CN203827206U - Nine-switch-group MMC hybrid converter - Google Patents

Abstract

The utility model provides a nine-switch-group MMC hybrid converter. The converter of the utility model comprises a three-phase AC input power supply, an AC input inductor group, a first DC power supply, a first DC input inductor, a second DC power supply, a second DC input inductor, a third DC power supply, a third DC input inductor, a first bridge arm, a second bridge arm, a third bridge arm and a load. According to the converter, the carrier phase shift PWM control is employed, the three-phase AC input power supply is converted into AC input with the voltage of 2N+1 levels, the voltage stress born by each switch tube in an MMC power switch unit is only 1/N of DC power supply voltage, a voltage equalizing problem of the switch tube is solved well, and the converter is suitable for being applied to the distributed power generation directly connected high voltage DC power transmission.

Description

Nine switches set MMC mixing transformation devices

Technical field

The utility model relates to module combination multi-level converter (MMC) field, is specifically related to a kind of nine switches set MMC mixing transformation devices.

Background technology

Along with the development of distributed power generation and high voltage direct current transmission, increasing low-voltage dc power supply and low-voltage alternating current power supply directly access in high-voltage direct current power grid., under this trend, there is the direction of two kinds of improvement converters: reduce passive device or improve converter topology structure at present power inverter forward miniaturization, high reliability and low-loss future development.Three-phase nine switch converters can directly be connected DC power supply with AC power with DC power supply, three-phase nine switch converters close converter with respect to traditional twelvemo and have reduced three switches and corresponding drive circuit, in the application of considering cost and volume, occupy certain advantage.Yet the single-phase input AC of nine switch converters is converted to three level.In addition, half that the voltage stress that in nine switches, each switch bears is DC bus-bar voltage, and the voltage-sharing of nine switches of existence, this has limited the application of three-phase nine switch converters in high pressure and large-power occasions greatly.

In recent years, multilevel technology is constantly promoted, and successful Application is at industrial circles such as high voltage direct current transmission, Electric Drive, active power filtering, static synchroballistic, common voltage-type multi-level converter topology is broadly divided into case bit-type and the large class of unit cascaded type two at present.Module combination multi-level converter (Modular Multilevel Converter, MMC) as a kind of novel many level topologys, except having advantages of traditional multi-level converter, module combination multi-level converter adopts Modular Structure Design, is convenient to System Expansion and redundancy of effort; Have unbalanced operation ability, fault traversing and recovery capability, system reliability is high; Owing to having common DC bus, module combination multi-level converter is particularly useful for HVDC (High Voltage Direct Current) transmission system application.Yet, when a plurality of DC power supply and AC power are during by MMC converter access electrical network, needing many cover MMC converters, this has increased engineering cost greatly.

Utility model content

The purpose of this utility model is to overcome above-mentioned the deficiencies in the prior art, proposes a kind of nine switches set MMC mixing transformation devices.

The technical solution adopted in the utility model is:

Nine switches set MMC mixing transformation devices, comprise three-phase alternating current input power, exchange and input inductive bank, the first DC power supply, the first direct current input inductance, the second DC power supply, the second direct current input inductance, the 3rd DC power supply, the 3rd direct current input inductance the first brachium pontis, the second brachium pontis, the 3rd brachium pontis and load, three-phase alternating current input power comprises u phase power supply, v phase power supply and w phase power supply, exchange input inductive bank and comprise u phase inductance, v phase inductance and w phase inductance, all each is freely gone up switches set, the first brachium pontis inductance, middle switches set, the second brachium pontis inductance, lower switches set and is in series for described the first brachium pontis, the second brachium pontis and the 3rd brachium pontis, the upper switches set of the first brachium pontis is in series by N power switch unit, the middle switches set of the first brachium pontis is in series by N power switch unit, the lower switches set of the first brachium pontis is connected by N power switch unit, the upper switches set of the second brachium pontis is in series by N power switch unit, the middle switches set of the second brachium pontis is in series by N power switch unit, the lower switches set of the second brachium pontis is in series by N power switch unit, the upper switches set of the 3rd brachium pontis is in series by N power switch unit, the middle switches set of the 3rd brachium pontis is in series by N power switch unit, the lower switches set of the 3rd brachium pontis is in series by N power switch unit, N is positive integer.

Further, two brachium pontis inductance of two of described the first brachium pontis brachium pontis inductance, the second brachium pontis and two brachium pontis inductance of the 3rd brachium pontis all each free coupling inductance substitute.

Further, the lower end of the upper switches set of described the first brachium pontis is connected with one end of the first brachium pontis inductance of the first brachium pontis, the other end of the first brachium pontis inductance of the first brachium pontis is connected with the upper end of the middle switches set of the first brachium pontis, the lower end of the middle switches set of the first brachium pontis is connected with one end of the second brachium pontis inductance of the first brachium pontis, and the other end of the second brachium pontis inductance of the first brachium pontis is connected with the upper end of the lower switches set of the first brachium pontis; The structure of the structure of the structure of the second brachium pontis, the 3rd brachium pontis and the first brachium pontis is in full accord; One end of u phase power supply is connected with one end of u phase inductance, the other end of u phase inductance is connected with the upper end of the middle switches set of the first brachium pontis, the other end of u phase power supply is connected with one end of one end of v phase power supply, w phase power supply, the other end of v phase power supply is connected with one end of v phase inductance, the other end of v phase inductance is connected with the upper end of the middle switches set of the second brachium pontis, the other end of w phase power supply is connected with one end of w phase inductance, and the other end of w phase inductance is connected with the upper end of the middle switches set of the 3rd brachium pontis; The positive pole of the first DC power supply is connected with one end of the first direct current input inductance, and the first direct current input other end of inductance and the middle switches set lower end of the first brachium pontis are connected; The positive pole of the second DC power supply is connected with one end of the second direct current input inductance, and the second direct current input other end of inductance and the middle switches set lower end of the second brachium pontis are connected; The positive pole of the 3rd DC power supply is connected with one end of the 3rd direct current input inductance, and the 3rd direct current input other end of inductance and the middle switches set lower end of the 3rd brachium pontis are connected; The upper end of the upper switches set of the first brachium pontis with the upper end of the upper switches set of the second brachium pontis, the upper end of upper switches set of the 3rd brachium pontis, one end of load be connected; The other end of load with the lower end of the lower switches set of the first brachium pontis, the lower end of the lower switches set of the second brachium pontis, the lower end of the lower switches set of the 3rd brachium pontis, hold and be connected.

Further, described power switch unit comprises the first switching tube, second switch pipe, the first diode, the second diode and electric capacity; Wherein, the positive pole of electric capacity is connected with the collector electrode of the first switching tube, the negative electrode of the first diode, the emitter of the first switching tube is connected with the anode of the first diode, the negative electrode of the collector electrode of second switch pipe, the second diode, and the emitter of second switch pipe is connected with the anode of the second diode, the negative pole of electric capacity; The collector electrode of second switch pipe is as the first output, and the emitter of second switch pipe is as the second output.

Further, the second output of j power switch unit of described each switches set is connected with the first output of j+1 power switch unit, and wherein the value of j is 1～N-1.

Above-mentioned nine switches set MMC mixing transformation devices, can adopt phase-shifting carrier wave PWM to control the opening and turn-offing of switching tube of each switches set; J power switch unit of the upper switches set of the first brachium pontis, j the power switch unit of lower switches set of the first brachium pontis, j the power switch unit of upper switches set of the second brachium pontis, j the power switch unit of lower switches set of the second brachium pontis, j power switch unit of j power switch unit of the upper switches set of the 3rd brachium pontis and the lower switches set of the 3rd brachium pontis adopts identical triangular wave as j carrier wave C _j, wherein the value of j is 1～N; N carrier wave be 360 °/N of lagging phase angle successively; The upper switches set of the first brachium pontis adopts primary sinusoid R _acustack direct current biasing R _dothe first modulating wave R as the first brachium pontis _acu+ R _do, the lower switches set of the first brachium pontis adopts constant value as the second modulating wave R of the first brachium pontis _dc1, the upper switches set of the second brachium pontis adopts the second sinusoidal wave R _acvstack direct current biasing R _dothe first modulating wave R as the second brachium pontis _acv+ R _do, the lower switches set of the second brachium pontis adopts constant value as the second modulating wave R of the second brachium pontis _dc2, the upper switches set of the 3rd brachium pontis adopts the 3rd sinusoidal wave R _acwstack direct current biasing R _dothe first modulating wave R as the 3rd brachium pontis _acw+ R _do, the lower switches set of the 3rd brachium pontis adopts constant value as the second modulating wave R of the 3rd brachium pontis _dc3; Primary sinusoid R _acu, the second sinusoidal wave R _acvwith the 3rd sinusoidal wave R _acwthe identical and phase difference of frequency be 120 °, the second modulating wave R of the first brachium pontis _dc1, the second brachium pontis the second modulating wave R _dc2, the 3rd brachium pontis the second modulating wave R _dc3size identical.

The first modulating wave R of the first brachium pontis _acu+ R _dowith j carrier wave C _jby the first comparator, obtain the control level of second switch pipe gate pole of j power switch unit of the upper switches set of the first brachium pontis, as the first modulating wave R of the first brachium pontis _acu+ R _dobe greater than j carrier wave C _jtime, the first comparator output high level, as the first modulating wave R of the first brachium pontis _acu+ R _dobe less than j carrier wave C _jtime, the first comparator output low level, wherein the value of j is 1～N; The second modulating wave R of the first brachium pontis _dc1with j carrier wave C _jby the second comparator, obtain the control level of second switch pipe gate pole in j the power switch unit of lower switches set of the first brachium pontis, as the second modulating wave R of the first brachium pontis _dc1be less than j carrier wave C _jtime, the second comparator output high level, as the second modulating wave R of the first brachium pontis _dc1be greater than j carrier wave C _jtime, the second comparator output low level; In the control level of second switch pipe gate pole of j power switch unit of the upper switches set of the first brachium pontis and j power switch unit of the lower switches set of the first brachium pontis, the control level of second switch pipe gate pole is by the first XOR gate, obtains the control level of second switch pipe gate pole in j the power switch unit of middle switches set of the first brachium pontis; The first modulating wave R of the second brachium pontis _acv+ R _dowith j carrier wave C _jby the 3rd comparator, obtain the control level of second switch pipe gate pole in j the power switch unit of upper switches set of the second brachium pontis, as the first modulating wave R of the second brachium pontis _acv+ R _dobe greater than j carrier wave C _jtime, the 3rd comparator output high level, as the first modulating wave R of the second brachium pontis _acv+ R _dobe less than j carrier wave C _jtime, the 3rd comparator output low level; The second modulating wave R of the second brachium pontis _dc2with j carrier wave C _jby the 4th comparator, obtain the control level of second switch pipe gate pole in j the power switch unit of lower switches set of the second brachium pontis, as the second modulating wave R of the second brachium pontis _dc2be less than j carrier wave C _j, the 4th comparator output high level, as the second modulating wave R of the second brachium pontis _dc2be greater than j carrier wave C _j, the 4th comparator output low level; In j power switch unit of the upper switches set of the second brachium pontis, in j power switch unit of the control level of second switch pipe gate pole and the lower switches set of the second brachium pontis, the control level of second switch pipe gate pole by the second XOR gate, obtains the control level of second switch pipe gate pole in j the power switch unit of middle switches set of second brachium pontis; The first modulating wave R of the 3rd brachium pontis _acw+ R _dowith j carrier wave C _jby the 5th comparator, obtain the control level of second switch pipe gate pole in j the power switch unit of upper switches set of the 3rd brachium pontis, as the first modulating wave R of the 3rd brachium pontis _acw+ R _dobe greater than j carrier wave C _j, the 5th comparator output high level, as the first modulating wave R of the 3rd brachium pontis _acw+ R _dobe less than j carrier wave C _j, the 5th comparator output low level; The second modulating wave R of the 3rd brachium pontis _dc3with j carrier wave C _jby the 6th comparator, obtain the control level of second switch pipe gate pole in j the power switch unit of lower switches set of the 3rd brachium pontis, as the second modulating wave R of the 3rd brachium pontis _dc3be less than j carrier wave C _j, the 6th comparator output high level, as the second modulating wave R of the 3rd brachium pontis _dc3be greater than j carrier wave C _j, the 6th comparator output low level; In j power switch unit of the upper switches set of the 3rd brachium pontis, in j power switch unit of the control level of second switch pipe gate pole and the lower switches set of the 3rd brachium pontis, the control level of second switch pipe gate pole by the 3rd XOR gate, obtains the control level of second switch pipe gate pole in j the power switch unit of middle switches set of the 3rd brachium pontis; In each power switch unit of each switches set, the control level of second switch pipe gate pole obtains the control level of the first switching tube gate pole in this power switch unit after anti-phase.

Compared with prior art, the advantage the utlity model has is: three-phase alternating current input power is converted to the interchange input that line voltage is 2N+1 level; The voltage stress that in power switch unit, each switching tube bears is only the 1/N of DC bus-bar voltage, can guarantee that the voltage that in the converter course of work, all switching tubes bear equates, has well solved the voltage-sharing of switching tube simultaneously.Compare with existing three-phase nine switch converters, the three-phase alternating current input power of nine switches set MMC mixing transformation devices provided by the utility model is converted to the interchange input that line voltage is 2N+1 level.In addition, the voltage stress bearing of each switching tube is only the 1/N of DC bus-bar voltage, and control method provided by the utility model equates the voltage that in the converter course of work, all switching tubes bear, well solved the voltage-sharing of switching tube, this will be very beneficial for the application of nine switches set MMC mixing transformation devices in high pressure and large-power occasions.Compare with existing MMC converter, nine switches set MMC mixing transformation devices provided by the utility model only use six groups of switches by two DC power supply and an AC power access direct current network, greatly reduce engineering cost.

Accompanying drawing explanation

Fig. 1 is the circuit structure diagram of nine switches set MMC mixing transformation devices of the present utility model;

Fig. 2 is the circuit structure diagram of the power switch unit of nine switches set MMC mixing transformation devices shown in Fig. 1;

Fig. 3 is the phase-shifting carrier wave PWM control structure figure of nine switches set MMC mixing transformation devices shown in Fig. 1;

Fig. 4 is the first modulating wave of nine switches set MMC mixing transformation device the first brachium pontis shown in Fig. 1 and the relation of the second modulating wave and carrier wave;

Fig. 5 is the simulation waveform figure of nine switches set MMC mixing transformation devices.

Embodiment

For further setting forth content of the present utility model and feature, below in conjunction with accompanying drawing, specific embodiments of the present utility model is specifically described.But enforcement of the present utility model is not limited to this.

With reference to figure 1, nine switches set MMC mixing transformation devices of the present utility model, comprise three-phase alternating current input power, exchange input inductive bank, the first DC power supply u _dc1, the first direct current input inductance L _dc1, the second DC power supply u _dc2, the second direct current input inductance L _dc2, the 3rd DC power supply u _dc3, the 3rd direct current input inductance L _dc3the first brachium pontis, the second brachium pontis, the 3rd brachium pontis and load R; Three-phase alternating current input power comprises u phase power supply u _acu, v phase power supply u _acvwith w phase power supply u _acw; Exchange input inductive bank and comprise u phase inductance L _acu, v phase inductance L _acvwith w phase inductance L _acw; All each is freely gone up switches set, the first brachium pontis inductance, middle switches set, the second brachium pontis inductance, lower switches set and is in series for described the first brachium pontis, the second brachium pontis and the 3rd brachium pontis; The upper switches set H of the first brachium pontis _uby N power switch unit (SM _hu1, SM _hu2..., SM _huN) be in series, the middle switches set M of the first brachium pontis _uby N power switch unit (SM _mu1, SM _mu2..., SM _muN) be in series, the lower switches set L of the first brachium pontis _uby N power switch unit (SM _lu1, SM _lu2..., SM _luN) series connection, the upper switches set H of the second brachium pontis _vby N power switch unit (SM _hv1, SM _hv2..., SM _hvN) be in series, the middle switches set M of the second brachium pontis _vby N power switch unit (SM _mv1, SM _mv2..., SM _mvN) be in series, the lower switches set L of the second brachium pontis _vby N power switch unit (SM _lv1, SM _lv2..., SM _lvN) be in series, the upper switches set H of the 3rd brachium pontis _wby N power switch unit (SM _hw1, SM _hw2..., SM _hwN) be in series, the middle switches set M of the 3rd brachium pontis _wby N power switch unit (SM _mw1, SM _mw2..., SM _mwN) be in series, the lower switches set L of the 3rd brachium pontis _wby N power switch unit (SM _lw1, SM _lw2..., SM _lwN) be in series; N is positive integer.

The upper switches set H of the first brachium pontis _ulower end p and the first brachium pontis inductance L of the first brachium pontis _huone end connect, the first brachium pontis inductance L of the first brachium pontis _huthe other end and the middle switches set M of the first brachium pontis _uupper end o connect, the middle switches set M of the first brachium pontis _ulower end and the second brachium pontis inductance L of the first brachium pontis _luone end connect, the second brachium pontis inductance L of the first brachium pontis _luthe other end and the lower switches set L of the first brachium pontis _uupper end connect; The structure of the structure of the structure of the second brachium pontis, the 3rd brachium pontis and the first brachium pontis is in full accord; U phase power supply u _acuone end and u phase inductance L _acuone end connect, u phase inductance L _acuthe other end and the middle switches set M of the first brachium pontis _uupper end connect, u phase power supply u _acuthe other end and v phase power supply u _acvone end, w phase power supply u _acwone end connect, v phase power supply u _acvthe other end and v phase inductance L _acvone end connect, v phase inductance L _acvthe other end and the middle switches set M of the second brachium pontis _vupper end connect, w phase power supply u _acwthe other end and w phase inductance L _acwone end connect, w phase inductance L _acwthe other end and the middle switches set M of the 3rd brachium pontis _wupper end connect; The first DC power supply u _dc1positive pole and the first direct current input inductance L _dc1one end connect, the first direct current input inductance L _dc1the other end and the middle switches set M of the first brachium pontis _ulower end connects; The second DC power supply u _dc2positive pole and the second direct current input inductance L _dc2one end connect, the second direct current input inductance L _dc2the other end and the middle switches set M of the second brachium pontis _vlower end connects; The 3rd DC power supply u _dc3positive pole and the 3rd direct current input inductance L _dc3one end connect, the 3rd direct current input inductance L _dc3the other end and the middle switches set M of the 3rd brachium pontis _wlower end connects; The upper switches set H of the first brachium pontis _uupper end and the upper switches set H of the second brachium pontis _vupper end, the upper switches set H of the 3rd brachium pontis _wone end of upper end, load R connect; The lower switches set L of the other end of load R and the first brachium pontis _ulower end, the lower switches set L of the second brachium pontis _vlower end, the lower switches set L of the 3rd brachium pontis _wlower end, hold n to connect.

Fig. 2 illustrates the circuit structure of the power switch unit of nine switches set MMC mixing transformation devices shown in Fig. 1.Power switch unit comprises the first switching tube S ₁, second switch pipe S ₂, the first diode D ₁, the second diode D ₂and capacitor C _sM; Wherein, capacitor C _sMpositive pole and the first switching tube S ₁collector electrode, the first diode D ₁negative electrode connect, the first switching tube S ₁emitter and the first diode D ₁anode, second switch pipe S ₂collector electrode, the second diode D ₂negative electrode connect, second switch pipe S ₂emitter and the second diode D ₂anode, capacitor C _sMnegative pole connect; Second switch pipe S ₂collector electrode as the first output, second switch pipe S ₂emitter as the second output.

As shown in Figure 1, the second output of j power switch unit of each switches set is connected with the first output of j+1 power switch unit, and wherein the value of j is 1～N-1.

Make u phase input power be v phase input power is w phase input power is the voltage of the first DC power supply is u _dc1=U _dc1, the voltage of the second DC power supply is u _dc2=U _dc2, the voltage of the 3rd DC power supply is u _dc3=U _dc3:

$R_{\mathrm{dc}1}=\frac{U_{\mathrm{dc}1}}{U_R/2},R_{\mathrm{dc}2}=\frac{U_{\mathrm{dc}2}}{U_R/2},R_{\mathrm{dc}3}=\frac{U_{\mathrm{dc}3}}{U_R/2}$

In formula, U _rvoltage for load R.

Nine switches set MMC mixing transformation devices shown in Fig. 1 adopt phase-shifting carrier wave PWM to control, as shown in Figure 3.

Upper switches set (the H of the first brachium pontis _u) j power switch unit (SM _huj), the lower switches set (L of the first brachium pontis _u) j power switch unit (SM _luj), the upper switches set (H of the second brachium pontis _v) j power switch unit (SM _hvj), the lower switches set (L of the second brachium pontis _v) j power switch unit (SM _lvj), the upper switches set (H of the 3rd brachium pontis _w) j power switch unit (SM _hwj) and the lower switches set (L of the 3rd brachium pontis _w) j power switch unit (SM _lwj) adopt identical triangular wave as j carrier wave C _j, wherein the value of j is 1～N; N carrier wave (C ₁, C ₂..., C _n) 360 °/N of lagging phase angle successively; Upper switches set (the H of the first brachium pontis _u) employing primary sinusoid R _acustack direct current biasing R _dothe first modulating wave R as the first brachium pontis _acu+ R _do, the lower switches set (L of the first brachium pontis _u) adopt constant value as the second modulating wave R of the first brachium pontis _dc1, the upper switches set (H of the second brachium pontis _v) employing the second sinusoidal wave R _acvstack direct current biasing R _dothe first modulating wave R as the second brachium pontis _acv+ R _do, the lower switches set (L of the second brachium pontis _v) adopt constant value as the second modulating wave R of the second brachium pontis _dc2, the upper switches set (H of the 3rd brachium pontis _w) employing the 3rd sinusoidal wave R _acwstack direct current biasing R _dothe first modulating wave R as the 3rd brachium pontis _acw+ R _do, the lower switches set (L of the 3rd brachium pontis _w) adopt constant value as the second modulating wave R of the 3rd brachium pontis _dc3; Primary sinusoid R _acu, the second sinusoidal wave R _acvwith the 3rd sinusoidal wave R _acwthe identical and phase difference of frequency be 120 °, the second modulating wave R of the first brachium pontis _dc1, the second brachium pontis the second modulating wave R _dc2, the 3rd brachium pontis the second modulating wave R _dc3size identical.

The first modulating wave R of the first brachium pontis _acu+ R _dowith j carrier wave C _jby the first comparator 301, obtain the upper switches set H of the first brachium pontis _uj power switch unit SM _hujsecond switch pipe S ₂the control level S of gate pole _huj, as the first modulating wave R of the first brachium pontis _acu+ R _dobe greater than j carrier wave C _jtime, the first comparator output high level, as the first modulating wave R of the first brachium pontis _acu+ R _dobe less than j carrier wave C _jtime, the first comparator output low level, wherein the value of j is 1～N; The second modulating wave R of the first brachium pontis _dc1with j carrier wave C _jby the second comparator 302, obtain the lower switches set L of the first brachium pontis _uj power switch unit SM _lujmiddle second switch pipe S ₂the control level S of gate pole _luj, as the second modulating wave R of the first brachium pontis _dc1be less than j carrier wave C _jtime, the second comparator output high level, as the second modulating wave R of the first brachium pontis _dc1be greater than j carrier wave C _jtime, the second comparator output low level; The upper switches set H of the first brachium pontis _uj power switch unit SM _hujsecond switch pipe S ₂the control level S of gate pole _hujlower switches set L with the first brachium pontis _uj power switch unit SM _lujmiddle second switch pipe S ₂the control level S of gate pole _lujby the first XOR gate 307, obtain the middle switches set M of the first brachium pontis _uj power switch unit SM _mujmiddle second switch pipe S ₂the control level S of gate pole _muj; The first modulating wave R of the second brachium pontis _acv+ R _dowith j carrier wave C _jby the 3rd comparator 303, obtain the upper switches set H of the second brachium pontis _vj power switch unit SM _hvjmiddle second switch pipe S ₂the control level S of gate pole _hvj, as the first modulating wave R of the second brachium pontis _acv+ R _dobe greater than j carrier wave C _jtime, the 3rd comparator output high level, as the first modulating wave R of the second brachium pontis _acv+ R _dobe less than j carrier wave C _jtime, the 3rd comparator output low level; The second modulating wave R of the second brachium pontis _dc2with j carrier wave C _jby the 4th comparator 304, obtain the lower switches set L of the second brachium pontis _vj power switch unit SM _lvjmiddle second switch pipe S ₂the control level S of gate pole _lvj, as the second modulating wave R of the second brachium pontis _dc2be less than j carrier wave C _j, the 4th comparator output high level, as the second modulating wave R of the second brachium pontis _dc2be greater than j carrier wave C _j, the 4th comparator output low level; The upper switches set H of the second brachium pontis _vj power switch unit SM _hvjmiddle second switch pipe S ₂the control level S of gate pole _hvjlower switches set L with the second brachium pontis _vj power switch unit SM _lvjmiddle second switch pipe S ₂the control level S of gate pole _lvjby the second XOR gate 308, obtain the middle switches set M of second brachium pontis _vj power switch unit SM _mvjmiddle second switch pipe S ₂the control level S of gate pole _mvj; The first modulating wave R of the 3rd brachium pontis _acw+ R _dowith j carrier wave C _jby the 5th comparator 305, obtain the upper switches set H of the 3rd brachium pontis _wj power switch unit SM _hwjmiddle second switch pipe S ₂the control level S of gate pole _hwj, as the first modulating wave R of the 3rd brachium pontis _acw+ R _dobe greater than j carrier wave C _j, the 5th comparator output high level, as the first modulating wave R of the 3rd brachium pontis _acw+ R _dobe less than j carrier wave C _j, the 5th comparator output low level; The second modulating wave R of the 3rd brachium pontis _dc3with j carrier wave C _jby the 6th comparator 306, obtain the lower switches set L of the 3rd brachium pontis _wj power switch unit SM _lwjmiddle second switch pipe S ₂the control level S of gate pole _lwj, as the second modulating wave R of the 3rd brachium pontis _dc3be less than j carrier wave C _j, the 6th comparator output high level, as the second modulating wave R of the 3rd brachium pontis _dc3be greater than j carrier wave C _j, the 6th comparator output low level; The upper switches set H of the 3rd brachium pontis _wj power switch unit SM _hwjmiddle second switch pipe S ₂the control level S of gate pole _hwjlower switches set L with the 3rd brachium pontis _wj power switch unit SM _lwjmiddle second switch pipe S ₂the control level S of gate pole _lwjby the 3rd XOR gate 309, obtain the middle switches set M of the 3rd brachium pontis _wj power switch unit SM _mwjmiddle second switch pipe S ₂the control level S of gate pole _mwj; Second switch pipe S in each power switch unit of each switches set ₂after the control level of gate pole is anti-phase, obtain the first switching tube S in this power switch unit ₁the control level of gate pole.

Described control method can guarantee the upper switches set H of the first brachium pontis of described converter _u, the first brachium pontis middle switches set M _ulower switches set L with the first brachium pontis _uat each, constantly have the output voltage u of N power switch unit _sM=E, the output voltage u of total 2N power switch unit _sM=0, meet u _hu+ u _mu+ u _lu=U _r; Guarantee the upper switches set H of the second brachium pontis _v, the second brachium pontis middle switches set M _vlower switches set L with the second brachium pontis _vat each, constantly have the output voltage u of N power switch unit _sM=E, the output voltage u of total 2N power switch unit _sM=0, meet u _hv+ u _mv+ u _lv=U _r; Guarantee the upper switches set H of the 3rd brachium pontis _w, the 3rd brachium pontis middle switches set M _wlower switches set L with the 3rd brachium pontis _wat each, constantly have the output voltage u of N power switch unit _sM=E, the output voltage u of total 2N power switch unit _sM=0, meet u _hw+ u _mw+ u _lw=U _r; U wherein _hu, u _hv, u _hwbe respectively the upper switches set H of the first brachium pontis _u, the second brachium pontis upper switches set H _vupper switches set H with the 3rd brachium pontis _woutput voltage, u _mu, u _mv, u _mwbe respectively the middle switches set M of the first brachium pontis _u, the second brachium pontis middle switches set M _vmiddle switches set M with the 3rd brachium pontis _woutput voltage, u _lu, u _lv, u _lwbe respectively the lower switches set L of the first brachium pontis _u, the second brachium pontis lower switches set L _vlower switches set L with the 3rd brachium pontis _woutput voltage, capacitor C in each power switch unit that E is each switches set _sMvoltage, and have E=U _r/ N, the voltage stress that in power switch unit, each switching tube bears is only the 1/N of DC bus-bar voltage, can guarantee that the voltage that in the converter course of work, all switching tubes bear equates, has well solved the voltage-sharing of switching tube simultaneously.

Fig. 4 illustrates the first modulating wave R of nine switches set MMC mixing transformation device the first brachium pontis _acu+ R _do, the first brachium pontis the second modulating wave R _dc1with j carrier wave C _jrelation.As can be seen from Figure 4, the first modulating wave R _acu+ R _dovalue be greater than all the time the second modulating wave R of the first brachium pontis _dc1.The first modulating wave R of the second brachium pontis _acv+ R _do, the 3rd brachium pontis the first modulating wave R _acw+ R _dothe first modulating wave R with the first brachium pontis _acu+ R _dowith j carrier wave C _jrelation identical, the second modulating wave R of the second brachium pontis _dc2, the 3rd brachium pontis the second modulating wave R _dc3the second modulating wave R with the first brachium pontis _dc1with j carrier wave C _jrelation identical.

Fig. 5 is the simulation waveform figure of nine switches set MMC mixing transformation devices (N=4), is three-phase alternating current input power (u successively _acuv, u _acvw, u _acwu), the many level input (u after three-phase alternating current input power conversion _aczuv, u _aczvw, u _aczwu), three DC power supply (u _dc1, u _dc2, u _dc3), the many level input (u after DC power supply conversion _dcz1, u _dcz2, u _dcz3), the voltage U of load R _r.As seen from Figure 5, alternating current input power supplying and direct-current input power supplying are all converted into many level, then through the conversion of MMC converter, obtain VD powering load, consistent with theory analysis.

Above-described embodiment is preferably execution mode of the utility model; but execution mode of the present utility model is not limited by the examples; other any do not deviate from change, the modification done under Spirit Essence of the present utility model and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection range of the present utility model.

Claims (5)

1. nine switches set MMC mixing transformation devices, is characterized in that: comprise three-phase alternating current input power, exchange input inductive bank, the first DC power supply ( u _dc1 ), the first direct current input inductance ( l _dc1 ), the second DC power supply ( u _dc2 ), the second direct current input inductance ( l _dc2 ), the 3rd DC power supply ( u _dc3 ), the 3rd direct current input inductance ( l _dc3 ) the first brachium pontis, the second brachium pontis, the 3rd brachium pontis and load ( r); Three-phase alternating current input power comprise u phase power supply ( u _acu ), v phase power supply ( u _acv ) and w phase power supply ( u _acw ); Exchange input inductive bank comprise u phase inductance ( l _acu ), v phase inductance ( l _acv ) and w phase inductance ( l _acw ); All each is freely gone up switches set, the first brachium pontis inductance, middle switches set, the second brachium pontis inductance, lower switches set and is in series for described the first brachium pontis, the second brachium pontis and the 3rd brachium pontis; Upper switches set (the H of the first brachium pontis _u) by N power switch unit (SM _hu1, SM _hu2..., SM _huN) be in series, the middle switches set (M of the first brachium pontis _u) by N power switch unit (SM _mu1, SM _mu2..., SM _muN) be in series, the lower switches set (L of the first brachium pontis _u) by N power switch unit (SM _lu1, SM _lu2..., SM _luN) series connection, the upper switches set (H of the second brachium pontis _v) by N power switch unit (SM _hv1, SM _hv2..., SM _hvN) be in series, the middle switches set (M of the second brachium pontis _v) by N power switch unit (SM _mv1, SM _mv2..., SM _mvN) be in series, the lower switches set (L of the second brachium pontis _v) by N power switch unit (SM _lv1, SM _lv2..., SM _lvN) be in series, the upper switches set (H of the 3rd brachium pontis _w) by N power switch unit (SM _hw1, SM _hw2..., SM _hwN) be in series, the middle switches set (M of the 3rd brachium pontis _w) by N power switch unit (SM _mw1, SM _mw2..., SM _mwN) be in series, the lower switches set (L of the 3rd brachium pontis _w) by N power switch unit (SM _lw1, SM _lw2..., SM _lwN) be in series; N is positive integer.

2. nine switches set MMC mixing transformation devices according to claim 1, is characterized in that: two brachium pontis inductance of the first brachium pontis ( l _hu , l _lu ), two brachium pontis inductance of the second brachium pontis ( l _hv , l _lv ) and two brachium pontis inductance of the 3rd brachium pontis ( l _hw , l _lw ) all each free coupling inductance is alternative.

3. nine switches set MMC mixing transformation devices according to claim 1, is characterized in that: the upper switches set (H of the first brachium pontis _u) lower end (p) and the first brachium pontis the first brachium pontis inductance ( l _hu ) one end connect, the first brachium pontis inductance of the first brachium pontis ( l _hu ) the other end and the middle switches set (M of the first brachium pontis _u) upper end (o) connect, the middle switches set (M of the first brachium pontis _u) lower end and the second brachium pontis inductance of the first brachium pontis ( l _lu ) one end connect, the second brachium pontis inductance of the first brachium pontis ( l _lu ) the other end and the lower switches set (L of the first brachium pontis _u) upper end connect; The structure of the structure of the structure of the second brachium pontis, the 3rd brachium pontis and the first brachium pontis is in full accord; U phase power supply ( u _acu ) one end and u phase inductance ( l _acu ) one end connect, u phase inductance ( l _acu ) the other end and the middle switches set (M of the first brachium pontis _u) upper end connect, u phase power supply ( u _acu ) the other end and v phase power supply ( u _acv ) one end, w phase power supply ( u _acw ) one end connect, v phase power supply ( u _acv ) the other end and v phase inductance ( l _acv ) one end connect, v phase inductance ( l _acv ) the other end and the middle switches set (M of the second brachium pontis _v) upper end connect, w phase power supply ( u _acw ) the other end and w phase inductance ( l _acw ) one end connect, w phase inductance ( l _acw ) the other end and the middle switches set (M of the 3rd brachium pontis _w) upper end connect; The first DC power supply ( u _dc1 ) positive pole and the first direct current input inductance ( l _dc1 ) one end connect, the first direct current input inductance ( l _dc1 ) the other end and the middle switches set (M of the first brachium pontis _u) lower end connection; The second DC power supply ( u _dc2 ) positive pole and the second direct current input inductance ( l _dc2 ) one end connect, the second direct current input inductance ( l _dc2 ) the other end and the middle switches set (M of the second brachium pontis _v) lower end connection; The 3rd DC power supply ( u _dc3 ) positive pole and the 3rd direct current input inductance ( l _dc3 ) one end connect, the 3rd direct current input inductance ( l _dc3 ) the other end and the middle switches set (M of the 3rd brachium pontis _w) lower end connection; Upper switches set (the H of the first brachium pontis _u) upper end and the upper switches set (H of the second brachium pontis _v) upper end, the upper switches set (H of the 3rd brachium pontis _w) upper end, load ( r) one end connect; Load ( r) the other end and the lower switches set (L of the first brachium pontis _u) lower end, the lower switches set (L of the second brachium pontis _v) lower end, the lower switches set (L of the 3rd brachium pontis _w) lower end, hold ( n) connect.

4. nine switches set MMC mixing transformation devices according to claim 1, is characterized in that: power switch unit comprise the first switching tube ( s ₁), second switch pipe ( s ₂), the first diode ( d ₁), the second diode ( d ₂) and electric capacity ( c _sM ); Wherein, electric capacity ( c _sM ) positive pole and the first switching tube ( s ₁) collector electrode, the first diode ( d ₁) negative electrode connect, the first switching tube ( s ₁) emitter and the first diode ( d ₁) anode, second switch pipe ( s ₂) collector electrode, the second diode ( d ₂) negative electrode connect, second switch pipe ( s ₂) emitter and the second diode ( d ₂) anode, electric capacity ( c _sM ) negative pole connect; Second switch pipe ( s ₂) collector electrode as the first output, second switch pipe ( s ₂) emitter as the second output.

5. nine switches set MMC mixing transformation devices according to claim 1, is characterized in that: the second output of j power switch unit of each switches set is connected with the first output of j+1 power switch unit, and wherein the value of j is 1 ~ N-1.