CN111416533A - Single-phase five-level rectifier based on four-port plug-in - Google Patents

Abstract

Based on a four-port plug-in single-phase five-level rectifier, it includes an AC power supply _ug , a double-coupling magnetic winding N ₁ , a double-coupling magnetic winding N ₂ , a capacitor C ₁ , a capacitor C ₂ , switching tubes Q ₁ to Q ₃ , and a diode D ₁ to D ₁₀ , load R. The invention is based on a four-port plug-in single-phase five-level rectifier, integrates double-coupling magnetic windings and a five-level circuit structure, and only uses three switching tubes in conjunction to raise the number of levels to five-level, under the condition of load fluctuation , still has good power quality. Compared with the traditional three-level rectifier, it has the advantages of low harmonic content, low voltage stress of the switch tube, and high power density. The invention is suitable for high-efficiency and high-reliability rectifier circuits under medium and small power levels.

Description

Single-phase five-level rectifier based on four-port plug-in

technical field

The invention belongs to the technical field of AC-DC multilevel converters, in particular to a single-phase five-level rectifier based on a four-port plug-in type.

Background technique

In the field of AC-DC conversion technology, traditional rectifiers, such as diode uncontrolled rectification and thyristor phase-controlled rectification, have the advantages of simple structure and easy control, but they will inject a large number of harmonics on the grid side, making the harmonics of the grid. The pollution is serious, it is difficult to control the harmonic content within the existing harmonic standard range, and the reliability and safety are low. Therefore, it has gradually withdrawn from industrial applications.

In order to solve the above problems, active power factor correction is currently adopted in many ways, that is, by controlling active devices such as switching tubes, the input current waveform follows the input voltage waveform. In the traditional three-level rectifier circuit, the withstand voltage value of the power device is limited. In order to achieve a better filtering effect, a larger inductor needs to be used, which increases the cost to a certain extent and reduces the power density and efficiency. It is not suitable for medium High voltage and high power occasions. Therefore, it is the key to solve the above problems to further study the circuit topology and take effective control methods.

SUMMARY OF THE INVENTION

For traditional three-level rectifiers, there are problems such as high harmonic content and limited withstand voltage value of power devices. The invention improves the structure of the traditional three-level rectifier circuit, and proposes a four-port plug-in single-phase five-level rectifier, which raises the number of levels to five levels, and further improves the work efficiency; Level rectifier, the rectifier of the invention has the advantages of low harmonic content, low voltage stress of switching tube, high power density, etc., and is suitable for high-efficiency and high-reliability rectifier circuits at medium and small power levels.

The technical scheme adopted in the present invention is:

Based on a four-port plug-in single-phase five-level rectifier, including:

Double-coupling magnetic winding N ₁ , double-coupling magnetic winding N ₂ , capacitor C ₁ , capacitor C ₂ , switch tubes Q ₁ -Q ₃ , diodes D ₁ -D ₁₀ ;

One end of the AC power source _ug , the cathode of the diode D1, and _one end _of the winding N1 are connected to form the terminal c;

The other end of the AC power source _ug , the cathode of the diode D ₂ , and one end of the winding N ₂ are connected to form a terminal d;

_The other end of the winding N1, the anode of the diode _D3 , and the collector _of the switch Q1 are connected to form the terminal a;

The other end of the winding N ₂ and the anode of the diode D ₄ are connected to form the terminal b;

_The cathode of diode _D4 , the anode of diode D5, and the cathode of diode D6 are connected to form terminal e _;

The cathode of the diode _D3 and the cathode of the diode _D7 are connected to form the terminal f;

_The cathode of the diode D5, the anode of the diode _D7 , the cathode of the diode _D8 , and the collector of the switch _Q3 are connected to form the terminal g;

_The anode of the diode D6, the anode of the diode _D9 , the emitter of the switch tube _Q3 , and the collector of the switch tube _Q2 are connected to form the terminal h;

_The anode of the diode D1, the anode of the diode D2, the cathode of the diode _D10 , the emitter of the switch Q1, and the emitter _of the switch _Q2 are connected to form the terminal i _;

The positive pole of the capacitor _C1 and one end of the load R are connected to form the terminal m, and the terminal m is connected to the terminal f;

_The anode of the diode D8, the cathode of the diode _D9 , the cathode of the capacitor _C1 , and the anode of the capacitor _C2 are connected to form the terminal o;

_The anode of the diode _D10 , the cathode of the capacitor C2, and the other end of the load R are connected to form a terminal n.

The double-coupling magnetic winding N ₁ includes a winding N ₁₁ and a winding N ₁₂ , and the windings N ₁₁ and N ₂₁ are wound in the same direction with a common core, which is an inductance L ₁ ;

The double-coupling magnetic winding N ₂ includes a winding N ₂₁ and a winding N ₂₂ ; the windings N ₁₂ and N ₂₂ are reversely wound with a common core, which is an inductance L ₂ ;

The above two sets of windings have the same number of turns, the magnetic cores are completely matched, and the inductance values are equal.

The end point e, the end point f, the end point i, and the end point o in the rectifier constitute a four-port plug-in structure.

The diodes D ₁ and D ₂ are common diodes; the diodes D ₁ and D ₂ connect the output end with the input end, provide a low-impedance current path for the loop current all the time, and attenuate common mode interference.

D ₃ to D ₁₀ are fast recovery diodes, wherein diodes D ₄ and D ₁₀ are used as voltage clamps, which can ensure unidirectional power flow and improve circuit reliability.

The capacitors C ₁ and C ₂ are both equivalent electrolytic capacitors, which are used to balance the mid-point potential of the DC side and have a voltage stabilization effect.

The switch tubes Q ₁ to Q ₃ are all N-channel insulated gate bipolar transistors N-IGBTs without body diodes.

The present invention is based on a four-port plug-in single-phase five-level rectifier, and the technical effects are as follows:

(1), compared with the traditional three-level rectifier, the circuit topology structure of the present invention, the fusion coupling magnetic winding and the five-level circuit structure, the harmonic content is reduced, the inductance volume is reduced, and the voltage stress of the switching tube is reduced by half;

(2) In the circuit of the present invention, a four-port plug-in structure is formed by the end points e, f, i, and o, which can realize both voltage clamping and multi-directional power flow. High reliability.

(3) Under the same power level, only three body diode-less N-channel insulated gate bipolar transistors N-IGBT are used in the circuit of the present invention, which overcomes the parasitic body diode in the power field effect transistor MOSFET to the circuit operating mode. The influence of , reduces the current flow path, and has the advantages of small loss and low cost.

(4) The circuit of the present invention integrates the double-coupling magnetic winding and the five-level circuit structure, and only uses three switching tubes in conjunction to raise the number of levels to five-level. Under the condition of load fluctuation, it still has better performance. power quality. Compared with the traditional three-level rectifier, it has the advantages of low harmonic content, low voltage stress of the switch tube, and high power density. The invention is suitable for high-efficiency and high-reliability rectifier circuits under medium and small power levels.

Description of drawings

1 is a circuit diagram of a topology structure of a single-phase five-level rectifier based on a four-port plug-in type of the present invention;

Fig. 2 is a circuit diagram of the circuit of the present invention in the working mode of the positive half cycle of the power supply voltage;

Fig. 3 is the circuit diagram of the present invention circuit in the positive half cycle of the power supply voltage working mode two;

Fig. 4 is the circuit diagram of the present invention in the positive half cycle of the power supply voltage working mode three circuit diagrams;

Fig. 5 is the circuit diagram of the present invention in the negative half cycle working mode of the power supply voltage four circuit diagrams;

Fig. 6 is the circuit diagram of the present invention in the negative half-cycle working mode of the power supply voltage;

7 is a six-circuit diagram of the circuit of the present invention in the negative half cycle of the power supply voltage working mode;

FIG. 8 is a diagram of six operating modes of the circuit switch tubes Q ₁ to Q ₃ of the present invention;

Fig. 9 is the pulse distribution principle diagram of the circuit switch tube of the present invention converted in four voltage intervals;

Figure 10 (1) is a waveform diagram of the circuit voltage u _ab of the present invention;

Figure 10 (2) is a waveform diagram of the AC side input voltage _ug and current _ig of the circuit of the present invention;

Figure 10 (3) is a waveform diagram of the DC output voltage u _dc of the circuit of the present invention;

Figure 11(1) is a waveform diagram of the voltage u _ab when the load of the circuit of the present invention increases or decreases by 50% during 0.2-0.3s;

Figure 11(2) is a waveform diagram of the AC side input voltage _ug and current ig when the load of the circuit of the present invention increases or decreases by 50% at _0.2-0.3s ;

Fig. 11(3) is a waveform diagram of the DC output voltage u _dc when the load of the circuit of the present invention increases or decreases by 50% in 0.2-0.3s.

Detailed ways

The circuit of the present invention is described in detail below in conjunction with the accompanying drawings:

The detailed experimental parameters of the circuit of the present invention are as follows:

The input voltage of AC power u _g is 220V, the power frequency is 50Hz, the inductance value of inductance L ₁ and L ₂ are both 1.5mH, the capacitance value of capacitor C ₁ and C ₂ are both 2200uF, the resistance value of load R is 30Ω, and the output voltage of DC side is 400V , among them, the switching frequency is 10KHz.

Fig. 1 is a kind of topological structure diagram of single-phase five-level rectifier based on four-port plug-in type of the present invention:

It consists of AC power supply _ug , double coupled magnetic windings N ₁ and N ₂ , capacitors C ₁ and C ₂ , switch tubes Q ₁ to Q ₃ , diodes D ₁ to D ₁₀ and load R.

_The double coupled magnetic winding N1 includes windings _N11 and _N12 ; the double coupled magnetic winding includes windings _N21 and _N22 ;

In Figure 1, based on a four-port plug-in single-phase five-level rectifier:

One end of the AC power source _ug , the cathode of the diode D1, and _one end _of the winding N1 together form the terminal c;

The other end of the AC power source _ug , the cathode of the diode D ₂ , and one end of the winding N ₂ are connected to form a terminal d;

_The other end of the winding N1, the anode of the diode _D3 , and the collector _of the switch Q1 are connected to form the terminal a;

The other end of the winding N ₂ and the anode of the diode D ₄ are connected to form the terminal b;

_The cathode of diode _D4 , the anode of diode D5, and the cathode of diode D6 are connected to form terminal e _;

The cathode of the diode _D3 and the cathode of the diode _D7 are connected to form the terminal f;

_The cathode of the diode D5, the anode of the diode _D7 , the cathode of the diode _D8 , and the collector of the switch _Q3 are connected to form the terminal g;

_The anode of the diode D6, the anode of the diode _D9 , the emitter of the switch tube _Q3 , and the collector of the switch tube _Q2 are connected to form the terminal h;

_The anode of the diode D1, the anode of the diode D2, the cathode of the diode _D10 , the emitter of the switch Q1, and the emitter _of the switch _Q2 are connected to form the terminal i _;

The positive pole of the capacitor _C1 and one end of the load R are connected to form the terminal m, and the terminal m is connected to the terminal f;

_The anode of the diode D8, the cathode of the diode _D9 , the cathode of the capacitor _C1 , and the anode of the capacitor _C2 are connected to form the terminal o;

_The anode of the diode _D10 , the cathode of the capacitor C2, and the other end of the load R are connected to form a terminal n.

The switches Q ₁ , Q ₂ and Q ₃ in the circuit are all N-channel insulated gate bipolar transistors (N-IGBTs) without body diodes, and have the following six working modes by controlling their on-off states:

Fig. ₂ is a working mode 1: the AC power supply _ug works in the positive half cycle, and the switches Q1, _Q2 , and _Q3 are all turned off. At this time, since the DC output voltage u _dc >|u _g |, the voltage frequency at the input side of the grid is much smaller than the operating frequency of the switch tube, so the winding current i _g decreases linearly, the capacitors C ₁ and C ₂ are in the charging state, and the charging current is i ₁ -i _dc , voltage u _ab =+u _dc .

Figure 3 shows the second working mode: the AC power source _ug works in the positive half cycle, the switches Q ₂ and Q ₃ are turned on, and Q ₁ is turned off. At this time, the capacitor C ₁ is charged, the charging current is i ₁ -i _dc , the voltage of the winding N ₁ is | _ug |-u ₁ , if | _ug |>u ₁ , the winding current i _g increases linearly, otherwise it decreases linearly Small, capacitor C ₂ discharges to provide load current i _dc , voltage u _ab =+u _dc /2.

Fig. 4 is the working mode three: the alternating current power source _ug works in the positive half cycle, the switch tube Q1 is turned _on , and _Q2 and _Q3 are turned off. At this time, the AC power source _ug charges the energy storage winding N ₁ , the winding current _ig increases linearly, and the capacitors C ₁ and C ₂ supply power to the load R at the same time, and the voltage u _ab =0.

Figure 5 shows the fourth working mode: the AC power source _ug works in the negative half cycle, the switch Q1 is turned off, and _Q2 and _Q3 are turned _on . At this moment, the AC power source _ug charges the energy storage winding N ₂ , the winding current _ig rises linearly, and the capacitors C ₁ and C ₂ supply power to the load R at the same time, and the voltage u _ab =0.

Fig. 6 is the working mode five: the AC power source _ug works in the negative half cycle, the switches Q1 and _Q2 are turned off, and _Q3 is turned _on . At this time, the capacitor C ₂ is charged, the charging current is io-i _dc , the voltage on the winding N ₂ is | _ug |-u ₂ , if | _ug |>u ₂ , the winding current i _g increases linearly, otherwise linearly Decrease, the capacitor C ₁ supplies power to the load R, and the voltage u _ab =-u _dc /2.

FIG. 7 shows the sixth working mode: the AC power source _ug works in the negative half cycle, and the switches Q ₁ , Q ₂ , and Q ₃ are all turned off. At this time, since the DC output voltage u _dc >| _ug |, the winding current i _g decreases linearly, the capacitors C ₁ and C ₂ are charged, the charging current is i ₁ -i _dc , and the voltage u _ab = -u _dc .

8 is a diagram of six operating modes of the switches Q ₁ to Q ₃ in the circuit of the present invention: when _ug >0, the circuit works in the positive half cycle, when _ug <0, the circuit works in the negative half cycle, and nodes a and b The inter-voltage u _ab has five level states: 0, +u _dc /2, -u _dc /2, +u _dc , -u _dc . The change of circuit parameters is shown in the figure, in which 1 and 0 represent the on and off of the switch tube respectively.

Fig. 9 is the switch tube pulse distribution diagram of the circuit of the present invention under PWM control:

According to the voltage level, the five level states can be divided into four voltage intervals, namely:

Interval one (+u _dc /2<u _g <+u _dc ), interval two (0<u _g <+u _dc /2), interval three (-u _dc /2<u _g <0), interval four ( -u _dc <u _g <-u _dc /2), during any two level transitions, the switches cooperate with each other to continuously switch their switching states to achieve five levels.

Figure 10 (1) is a waveform diagram of the voltage u _ab in the circuit of the present invention: the waveform shown in Figure 10 (1) is a five-level, with four voltage intervals with equal upper and lower amplitudes. Due to the function of balancing the voltage, the voltage stress of the switch tube is correspondingly reduced by 50%, which further verifies that the circuit of the present invention has the function of realizing a five-level circuit.

Figure 10(2) is a waveform diagram of the voltage _ug and current _ig on the AC input side of the circuit of the present invention: it can be seen from Figure 10(2) that the input current _ig on the grid side has followed the waveform of the input voltage _ug after power factor correction Sine, compared with the traditional three-level rectifier circuit, the harmonic content is greatly reduced, and the power conversion efficiency is further improved.

Figure 10(3) is a waveform diagram of the DC output side voltage u _dc of the circuit of the present invention: the DC side output voltage shown in Figure 10(3) can be stabilized at 400V in 0.05s, and the dynamic adjustment performance is good.

Figure 11(1) is a waveform diagram of the voltage u _ab when the load increases or decreases by 50% in the circuit of the present invention at 0.2 to 0.3s: when the circuit halves the load at 0.2s, the load returns to the original value at 0.3s, as shown in Figure 11 ( 1), the waveform of the voltage u _ab has no obvious change, indicating that the circuit of the present invention has high reliability.

Fig. 11(2) is the waveform diagram of the AC side input voltage _ug and current i _g when the load increases or decreases by 50% at 0.2～0.3s: when the load changes at 0.2s～0.3s, the input current at the grid side i _g and the voltage _ug are still in the same phase, and have better power quality.

Figure 11(3) is the waveform diagram of the DC output voltage u _dc when the load of the circuit of the present invention increases or decreases by 50% at 0.2~0.3s: as shown in Figure 11(3), the load changes at 0.2s~0.3s, the The output voltage is still maintained at about 400V, the circuit maintains a stable DC output, and has a relatively stable boost and rectification function.

Claims (7)

1. Based on five level rectifier of four port plug-in single-phase, its characterized in that includes:

double-coupling magnetic winding N₁Double-coupling magnetic winding N₂Capacitor C₁Capacitor C₂And a switching tube Q₁～Q₃Diode D₁～D₁₀；

AC power supply u_gOne terminal of (1), diode D₁Cathode of (2), winding N₁Is connected to form an end point c;

AC power supply u_gAnother terminal of (1), diode D₂Cathode of (2), winding N₂Is connected to form an end point d;

winding N₁Another terminal of (1), diode D₃Anode of (2), switching tube Q₁Is connected to form an end point a;

winding N₂Another terminal of (1), diode D₄To form an endpoint b;

diode D₄Cathode of (2), diode D₅Anode of (2), diode D₆To form an endpoint e;

diode D₃Cathode of (2), diode D₇To form an endpoint f;

diode D₅Cathode of (2), diode D₇Anode of (2), diode D₈Cathode and switching tube Q₃Is connected to form an end point g;

diode D₆Anode of (2), diode D₉Anode of (2), switching tube Q₃Emitter and switching tube Q₂Is connected to form an end point h;

diode D₁Anode of (2), diode D₂Anode of (2), diode D₁₀Cathode and switching tube Q₁Emitter and switching tube Q₂To form a terminal i;

capacitor C₁The positive pole of the load R is connected with one end of the load R to form an end point m, and the end point m is connected with an end point f;

diode D₈Anode of (2), diode D₉Cathode and capacitor C₁Negative electrode of (1), capacitor C₂Is connected to form an end point o;

diode D₁₀Anode and capacitor C₂And the other end of the load R is connected to form an end point n.

2. The four-port based plug-in single-phase five-level rectifier according to claim 1, wherein: the double-coupling magnetic winding N₁Comprising a winding N₁₁Winding N₁₂Winding N₁₁、N₂₁Adopts concentric same-direction winding to form an inductor L₁；

Double-coupling magnetic winding N₂Comprising a winding N₂₁Winding N₂₂(ii) a Winding N₁₂、N₂₂Adopting concentric reverse winding to form inductor L₂；

The two groups of windings have the same turns, the magnetic cores are completely matched, and the inductance values are equal.

3. The four-port based plug-in single-phase five-level rectifier according to claim 1, wherein: the end point e, the end point f, the end point i and the end point o in the rectifier form a four-port plug-in structure.

4. The four-port based plug-in single-phase five-level rectifier according to claim 1, wherein: the diode D₁、D₂Is a common diode; d₃～D₁₀Is a fast recovery diode, wherein the diode D₄、D₁₀Serving as a voltage clamp.

5. The four-port based plug-in single-phase five-level rectifier according to claim 1, wherein: the capacitor C₁Capacitor C₂All are equivalent electrolytic capacitors used for balancing the midpoint potential on the direct current side.

6. The four-port based plug-in single-phase five-level rectifier according to claim 1, wherein: the switch tube Q₁～Q₃All are N-channel insulated gate bipolar transistors N-IGBTs without body diodes.

7. The rectifier according to any one of claims 1 to 6, wherein:

by controlling the switching tube Q in the circuit₁、Q₂、Q₃The circuit has the following six working modes:

the first working mode is as follows: AC power supply u_gOperating in the positive half-cycle, switching tube Q₁、Q₂、Q₃All are turned off, and the voltage u is output due to direct current_dc>|u_gThe input side voltage frequency of the power grid is far less than the working frequency of the switching tube, so that the winding current i_gLinear reduction, capacitance C₁、C₂In a charging state with a charging current of i₁-i_dcVoltage u_ab＝+u_dc；

The second working mode is as follows: AC power supply u_gOperating in the positive half-cycle, switching tube Q₂、Q₃On, Q₁Is turned off when the capacitor C is turned off₁Charging with a charging current of i₁-i_dcDouble coupled magnetic winding N₁A voltage of | u_g|-u₁If u_g|>u₁Then the winding current i_gLinearly increasing and inversely linearly decreasing, capacitance C₂Discharging to provide a load current i_dcVoltage u_ab＝+u_dc/2；

The working mode is three: AC power supply u_gOperating in the positive half-cycle, switching tube Q₁On, Q₂、Q₃Turn off the AC power u_gTo two coupling magnetic winding N₁Charging, winding current i_gIn a linearly rising state while the capacitor C is in₁And C₂Supply voltage u to load R_ab＝0；

Working mode four: AC power supply u_gOperating in the negative half-cycle, switching tube Q₁Off, Q₂、Q₃Is conducted at the time of the AC power u_gTo two coupling magnetic winding N₂Charging, winding current i_gLinearly rising while capacitance C₁、C₂Supply voltage u to load R_ab＝0；

Working mode five: AC power supply u_gOperating in the negative half-cycle, switching tube Q₁、Q₂Off, Q₃Is turned on, at this time, the capacitor C₂Charging with a charging current io-i_dcDouble coupled magnetic winding N₂Upper voltage is | u_g|-u₂If u_g|>u₂Then the winding current i_gLinearly increasing and inversely linearly decreasing, capacitance C₁Supply voltage u to load R_ab＝-u_dc/2；

The working mode is six: AC power supply u_gOperating in the negative half-cycle, switching tube Q₁、Q₂、Q₃All are turned off, and the voltage u is output due to direct current_dc>|u_gL, winding current i_gLinear reduction, capacitance C₁、C₂Charging with a charging current of i₁-i_dcVoltage u_ab＝-u_dc。

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