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

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 one-dimensional modulation common-mode current suppression technology for a three-phase neutral point-clamped three-level inverter. Three bridge arms of a non-isolated three-phase neutral point-clamped three-level inverter respectively work in three vector states 0, 1 and 2 or the three bridge arms all work in the vector state 1; and the condition that common-mode voltage is constantly equal to 1 / 2 of direct-current bus voltage is ensured, so that the common-mode current in a non-isolated grid-connected photovoltaic power generation system is effectively suppressed. Compared with an existing common-mode current suppression technology, according to the one-dimensional modulation common-mode current suppression technology, no hardware facility is added to the photovoltaic power generation system, so that the cost of the system is reduced; the energy conversion efficiency is improved; the improved one-dimensional modulation strategy is simple in algorithm, high in operation speed and convenient to achieve; and the one-dimensional modulation common-mode current suppression technology conforms to the requirements of renewable energy source and new energy power generation technologies, and is suitable for the non-isolated grid-connected photovoltaic power generation system which does not include a transformer.

The invention discloses a multi-module motor, a PWM modulation method and system for suppressing vibration and common mode current. The motor stator is composed of an even number of sets of Y-connected three-phase windings, and the back electromotive force of the two sets of windings in the complementary unit differs by 180° in electrical angle. , the back electromotive force is the same between each complementary unit. The method includes adopting the classic inner and outer loop control framework, obtaining the current command value in the closed loop of the speed, and obtaining the modulation wave in the closed loop of the current; determining the carrier phase of each complementary unit, and modifying the PWM modulation action inside the complementary unit so that the two sets of windings in the complementary unit correspond to each other. The phase PWM is always reversed; the modulation wave is compared with the carrier, and the PWM wave is output according to the modified modulation action, which is output to the three-phase voltage source inverter to drive the entire motor. The control scheme proposed by the invention makes full use of its degree of freedom, takes into account its performance to the greatest extent, does not add additional equipment, reduces the vibration noise of the motor at the switching frequency, and can effectively reduce the common mode current of the motor control system.

The invention discloses a model direct power prediction control method, device and system, which belong to the technical field of photovoltaic power generation conversion control. The method includes: obtaining the output voltage uout, common-mode voltage ucm and each Correspondence between a group of switch state combinations; calculate the value of the objective function g(k+1) of the model direct power predictive control corresponding to each group of switch state combinations; calculate the value of the objective function g(k+1) The minimum value gop(k+1) of the minimum value gop(k+1); obtain the switch state combination corresponding to the minimum value gop(k+1), and realize the low common mode current model direct power predictive control of the single-phase photovoltaic grid-connected inverter. The invention can flexibly control the active power and reactive power of the inverter, has good static and dynamic performance, and can effectively suppress the common-mode current of the single-phase photovoltaic grid-connected inverter.

The invention discloses an electromagnetic loss-based electric vehicle common mode current suppressor. The suppressor circuit adopts a ladder-shaped network form of a lumped element, and the unit structure is a low-pass circuit composed of a series inductance coil and a parallel capacitor. In view of common mode current at the frequency range of 1 to 30MHz conducted along a cable-chassis in the electric vehicle, in consideration of the length Pu of the unit structure being far smaller than the wavelength of the common mode current and convenience of circuit preparation, Pu is approximately equal to 2cm, the inductance coil is filled with composite magnetic material with the solid part and the imaginary part of magnetic permeability to be 10 magnitude, and the capacitor is filled with composite dielectric material with the solid part and the imaginary part of the dielectric constant to be 10 magnitude. The common mode current suppressor is serially connected onto the cable of the electric vehicle, and as the suppressor has a large attenuation coefficient, the common mode current is rapidly attenuated exponentially, and the common mode current in the subsequent circuit can be strongly suppressed. The suppressor of the invention is simple in structure, convenient to prepare, and can selectively and high-efficiently suppress common mode current at a wide frequency band range.

The invention discloses an inverter system in which three-phase common-mode current and switching loss are suppressed cooperatively. The system includes a DC 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 DC power supply system provides DC voltage. The three-phase three-level ANPC inverter circuit includes an inverter main circuit and two identical support capacitors, and the three-phase current-limiting capacitor includes three identical current-limiting capacitors. The filter circuit includes two different circuit structures and is pulled back to the midpoint of the DC bus, and the three-phase load includes three AC buses. A three-phase common-mode current and switching loss cooperatively suppressed inverter system designed by the present invention uses a small number of auxiliary capacitors and inductances, occupies a small volume, and can cooperatively suppress the three-phase common-mode current and switching losses in a high switching frequency working environment. loss.

The invention discloses an electrical excitation motor excitation device and parameter obtaining method thereof. The electrical excitation motor excitation device includes an excitation winding, an excitation winding buck circuit, an isolation type DC / DC converter, a three-phase winding and a bus power supply; the bus power supply is connected with the three-phase winding and is used for providinga bus voltage for the three-phase winding; the input end of the isolation type DC / DC converter is connected with the bus power supply, the output end is connected with the input end of the excitationwinding buck circuit, and the isolation type DC / DC converter is used for performing isolation ratio transformation on the bus voltage provided by the bus power supply to serve as an input voltage ofthe excitation winding buck circuit; and the output end of the excitation winding buck circuit is connected with the excitation winding, the buck circuit is used for performing chopping on the bus voltage after isolation ratio transformation, and a voltage obtained after chopping serves as a terminal voltage of the excitation winding. The electrical excitation motor excitation device provided by the invention eliminates a common-mode access between an excitation loop and a three-phase loop, suppresses common-mode current, and considers optimization of a power device duty ratio, thereby achieving better power device control performance.

According to one embodiment, a grid-tie inverter includes: a single-phase or three-phase inverter (1) that performs pulse width modulation for a DC voltage supplied from a DC power supply (5); a first capacitor circuit (41) connected to an input side of the inverter (1) so as to form a neutral point (c); a second capacitor circuit (42) connected to an output side of the inverter (1) so as to form a neutral point (f); a common mode current bypass channel (g) formed by connecting the neutral point (c) of the first capacitor circuit (41) and the neutral point (f) of the second capacitor circuit (42) to each other; a grounded capacitor (11) provided between the bypass channel (g) and a ground; a first common mode choke coil unit (31, 32) that includes a common mode choke coil (31, 32) at least one of between the first capacitor circuit (41) and the inverter (1) and between the inverter (1) and the second capacitor circuit (42), and suppresses a common mode current occurring in the inverter (1); and an output filter (2) that converts a pulse width-modulated voltage waveform outputted from the inverter (1) into a sine single-phase or three-phase AC voltage.