductance on the reactive power flow and introduces an analytical formula for calculating the necessary leakage inductance based on the specified rated power of the DAB converter. By employing the inductance values determined through the proposed formula, the developed power control-based modulation method, implemented in discrete time, successfully achieves zero reactive power caused by the first harmonic components under all load conditions. This selection of leakage inductance optimizes the performance of the converter ensuring efficient power delivery across various applications. The applicability of this method extends to various DAB applications, including electric vehicles, integration with asynchronous microgrids, and aerospace systems. [ABSTRACT FROM AUTHOR]

We have developed a pure-integration-based flux acquisition method for ac adjustable-speed drives. Based on the current-measurement-error analysis, a simple resonant-type observer is utilized to eliminate the drift or dc offset that originated in the current acquisition process. All the processes in correcting the problem do not rely on motor parameters and do not interfere with other higher frequency contents such as inverter non-linearity and motor cogging effects. The proposed technique further contains a residual error compensator to completely correct the initial value error and to eliminate miscellaneous dc offset errors of the integrator. The acquisition accuracy of the flux is significantly improved through pure integration by restraining the error of the flux magnitude and phase angle at a low stator frequency. Since the proposed scheme is based on a two-phase current measurement system, it is suitable for retrofitting ac drives, where two current sensors are commonly used. Index Terms--Current measurement error, pure-integration-based flux acquisition, residual error compensator, resonant-type observer (RTO).

This paper analyzes a high-frequency (HF) voltage-injection-based rotor winding temperature estimation method for current-regulated squirrel-cage induction motors (IMs). We develop a theoretical I-IF model of the rotor bar and then first provide an analysis of relevant HF model-based estimation aspects, such as the dependence of the rotor leakage inductance on the temperature and the relationship between the rotor resistance and rotor leakage inductance. We also include an analysis of magnetic saturation to improve the estimation accuracy, as well as an analysis of the phase delay effect resulting from the drive that significantly affects the HF signal precision. Then, a specialized offline commissioning scheme is proposed to compensate for the effect of the phase delay and magnetic saturation. The estimation technique and sensitivity analysis are verified by means of experiments performed on an inverter-fed 1.5-kW IM. Index Terms--High-frequency (HF) model of rotor bar, high-frequency (HF) voltage injection, inverter-fed induction motor (IM), phase delay resulting from the drive, rotor winding temperature estimation.

In this paper, we propose an injection-based axis switching (IAS) sensorless control scheme using a pulsating high-frequency (HF) signal to minimize position detection error and velocity estimation ripple resulting from the zero-current-clamping (ZCC) effect for surface-mounted permanent-magnet motors. When a pulsating carrier-signal voltage is injected in an estimated synchronous frame, the envelope of the resulting HF current measured in the stationary reference frame follows an amplitade-modulated pattern. Using this information, the IAS technique allows one to avoid multiple zero crossings of HF currents by adjusting the current phase angle according to the load condition. At no-load condition, the pulsating voltage is injected only on the d-axis, while the d-axis current is controlled to a certain nonzero value. Under a load condition, the injection voltage is switched to the q-axis, while the d-axis current drops back to zero. Thus, the proposed sensorless control enforces a much better estimation performance in a region of ZCC without a predefined offline commissioning test than the standard pulsating injection scheme. Experiments illustrate the effectiveness of the proposed method in suppressing the estimation error caused by the ZCC disturbance and in extending the system bandwidth. Index Terms--Estimated position error and velocity ripple, injection-based axis switching (IAS) sensorless control, pulsating high-frequency (HF) signal injection, zero-current-clamping (ZCC) effect.

This paper presents an online-correction method for current measurement errors for a pure-integration-based flux estimation down to a stator frequency of 1 Hz. A measurement-disturbance-observer (MDO)-based approach is taken as one possible solution for eliminating the dc offset and the additional negative-sequence component due to unbalanced current measurement gains in the synchronous coordinate. From the motor parameter sensitivity analysis, an MDO gain selection method is proposed to remove the estimation error resulting from a parameter mismatch. At the same time, the positive-sequence component estimation is performed by creating an error signal between a motor model reference and an estimated q-axis rotor flux established by a permanent magnet in the synchronous coordinate. The compensator utilizes a PI controller that controls the error signal to zero. Experimental results confirm that the proposed scheme has great potential for applications to acquire the accurate motor flux at a low stator frequency. Index Terms--DC offset, measurement disturbance observer (MDO), negative-sequence component due to unbalanced current measurement gains, online-correction method of current measurement errors, positive-sequence component estimation, pure-integration-based flux estimation.

Conventional proportional/proportional-integral (P/PI) speed controller for today's servo drives has to be manually tuned at the controller switching set point by trial and error, which may translate into drive system downtime and a subsequent loss of productivity. The adjustable drive performance is heavily dependent on the quality of expert knowledge. The performance becomes inadequate in applications where the operating conditions change in a wide range, i.e., tracking command, acceleration/deceleration time, and load disturbances. In this paper, we discuss the demands on simple controls/setups for industry servo drives. Analyzing the frequency content of the motor torque command, P/PI speed control mode switching is automatically performed with only a prior knowledge of the mechanical time constant. The dynamic performance of the proposed scheme assures a desired tracking response curve with minimal oscillation and settling time over the entire set of operating conditions. For a comprehensive comparison of conventional P/PI control scheme, we carried out extensive tests on an actual servo system. Index Terms--Frequency content of motor torque, industry servo drive, proportional/proportional-integral (P/PI) speed controller, simple controls/setups.

This paper describes our research on a force ripple compensation and closed-loop position control scheme using linear hybrid stepping motors (LHSMs) with significant thrust vibrations. In order to estimate unobservable force ripple components, we propose the Jacobian linearization observer that guarantees the convergence of state estimates into true states. For the precise control of velocity and position, an input--output feedback linearization controller is derived from a nonlinear positiondependent model of the LHSM based on elaborate reluctance network analysis. In addition, we discuss the separation principle used to separate the observer design from the controller design. Common problems associated with the force ripple, such as the positioning error, mechanical stress, and acoustic noise, are efficiently handled using the proposed active damping control scheme. Experimental results show that the positioning accuracy is significantly improved through a closed-loop control while restraining the thrust ripple. Index Terms--Feedback linearization controller, Jacobian linearization observer, linear hybrid stepping motors (LHSMs), separation principle, thrust vibrations.

This paper proposes an online compensation strategy for the unwanted disturbance voltage resulting from the zero-current clamping effect for high-frequency-signal-injection-based sensorless control schemes. We derive an analytical model that reveals intrinsic characteristics of the zero clamping effect for high-frequency signal injection. The model in this form is subsequently incorporated into the development of a specialized offline commissioning test to find motor inductances and a voltage distortion factor. From the sensitivity analysis of the effect on magnetic saturation, we confirm that the compensation error due to saturation has little negative impact on the proposed compensation method. The compensation result leads to an accurate position estimate in the zero-current clamping region. The proposed scheme does not rely on a complicated lookup table. Experiments demonstrate the superiority of the proposed method in suppressing the voltage distortions caused by the zero-current clamping effect. Index Terms--Analytical model, offline commissioning test, online compensation strategy for the unwanted disturbance voltage, zero-current clamping effect for high-frequency-signal-injection-based sensorless control.

This paper proposes a compensation strategy for the unwanted disturbance voltage due to inverter nonlinearity. We employ an emerging learning technique called support vector regression (SVR). SVR constructs a motor dynamic voltage model by a linear combination of the current samples in real time. The model exhibits fast observer dynamics and robustness to observation noise. Then the disturbance voltage is estimated by subtracting the constructed voltage model from the current controller output. The proposed method compensates for all of the inverter nonlinearity factors at the same time. All the processes in estimating distortions are independent of the dead time and power device parameters. From the analysis of the effect on current measurement errors, we confirmed that the sampling error had little negative impact on the proposed estimation method. Experiments demonstrate the superiority of the proposed method in suppressing voltage distortions caused by inverter nonlinearity. Index Terms--Current :measurement errors, disturbance voltage resulting from inverter nonlinearity, power device parameters, support vector regression (SVR).

This paper presents a frequency-spectrum-based conditional-integration antiwindup strategy for a general proportional-integral-type controller. The ON/OFF condition of integral action is determined by a frequency-domain analysis of the actuator-input command without prior knowledge of set-point changes. The dynamic performance of the proposed scheme assures a desired tracking-response curve with minimal oscillation and settling time even with a change of operating conditions. This algorithm is useful in many high-performance induction-machine applications, as it does not allow the oscillation and overshoot of speed/torque responses. The main idea can be extended to general applications such as those involving chemical processes and industrial robots. Index Terms--Antiwindup, frequency-domain analysis, frequency-spectrum-based conditional integration, induction machine, proportional-integral (PI)-type controller.

This paper presents a simple and economical way to accurately estimate an initial position for linear hybrid stepping motor (LHSM) drives by utilizing dc excitation. In order to detect an absolute position of the mover, two preliminary tests are carried out under two different dc conditions: single-phase and two-phase dc excitation. The proposed algorithm has been successfully applied to a practical system with a rated initial load and stiction without causing any mechanical damage. The proposed scheme is not affected by the harmonic force ripple of the LHSM and its benefits are much more significant for multi-axis systems. The paper presents experimental results to prove the effectiveness of the scheme. Index Terms--DC excitation, initial load and stiction, initial position for LHSM drives.

This paper presents a new velocity estimation strategy of a nonsalient permanent-magnet synchronous motor (PMSM) drive without a high-frequency signal injection or special pulsewidth-modulation (PWM) pattern. This approach is based on the d-axis current regulator output voltage of the drive system that has the information of rotor position error. Rotor velocity can be estimated through a rotor-position-tracking proportional-integral (PI) controller that controls the position error to zero. For zero and low-speed operation, the PI controller gains of rotor position tracking controller have a variable structure according to the estimated rotor velocity. In order to boost the bandwidth of the PI controller around zero speed, a loop recovery technique is applied to the control system. The proposed method only requires the flux linkage of the permanent magnet and is insensitive to parameter estimation error and variation. The designers can easily determine the possible operating range with a desired bandwidth and perform vector control even at low speeds. The experimental results show the satisfactory operation of the proposed sensorless algorithm under rated load conditions. Index Terms--d-axis current regulator output voltage, non-salient permanent-magnet synchronous motor (PMSM) drive, rotor-position-tracking proportional-integral (PI) controller, velocity estimation strategy.

Linear hybrid stepping motors (LHSMs) have a simple structure and provide ripple-free holding force at the aligned position. Despite these attractive features, however, an LHSM delivers strong thrust vibrations during position-to-position movement that are the dominant cause of the positioning error, mechanical stress, and acoustic noise. In order to overcome this defect, we have developed an active control scheme to damp the vibration of a [pi]/4-multiple-pitched LHSM by a feed-forward compensation signal. Utilizing an elaborate reluctance network based on the finite-element analysis to take the nonlinear magnetic properties into account, we model the LHSM with force ripple components as a nonlinear position-dependent function. We estimate the damping force signal from the Jacobian linearization observer. The positioning accuracy is significantly improved through a closed-loop control scheme for restraining the thrust ripple. Index Terms--Active control scheme, closed-loop control, feed-forward compensation, linear hybrid stepping motors (LHSMs), thrust vibrations.

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics in series-type active power filter systems combined with shunt passive filters is proposed, which focuses on reducing the delay time effect required to generate the reference voltage. Using digital all-pass filters, the positive voltage sequence component out of the unbalanced source voltage is derived. The all-pass filter can give a desired phase shift and no magnitude reduction, unlike conventional low- or high-pass filters. Based on this positive-sequence component, the source phase angle and the reference voltage for compensation are derived. This method is easier to implement and to tune controller gains. In order to reduce the delay time effect in the voltage control loop, the reference voltage is predicted a sampling period ahead. The validity of the proposed control scheme has been verified by experimental results. Index Terms--All-pass filter, current harmonics, reference prediction, series active filter, voltage unbalance.

The optimal flux-searching algorithms of an induction machine have reached a stage of development permitting maximum torque operation over an entire flux-weakening region. In the high-speed region, however, the sensitivity to parameter errors of an induction machine still remains a problem. This paper presents an approach that ensures maximum torque operation maintaining robustness to parameter error in the flux-weakening region. To guarantee the performance in the high-speed region, the machine leakage inductance is adapted on line, based on the injection of sinusoidal current. Also, the detuned effect on machine inductance is thoroughly analyzed to relate the sensitivity of parameters to the performance of the flux-weakening region. Experimental results demonstrate that the proposed adaptation scheme effectively selects the optimal flux level regardless of variation of leakage inductance. Index Terms: Flux-weakening, induction machine.

In the overmodulation region, the operation of the electrical drive system with a current controller is characterized by a rapid deterioration of motor torque and speed. It is desirable to use the overmodulation strategy, which guarantees the fast response even in transient state and satisfies the overall closed-loop control performance. In this paper, in order to improve the dynamic characteristics of the electrical drive, a new overmodulation technique is proposed. Considering the current transition characteristics, an efficient overmodulation strategy is introduced to achieve better transient performance through an adequate voltage selection. With the help of a new overmodulation strategy, required electrical torque can be directly produced as quickly as possible, and stable drive characteristics can be achieved in the transient condition. The proposed method has been implemented on an actual inverter system and thoroughly tested on a 900W interior permanent magnet synchronous machine (IPMSM) to confirm its feasibility. Index Terms - Current regulation, IPMSM, overmodulation.

In an induction machine with deep rotor bars, the rotor parameters change due to skin effect and saturation, and the skin effect is often modeled as a ladder network. For the high-performance drive of an induction machine with deep bars, many sophisticated control strategies and machine models have been discussed. As a control strategy, a complicated airgap flux-oriented control scheme is mostly adopted, because it is not possible to define a unique rotor flux in deep bar model. However, a unique pseudorotor flux can be defined, and it is straightforward to achieve independent control of pseudorotor flux and torque. This control scheme can be applied to any nth multiple ladder network. In this paper, it is described how a deep-bar effect of an induction machine can be negligible by performing the proper field-oriented control. By using the concept of pseudorotor flux, the conventional rotor-flux-oriented control using equivalent rotor parameters is effective for deep-bar and/or double-cage machines. The actual insulated gate bipolar transistor (IGBT) inverter systems with a high-precision torque transducer are implemented and thoroughly tested on a 250-hp induction machine and a 5.5-kW double-cage induction machine to confirm their validity. Index Terms - Deep rotor bars, pseudorotor flux, skin effect.

This paper presents a new approach to identify the induction machine parameters using the PWM inverter. For the field oriented control of induction machine, accurate induction machine parameters are necessary. Usually, the inverter utilizes the machine parameters supplied from the manufacturer or estimated by extraneous tests. To overcome this problem, the proposed method utilizes the PWM inverter itself for machine parameter identification at standstill. All the test procedures are performed and the parameters are identified by the PWM inverter and its own controlling computer. The proposed method has been implemented on actual inverter systems and thoroughly tested on two different induction machines to confirm its feasibility.

This paper presents a [pi]/4-multiple-coupled two-phase linear hybrid stepping motor (LHSM) that has two windings per phase, one of which shares the other phase winding. The proposed motor shows a unique ability to deliver low cogging force without any complex control scheme or additional power electronics hardware in microstepping control. An analytical and experimental comparison between conventional [pi]/2- and [pi]/4-multiple-coupled LHSM confirms the effectiveness of the proposed design. Index Terms--Linear hybrid stepping motors, low cogging force, [pi]/4-multiple-coupled LHSM.

A new approach to parameter tuning of induction motors in the course of drive commissioning is proposed. Usually, the motors originate from different manufacturers, and so the parameters are not known prior to startup of the drive. The control system of the drive utilizes the parameters obtained by extraneous tests and based on a number of assumptions that are not valid under all operating conditions. Therefore, completion of the tuning of all motors at an industrial site is quite time consuming, and it is a very difficult job, even to skilled engineers. To overcome these problems, the proposed tuning procedure is sensitive to detuning and independent of information on other parameters. The state of detuning is clearly noticeable in the shape of the controller output signal of the drive system. The proposed scheme has the advantage of being general and readily applicable to a wide range of other systems, such as ac/dc boost converters, surface-mounted permanent-magnet synchronous motors, interior permanent-magnet synchronous motors, and so on. Experimental results are offered to validate the feasibility of the proposed tuning algorithm. Index Terms--Controller output signal, drive commissioning, induction motor, parameter tuning.