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This paper presents a voltage injection method for reconstructing phase currents from current signals measured on single current-shunt circuits with cost-effective and high-performance configurations in the pulsewidth modulation (PWM) inverters that are used for digital appliances. This method involves the injection of voltage signals at the carrier frequency for reconstructing the phase currents in PWM inverters using a single current sensor in the dc-link. It uses minimum signals to reduce the voltage and current harmonics caused by the injected signals. The vector of the injected voltage is at a minimum distance from the original reference to ensure the measurement time in the reconstruction of the phase currents. An injection sequence control method is also proposed to avoid an abrupt change in the injection signals. A PWM scheme for splitting phase voltages is proposed to reduce any audible noise, especially in low-speed operation. The proposed method reconstructs the phase currents with signals from a single current sensor and minimizes the amplitude of the injected signals to reduce the harmonics at audible noise frequencies in the injection signals. Experimental results showed the effectiveness of the proposed method. Index Terms--AC motor drives, current reconstruction, noise, pulsewidth modulated (PWM) inverters.

The CLLC converter is a promising topology for bidirectional power conversation applications, such as vehicle-to-grid (V2G) systems and battery energy storage (BES) systems. Battery charging is one of the most important functions of the CLLC converter in V2G and BES applications. Synchronous rectification (SR) is of vital importance in these applications because it can increase efficiency. In this article, a battery charging method with natural SR features is proposed for the full-bridge CLLC converter. The proposed method consists of a parameter matching design procedure and SR control. A novel SR principle is adopted in this article. Different from the current SR methods, the parameter design process is taken into consideration for the SR realization. After the parameter matching design procedure, the required on-state time of the secondary side switches for the SR is nearly fixed during the whole charging process. As a result, the SR drive signal can be generated directly according to the switching frequency. No sensor detection or software estimation is needed, allowing natural SR to be realized. A lab-level prototype was built to verify the proposed method. The experimental results show an obvious efficiency improvement (up to 2.11%) over the uncontrolled rectification, and the SR of the proposed method is nearly the same as complete SR (with maximum efficiency difference of 0.31%) during the whole battery charging process. [ABSTRACT FROM AUTHOR]

This paper presents a novel family of single-switch resonant dc–dc converters with low switch voltage stress. The single-switch resonant converter which has a ground-referenced switch is advantageous for implementing the gate drive circuit and operating at several-MHz switching frequency. However, the conventional ones mostly have high voltage stress on the switch, roughly 4–5 times the input voltage. In this paper, we propose the single-switch converter topologies derived from the drain-source impedance networks consisting of two inductors and two capacitors. The switch voltage of the proposed converters is shaped into a near trapezoid by designing the resonant networks to have the desired drain-source impedance. Furthermore, a simple and specific design scheme is presented here so that the peak switch voltage is lowered to 2.2–2.5 times the input voltage while zero voltage switching is achieved. Experimental results from a 20-W GaN-based prototype operating at 10 MHz demonstrate the feasibility of the proposed converter topologies and the design method. [ABSTRACT FROM AUTHOR]

This paper proposes the novel control method for a monoinverter dual parallel (MIDP) drive system with interior permanent magnet synchronous machines (IPMSMs). It includes maximum torque per ampere (MTPA) control to elevate drive efficiency and active damping control to alleviate inherent stability problem of an MIDP motor drive system. Due to the combination of reluctance and electromagnetic torques, the d- and q-axis currents of IPMSM are coupled unlike those of induction and surface-mounted permanent magnet machines. For this reason, MTPA and active damping control of a MIDP IPMSM drive system are far more complex than those with nonsalient motors. In this paper, model-based mathematical analysis about MTPA and active damping control for MIDP IPMSM drive system are provided. Experimental results with two 1.6-kW IPMSMs are presented to verify the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper describes phase current reconstruction methods from dc-link currents in three-phase three-level PWM inverters. Since the three-level inverters have three paths between dc-link and power switches, the reconstructions differ from that in two-level inverters which have two paths there. Considering these paths in three-level inverter, this paper proposes the methods for phase current reconstruction. While the reconstruction method is executed by the currents sampled on the dc-links, the system encounters current-unmeasurable areas where the dc currents cannot be sampled due to the lack of measurement time according to the PWM status. This paper analyzes the areas and proposes a minimum voltage injection method for minimizing them to guarantee accurate current reconstruction. The method provides the expanded operating areas especially in low-output voltage operation and the minimized distortions in output voltages. The feasibility of the proposed method has been assessed in experiments. [ABSTRACT FROM AUTHOR]