Abstract: The present disclosure provides a magnetic element and a method for manufacturing same. The method includes: forming a first metal wiring layer on a surface of at least one segment of a magnetic core; forming a first metal protection layer on the first metal wiring layer; removing a portion of the first metal protection layer with a direct writing technique to expose a portion of the first metal wiring layer; and etching the exposed first metal wiring layer in such a manner that the first metal wiring layer forms at least one first pattern to function as a winding, where at least one turn of the first pattern surrounds the magnetic core. The magnetic element and the method for manufacturing the magnetic element provided in the present disclosure can improve space utilization of the magnetic element.

Abstract: The disclosure discloses a method and device for detecting insulation state in a conversion system, wherein the conversion system includes an excitation source, a converter having an input end coupled to the excitation source, a connection element coupled between an output end of the converter and a reference point, and a coupling impedance having a first end coupled to the excitation source and a second end coupled to the reference point, the method for detecting insulation state including steps of: S1, controlling at least one main power switch of the converter not to switch; S2, detecting a pulse current signal of the connection element; and S3, processing the pulse current signal and outputting a partial discharge information, the partial discharge information indicating an insulation state of an isolating transformer in the converter. The disclosure can overcome electromagnetic interference of high frequency steep waves on a partial discharge signal.

Abstract: A circuit for preventing false turn-on of a semiconductor switching device includes an active clamp circuit, a control circuit, a power amplifier circuit, and a suppression circuit. The control circuit is coupled to an input of the power amplifier circuit. An output of the power amplifier circuit is coupled to a gate of the semiconductor switching device. The active clamp circuit is configured to operate within a preset period when a voltage between the first end of the semiconductor switching device and a second end of the semiconductor switching device is greater than a preset voltage. The suppression circuit includes a controllable switch, which is configured to turn on after the operation of the active clamp circuit is completed, such that potential at the input of the power amplifier circuit is clamped to a fixed potential.

Abstract: The present disclosure provides a magnetic element and a method for manufacturing same. The method includes: forming a first metal wiring layer on a surface of at least one segment of a magnetic core; forming a first metal protection layer on the first metal wiring layer; removing a portion of the first metal protection layer with a direct writing technique to expose a portion of the first metal wiring layer; and etching the exposed first metal wiring layer in such a manner that the first metal wiring layer forms at least one first pattern to function as a winding, where at least one turn of the first pattern surrounds the magnetic core. The magnetic element and the method for manufacturing the magnetic element provided in the present disclosure can improve space utilization of the magnetic element.

Abstract: A hybrid compensation system is electrically connected between a power grid and a load. The hybrid compensation system includes an active filter, a passive filter and a control unit. The active filter generates an output current. The active filter includes a switching circuit, a DC bus capacitor and a filtering inductor. The control unit includes a voltage controller, a first reactive current detector, a harmonic current compensator, a current loop controller and a modulator. The voltage controller generates a first current given signal according to a bus voltage of the DC bus capacitor and a reference voltage. The first reactive current detector generates a second current given signal. The harmonic current compensator generates a third current given signal. The current loop controller generates a control signal. The modulator generates a driving signal according to the control signal.

Abstract: A power converter includes a PCB having opposing first and second sides, and a plurality of first commutation units and first capacitor unit disposed on the PCB. Each first commutation unit includes a first discrete component and a second discrete component. The second end of the first discrete component is electrically coupled to the first end of the second discrete component, and the first capacitor unit is electrically coupled to the first ends of the first discrete components and the second ends of the second discrete components in the plurality of first commutation units, respectively. The first discrete components and the second discrete components in the plurality of first commutation units are arranged in a row. The first discrete component and the second discrete component in each first commutation unit form a commutation loop together with the first capacitor unit.

Abstract: The present disclosure provides a magnetic element and a method for manufacturing same. The method includes: forming a first metal wiring layer on a surface of at least one segment of a magnetic core; forming a first metal protection layer on the first metal wiring layer; removing a portion of the first metal protection layer with a direct writing technique to expose a portion of the first metal wiring layer; and etching the exposed first metal wiring layer in such a manner that the first metal wiring layer forms at least one first pattern to function as a winding, where at least one turn of the first pattern surrounds the magnetic core. The magnetic element and the method for manufacturing the magnetic element provided in the present disclosure can improve space utilization of the magnetic element.

Abstract: An electrical conversion system includes: an inductor electrically connected to an alternating current (AC) power grid; a medium voltage direct current (MVDC) bus; a non-isolated AC/DC converter, provided with a first terminal electrically connected to the inductor and a second terminal electrically connected to the MVDC bus, wherein the non-isolated AC/DC converter is configured to output a bus voltage based on an input voltage from the AC power grid; a plurality of circuit branches connected in parallel, wherein each circuit branch is connected to the MVDC bus via a corresponding converter; and a filtering network disposed between the AC power grid and the MVDC bus and is grounded through at least one capacitor.

Abstract: The disclosure discloses a method and device for detecting insulation state in a conversion system, wherein the conversion system includes an excitation source, a converter having an input end coupled to the excitation source, a connection element coupled between an output end of the converter and a reference point, and a coupling impedance having a first end coupled to the excitation source and a second end coupled to the reference point, the method for detecting insulation state including steps of: S1, controlling at least one main power switch of the converter not to switch; S2, detecting a pulse current signal of the connection element; and S3, processing the pulse current signal and outputting a partial discharge information, the partial discharge information indicating an insulation state of an isolating transformer in the converter. The disclosure can overcome electromagnetic interference of high frequency steep waves on a partial discharge signal.

Abstract: A conversion device includes: an inductor connected to the AC power grid; a first-stage converter configured to output a bus voltage based on the AC power grid; a second-stage converter configured to convert the bus voltage into an output voltage to the load; and a filtering network, wherein a first resistance-capacitance circuit is disposed between the first and third terminals of the filtering network, a second resistance-capacitance circuit is disposed between the second and third terminals of the filtering network, the first terminal of the filtering network is connected to the AC power grid, the second terminal of the filtering network is connected to the bus or the second terminal of the second-stage converter, and the third terminal of the filtering network is grounded through a first capacitor.

Abstract: A conversion device includes: an inductor electrically connected to the AC power grid; a first-stage converter configured to output a bus voltage according to the AC power grid, wherein the first-stage converter includes an N-level alternating current-direct current (AC-DC) converter, and the N-level AC-DC converter includes a plurality of switch bridge arms, wherein both an upper bridge arm and a lower bridge arm of each of the plurality of switch bridge arms of the N-level AC-DC converter include a plurality of semiconductor devices connected in series, and a rated withstand voltage Vsemi of each of the semiconductor devices is greater than or equal to (Vbus*?)/((N?1)*Nseries*?); and a second-stage converter configured to convert the bus voltage into an output voltage to supply energy to the load.

Abstract: A ground fault detection method for a power converter is provided, including: measuring, by a voltage sensor, a first voltage and a second voltage respectively, and converting the first voltage and the second voltage into a first digital voltage signal and a second digital voltage signal; receiving, by a controller, the first digital voltage signal and the second digital voltage signal, extracting a corresponding feature quantity of the first voltage and a corresponding feature quantity of the second voltage according to the first digital voltage signal and the second digital voltage signal; and further determining a type of the ground fault of the power converter and locating a ground fault; and when the power converter has a ground fault, shutting down the power converter.

Abstract: A circuit for preventing false turn-on of a semiconductor switching device includes an active clamp circuit, a control circuit, a power amplifier circuit, and a suppression circuit. The control circuit is coupled to an input of the power amplifier circuit. An output of the power amplifier circuit is coupled to a gate of the semiconductor switching device. The active clamp circuit is configured to operate within a preset period when a voltage between the first end of the semiconductor switching device and a second end of the semiconductor switching device is greater than a preset voltage. The suppression circuit includes a controllable switch, which is configured to turn on after the operation of the active clamp circuit is completed, such that potential at the input of the power amplifier circuit is clamped to a fixed potential.

Abstract: Disclosed are a control method and control system for a modular multilevel converter and a power transmission system. The control method includes calculating an actual capacitor voltage of the sub-module; calculating a reference capacitor voltage of the sub-module; dividing the plurality of sub-modules into a plurality of modules, reference capacitor voltages of the sub-modules in the same module are the same, and reference capacitor voltages of the sub-modules from different modules are different; sorting in the module to obtain a first voltage sequence; sorting among different modules to obtain a second voltage sequence; and determining the sub-modules to be switched on or switched off according to charging and discharging states of the sub-module, the first voltage sequence and the second voltage sequence, until an actual level of the bridge arm is consistent with a desired level, wherein the desired level changes using a first preset value as a step.

Abstract: A modular power supply system includes: a main controller, configured to output a main control signal; N local controllers, wherein each of the local controllers is configured to receive the main control signal to output at least one local control signal; and N power units, in one-to-one correspondence with the N local controllers, wherein each of the power units includes a first end and a second end, and the second end of each of the power units is connected to the first end of an adjacent one of the power units, each of the power units is configured to include M power converters, each of the power converters is configured to operate according to the local control signal, wherein the same local control signal controls the power semiconductor switches at an identical position in at least two of the M power converters to be simultaneously turned on and off.

Abstract: A magnetic element includes at least one first air gap. A first portion of the first air gap is arranged between the first projection line and the second projection line. A second portion of the first air gap is beyond the region between the third projection line and the fourth projection line. Due to the air gap, the dielectric constant between the first end part of the winding and the magnetic leg and the dielectric constant between the second end part of the winding and the magnetic leg are reduced. Moreover, the electric field distribution of the first end part and the second end part will be more uniform, and the partial discharge extinction voltage will be increased. The volume and the cost of the magnetic element are both reduced. In addition, the equalizing rings are not required. Consequently, the fabricating process of the magnetic element is simplified.

Abstract: A power unit includes: a DC/DC conversion circuit; a bypass circuit, including a mechanical switch, an impedance network, and a semiconductor switch, wherein the semiconductor switch and the impedance network are connected in series to form a series branch, the series branch, the mechanic switch and the DC/DC conversion circuit are connected in parallel between a positive end and a negative end at one side of the power unit; a detecting unit, configured to detect a working signal of the DC/DC conversion circuit and generate a detection signal according to the working signal; and a controller, configured to, when the fault occurs in the DC/DC conversion circuit, output a first control signal to a control end of the mechanical switch and output a second control signal to a control end of the semiconductor switch.

Abstract: The present disclosure mainly provides a clamping circuit, coupled to a first end and a second end of a switching transistor through a first node and a second node, comprising: an RCD circuit, comprising a first resistor and a first capacitor connected in parallel between the second node and a third node, and a diode having a negative electrode coupled to the third node; and a first stabilivolt diode, having a negative electrode coupled to the first node and a positive electrode coupled to a positive electrode of the diode at a fourth node.

Abstract: A transformer includes a magnetic core, a first winding and at least one second winding. The magnetic core has a window through which the first winding passes through without contacting the magnetic core. The second winding passes through the window of the magnetic core and is wound on the magnetic core. The second winding has a distance from the first winding, and the second winding has a first insulating part disposed on an outer surface of the second winding facing the first winding.

Abstract: A control method of a multilevel converter includes: classifying power modules that start working, need to update an output state or stop working to form m power module groups; and controlling power modules in a same one of the power module groups to start working, update the output state or stop working at the same time, and sequentially controlling the m power module groups to start working, or update the output state or stop working, according to a preset time interval. The number of power modules in each power module group is less than or equal to a preset value, causing a change value of an output level of the each power module group to be less than or equal to a preset voltage value.