Unipolar sinusoidal pulsewidth modulation (SPWM) full-bridge inverter brings high-frequency common-mode voltage, which restricts its application in transformerless photovoltaic grid-connected inverters. In order to solve this problem, an optimized structure with two additional switches and a capacitor divider is proposed paper, guarantees that freewheeling path clamped half input voltage the period. Sequentially, has been avoided unipolar SPWM inverter, output current flows through only...

Due to the characteristics of low cost and high efficiency, transformerless photovoltaic (PV) grid-connected inverters have been popularized in application solar electric generation system residential market. Unfortunately, leakage current through stray capacitors between PV array ground is harmful. This paper focuses on suppressing method, which all common-mode paths are considered. First, analytical model at switching frequency developed, rules eliminating source summarized based this...

The current-voltage-fed bidirectional dc-dc converter, which refers to a current-fed inverter at low voltage side and voltage-fed high side, can realize zero switching (ZVS) for the switches with use of phase-shift (PS) technology. However, suffer from spike circulating conduction loss. In order solve these problems, novel plus pulsewidth modulation (PSP) control ZVS converter is proposed in this paper. By adopting active clamping branch PSP technology, all wide range load variation while...

Characterized by low leakage current and voltage stress of the power device, a neutral point clamped three-level inverter (NPCTLI) is suitable for transformerless photovoltaic (PV) grid-connected system. Unfortunately, shoot-through problem bridge legs still exists in an NPCTLI, so its operation reliability degraded. An improved proposed based on NPCTLI dual-buck half-bridge (DBHBI), which avoids problem. The topology guarantees no switching-frequency common-mode risk. Furthermore,...

Transformerless grid-connected inverters (TLI) feature high efficiency, low cost, volume, and weight due to using neither line-frequency transformers nor high-frequency transformers. Therefore, TLIs have been extensively investigated in the academic community popularly installed distributed photovoltaic systems during past decade. This article analyzes summarizes state of art TLI techniques, three rules maintaining constant common-mode voltage (CMV) at switching frequency concluded from a...

An integrated power conversion system is proposed for electric vehicles (EVs), which consists of a dual active bridge (DAB) dc-dc converter cascaded by three-phase four-leg (TPFL) dc-ac converter. The can realize both vehicle-to-grid (V2G) operation and traction EVs. large capacitor avoided in the dc link system. Instead, an snubber with small film connected to suppress voltage oscillation, induced removal dc-link capacitor. By designing phase-shifting control primary H-bridge DAB,...

Brushless modular spoke type permanent magnet (MSTPM) machine has exhibited prior electromagnetic (EM) performance over conventional surface-mounted PM machines for in-wheel traction system in electric vehicles (EVs). However, analysis of thermal behavior MSTPM is rather insufficient, even accurate significant importance due to poor heat dissipation condition inside the wheel hub. Conventionally, losses produced electrical by EM prediction equivalent source normal analysis, and only...

Soft-switching techniques of transformerless photovoltaic grid-connected inverters (TLIs) can significantly reduce switching losses, as well soften processes. Conventional dc–ac soft-switching configurations proposed by Dr. Deepakraj M. Divan are invalid in TLIs because the leakage current problem. In order to develop TLIs, this paper proposes a new configuration and procedure guide invention TLIs. First, two basic resonance tanks related dc bus polarities, then, uses these elevate four...

For current-controlled grid-connected inverters with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filter, the essence of grid voltage full feedback is to improve output impedance infinity, which can eliminate influences distortion and non-negligible impedance. However, existing feedforward strategies are complex control delay cannot be compensated precisely, leads instability system when at point common coupling under weak adopted....

The unipolar sinusoidal pulse width modulation (SPWM) full-bridge inverter brings high-frequency common-mode voltage, which restricts its application in transformerless photovoltaic grid-connected inverter. freewheeling path added ac side is adopted to restrict leakage current, but the voltage variable at switching frequency scale. To solve this problem, an improved structure with two switches and a capacitor divider has been proposed, guarantees that freewheel clamped half of input period....

The double-switch buck–boost converter, characterised with non-inverting and step-up/step-down conversion, is suitable for the front stage of two-stage photovoltaic (PV) grid-connected inverter. However, one strategy named as 'synchronisation control', requires a considerable inductor another control strategy, 'combined sophisticated to operation modes transition smoothly. In order reduce inductance in synchronisation resolve complexity combined an interleaving converter proposed. This paper...

Thermal drift-caused current measurement offset error usually results in unfavorable torque ripples of fundamental frequency, and hence a compensation method for is proposed this article, which initially derived based on the nonsalient-pole machines then extended to salient-pole machines. By filtering difference between predicted currents from simple nominal model measured currents, directly estimated compensated with minimal effects dynamics. It proved that estimation accurate if filter has...

This article proposes an improved space vector modulation (SVM) for the current-source rectifier (CSR). Due to overlap time during commutations of power switches, pulsewidth-modulation (PWM) currents CSR may suffer from a number low-order (mainly fifth and seventh) harmonics, which seriously degrade harmonic performance voltages on grid side. Especially, overlap-time effect becomes important issue when increased switching frequency is applied CSR. To mitigate these harmonics PWM converter...

The grid inverters play an important role in renewable energy systems, transferring the dc power to ac grid. Galvanic isolation is usually needed between source and due safety reasons grounding leakage current mitigation. In this article, a soft-switching isolated inverter proposed based on current-fed matrix-type configuration. topology of converter composed H-bridge side direct matrix side, which are linked by high-frequency transformer. primary-side can smooth dc-source control directly....

Neutral point clamped inverter (NPC) features low harmonics, high efficiency, and voltage stress, et al. NPC is widely applied in renewable energy power generation systems, such as wind turbine photovoltaic. However, due to unbalanced losses, suffers inherent thermal unbalance among inner outer switches. A split-inductor active neutral (SI-ANPC) was initially proposed improve the operating reliability, providing structural basis for balanced loss distributions. With this purpose, a novel...

The differential feedback of grid-side inductor voltage can effectively increase the damping grid-connected inverters. Compared with proportional filter capacitor current, it output impedance inverters, which is more conducive to reducing impact grid background harmonics on grid-in current. However, there a link in its branch, and existing implementation methods were pursuing be ideal wide frequency band, as consequence, high-frequency components are amplified, affects quality For this...

This letter proposes a fast current control scheme for ac drives by minimizing the latency from sampling to updation of pulsewidth-modulation (PWM) command. By reconstructing architecture linear controller, minimal necessary steps obtain output voltage are deduced as <i>primary calculation</i>, and other computation work loop is done in <i>postcalculation</i> after updating PWM With proposed method, computational delay reduced with negligible loss available modulation index, higher stability...