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Trade-off between transient response and grid-side current quality is a well-known issue of single-phase mains-connected power converters. A dual-loop control structure (usually based on PI or type-II controllers) is typically employed in such systems to regulate the DC link voltage to a constant reference (in order to maintain power balance) while forcing the grid-side current to have a specific shape (in order to comply with power quality requirements). Introducing notch term/s (tuned to certain multiple/s of the mains base frequency) into one of the loops allows either for the improvement of the dynamic performance without worsening the total harmonic distortion of grid-side current or for the enhancement of the current quality without impairing the dynamic response. Since the maximum tolerable value of total harmonic distortion is typically imposed by a certain power quality standard, it is desirable to enhance the transient response of the power converter system as much as possible while keeping the total harmonic distortion at the maximum allowed value. However, universal off-grid operating power conversion systems must support both 50 Hz and 60 Hz mains; consequently, tuning the notch term/s to 50 Hz multiple/s would not be sufficient for a 60 Hz mains operation and vice-versa. Consequently, this work examines the possibility of introducing a dual-notch term into the control loop in order to cover both above-mentioned base frequencies. It is demonstrated that under typical base frequency uncertainty values, the performances of dual-notch terms are nearly decoupled so that the term tuned to a 50 Hz frequency (and optionally to its multiples) has nearly no influence at a 60 Hz mains operation and vice-versa. Consequently, the methodology allows for the improvement of the dynamics of universal grid-connected power converters without total harmonic distortion (THD) deterioration. A stability analysis of the proposed control structure is carried out and quantitative design guidelines, allowing for the attainment of an optimized dynamic response for a given maximum tolerable total harmonic distortion, minimum allowed phase margin and a certain base frequency uncertainty, are established. It is shown that a DC link voltage loop bandwidth of 52 Hz may be attained while keeping the grid-side current THD below 5%. Simulations and experimental results support well the proposed design methodology. [ABSTRACT FROM AUTHOR]

It is well-known that adding a notch filter in series with the typically employed type-II (or PI) regulator allows improving the tradeoff between dc-link voltage dynamics and grid-side current total harmonic distortion (THD) in practical single-phase power factor correction rectifiers. The article demonstrates that notch filter utilization alternatively allows reducing the value of dc-link capacitance in case hold-up time requirement is absent. The revealed value of minimum capacitance is expressed by explicit function of possible mains frequency values range, maximum expected grid voltage magnitude, rated system power, dc-link voltage set point, maximum tolerable grid-side current THD, and the desired phase margin (PM) of dc-link voltage loop. It is demonstrated that the proposed approach yields fourfold reduction of dc-link capacitance for typical values of 5% tolerable grid-side current THD under 40° PM constraint. Experimental results exhibit close-fitting resemblance to corresponding analytical predictions, verifying the proposed methodology. [ABSTRACT FROM AUTHOR]

Wireless power transfer systems are typically required to operate under varying geometrical positioning (vertical distance, misalignment) between the transmitter and receiver coils while supporting a load with non-constant characteristics. This creates the need for robust systems that can operate over a range of coupling coefficients under time-varying load. Widespread control methods utilized to support such an operation typically suffer from volt-ampere (VA) over-rating of the inductive wireless power transfer link (IWPTL) transmitter. Sub-resonant frequency control has proven to be an effective solution to this problem, attaining robust operation and minimized transmitter VA rating by utilizing operational frequency as the control variable for system output regulation under above-mentioned constraints. However, allowed operating frequency range is usually restricted in practical applications (e.g. to 79 kHz–90 kHz by SAE J2954 EV charging standard), limiting the misalignment tolerance of sub-resonant control method. Recently, extension of the classical sub-resonant control methodology was proposed in order to overcome this limitation. However, no clear guidelines were given for designing practical IWPTLs operating under extended sub-resonant control. To this end, this work bridges the gap between academical findings and practical applications by establishing generalized guidelines for designing sub-resonant controlled series-series (SS) compensated IWPTL with minimized transmitter VA rating, allowing to maximize misalignment tolerance under given operating frequency and output voltage ranges. The proposed methodology is accurately validated by simulations and experiments, demonstrate close correlation with analytical predictions. Experimental framework reveals that IWPTL operating under extended sub-resonant control methodology attains 50 % increase of tolerable coupling coefficients range compared to a classical system designed to operate under sub-resonant control under identical operating conditions while achieving nearly similar DC-to-DC efficiency. • Novel design guidelines SS-IWPTL operating with constant output current in sub-resonant frequency region are proposed. • Classical design methodology is shown to be a particular case of the proposed approach. • Experimental validation of a system designed according to the proposed method demonstrates improved misalignment tolerance. [ABSTRACT FROM AUTHOR]

This paper presents a simple method to obtain effects similar to those obtained by real mechanical loading and real inertia variation but without any mechanical parts supplementary to the electric motor of the studied electric drive. The electric motor itself produces the load torque and the inertia variation using digital signal processing software. Therefore, the electric drive is virtually torque and inertia loaded, while its behavior is similar to that of the actual loaded drive. The present method could be used to test the implementation of control algorithms or for didactic purposes using motion control kits found on the market. The present method is used with laboratory works of the DSP Fundamentals in Power Electronics course at the Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel. Index Terms--Digital control, load and inertia emulation.