40results about How to "Reduce common mode current" patented technology

The embodiment of the invention discloses a wireless electric energy transmission device. A primary side compensation capacitor (or a secondary side compensation capacitor) is set to comprise N sub-compensation capacitors, and the N sub-compensation capacitors are uniformly connected with an electric energy transmitting coil (or an electric energy receiving coil), so that the electric energy transmitting coil (or the electric energy receiving coil) is correspondingly and equally divided into N equal parts. Through the connecting structure of the distributed capacitors, the voltage of each section of electric energy transmitting coil (or electric energy receiving coil) can be reduced, so that the common-mode current of the transmitting coil to the ground or the circulating current of the receiving coil to metal is reduced; the total compensation capacitance of the primary side or the secondary side and the resonant frequency of the coil are consistent with the working frequency of a system, and the highest energy transmission efficiency can be ensured.

A system for converting at least one electrical input direct current into an electrical output alternating current comprising M phases and supplied to M output terminals includes N polyphase inverters, connected in parallel, each converting the input direct current into an intermediate alternating current comprising M phases and supplied to M intermediate terminals; N×M first electromagnetic coupling coils, each being connected to a respective intermediate terminal; N×M magnetic cores, each first coil being wound around a respective core.This system comprises N×M second electromagnetic coupling coils, each being connected to a respective first coil and wound around a distinct core from that of the respective first coil. The first and second coils of a same core correspond to a single phase, and generate respective common mode fluxes of opposite directions. Each output terminal is connected to the M second coils of a single phase.

The invention belongs to the field of power electronics, and particularly relates to a modulation method for reducing common-mode voltage of a three-phase pulse-width modulation (PWM) converter. The modulation method is characterized in that three nonadjacent nonzero basic space vectors are used for synthesizing a target vector, and is further characterized in that two comparison value counting modules are adopted to generate control pulse, and the counting modules are different in counting mode. Counting modes of the comparison value counting modules used for generation of out-phase bridge arm control pulse in the same sector of voltage commands are different, and in the different sectors, the counting modes of the comparison value counting modules used by the same-phrase bridge arm are also different. The modulation method has a good common-mode voltage restraining effect, the common-mode voltage maximum peak is one-sixth of direct current bus voltage, and therefore common-mode currents can be effectively reduced when the modulation method is applied to fields of photovoltaic power stations, motor drive and charging stations.

The invention discloses a common-mode voltage suppression method of a non-isolated T-type three-level photovoltaic grid-connected inverter, which collects the voltage of the capacitor C1 on the DC bus and the voltage of the capacitor C2 under the DC bus in real time, and obtains the voltage of the capacitor C1 on the DC bus and the voltage of the DC bus. The absolute value of the voltage difference dUdc of the capacitor C2 under the bus bar, by judging whether dUdc>dUref is true, and judging whether it is true, choose to use the large and medium zero vector synthesis method or the large, medium and small vector synthesis method or the large and small zero vector synthesis method for non-isolated T-type Three-level photovoltaic grid-connected inverter for modulation. The invention adopts three kinds of vector synthesis methods to modulate the non-isolated T-type three-level photovoltaic grid-connected inverter, which can not only balance the midpoint potential of the DC side of the three-level inverter, but also suppress the amplitude of the common-mode voltage change and frequency, thereby suppressing the common-mode current of the non-isolated T-type three-level photovoltaic grid-connected inverter, and optimizing the efficiency, volume, weight, and cost of the system.

The technical problem addressed by the present invention is solved by providing a plurality of circuit blocks, each circuit block including a first series circuit that includes a first diode and a first MOSFET, a second series circuit that includes a second diode and a second MOSFET, and a capacitor, wherein the output terminals are connected to the first series circuit, the second series circuit, and both ends of the capacitor. The input terminals of the circuit blocks are connected in series, and an AC power supply is connected to the interconnected input terminals via a choke.

The invention relates to a converter connection assembly with a direct voltage intermediate circuit (3) containing a transformer (8) with at least two windings (9 and 10). The transformer is connected in the intermediate circuit (3) in such a way that the undesired, asymmetric current components lead to a magnetization of the transformer core, and are thus suppressed. A grounded LC filter (Lf, Cf) is connected in front of the load (6). The filter effects a sinusoidal voltage on the load (6). As a result, the connection can be utilized with any polyphase machines and also during the expansion of existing systems.