38results about How to "Suppresses common mode current" patented technology

The disclosed grid-tie inverter is provided with: a single-phase or three-phase inverter (1) which changes a DC voltage supplied from a DC power supply (5) to a pulse-width modulated voltage; a first capacitor circuit (41) which is connected so as to form a neutral point (c) on the input side of the inverter (1); a second capacitor circuit (42) which is connected so as to form a neutral point (f) on the output side of the inverter (1); a common mode current bypass channel (g) which is formed by connecting the neutral point (c) on the first capacitor circuit (41) and the neutral point (f) on the second capacitor circuit (42); a grounded capacitor (11) which is provided between the bypass channel (g) and the earth; a first common mode choke coil unit which is provided with common mode choke coils (31, 32) in at least one location between the first capacitor circuit (41) and the inverter (1) or the inverter (1) and the second capacitor circuit (42), and which uses the inverter (1) to suppress generated common mode current; and an output filter (2) which converts the pulse-width modulated voltage waveform output from the inverter (1) to a sinusoidal single-phase or three-phase AC voltage.

The invention discloses a single-phase non-isolation type photovoltaic grid-connected inverter and a control method. The photovoltaic grid-connected inverter comprises a full-bridge circuit, a control circuit and a fly-wheel diode, wherein the control circuit is used for controlling conduction and cut-off of all switching tubes in the full-bridge circuit so as to convert direct current voltage generated by a photovoltaic array of the full-bridge circuit to sine wave voltage required for grid connection; and the fly-wheel diode is used for providing a fly-wheel loop so as to thoroughly disconnect the input side from a power grid. The photovoltaic grid-connected inverter can effectively inhibit common-mode current (namely drain current) of the single-phase non-isolation type photovoltaic grid-connected inverter and improve the electrical energy conversion efficiency of the inverter.

The invention relates to a magnetic integrated inductor. The magnetic integrated inductor comprises an upper yoke magnetic core, a lower yoke magnetic core, at least two middle column magnetic cores with windings and at least one high-magnetoconductivity magnetic core, wherein the upper yoke magnetic core and the lower yoke magnetic core are arranged oppositely; the at least two middle column magnetic cores are arranged between the upper yoke magnetic core and the lower yoke magnetic core; the at least one high-magnetoconductivity magnetic core is arranged between the upper yoke magnetic core and the lower yoke magnetic core; the at least two middle column magnetic cores, the upper yoke magnetic core and the lower yoke magnetic core form a plurality of first magnetic circuits; the at least one high-magnetoconductivity magnetic core, the upper yoke magnetic core and the lower yoke magnetic core form at least one second magnetic circuit, wherein the relative permeability of each high-magnetoconductivity magnetic core is greater than or equal to 1000; given that the saturation flux density of each of the upper yoke magnetic core and the lower yoke magnetic core is Bs(B), the net sectional area of each magnetic circuit is Ae(B), the saturation flux density of each high-magnetoconductivity magnetic core is Bs(A), and the net sectional area of each magnetic circuit is Ae(A), Ae(A)* Bs(A)<= Ae(B)* Bs(B)*50%.

The invention discloses a model direct power forecast control method, device and system, and belongs to the technical field of photovoltaic power generation conversion control. The method comprises the following steps of acquiring an output voltage u<out> of a single-phase photovoltaic grid-connected inverter, a common-mode voltage u<cm> and a corresponding relation of each group of on-off state combinations; calculating a value of a target function g(k+1) of model direct power forecast control corresponding to each group of on-off state combinations; calculating the minimum value g<op>(k+1) in the target functions g(k+1); and acquiring the on-off state combination corresponding to the minimum g<op>(k+1), and achieving low common-mode model direct power forecast control of the single-phase photovoltaic grid-connected inverter. By the method, the active power and the reactive power of the inverter can be flexibly controlled, moreover, high static and dynamic performance is achieved, and the common-mode current of the single-phase photovoltaic grid-connected inverter can be effectively inhibited.

The invention discloses a high-frequency isolated AC-DC conversion circuit and a control method thereof. The circuit comprises an input filter, an input transformer, an AC rectifier unit, an energy storage filter unit, a resonant conversion unit, an isolation transformer, a DC side rectifier unit and an output energy storage unit. The conversion circuit of the invention can work in three modes ofrectification, inverter or standby. By using the input transformer, the common-mode current on the AC side and the AC anti-deviation function can be effectively rejected while the energy storage function is realized, and the common-mode interference of the AC rectifier unit to the ground can be effectively reduced. In addition, the resonant conversion unit can realize the bi-directional conversionof soft switch, which reduces the on and off stress of each component and reduces the switching loss. Finally, multi-state conversion can be realized in the bi-directional conversion of DC voltage ina wide range by using the combination of resonant conversion unit and DC side rectifier unit to turn on the timing control.

The invention discloses a filtering reactance level and a variable frequency driving system using same. The variable frequency driving system using the filtering reactance level comprises a rectifying input level, an inverter output level and a filtering reactance level. The filtering reactance level which is coupled between the rectifying input level and the inverter output level and comprises a magnetic core module, a first winding group, a second winding group and a third winding group. The magnetic core module comprises a middle column, a first edge column and a second edge column. The first winding group is wound on the first edge column, the second winding column is wound on the second edge column, and the first winding group and the second winding group are in series connection with a first direct current arm which is arranged between the rectifying input level and the inverter output level. The third winding group is wound on the middle column and two ends of the third winding group are in series connection with a second direct current arm between the rectifying input circuit and the inverter output circuit. The three winding groups of the filtering reactance level are capable of supplying enough common mode choke to restrain common mode currents and form adjustable different mode inductance to reduce energy loss of a filtering reactance.

The invention discloses an isolated bidirectional AC/DC conversion circuit and a control method thereof. The conversion circuit comprises an input filter, an input transformer, an AC rectifier unit, an energy storage filter unit, a DC. DC conversion unit, output energy storage unit. The circuit of the invention can make the circuit work in different modes of rectification, inversion or standby modes according to external communication commands or judgement of other external voltage and current signals. At the same time, the input transformer can realize the energy storage function of the circuit in inverter or rectifier mode, at the same time, it can effectively restrain the common-mode current of the AC side and the AC anti-bias detection function, and effectively reduce the common-mode interference of the AC rectifier unit to the ground.

The present invention belongs to the technical field of power electronics and provides a common mode current suppression circuit of a motor drive system for solving the interference of high frequency interference generated by a controllable rectifier and an inverter on a motor drive system and surrounding devices. The present invention includes three LC filter circuits, a transmission device and a micro control unit; the three LC filter circuits are respectively connected in series between the inverter output end and the motor input end, each LC filter circuit is formed by an adjustable inductor and a non-polar capacitor connected in series; the micro control unit controls the transmission device according to the frequency of the modulated wave signal output by the inverter; and the transmission device controls the inductance value of the adjustable inductor in each LC filter circuit separately by a sliding sheet, so that the driving current of the motor reaches the resonance in the LC filter circuit . The common mode current suppression circuit effectively suppresses the total conduction path of the common mode current to realize the common mode current suppression of the motor drive system, and ensures that the driving signal of the motor cannot be attenuated.

The invention discloses an inverter system of three-phase common-mode current and switch loss cooperation suppression. The system comprises a direct-current power supply system, a three-phase three-level ANPC inverter circuit, a three-phase current-limiting capacitor, a filter circuit and a three-phase load. The direct-current power supply system provides a direct-current voltage. The three-phasethree-level ANPC inverter circuit comprises an inverter main circuit and two identical support capacitors. The three-phase current-limiting capacitor comprises three identical current-limiting capacitors. The filter circuit comprises two different circuit structures and is pulled back to a midpoint of a direct-current bus, and the three-phase load comprises three alternating-current buses. By using the inverter system of the three-phase common-mode current and switch loss cooperation suppression, a small number of auxiliary capacitors and inductors are used, an occupied volume is small, and three-phase common-mode current and switch losses in a high switch frequency working environment can cooperatively restrained.

The embodiment of the invention provides a two-level inverter common-mode voltage suppression method and system, and the method comprises the steps: carrying out the Clark transformation of a three-phase modulation wave, converting the three-phase modulation wave from a three-phase static coordinate system to a two-phase static coordinate system, obtaining a current reference voltage vector, and carrying out the Clark transformation of the current reference voltage vector; determining a sector where the current reference voltage vector is located by using the current reference voltage vector and a sector division rule; according to the current reference voltage vector, the sector where the current reference voltage vector is located and the direct current side voltage of the two-level inverter, the duty ratio of a zero voltage vector and the duty ratio of an odd effective voltage vector to be selected are obtained; and according to the duty ratio of the zero voltage vector and the duty ratio of the odd effective voltage vector to be selected, generating a corresponding PWM driving waveform to drive an inverter switching tube. The common-mode voltage can be effectively suppressed, sector selection of the reference voltage vector is reduced, the calculation amount is reduced, and the method is easier to implement.

The invention discloses a vehicle-mounted power supply photovoltaic inverter which comprises a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a first filter inductor, a second filter inductor, an energy storage capacitor, a first follow-current circuit and a second follow-current circuit, wherein the input end of the first follow-current circuit is in circuit connection with the second switching circuit to form a node E, the output end of the first follow-current circuit is in circuit connection with the first switching circuit to form a node C, the input end of the second follow-current circuit is in circuit connection with the fourth switching circuit to form a node F, the output end of the second follow-current circuit is in circuit connection with the third switching circuit to form a node D, the filter inductor comprises a first winding and a second winding, the second inductor comprises a third winding and a fourth winding, one end of the first winding is connected with the node C, the other end of the first winding is connected with one end of the second winding and the node F respectively, one end of the fourth winding is connected with the node D, and the other end of the fourth winding is connected with one end of the third winding and the node E. With the adoption of the coupling inductors, ripple can be effectively suppressed, the impact of the device damage to the circuit is reduced, and short circuit is avoided.

The invention discloses a control method for an optically-coupled isolation vehicle power supply photovoltaic inverter. The inverter comprises a first switching circuit, a second switching circuit, a third switching circuit, and a fourth switching circuit, and control terminals of the switching circuits are connected with an optically-coupled isolation circuit. The method includes: firstly, in the positive half-circle for outputting current, the third switching circuit, the fourth switching circuit, and a second free-wheeling circuit are controlled to always maintain the turn-off state, a first free-wheeling circuit is controlled to always maintain the turn-on state, the optically-coupled isolation circuit is controlled to maintain the same time sequence with the switching circuits, and same-direction or reverse turn-on of signals is controlled; and in the negative half-circle for outputting current, the first switching circuit , the second switching circuit, and the first free-wheeling circuit are controlled to always maintain the turn-off state, and the second free-wheeling circuit is controlled to always maintain the turn-on state. By employing the method, only two switching devices are controlled to simultaneously perform high-frequency switching so that the switching loss is reduced; and the current only flows through two devices during energy output so that the conduction loss is reduced.

The invention provides an omnidirectional WLAN (Wireless Local Area Networks) antenna with common-mode current suppression. The antenna comprises a radiation structure and a coaxial line, the radiation structure is formed by a first radiation unit, a second radiation unit and a third radiation unit (13) which have the same structure; each radiation unit is provided with three feed ports with the same structure, a first polygonal groove, a second polygonal groove and two same cutting angles; metal branches are arranged between the first polygonal grooves and the second polygonal grooves, the centers of the metal branches are provided with gaps; one end of the coaxial line is led in along one sides of the feed ports and is distributed at the edges of the first radiation units, and the otherend of the coaxial line is led out along the opposite sides of the feed ports and is connected with an SMA joint. The omnidirectional WLAN antenna can suppress the common mode current on the outer surface of the feed coaxial line and can reduce the distortion of the antenna directional diagram while meeting the performance of the omnidirectional WLAN antenna, and can be used for a wireless local area network communication system.

The invention provides an alternating current-direct current coupling type common mode inductor for a direct current inverter power supply system. The alternating current-direct current coupling type common mode inductor comprises a direct current side common mode inductor (1) and an alternating current side common mode inductor (2); the direct current side common mode inductor (1) comprises an annular first magnetic core (11) and two windings (12) which are wound on the first magnetic core (11) and have the same direction; and the alternating current side common mode inductor (2) comprises an annular second magnetic core (21) and two or three alternating current phase lines (22) penetrating through a window of the second magnetic core (21). According to the alternating current and direct current coupling type common mode inductor for the direct current inversion power supply system of the invention, the second magnetic core (21) is supported and nested in the window of the first magnetic core (11) through an insulating material (4), and coupling of the direct current side common mode inductor (1) and the alternating current side common mode inductor (2)of an inverter is realized, so that the size miniaturization of the alternating current-direct current coupling type common mode inductor is realized on the premise of ensuring effective suppression of common-mode currents at the alternating current side and the direct current side of the direct current inversion power supply system.