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48results about How to "Solve the pressure equalization problem" patented technology

Photovoltaic grid-connected inverter and control method

The invention discloses a photovoltaic grid-connected inverter. The photovoltaic grid-connected inverter comprises a photovoltaic array, a plurality of unit bodies, three unit body series branches, an alternating current reactor, a grid-connected switch, unit body controllers and a master controller, wherein the preceding stage of each unit body is respectively connected with the photovoltaic array; the unit body series branches are connected into a power grid after being connected with the alternating current reactor and the grid-connected switch in series; and each unit body comprises one of the unit body controllers. The invention also discloses a photovoltaic grid-connected inverter control method. In the inverter and the control method disclosed by the invention, the unit bodies are connected in series instead of directly connecting power devices in series, so that the problem of voltage-sharing of devices are solved; the power level is high; the limitation of load capacity of power electronic devices is overcome; a unit phase shift wave overlapping technology is adopted, so that an output harmonic wave is small; because of the action of an energy storage battery, when illumination disappears suddenly, a system cannot be off-grid and standby suddenly; and because of adopting a unit body automatic bypass technology, the security of the system is improved.
Owner:GUANGZHOU ZHIGUANG ELECTRIC CO LTD +1

Dual-output single-phase three-switch-group MMC inverter without direct current bias and control method thereof

The invention provides a dual-output single-phase three-switch-group MMC inverter without direct current bias and a control method of the inverter. The inverter comprises a direct current power supply, a first capacitor, a second capacitor, a third capacitor, a switch bridge arm, a first load and a second load. The switch bridge arm is formed by connecting an upper switch group, a middle switch group, a lower switch group and a coupled inductor in series. The upper switch group, the middle switch group and the lower switch group are respectively formed by connecting N power switch units in series. One end of the first load is connected to the middle point of the first capacitor and the middle point of the second capacitor, and the other end of the first load is connected to the upper end of the middle switch group. One end of the second load is connected to the middle point of the second capacitor and the middle point of the third capacitor, and the other end of the second load is connected to the lower end of the middle switch group. Carrier phase shifting PWM control is adopted for the inverter, two paths of N+1 level alternating voltages without direct current bias can be output, and the inverter is suitable for high-pressure, high-power and dual-load occasions. The coupled inductor in the inverter can be replaced by two independent inductors.
Owner:SOUTH CHINA UNIV OF TECH

Method for controlling voltages of direct current capacitors of six-switching-group or nine-switching-group MMC converter

The invention provides a method for controlling voltages of direct current capacitors of a six-switching-group or nine-switching-group MMC converter. The method includes the steps of voltage averaging control and voltage balance control. A voltage loop and a current loop are used in the voltage averaging control. The voltage balance control includes voltage balance control over the direct current capacitors of power switch units of upper switching groups, middle switching groups and lower switching groups of bridge arms. The voltages of the direct current capacitors of the power switch units of the upper switching groups, the middle switching groups and the lower switching groups are sampled and stabilized through voltage feedback and PI adjustment. By means of the control method, the voltages of the direct current capacitors of the six-switching-group or nine-switching-group MMC converter are balanced and stabilized, it is guaranteed that the direct current capacitors have dual 2N+1 level alternating current outputs, the quality of waveforms of output currents is high, voltage stress borne by each switch tube in the power switch units is only one Nth of the direct current bus voltage, and the voltage sharing aim of the switch tubes is well achieved.
Owner:SOUTH CHINA UNIV OF TECH

Distributed energy consumption device and module fault bypass control method

The invention provides a distributed energy consumption device and a module fault bypass control method. The device comprises at least two voltage-sharing energy dissipation modules, at least one one-way conduction module, at least one charging module and at least one isolation switch, wherein each voltage-sharing energy dissipation module comprises an energy storage unit, an energy consumption unit and a bypass switch which are connected in parallel; the energy storage unit comprises an energy storage capacitor and a current limiter which are connected in series; the energy dissipation unit comprises an energy dissipation resistor and a first power semiconductor device which are connected in series; the at least one one-way conduction module comprises at least one second power semiconductor device; the at least one charging module comprises at least one resistor and at least one switch which are connected in parallel; and the at least one isolation switch is connected with the voltage-sharing energy dissipation modules, the one-way conduction module and the charging module in the same direction in series. According to the modular design scheme, the voltage sharing problem of the power device is solved, and the control strategy is simplified; the design scheme that the energy storage capacitor is connected with the current limiter in series to limit the current of the bypass switch is adopted, so that the current impact of the bypass switching on is reduced, and the reliability of the fault bypass is improved.
Owner:NR ENG CO LTD +1

Modularized device for conversion between high-voltage direct current and direct current

The invention discloses a modularized device for conversion between high-voltage direct current and direct current. The modularized device for conversion between the high-voltage direct current and the direct current comprises at least two direct-current-direct-current conversion modules which are the same in structure, wherein the input ends of all the direct-current-direct-current conversion modules are connected in series in sequence in the forward direction and then are arranged between a positive pole and a negative pole of a high-voltage side in a connected mode, and the output ends of all the direct-current-direct-current conversion modules are connected in series or in parallel or in a series-parallel mode according to the voltage class requirement of a low-voltage side, and then are arranged between a positive pole and a negative pole of the low-voltage side in a connected mode. Each direct-current-direct-current conversion module comprises a high-voltage side converter module, a low and medium frequency sine wave transformer and a low-voltage side converter module, wherein the output end of each high-voltage side converter module is connected with an input winding of each low and medium frequency sine wave transformer, and an output winding of each low and medium frequency sine wave transformer is connected with the input end of each low-voltage side converter module. The modularized device for conversion between the high-voltage direct current and the direct current can solve the problems of voltage resistance and voltage sharing of switching devices on the high-voltage side, improve the transmission capacity, and have a certain application prospect in places with high-voltage input high power.
Owner:NR ELECTRIC CO LTD +1

N input single-phase 2N+2 switching group MMC rectifier and control method thereof

The invention provides an N input single-phase 2N+2 switching group MMC rectifier and a control method of the N input single-phase 2N+2 switching group MMC rectifier. The rectifier comprises N alternating-current inputting power supplies, N alternating-current inductors, a first bridge arm, a second bridge arm and a rectification output end load. Each of the first bridge arm and the second bridge arm is formed by connecting N+1 switching groups and two inductors in series. The ith switches in the first bridge arm and the second bridge arm are formed by connecting N power switching units in series and i is selected between 1 and N+1. The two ends of the kth alternating-current power supply serve as the kth circuit input, wherein k is selected between 1 and N and N is larger than two. The rectifier is controlled through carrier phase-shifting PWM, the N inputting alternating-current power supplies are converted into alternating-current inputting of N circuits of 2n+1 levels and after currents are rectified and overlapped, the load is powered. In an MMC power switching unit, the voltage stress borne by each switching tube is only one nth of the voltage of the direct-current power supplies and the problem of voltage sharing of the switching tubes is well solved. The N input single-phase 2N+2 switching group MMC rectifier is applicable to multiple-alternating-current-power-supply-inputting, high-voltage and large-power occasions.
Owner:SOUTH CHINA UNIV OF TECH

Novel method for equalizing voltage of series transformers, and application thereof

The invention relates to a novel method for equalizing voltage of series transformers, and application thereof, which belongs to the field of high-power high voltage or ultrahigh voltage. The method is applied to accelerating-level power sources of high-power radar transmitters, accelerators, CT, high-energy gas ion sources and high-energy metal ion sources. The method is characterized in that one more secondary winding is left on every transformer when switch transformers are designed; primary poles of the switch transformers are connected in series for power supply; a plurality of secondary windings of the transformers are segmented and rectified and then connect output in series so as to reach the needed output voltage of a power source; the reserved secondary windings of every transformer are connected in parallel so as to reach the effect of equalizing the voltage of a rectifier; and the voltage-equalizing windings need to be realized through high voltage insulation. The method has the advantage of solving the problem of equalizing voltage when the primary poles of the transformers are connected in series, along with simplicity, reliability and capability of applying to switch power sources at various types of power and voltage level. The appearance of the technique has great significance for improving the performances of radar transmitters and radar complete appliances.
Owner:CHINA ELECTRONICS TECH GRP CORP NO 14 RES INST

An energy consumption apparatus and a control method thereof

The invention discloses an energy consumption apparatus and a control method thereof. The apparatus includes N (N is an integer greater than 1) series sub-modules. A series circuit is connected between positive and negative DC polars for converting the surplus active power on the connected DC polar into heat through an energy dissipation resistor in the sub-modules of the apparatus. The technicalsolution proposed by the invention can effectively solve the problem of fault traversal in the field of high voltage direct current transmission and improve the ability of the system to operate stably.
Owner:詹长江

Dual-output single-phase six-switch block MMC inverter and control method thereof

The invention discloses a dual-output single-phase six-switch block modular multilevel converter (MMC) inverter and a control method thereof. The inverter is composed of a direct-current power supply, a first bridge arm, a second bridge arm, a first load and a second load. The first bridge arm and the second bridge arm are formed by series connection of upper switch blocks, intermediate switch blocks, lower switch blocks and coupling inductors; the two ends of the first load are respectively connected to the upper ends of the intermediate switch block of the first bridge arm and the intermediate switch block of the second bridge arm; and the two ends of the second load are respectively connected to the lower ends of the intermediate switch block of the first bridge arm and the intermediate switch block of the second bridge arm. According to the inverter, the carrier phase-lifting PWM control is used; and the inverter has two paths of alternating-current outputs with the 2N+1 levels. The voltage stress carried by each switching tube in a power switch unit is one-Nth of that of the direct-current power supply voltage; and thus the inverter is suitable for high-voltage high-power and dual-load occasions. Besides, both the primary side and the secondary side of the coupling inductor of the first bridge arm and the primary side and the second side of the coupling inductor of the second bridge arm can be replaced by two independent inductors of first inductors and second inductors.
Owner:SOUTH CHINA UNIV OF TECH

Novel high-capacity multi-level hybrid clamping topology and topological method

The invention relates to a novel high-capacity multi-level hybrid clamping topology and a topological method. The structure is a three-phase four-bridge arm structure; one bridge arm is added based ona conventional hybrid three-phase structure and is specially used for clamping; further, the structure does not need a voltage balancing circuit and an independent DC voltage source, and can realizemidpoint potential balance under all load characteristics; the conventional clamping device is improved, namely, a diode clamping device with a three-phase four-bridge arm topology is transformed intocapacitor clamping; an active switch transistor is added as a clamping device, so that the topology realizes current bidirectional path, and solves a problem of imbalance capacitance and voltage. Thestanding voltage balance problem in power switch in series operation is solved, further, a better way for realizing high voltage energy control based on low withstand voltage power switch is provided.
Owner:SHENYANG POLYTECHNIC UNIV

Six-switch-block MMC mixed converter and control method thereof

The invention provides a six-switch-block MMC mixed converter and a control method of the six-switch-block MMC mixed converter. The converter comprises an alternating-current input power source, an alternating-current input inductor, a first direct-current power source, a first direct-current input inductor, a second direct-current power source, a second direct-current input inductor, a first bridge arm, a second bridge arm and a load. The first bridge arm and the second bridge arm are respectively formed by connecting an upper switch block, a middle switch block, a lower switch block, a first bridge arm inductor and a second bridge arm inductor in series. Each switch block is formed by connecting N power switch units in series, wherein N is a positive integer. The converter is controlled by the carrier phase-shifting PWM, the alternating-current input power source is converted into the alternating-current input of the 2N+1 levels, the direct-current input power source is converted into multiple levels which are converted into direct-currents through the converter, and then the direct-currents are output to provide power for the load. The voltage stress borne by each switching tube in an MMC power switch unit is only 1 / N that of the direct-current power voltage, the voltage equalizing problem of the switching tubes is well solved, and the six-switch-block MMC mixed converter and the control method of the six-switch-block MMC mixed converter are suitable for the application of direct access of direct-current high-voltage transmission in distributed generation.
Owner:SOUTH CHINA UNIV OF TECH

Dynamic voltage-sharing control method for power module of chained multi-level converter

The invention discloses a dynamic voltage-sharing control method for a power module of a chained multi-level converter. The voltage-sharing method is performed by a single-phase software phase-locked loop, a sign function and a proportional controller connected in series, and comprises the steps that: the software phase-locked loop detects the phase of a power frequency component in the output current of the chained multi-level converter and inputs the phase information into the sign function to obtain the regulating direction of the voltage-sharing control, then the regulating variable of the voltage-sharing control is obtained by the proportional controller according to the direct voltage deviation of a single power module, at last the voltage-sharing component in the output voltage of the power module is obtained through multiplying the regulating direction with the regulating variable, and thus the output voltage of the module is obtained by summing the voltage-sharing component with the momentary value of the output voltage of the phase. The dynamic voltage-sharing control method overcomes harmonic current under the working condition of small current and influence of dynamic load which changes rapidly on the voltage sharing of the power module, and effectively solves the voltage-sharing problem of the chained multi-level converter under the working conditions of light load and dynamic load.
Owner:BEIJING SIFANG JIBAO AUTOMATION +1

Directly tandem high-voltage impulse power supply for insulation detection

InactiveCN101430356AEasy to adjust the amplitudeRising edge is steepElectrical measurement instrument detailsElectrical testingPower inverterSingle phase
The invention discloses a direct series high-voltage pulse power source for insulation test. The high-voltage pulse power source is characterized in that power supply outputs of a plurality of electrically isolated AC / DC DC power sources are respectively connected with power supply input terminals of the corresponding single-phase full bridge inverters; or the AC / DC DC power supply outputs are connected in parallel with a plurality of inputs of electrically isolated DC / DC DC power sources, outputs of a plurality of DC / DC DC power sources are electrically isolated from each other, and the output of each DC / DC DC power source is connected with the power supply input terminal of the corresponding single-phase full bridge inverter. An output of an inverter control system is connected with the input of an inverter driver, and the inverter driver is provided with a plurality of sets of electrically isolated outputs which are connected with control terminals of the corresponding single-phase full bridge inverter respectively. The power supply output terminals of a plurality of single-phase full bridge inverters are sequentially connected in series. The pulse power source can generate high-voltage pulses with adjustable amplitude and frequency, and the pulse voltage rising edge is steep.
Owner:SOUTHWEST JIAOTONG UNIV

Method for controlling voltage of direct current capacitors in double-output and three-switch-set MMC inverter

The invention provides a method for controlling voltage of direct current capacitors in a double-output and three-switch-set MMC inverter. The method comprises the step of controlling the voltage of the direct current capacitors of power switch units of the upper switch set, the middle switch set and the lower switch set, and the step of sampling the voltage of the direct current capacitors of the power switch units of the upper switch set, the middle switch set and the lower switch set and stabilizing the voltage of the direct current capacitors of the power switch units through voltage feedback and PI adjustment. According to the method, the voltage of the direct current capacitors in the double-output, one-phase and three-switch-set MMC inverter is balanced and stabilized, the double-output, one-phase and three-switch-set MMC inverter can have two paths of N+1 electrical level alternating current output, the quality of the output current waveform is very high, the voltage stress borne by each switch tube in the power switch units is only 1 / N of the direct current bus voltage, the voltages borne by all the switch tubes are equal in the working process of a converter, and the voltage-sharing problem of the switch tubes is solved very well.
Owner:SOUTH CHINA UNIV OF TECH

3N+3 switch set MMC AC-AC converter and control method thereof

The invention provides a 3N+3 switch set MMC AC-AC converter and a control method thereof. The 3N+3 switch set MMC AC-AC converter is composed of N three-phase alternating-current input / outputs, a first bridge arm, a second bridge arm, a third bridge arm and a first capacitor, each of the first bridge arm, the second bridge arm and the third bridge arm is formed by serially connecting N+1 switch sets and two inductors, each switch set is formed by serially connecting n power switch units, and three ends of each three-phase inductive load serve as a three-phase alternating-current output, wherein N and n are positive integers. Carrier phase-shifting PWM (pulse-width modulation) control is adopted, and each three-phase alternating-current output is converted into an alternating-current input with line voltage to be 2n+1 levels and converted into an alternating-current output with line voltage to be 2n+1 levels through AC-AC conversion to power a load; voltage stress borne by each switch tube in an MMC power switch unit is 1 / n of voltage of a direct-current power source, so that the problem of voltage sharing of the switch tubes is solved, and the 3N+3 switch set MMC AC-AC converter is suitable for being used in places with high voltage and high power.
Owner:SOUTH CHINA UNIV OF TECH

Single-phase six-switching-group MMC AC-AC converter and control method thereof

The invention provides a single-phase six-switching-group MMC AC-AC converter and a control method of the single-phase six-switching-group MMC AC-AC converter. The converter comprises an alternating current input power supply, an input inductor, a first bridge arm, a second bridge arm, a first capacitor and a load. The first bridge arm and the second bridge arm are respectively formed by connecting an upper switching group, a middle switching group, a lower switching group, a first inductor and a second inductor in series. Each switching group is formed by connecting N power switching units in series. The two ends of the load serve as output. N is a positive integer. The converter is controlled by a carrier phase-shifting PWM, the alternating current input power supply is converted into alternating current input at the 2N+1 level and supplies power to the load after being converted into alternating current output at the 2N+1 level through AC-AC conversion, stress of voltage borne by each switching pipe in each MMC power switch unit is only one Nth that of the voltage of a direct current power supply, the problem of voltage equalizing of the switching pipes is well solved, and the single-phase six-switching-group MMC AC-AC converter is suitable for places with high voltages and high power.
Owner:SOUTH CHINA UNIV OF TECH

Double-input three-phase nine-switch group mmc rectifier and its control method

The invention provides a double-input three-phase nine-switch-block MMC rectifier and a control method thereof. The rectifier comprises two three-phase voltage sources, two sets of three-phase inductors, a first bridge arm, a second bridge arm, a third bridge arm and a rectification load. Each of the first bridge arm, the second bridge arm and the third bridge arm is formed by connecting an upper switch block, a middle switch block, a lower switch block and two inductors in series. Each switch block is formed by connecting N power switch units. The rectifier is controlled through carrier phase-shifting PWM. Two input alternating-current power supplies are converted into alternating-current input of the three-phase 2N+1 level, rectified and overlapped and provide power for the load. The voltage stress borne by each switching tube in each MMC power switch unit is only 1 / N of the voltage of a direct-current power supply, the voltage sharing problem of the switching tubes is well solved, and the double-input three-phase nine-switch-block MMC rectifier is suitable for high-voltage and large-power occasions where two three-phase alternating-current power supplies are input.
Owner:SOUTH CHINA UNIV OF TECH

N-output three-phase 3N+3-switch-group MMC inverter and control method of N-output three-phase 3N+3-switch-group MMC inverter

The invention provides an N-output three-phase 3N+3-switch-group MMC inverter and a control method of the N-output three-phase 3N+3-switch-group MMC inverter. The inverter comprises a direct current power source, a first bridge arm, a second bridge arm, a third bridge arm and N three-phase loads. The three bridge arms are respectively formed by N+1 switch groups and two inductors in a series connection mode, and each switch group of each bridge arm is formed by n power switch units in a series connection mode. The three ends of the kth three-phase load are connected with the upper ends of the k+1th switch groups of the three bridge arms respectively, wherein the k ranges from 1 to N-1. The three ends of the Nth three-phase load are connected with the lower ends of the Nth switch groups of the three bridge arms. According to the inverter, carrier phase-shifting PWM control is adopted, N three-phase alternating currents with the 2n+1-level line voltages are output, the voltage stress borne by each switch tube in each MMC power switch unit is only 1 / n of the voltage stress of the direct current power source, and the inverter and the control method are suitable for high-voltage, high-power and three-phase alternating current double-load occasions.
Owner:SOUTH CHINA UNIV OF TECH

Photovoltaic grid-connected inverter and control method

The invention discloses a photovoltaic grid-connected inverter. The photovoltaic grid-connected inverter comprises a photovoltaic array, a plurality of unit bodies, three unit body series branches, an alternating current reactor, a grid-connected switch, unit body controllers and a master controller, wherein the preceding stage of each unit body is respectively connected with the photovoltaic array; the unit body series branches are connected into a power grid after being connected with the alternating current reactor and the grid-connected switch in series; and each unit body comprises one of the unit body controllers. The invention also discloses a photovoltaic grid-connected inverter control method. In the inverter and the control method disclosed by the invention, the unit bodies are connected in series instead of directly connecting power devices in series, so that the problem of voltage-sharing of devices are solved; the power level is high; the limitation of load capacity of power electronic devices is overcome; a unit phase shift wave overlapping technology is adopted, so that an output harmonic wave is small; because of the action of an energy storage battery, when illumination disappears suddenly, a system cannot be off-grid and standby suddenly; and because of adopting a unit body automatic bypass technology, the security of the system is improved.
Owner:GUANGZHOU ZHIGUANG ELECTRIC CO LTD +1

Six switch group mmc hybrid converter and its control method

The invention provides a six-switch-block MMC mixed converter and a control method of the six-switch-block MMC mixed converter. The converter comprises an alternating-current input power source, an alternating-current input inductor, a first direct-current power source, a first direct-current input inductor, a second direct-current power source, a second direct-current input inductor, a first bridge arm, a second bridge arm and a load. The first bridge arm and the second bridge arm are respectively formed by connecting an upper switch block, a middle switch block, a lower switch block, a first bridge arm inductor and a second bridge arm inductor in series. Each switch block is formed by connecting N power switch units in series, wherein N is a positive integer. The converter is controlled by the carrier phase-shifting PWM, the alternating-current input power source is converted into the alternating-current input of the 2N+1 levels, the direct-current input power source is converted into multiple levels which are converted into direct-currents through the converter, and then the direct-currents are output to provide power for the load. The voltage stress borne by each switching tube in an MMC power switch unit is only 1 / N that of the direct-current power voltage, the voltage equalizing problem of the switching tubes is well solved, and the six-switch-block MMC mixed converter and the control method of the six-switch-block MMC mixed converter are suitable for the application of direct access of direct-current high-voltage transmission in distributed generation.
Owner:SOUTH CHINA UNIV OF TECH

N output single-phase 2N+2 switching group MMC inverter and control method thereof

The invention provides an N output single-phase 2N+2 switching group MMC inverter and a control method of the N output single-phase 2N+2 switching group MMC inverter. The inverter comprises a direct-current power supply, a first bridge arm, a second bridge arm and N loads. Each of the two bridge arms is formed by connecting N+1 switching groups and two inductors in series. Each switching group of each bridge arm is formed by connecting n power switching units in series. The two ends of the kth load are connected with the upper ends of the (k+1)th switching groups of the two bridge arms respectively, wherein k is selected between 1 and N-1. The two ends of the Nth load are connected with the lower ends of the Nth switching groups of the two bridge arms respectively. The inverter is controlled through carrier phase-shifting PWM and has alternating current outputting of N circuits of 2n+1 levels. In an MMC power switching unit, the voltage stress borne by each switching tube is only one nth of the voltage of the direct-current power supply and the problem of voltage sharing of the switching tubes is well solved. The N output single-phase 2N+2 switching group MMC inverter is applicable to high-voltage and large-power occasions. The two inductors of each bridge arm can be mutually coupled to form a pair of coupled inductors.
Owner:SOUTH CHINA UNIV OF TECH

A driving signal timing method for hybrid clamped three-level h-bridge inverter

ActiveCN110176869BCapacitor equalizationEasy to use and understandAc-dc conversionCapacitanceCarrier signal
The invention relates to a driving signal timing method of a hybrid clamping type three-level H-bridge inverter. The inverter comprises two bus capacitor banks; the two bus capacitor banks are connected in series; in a driving signal timing process, the inverter is used for outputting pulse width modulation waves; in each modulation wave period, only one bus capacitor bank of the inverter is connected to a load for charging and discharging in a plurality of carrier periods near an output voltage zero crossing point; a charging time and a discharging moment of the same bus capacitor bank are symmetric relative to the zero crossing point on a time axis; a zero crossing point of an output voltage falling section is a first zero crossing point; a zero crossing point of a voltage rising sectionis a second zero crossing point; the moment when the first bus capacitor bank is connected to the load for charging and discharging, and the moment when the second bus capacitor bank is connected tothe load for charging and discharging are located at the first zero crossing point and the second zero crossing point respectively or vice versa; and the total time for the first bus capacitor bank tobe independently connected to the load for charging and discharging is equal to the total time for the second bus capacitor bank to be independently connected to the load for charging and discharging.
Owner:达微智能科技(厦门)有限公司

A Novel Large-capacity Multi-level Hybrid Clamp Topology Structure and Topology Method

The invention relates to a novel high-capacity multi-level hybrid clamping topology and a topological method. The structure is a three-phase four-bridge arm structure; one bridge arm is added based ona conventional hybrid three-phase structure and is specially used for clamping; further, the structure does not need a voltage balancing circuit and an independent DC voltage source, and can realizemidpoint potential balance under all load characteristics; the conventional clamping device is improved, namely, a diode clamping device with a three-phase four-bridge arm topology is transformed intocapacitor clamping; an active switch transistor is added as a clamping device, so that the topology realizes current bidirectional path, and solves a problem of imbalance capacitance and voltage. Thestanding voltage balance problem in power switch in series operation is solved, further, a better way for realizing high voltage energy control based on low withstand voltage power switch is provided.
Owner:SHENYANG POLYTECHNIC UNIV

n-input single-phase n+1 switch group mmc rectifier and its control method

The invention provides an N input single-phase N+1 switching group MMC rectifier and a control method of the N input single-phase N+1 switching group MMC rectifier. The rectifier comprises N alternating-current inputting power supplies, N alternating-current inductors, a capacitance bridge arm, a switching bridge arm and a rectification load. The capacitance bridge arm is formed by connecting N+1 capacitors in series and the switching bridge arm is formed by connecting N+1 switching groups, a first inductor and a second inductor in series. The ith switching group of the switching bridge arm is formed by connecting n power switching units in series, wherein i is selected between 1 and N+1. The two ends of the kth alternating-current power supply serve as inputting of the kth circuit, wherein k is selected between 1 and N. The N input single-phase N+1 switching group MMC rectifier is controlled through carrier phase-shifting PWM, the N input alternating current power supplies are converted into alternating current inputting of N circuits of n+1 levels and after currents are rectified and overlapped, the load is powered. The voltage stress borne by each switching tube in an MMC power switching unit is only one nth of the voltage of the direct-current power supplies and the problem of voltage sharing of the switching tubes is solved. The N input single-phase N+1 switching group MMC rectifier is applicable to multiple-alternating-current-power-supply-inputting, high-voltage and large-power occasions.
Owner:SOUTH CHINA UNIV OF TECH

n-input single-phase 2n+2 switch group mmc rectifier and its control method

The invention provides an N input single-phase 2N+2 switching group MMC rectifier and a control method of the N input single-phase 2N+2 switching group MMC rectifier. The rectifier comprises N alternating-current inputting power supplies, N alternating-current inductors, a first bridge arm, a second bridge arm and a rectification output end load. Each of the first bridge arm and the second bridge arm is formed by connecting N+1 switching groups and two inductors in series. The ith switches in the first bridge arm and the second bridge arm are formed by connecting N power switching units in series and i is selected between 1 and N+1. The two ends of the kth alternating-current power supply serve as the kth circuit input, wherein k is selected between 1 and N and N is larger than two. The rectifier is controlled through carrier phase-shifting PWM, the N inputting alternating-current power supplies are converted into alternating-current inputting of N circuits of 2n+1 levels and after currents are rectified and overlapped, the load is powered. In an MMC power switching unit, the voltage stress borne by each switching tube is only one nth of the voltage of the direct-current power supplies and the problem of voltage sharing of the switching tubes is well solved. The N input single-phase 2N+2 switching group MMC rectifier is applicable to multiple-alternating-current-power-supply-inputting, high-voltage and large-power occasions.
Owner:SOUTH CHINA UNIV OF TECH

Three-phase nine-switch group mmc AC-AC converter and its control method

The invention provides a three-phase nine-switch group MMC AC-AC converter and a control method thereof. The converter of the present invention includes a three-phase AC input power supply, an AC input inductance group, a first bridge arm, a second bridge arm, a third bridge arm, a first capacitor and a three-phase load; the first bridge arm, the second bridge arm The arm and the third bridge arm are each formed by connecting an upper switch group, a first inductor, a middle switch group, a second inductor, and a lower switch group in series; each switch group is formed by connecting N power switch units in series. The converter adopts carrier phase-shift PWM control, and the three-phase AC input power is converted into an AC input with a line voltage of 2N+1 level, which is transformed by AC-AC into an AC output with a line voltage of 2N+1 level to supply power to the load. In addition, the voltage stress of each switch tube in the MMC power switch unit is only 1 / N of the DC power supply voltage, which solves the problem of voltage equalization of the switch tubes and is suitable for high-voltage and high-power applications.
Owner:SOUTH CHINA UNIV OF TECH

Double-input single-phase six-switch group mmc rectifier and its control method

The invention provides a double-input single-phase six-switch-block MMC rectifier and a control method thereof. The rectifier comprises a first alternating-current input power supply, a second alternating-current input power supply, a first inductor, a second inductor, a first bridge arm, a second bridge arm and a rectification load. Each of the first bridge arm and the second bridge arm is formed by connecting an upper switch block, a middle switch block, a lower switch block ,a third inductor and a fourth inductor in series. The upper switch blocks, the middle switch blocks and the lower switch blocks of the first bridge arm and the second bridge arm are formed by connecting N power switch units in series. The rectifier is controlled through carrier phase-shifting PWM, and the two input alternating-current power supplies are converted into two circuits of alternating current input of the 2N+1 level, rectified and overlapped and provide power for the load. In addition, the voltage stress borne by each switching tube in each MMC power switch unit is only 1 / N of the voltage of a direct-current power supply, the voltage sharing problem of the switching tubes is well solved, and the double-input single-phase six-switch-block MMC rectifier is suitable for high-voltage and large-power occasions where two single-phase alternating-current power supplies are input.
Owner:SOUTH CHINA UNIV OF TECH

N-output single-phase N+1-switch-group MMC inverter and control method of N-output single-phase N+1-switch-group MMC inverter

The invention provides an N-output single-phase N+1-switch-group MMC inverter and a control method of the N-output single-phase N+1-switch-group MMC inverter. The inverter comprises a direct current power source, a capacitor bridge arm, a switch bridge arm and N loads. The capacitor bridge arm is formed by N+1 capacitors in a series connection mode, and the switch bridge arm is formed by N+1 switch groups, a first inductor and a second inductor in a series connection mode. The ith switch group of the switch bridge arm is formed by n power switch units in a series connection mode, wherein the i ranges from 1 to N+1. One end of the kth load is connected to the positive pole of the k+1th capacitor of the capacitor bridge arm, and the other end of the kth load is connected to the upper end of the k+1th switch group of the switch bridge arm, wherein the k ranges from 1 to N-1. One end of the Nth load is connected to the positive pole of the N+1th capacitor of the capacitor bridge arm, and the other end of the Nth load is connected to the lower end of the N+1th switch group of the switch bridge arm. According to the inverter, carrier phase-shifting PWM control is adopted, and N n+1-level alternating voltages can be output.
Owner:SOUTH CHINA UNIV OF TECH
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