CN203722506U - Double-output single-phase three-switch-group MMC inverter - Google Patents

Abstract

The utility model provides a double-output single-phase three-switch-group MMC inverter. The inverter comprises a first direct current power supply, a second direct current power supply, an upper switch group, a middle switch group, a lower switch group, a coupling inductor, a first load and a second load, one terminal of the first load and one terminal of the second load are both connected to central points of the first direct current power supply and the second direct current power supply, the other terminal of the first load is connected to the upper terminal of the middle switch group, and the other terminal of the second load is connected to the lower terminal of the middle switch group. According to the inverter, the carrier wave phase-shifting PWM is employed to control the inverter, two channels of alternating current voltage with N+1 level can be outputted, the voltage stress born by each switch tube of a power switch unit is merely 1/N of the total of the voltages of the first direct current power supply and the second direct current power supply, the voltage in the operating process of a converter can be remained, the voltage-equalizing effect is good, and the inverter is applicable to occasions of high voltage, high power, and double loads. The coupling inductor of the inverter can be replaced by two independent inductors.

Description

The single-phase three switches set MMC inverters of dual output

Technical field

The module that relates to the utility model combines many level (MMC) converter field, is specifically related to the single-phase three switches set MMC inverters of a kind of dual output.

Background technology

, there is the direction of two kinds of improvement converters at present power inverter forward miniaturization, high reliability and low-loss future development: reduce passive device or improve converter topology structure and using and reduce active device as the new development that reduces active device direction under this trend.Single-phase three switch converters have reduced a switch and corresponding drive circuit with respect to four traditional switch converters, in the application of considering cost and volume, occupy certain advantage.Yet the single-phase output of two-way of three switch converters is two level, output AC waveform is poor.In addition, half that the voltage stress that in three switches, each switch bears is DC bus-bar voltage, and the voltage-sharing of three switches of existence, this has limited single-phase three switch converters greatly in the application of high pressure and large-power occasions.

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 the alternating current circuit of two different frequencies connected, needing 2 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 the single-phase three switches set MMC inverters of a kind of dual output.

The technical solution adopted in the utility model is as follows.

The single-phase three switches set MMC inverters of dual output comprise the first DC power supply, the second DC power supply, upper switches set, middle switches set, lower switches set, coupling inductance, the first load and the second load; Upper switches set is in series by N power switch unit, and middle switches set is in series by N power switch unit, and lower switches set is in series by N power switch unit; Coupling inductance is connected with upper switches set, middle switches set and three switches set of lower switches set; The first DC power supply and the second DC power supply series-fed; The mid point of the first DC power supply and the second DC power supply is all received in one end of one end of the first load and the second load, and the other end of the first load is received the upper end of middle switches set, and the other end of the second load is received the lower end of middle switches set; Export as the first via at the two ends of the first load, and export as the second tunnel at the two ends of the second load; The former secondary of coupling inductance can be substituted by two separate inductors.In employing phase-shifting carrier wave pwm controlled converter, the switching tube of upper switches set, middle switches set and lower switches set opening and turn-offing.

In the single-phase three switches set MMC inverters of above-mentioned dual output, in the single-phase three switches set MMC inverters of described dual output, the positive pole of the first DC power supply is connected with the upper end of upper switches set, the lower end of upper switches set is connected with the Same Name of Ends on the former limit of coupling inductance, the non-same polarity on the former limit of coupling inductance is connected with the upper end of middle switches set, the lower end of middle switches set is connected with the Same Name of Ends of coupling inductance secondary, the non-same polarity of coupling inductance secondary is connected with the lower end of lower switches set, the lower end of lower switches set is connected with the negative pole of the second DC power supply, the positive pole of the second DC power supply is connected with the negative pole of the first DC power supply, the negative pole of the first DC power supply is connected with ground end, one end of the first load is connected with the upper end of middle switches set, and the other end of the first load is connected with ground end, and one end of the second load is connected with the lower end of middle switches set, and the other end of the second load is connected with ground end.

In the single-phase three switches set MMC inverters of above-mentioned dual output, power switch unit is by 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.

In the single-phase three switches set MMC inverters of above-mentioned dual output, the second output of i power switch unit of upper switches set is connected with the first output of i+1 power switch unit of upper switches set, and wherein the value of i is 1～N-1; The second output of i power switch unit of middle switches set is connected with the first output of i+1 power switch unit of middle switches set; The second output of i power switch unit of lower switches set is connected with the second output of i+1 power switch unit of lower switches set.

In the control method of the single-phase three switches set MMC inverters of above-mentioned dual output, in employing phase-shifting carrier wave PWM control, the switching tube of switches set, middle switches set and lower switches set opening and turn-offing; I power switch unit of upper switches set and i power switch unit of lower switches set adopt identical triangular wave as carrier wave C _i, wherein the value of i is 1～N; N carrier wave be 360 °/N of lagging phase angle successively; Described first via output adopts sinusoidal wave as the first modulating wave R _an, the second tunnel output adopts sinusoidal wave as the second modulating wave R _bn.

In above-mentioned control method, the first modulating wave R _anwith i carrier wave C _iby the first comparator, obtain the control level of second switch pipe gate pole in i power switch unit of upper switches set, as the first modulating wave R _anbe greater than i carrier wave C _itime, the first comparator output high level, as the first modulating wave R _anbe less than i carrier wave C _itime, the first comparator output low level, wherein the value of i is 1～N; The second modulating wave R _bnwith i carrier wave C _iby the second comparator, obtain the control level of second switch pipe gate pole in i power switch unit of lower switches set, as the second modulating wave R _bnbe less than i carrier wave C _itime, the first comparator output high level, as the second modulating wave R _bnbe greater than i carrier wave C _itime, the first comparator output low level; In i power switch unit of upper switches set, in the control level of second switch pipe gate pole and i power switch unit of lower switches set, the control level of second switch pipe gate pole obtains the control level of second switch pipe gate pole in i power switch unit of middle switches set by XOR gate; In each power switch unit of described 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: have two-way N+1 level and exchange output, output current wave is of high quality, 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 single-phase three switch converters, the two-way output of the single-phase three switches set MMC inverters of dual output provided by the utility model is N+1 level and exchanges output, and the quality of output AC waveform is greatly improved.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 the single-phase three switches set MMC inverters of dual output in high pressure and large-power occasions.Compare with existing MMC converter, the single-phase three switches set MMC inverters of dual output provided by the utility model have two-way and exchange output, can be directly used in being connected of alternating current circuit of two different frequencies, greatly reduce engineering cost.

Accompanying drawing explanation

Fig. 1 is the circuit structure diagram of the single-phase three switches set MMC inverters of dual output of the present utility model;

Fig. 2 is the circuit structure diagram of power switch unit in the single-phase three switches set MMC inverters of dual output of the present utility model;

Fig. 3 is the structure chart of the phase-shifting carrier wave PWM control method of the single-phase three switches set MMC inverters of the dual output shown in Fig. 1;

Fig. 4 is the oscillogram that the single-phase five level three switches set MMC inverters of dual output adopt control method shown in Fig. 2;

Fig. 5 is the simulation waveform figure of the single-phase five level three switches set MMC inverters of dual output.

Embodiment

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

With reference to figure 1, the single-phase three switches set MMC inverters of dual output of the present utility model, comprise the first DC power supply dc ₁, the second DC power supply dc ₂, upper switches set H, middle switches set M, lower switches set L, coupling inductance (L _h: L _l), the first load and the second load; Upper switches set H is by N power switch unit (SM _h1, SM _h2..., SM _hN) be in series, middle switches set M is by N power switch unit (SM _m1, SM _m2..., SM _mN) be in series, lower switches set L is by N power switch unit (SM _l1, SM _l2..., SM _lN) be in series; Coupling inductance (L _h: L _l) connect with upper switches set H, middle switches set M and lower switches set L3 switches set; The first DC power supply dc ₁with the second DC power supply dc ₂series-fed; The first DC power supply dc is all received in one end of one end of the first load and the second load ₁with the second DC power supply dc ₂mid point n, the other end of the first load is received the upper end o of middle switches set M, the other end of the second load is received the lower end p of middle switches set M; Export as the first via at the two ends of the first load, and export as the second tunnel at the two ends of the second load.Wherein, the positive pole of the first DC power supply dc1 is connected with the upper end o of upper switches set H, the lower end p of upper switches set H and coupling inductance L _h: L _lformer limit L _hsame Name of Ends w connect, coupling inductance (L _h: L _l) former limit L _hnon-same polarity a be connected with the upper end o of middle switches set M, the lower end p of middle switches set M and coupling inductance (L _h: L _l) secondary L _lsame Name of Ends b connect, coupling inductance (L _h: L _l) secondary L _lnon-same polarity z be connected with the lower end p of lower switches set L, the lower end p of lower switches set L is connected with the negative pole of the second DC power supply dc2, the positive pole of the second DC power supply dc2 is connected with the negative pole of the first DC power supply dc1, and the negative pole of the first DC power supply dc1 is connected with ground end n; One end of the first load is connected with the upper end o of middle switches set M, and the other end of the first load is connected with ground end n, and one end of the second load is connected with the lower end p of middle switches set M, and the other end of the second load is connected with ground end n.

Fig. 2 illustrates the circuit structure diagram of power switch unit in the single-phase three switches set MMC inverters of the dual output shown in Fig. 1.Power switch unit is by 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, i the power switch unit SM of upper switches set H _hithe second output and i+1 the power switch unit SM of upper switches set H _{h (i+1)}the first output connect, wherein the value of i is 1～N-1; I the power switch unit SM of middle switches set M _mithe second output and i+1 the power switch unit SM of middle switches set M _{m (i+1)}the first output connect; I the power switch unit SM of lower switches set L _lithe second output and i+1 the power switch unit SM of lower switches set L _{l (i+1)}the second output connect.

As shown in Figure 1, the voltage u at the first load two ends _anvoltage u with the second load two ends _bnfor:

$\left\{\begin{array}{c}{u}_{\mathrm{an}}=\frac{u_L+u_M-u_H}{2}\\ u_{\mathrm{bn}}=\frac{u_L-u_M-u_H}{2}\end{array}\right.$

In formula, u _hfor the output voltage of upper switches set H, u _mfor the output voltage of upper switches set M, u _loutput voltage for lower switches set L.

The single-phase three switches set MMC inverters of dual output shown in Fig. 1 adopt phase-shifting carrier wave PWM to control, as shown in Figure 3.I the power switch unit SM of upper switches set H _hii the power switch unit SM with lower switches set L _liadopt identical triangular wave as carrier wave C _i, wherein the value of i is 1～N; N carrier wave (C ₁, C ₂..., C _n) 360 °/N of lagging phase angle successively; Described first via output adopts sinusoidal wave as the first modulating wave R _an, the second tunnel output adopts sinusoidal wave as the second modulating wave R _bn.The first modulating wave R _anwith carrier wave C _iby the first comparator, obtain i the power switch unit SM of upper switches set H _himiddle second switch pipe S ₂the control level S of gate pole _hi, as the first modulating wave R _anbe greater than carrier wave C _itime, the first comparator output high level, as the first modulating wave R _anbe less than carrier wave C _itime, the first comparator output low level, wherein the value of i is 1～N; The second modulating wave R _bnwith carrier wave C _iby the second comparator, obtain i the power switch unit SM of lower switches set L _limiddle second switch pipe S ₂the control level S of gate pole _li, as the second modulating wave R _bnbe less than carrier wave C _itime, the first comparator output high level, as the second modulating wave R _bnbe greater than carrier wave C _itime, the first comparator output low level; I the power switch unit SM of upper switches set H _himiddle second switch pipe S ₂the control level S of gate pole _hii the power switch unit SM with lower switches set L _limiddle second switch pipe S ₂the control level S of gate pole _liby XOR gate, obtain i the power switch unit SM of middle switches set M _mimiddle second switch pipe S ₂the control level S of gate pole _mi; Second switch pipe S in each power switch unit of described 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.

The single-phase five level three switches set MMC inverters of the dual output of take are further described described Carrier-based PWM phase shifting control as example, and oscillogram as shown in Figure 4.

I the power switch unit SM of upper switches set H _hii the power switch unit SM with lower switches set L _liadopt identical triangular wave as carrier wave C _i, wherein the value of i is 1～4; 4 carrier wave (C ₁, C ₂, C ₃, C ₄) 90 ° of lagging phase angles successively; First via output adopts sinusoidal wave as the first modulating wave R _an, the second tunnel output adopts sinusoidal wave as the second modulating wave R _bn.The first modulating wave R _anrespectively with 4 carrier wave (C ₁, C ₂, C ₃, C ₄) relatively, obtain 4 power switch unit (SM of switches set H _h1, SM _h2, SM _h3, SM _h4) middle second switch pipe S ₂control level (the S of gate pole _h1, S _h2, S _h3, S _h4), as the first modulating wave R _anbe greater than carrier wave C _itime, the control level S obtaining _hifor high level, as the first modulating wave R _anbe less than carrier wave C _itime, the control level S obtaining _hifor low level, wherein the value of i is 1～4; The second modulating wave R _bnrespectively with 4 carrier wave (C ₁, C ₂, C ₃, C ₄) relatively, obtain 4 power switch unit (SM of switches set L _l1, SM _l2, SM _l3, SM _l4) middle second switch pipe S ₂control level (the S of gate pole _l1, S _l2, S _l3, S _l4), as the second modulating wave R _bnbe greater than carrier wave C _itime, the control level S obtaining _lifor high level, as the second modulating wave R _bnbe less than carrier wave C _itime, the control level S obtaining _lifor low level; I the power switch unit SM of upper switches set H _himiddle second switch pipe S ₂the control level S of gate pole _hii the power switch unit SM with lower switches set L _limiddle second switch pipe S ₂the control level S of gate pole _liby XOR, calculate i the power switch unit SM of middle switches set M _mimiddle second switch pipe S ₂the control level S of gate pole _mi; Second switch pipe S in each power switch unit of described 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.Thereby obtain respectively the output voltage u of switch H _h, upper switch M output voltage u _moutput voltage u with upper switch L _lwaveform, further can obtain the voltage u of first via output _anvoltage u with the second tunnel output _bnwaveform.

Described control method can guarantee inverter each time be carved with N power switch unit output voltage be U _sM=E, the output voltage of 2N power switch unit is U _sM=0, meet u _h+ u _m+ u _l=U _dc1+ U _dc2, electric capacity (C in each power switch unit that wherein E is each switches set _sM) voltage, and E=(U _dc1+ U _dc2)/N.

Fig. 5 is the simulation waveform figure of the single-phase five level three switches set MMC inverters of dual output, that the voltage of the first load is, the voltage of the electric current of the first load, the second load and the electric current of the second load from top to bottom successively, the electric current of the electric current of the first load and the second load is sine wave as seen from the figure, has verified the correctness of described phase-shifting carrier wave PWM control method.

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. the single-phase three switches set MMC inverters of dual output, is characterized in that: comprise the first DC power supply (dc ₁), the second DC power supply (dc ₂), upper switches set (H), middle switches set (M), lower switches set (L), coupling inductance (L _h: L _l), the first load and the second load; Upper switches set (H) is by N power switch unit (SM _h1, SM _h2..., SM _hN) be in series, middle switches set (M) is by N power switch unit (SM _m1, SM _m2..., SM _mN) be in series, lower switches set (L) is by N power switch unit (SM _l1, SM _l2..., SM _lN) be in series; Coupling inductance (L _h: L _l) connect with upper switches set (H), middle switches set (M) and 3 switches set of lower switches set (L); The first DC power supply (dc ₁) and the second DC power supply (dc ₂) series-fed; The first DC power supply (dc is all received in one end of one end of the first load and the second load ₁) and the second DC power supply (dc ₂) mid point (n), the other end of the first load is received the upper end (o) of middle switches set (M), the other end of the second load is received the lower end (p) of middle switches set (M); Export as the first via at the two ends of the first load, and export as the second tunnel at the two ends of the second load.

2. the single-phase three switches set MMC inverters of dual output according to claim 1, is characterized in that: coupling inductance (L _h: L _l) former limit and secondary by the first inductance (L _h) and the second inductance (L _l) two separate inductors substitute.

3. the single-phase three switches set MMC inverters of dual output according to claim 1, is characterized in that: the positive pole of the first DC power supply (dc1) is connected with the upper end of upper switches set (H), the lower end of upper switches set (H) and coupling inductance (L _h: L _l) former limit (L _h) Same Name of Ends (w) connect, coupling inductance (L _h: L _l) former limit (L _h) non-same polarity (a) be connected with the upper end of middle switches set (M), the lower end of middle switches set (M) and coupling inductance (L _h: L _l) secondary (L _l) Same Name of Ends (b) connect, coupling inductance (L _h: L _l) secondary (L _l) non-same polarity (z) be connected with the lower end of lower switches set (L), the lower end of lower switches set (L) is connected with the negative pole of the second DC power supply (dc2), the positive pole of the second DC power supply (dc2) is connected with the negative pole of the first DC power supply (dc1), and the negative pole of the first DC power supply (dc1) is connected with ground end (n); One end of the first load is connected with the upper end of middle switches set (M), and the other end of the first load is connected with ground end (n), and one end of the second load is connected with the lower end of middle switches set (M), and the other end of the second load is connected with ground end (n).

4. the single-phase three switches set MMC inverters of dual output according to claim 1, is characterized in that: power switch unit comprises 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. the single-phase three switches set MMC inverters of dual output according to claim 1, is characterized in that: i power switch unit (SM of upper switches set (H) _hi) the second output and i+1 power switch unit (SM of upper switches set (H) _{h (i+1)}) the first output connect, wherein the value of i is 1 ~ N-1; I power switch unit (SM of middle switches set (M) _mi) the second output and i+1 power switch unit (SM of middle switches set (M) _{m (i+1)}) the first output connect; I power switch unit (SM of lower switches set (L) _li) the second output and i+1 power switch unit (SM of lower switches set (L) _{l (i+1)}) the second output connect.