CN104092396A - Single-inductor dual-boost invertor and control method thereof - Google Patents

Abstract

The invention discloses a single-inductor dual-boost invertor. Two boost units share one boost inductor, in this way, the efficiency of a traditional dual-boost invertor can be effectively enhanced, and the size of the invertor can be reduced. Meanwhile, the invention provides a control method of the single-inductor dual-boost invertor. According to the control method, switching tubes of the two boost units are controlled to alternately work in positive and negative half cycles of a sine wave respectively, the voltage stress and current stress of the switching tubes are reduced, inductive current ripple waves are reduced, and the conduction loss of ring current in a converter is reduced.

Description

The two Boost inverters of a kind of single inductance and control method thereof

Technical field

The invention belongs to Technics of Power Electronic Conversion technical field, be specifically related to the two Boost inverters of a kind of single inductance and control method thereof.

Background technology

New forms of energy are owing to being subject to the impact of the factors such as environment, and its output voltage range is wide, need to be reverse into available stable alternating voltage by buck inverter.Traditional inverter when DC voltage lower than output alternating voltage time, need in the prime of inverter, add booster converter to reach boost function.But two-stage type power conversion makes system configuration complexity and affects efficiency.By Industrial Frequency Transformer, boost, have the defects such as Industrial Frequency Transformer is heavy, bulky.

The advantages such as the inverter of single stage power converter is conducive to the lifting of power density and efficiency, and single stage type inverter has power stage and only has one-level, and efficiency is high, and volume is little.The inverter of double-boost converter, adopts two groups of independent symmetrical two-way DC/DC converter differential outputs, obtains pure sinusoid alternating voltage.Common modulation system is to make two groups of Boost converters respectively export a road to differ 180 ° with the voltage of direct current biasing, obtains the ac output voltage of lifting press through differential output.The all power switchs of this modulation system downconverter in whole power frequency period all in high frequency modulated state, and inductive current is large, switch tube voltage current stress is also larger, cause inductor loss, switching tube on-state loss and switching loss to increase, there is inner circulation in whole converter simultaneously, is unfavorable for the lifting of efficiency.

Summary of the invention

Technical problem to be solved by this invention is: propose the two Boost inverters of a kind of single inductance, two Boost boosting units share a boost inductance, can effectively promote the efficiency and the volume that has dwindled inverter of traditional double Boost inverter; The control method of the two Boost inverters of a kind of single inductance has been proposed simultaneously, control the switching tube alternation in sinusoidal wave positive and negative half period respectively of two Boost boosting units, reduce switch tube voltage, current stress, reduce inductive current ripple, eliminate the inner circulation of converter.

The present invention, for solving the problems of the technologies described above, adopts following technical scheme:

The two Boost inverters of a kind of single inductance, comprise Boost boosting unit I, Boost boosting unit II, boost inductance, switching tube I, the input of the input of Boost boosting unit I and Boost boosting unit II is connected in parallel, the output of the output of Boost boosting unit I and Boost boosting unit II is connected in series the rear output as this inverter, and the output of inverter comprises first end, the second end, and Boost boosting unit I comprises switching tube II, switching tube III; Boost boosting unit II comprises switching tube IV, switching tube V; Described switching tube includes input, output, control end, also comprise switching tube VI, switching tube VII, connecting valve pipe VI between the first end of inverter output end and the positive pole of DC power supply, connecting valve pipe VII between the second end of inverter output end and DC power anode; Boost boosting unit I and Boost boosting unit II share a boost inductance and switching tube I, wherein, the output of one end of boost inductance, switching tube I is all connected with the positive pole of DC power supply, and the input of the other end of boost inductance, switching tube I is all connected with the positive pole of Boost boosting unit I input, the positive pole of Boost boosting unit II input.

Equal parallel diode between the input of switching tube, output, the anode of diode is connected with the output of switching tube, and the negative electrode of diode is connected with the input of switching tube.

In sinusoidal wave positive half period, control switch pipe I is in HF switch state, and switching tube II, switching tube VII be in normal open state, the complementary conducting of control switch pipe III and switching tube I; In sinusoidal wave negative half-cycle, control switch pipe I is in HF switch state, and switching tube IV, switching tube VI be in normal open state, the complementary conducting of control switch pipe V and switching tube I.

Compared with prior art, the present invention has following beneficial effect:

1, the two Boost inverter circuits of single inductance of the present invention share a boost inductance and HF switch pipe, are conducive to improve power density, have dwindled the volume of inverter.Make the voltage stress of switching tube and the current stress of inductance less than traditional approach, share boost inductance L1 and HF switch pipe S1.

2, application half cycle modulation method, makes the switching tube of two Boost boosting units in half cycle high-frequency work, and by-pass switch plumber is switching state frequently, has reduced the switching loss of inverter.Compare with traditional control method, reduced again conduction loss, eliminated the inside circulation of converter simultaneously.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of the two Boost inverters of list inductance of the present invention.

Fig. 2 is the modulation system schematic block diagram of traditional double Boost inverter.

Fig. 3 is the modulation system schematic diagram of the two Boost inverters of list inductance of the present invention.

Fig. 4 is the two Boost inverter experiment of list inductance of the present invention drive waveforms.

Fig. 5 is the two Boost inverter experiment of list inductance of the present invention drive waveforms.

Fig. 6 is the two Boost inverter switching device tube voltage stress of list inductance of the present invention.

Fig. 7 is list inductance Boost inverter input and output voltage of the present invention and inductive current.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is elaborated:

As shown in Figure 1, the two Boost inverters of single inductance, comprise Boost boosting unit I, Boost boosting unit II, boost inductance L1, switching tube S1～S7, capacitor C 1, C2, diode D1～D7, the input of each switching tube, a diode all in parallel between output, the anode of diode is connected with the output of switching tube, the negative electrode of diode is connected with the input of switching tube, switching tube S6, S7 is as the by-pass switch pipe of this inverter circuit, Boost boosting unit I comprises switching tube S2, S3, the input of switching tube S2 is as the input of Boost boosting unit I, the output of switching tube S2 is connected with the output of switching tube S3, the input of switching tube S3 is as the first end of this inverter output end, Boost boosting unit II comprises switching tube S4, S5, and the input of switching tube S4 is as the input of Boost boosting unit II, and the output of switching tube S4 is connected with the output of switching tube S5, and the input of switching tube S5 is as the second end of this inverter output end, series capacitance C1, C2 between the two ends of inverter output end, the positive pole of DC power supply Vin is connected with the output of switching tube S6, one end of the output of switching tube S7, boost inductance L1 respectively, and the negative pole of DC power supply Vin is connected with the mid point of C2 series circuit with output, the capacitor C 1 of switching tube S1 respectively, the other end of boost inductance is connected with input, the input of Boost boosting unit II, the input of switching tube S1 of Boost boosting unit I respectively, the input of switching tube S6 is connected with the first end of inverter output end, and the input of switching tube S7 is connected with the second end of inverter output end.

In the present embodiment, Boost boosting unit I is hereinafter to be referred as Boost1, and Boost boosting unit II is hereinafter to be referred as Boost2.

Common modulation system is to make two groups of Boost converters respectively export a road to differ 180 ° with the voltage of direct current biasing, obtains the ac output voltage of lifting press through differential output.Make Boost1 and Boost2 simultaneously in pressure-increasning state, so four switching tubes are all in HF switch state, as shown in Figure 2.By corresponding control logic, the output voltage of two groups is met:

$V_{o1}\left(t\right)=V_{\mathrm{dc}}+\frac{1}{2}\×U_m\×\sin \left(\mathrm{wt}\right)---\left(1\right)$

$V_{o2}\left(t\right)=V_{\mathrm{dc}}+\frac{1}{2}\×U_m\×\sin (\mathrm{wt}-\mathrm{\π})---\left(2\right)$

$V_{\mathrm{dc}}\≥V_{\mathrm{in}}+\frac{U_m}{2}---\left(3\right)$

$V_{o1}=V_{o2}=\frac{1}{1-D}\×V_{\mathrm{in}}---\left(4\right)$

V wherein _dcfor DC offset voltage, U _mfor expectation output voltage peak value, V _o1for obtaining the output voltage of Boost1, V _o2for the output voltage of Boost2, V _infor DC power supply voltage.

Simultaneous above formula pushes away to obtain the change in duty cycle rule of Boost1 and Boost2:

$D_1\left(t\right)=\frac{\frac{U_m}{2}+\frac{U_m}{2}\×\sin \left(\mathrm{wt}\right)}{V_{\mathrm{in}}+\frac{U_m}{2}+\frac{U_m}{2}\×\sin \left(\mathrm{wt}\right)}---\left(5\right)$

$D_2\left(t\right)=\frac{\frac{U_m}{2}-\frac{U_m}{2}\×\sin \left(\mathrm{wt}\right)}{V_{\mathrm{in}}+\frac{U_m}{2}-\frac{U_m}{2}\×\sin \left(\mathrm{wt}\right)}---\left(6\right)$

By modulation duty cycle, make the duty ratio of Boost1 and Boost2 respectively by D so ₁and D (t) ₂(t) rule changes, and can make the output voltage of traditional modulation be:

V _o(t)＝V _o1(t)-V _o2(t)＝U _m×sin(wt) (7)

The method that the two Boost inverters of list inductance of the present invention adopt timesharing to control only has a road DC/DC boosting unit in HF switch state in making during arbitrary half-wave of output AC electricity, and another road is in power frequency switching state.As shown in Figure 3,

In the positive half period of output sinusoidal voltage (being load voltage), control switch pipe S1 is in HF switch state, control switch pipe S2, S7 are in the complementary conducting of normal open state, S3 and S1 signal, Boost1 unit is in pressure-increasning state, and this road output voltage is the half period half-sinusoid with direct current biasing; Boost2 unit is in power frequency switching state, and switching tube S4, S5, S6 are all in off state, and Boost2 output voltage is input direct voltage.Boost1 and Boost2 two-way differential output are the voltage that exports load two ends to.

In the negative half-cycle of output sinusoidal voltage, control switch pipe S1 is still in HF switch state, control switch pipe S4 and S6 are in normal open state, the complementary conducting of switching tube S5 and S1, Boost2 unit is in pressure-increasning state, and this road output voltage is the half-sinusoid with the half period of direct current biasing; Boost1 is in power frequency switching state, and switching tube S2, S3, S7 are all in off state, and the output voltage of Boost1 unit is input direct voltage.Through Boost1 and the differential negative half-cycle power frequency sinusoidal voltage that obtains of Boost2 two-way output.Like this during whole power frequency period, the two-way boosting unit timesharing work of boosting, can obtain desired pure sinusoid alternating voltage at load end differential output.The gain of this converter is identical with single Boost.By the following derivation of equation, draw:

$\mathrm{Vo}=\frac{1}{1-D}\×V_{\mathrm{in}}---\left(8\right)$

Wherein, the output voltage that Vo is inverter, D is the duty ratio of Boost circuit.

Require the unit single channel output voltage in boosting to meet in the half period in power frequency simultaneously:

Vo (t)=U _m* sin (wt)+V _in(9) associating above formula can obtain:

$D\left(t\right)=\frac{U_m\×\sin \left(\mathrm{wt}\right)}{V_{\mathrm{in}}+U_m\×\sin \left(\mathrm{wt}\right)}---\left(10\right)$

So timesharing makes the duty ratio of Boost1 boosting unit and Boost2 boosting unit change by formula (10), can make output voltage obtain the sinusoidal voltage of expecting, as shown in Figure 3.

Fig. 4 is the driving signal of switching tube S1, S3, S5, and Fig. 5 is the driving signal of switching tube S2, S7, S4, S6.Fig. 6 has represented collection radio pressure and the inductive current that switching device bears, and ordinate is followed successively by the electric current of penetrating collecting voltage, inductance L, switching tube S1 collection radio pressure, the switching tube S2 collection radio of switching tube S6 and presses.The ordinate of Fig. 7 is indication circuit output capacitance C1 both end voltage, capacitor C 2 both end voltage, input direct voltage, output AC voltage successively.

Claims (3)

1. two Boost inverters of a single inductance, comprise Boost boosting unit I, Boost boosting unit II, boost inductance, switching tube I, the input of the input of Boost boosting unit I and Boost boosting unit II is connected in parallel, the output of the output of Boost boosting unit I and Boost boosting unit II is connected in series the rear output as this inverter, and the output of inverter comprises first end, the second end, and Boost boosting unit I comprises switching tube II, switching tube III; Boost boosting unit II comprises switching tube IV, switching tube V; Described switching tube includes input, output, control end, it is characterized in that, also comprise switching tube VI, switching tube VII, connecting valve pipe VI between the first end of inverter output end and the positive pole of DC power supply, connecting valve pipe VII between the second end of inverter output end and DC power anode; Boost boosting unit I and Boost boosting unit II share a boost inductance and switching tube I, wherein, the output of one end of boost inductance, switching tube I is all connected with the positive pole of DC power supply, and the input of the other end of boost inductance, switching tube I is all connected with the positive pole of Boost boosting unit I input, the positive pole of Boost boosting unit II input.

2. two Boost inverters of single inductance according to claim 1, is characterized in that: equal parallel diode between the input of switching tube, output, and the anode of diode is connected with the output of switching tube, and the negative electrode of diode is connected with the input of switching tube.

3. the control method based on the two Boost inverters of single inductance described in claim 1, it is characterized in that: in sinusoidal wave positive half period, control switch pipe I is in HF switch state, and switching tube II, switching tube VII be in normal open state, the complementary conducting of control switch pipe III and switching tube I; In sinusoidal wave negative half-cycle, control switch pipe I is in HF switch state, and switching tube IV, switching tube VI be in normal open state, the complementary conducting of control switch pipe V and switching tube I.