CN103825455B - The double Buck full-bridge inverter of single inductance - Google Patents

Abstract

A single-inductance double-Buck full-bridge inverter includes an inversion circuit and a double-Buck circuit, and realizes inversion through the inversion circuit. The single-inductance double-Buck full-bridge inverter of the present invention solves the bridge arm direct-through problem on the traditional circuit. Compared with the traditional half-bridge inverter, the voltage stress of the power device is reduced, and it is more suitable for high-voltage and high-power occasions; and Compared with the double step-down inverter (DBI) circuit, only one filter inductor is needed, which reduces the volume and weight of the entire circuit and the corresponding loss, and has high conversion efficiency; the control scheme is simple, easy to implement, and has a high reliability.

Description

Single Inductor Double Buck Full Bridge Inverter

Technical field:

The invention relates to a single-inductance double-Buck full-bridge inverter, which belongs to an inverter in an electric energy conversion device.

Background technique:

With the development of power electronics technology, inverters have been extensively researched and applied. Dual Buck Inverter (DBI for short) is a new inverter topology that has been proposed and extensively studied in recent years. Compared with traditional push-pull and full-bridge inverters, DBI has the outstanding characteristics of no bridge arm direct connection and no switch tube parasitic diode reverse recovery problem. It is especially suitable for occasions with high power reliability requirements. DBI provides a simple way to simultaneously achieve high efficiency and high reliability of the inverter, which has high research value and broad development background. Like traditional half-bridge inverters, DBI has the following disadvantages: DBI requires external positive and negative DC bus voltages, whose amplitude exceeds twice the maximum output voltage, low DC voltage utilization, and device voltage stress is twice the input voltage , not suitable for high-voltage input occasions; the bridge arm can only output +1 and -1 two-state levels, and it works in bipolar modulation mode. The output waveform of the bridge arm has a large harmonic content, which requires a higher switching frequency and a larger filter device. In addition, DBI contains two filter inductors, and the volume, weight and loss of magnetic components in switching power supplies occupy a considerable proportion, and the proportion will also increase with the increase of power.

Invention content:

The invention provides a single-inductance double-Buck full-bridge inverter capable of retaining the advantages of high reliability and high efficiency of a double step-down inverter (DBI).

The present invention adopts the following technical scheme: a single-inductance double-Buck full-bridge inverter, including an external power supply U, an inversion circuit and a double-Buck circuit, and the inversion circuit includes a first power triode switch tube S ₁ , a second Power three-pole switch tube S ₂ , third power three-pole switch tube S ₃ and fourth power three-pole switch tube S ₄ , the double Buck circuit includes fifth power three-pole switch tube S ₅ , sixth power three-pole switch tube S 5 tube _S6 , the cathode of the _first freewheeling diode D1, the _second freewheeling diode D2, the output filter inductor L, the output filter capacitor C and the load R, the drain of the _first power triode switch S1 and The positive pole of the external power supply U is connected; the source of the _first power triode switch S1 and the drain of the _third power triode switch S3 are connected to the drain of the _fifth power triode switch S5; the third _The source of the power triode switch S3 is connected to the negative pole of the external power supply U; the drain of the _second power triode switch S2 is connected to the positive pole of the external power supply U; the source of the _fourth power triode switch S4 Connect to the negative pole of the external power supply U; the source of the _second power triode switch S2 and the drain of the _fourth power triode switch S4 are connected to one end of the output filter capacitor C connected to the load R; the output filter capacitor C is also connected to the other end of the load R, connected to one end of the output filter inductor L; the cathode of the _first freewheeling diode D1 and the anode of the _second freewheeling diode D2 are connected to the other end of the output filter inductor L; The anode of _a freewheeling diode D1 is connected to the negative pole of the external power supply U; the cathode of the _second freewheeling diode D2 is connected to the positive pole of the external power supply U; the drain of the _sixth power triode switch S6 is connected to the first continuous The connection point between the cathode _of the freewheeling diode D1 and the anode of the _second freewheeling diode D2; the source of the sixth power triode switch _S6 is connected to the source of the _fifth power triode switch S5.

The present invention has following beneficial effect:

(1) Solve the problem of bridge arm direct connection on the traditional circuit;

(2) Compared with the traditional half-bridge inverter, the voltage stress of the power device is reduced, which is more suitable for high-voltage and high-power occasions;

(3) Compared with the DBI circuit, only one filter inductor is needed, which reduces the volume and weight of the entire circuit and the corresponding loss, and has higher conversion efficiency;

(4) The control scheme is simple, easy to implement, and has high reliability.

Description of drawings:

FIG. 1 is a schematic structural diagram of a single-inductance double-Buck full-bridge inverter circuit of the present invention.

FIG. 2 is a schematic diagram of each switch mode of the single-inductance double-Buck full-bridge inverter circuit of the present invention.

Fig. 3 is a control block diagram adopted by the single-inductance double-Buck full-bridge inverter circuit of the present invention.

in:

1——reverse circuit; 2——double Buck circuit; S ₁ ~ S ₆ —— first to sixth power triode switches; D ₁ , D ₂ —— first and second freewheeling diodes; L— —output filter inductance; C—output filter capacitor; U—external power supply; u _o —inverter output voltage; u _of —output voltage feedback; u _r —voltage loop reference; i _o —inverter i _of ——output current feedback; i _r ——voltage loop output, that is, the current loop reference; drv1~drv6——drive of power triode switch tubes S ₁ ~S ₆ .

detailed description:

As shown in Figure ₁ , the drain of the first power triode switching tube S1 in the single inductance double Buck full bridge inverter of the present invention is connected to the positive pole of the external power supply U; the source of the _first power triode switching tube S1 and the drain of the _third power triode switch S3 are connected to the drain of the _fifth power triode switch S5; the source of the _third power triode switch S3 is connected to the negative pole of the external power supply U; The drain of the _second power triode switch S2 is connected to the positive pole of the external power supply U; the source of the _fourth power triode switch S4 is connected to the negative pole of the external power supply U; the source of the _second power triode switch S2 pole and the drain of the _fourth power triode switching tube S4, connected to one end of the output filter capacitor C connected to the load R; the output filter capacitor C is also connected to the other end of the load R, connected to one end of the output filter inductor L; The cathode of the _first freewheeling diode D1 and the anode of the _second freewheeling diode D2 are connected to the other end of the output filter inductor L; the anode of the _first freewheeling diode D1 is connected to the negative pole of the external power supply U; the second continuous _The cathode of the freewheeling diode D2 is connected to the positive pole of the external power supply U; the drain of the _sixth power triode switch S6 is connected to the junction of the cathode of the _first freewheeling diode D1 and the anode of the _second freewheeling diode D2 ; The source of the sixth power triode switch _S6 is connected to the source of the _fifth power triode switch S5.

The working principle of the present invention is: in the positive half cycle when the output voltage is greater than zero, the first power triode switch S ₁ and the fourth power triode switch S ₄ are normally open, the second power triode switch S ₂ and the third power triode switch S 2 The power triode switch S ₃ is normally closed, and in the positive half cycle when the output current is greater than zero, the body diodes of the fifth power triode switch S ₅ , the sixth power triode switch S ₆ , and the first freewheeling diode D _1. Buck circuit 1 composed of output filter inductor L and output filter capacitor C works. In the positive half cycle when the output current is less than zero, the sixth power triode switch S ₆ , the body diode of the fifth power triode switch S ₅ , the second freewheeling diode D ₂ , the output filter inductor L, and the output filter capacitor The buck circuit 2 composed of C works; in the negative half cycle when the output voltage is less than zero, the second power triode switch S ₂ and the third power triode S ₃ are normally open, the first power triode switch S ₁ and the fourth power The triode switch S ₄ is normally closed, the buck circuit 1 works when the output current is greater than zero in the negative half cycle, and the buck circuit 2 works when the output current is greater than zero in the negative half cycle. Among them, the first, second, third, and fourth power three-pole switch tubes are modulated by power frequency, which acts as circuit inversion, so as to achieve the purpose of inversion; the fifth and sixth power three-pole switch tubes of the double Buck circuit part are high Frequency SPWM modulation to ensure the output voltage waveform. Since there is only one filter inductance in the present invention, compared with DBI, there is no need to consider the problem of circulating current, which can ensure that no bias current is needed when the buck circuit is working, and the inverter can be guaranteed to work at higher efficiency and frequency.

Below with the main circuit structure of accompanying drawing 1, in conjunction with accompanying drawing 2, describe the specific working principle and working mode of the present invention.

1. The output voltage is greater than zero, and the output current is greater than zero. At this time, the circuit includes two working modes:

Working mode I: As shown in Figure 2(a), the first power triode switch S ₁ and the fourth power triode S ₄ are normally open, the second power triode S ₂ , the third power three The pole switch S ₃ is normally closed, the fifth power triode switch S ₅ is turned on, the sixth power triode switch S ₆ is turned off, the buck circuit 1 works, the inductor current starts to rise linearly, and supplies power to the load R.

Working Mode II: As shown in Figure 2(b), the first power triode switch S ₁ and the fourth power triode S ₄ are normally open, the second power triode S ₂ , the third power three _The pole switch S3 is normally closed, the _fifth power triode switch S5 is turned off, the sixth power triode switch _S6 is turned off, and the inductor current freewheels from the _first freewheeling diode D1 and decreases linearly.

2. The output voltage is less than zero, and the output current is less than zero. At this time, the circuit includes two working modes:

Working mode III: As shown in Figure 2(c), the second power triode switch S ₂ and the third power triode S ₃ are normally open, the first power triode S ₁ , the fourth power three The pole switch S ₄ is normally closed, the sixth power triode switch S ₆ is turned on, the fifth power triode switch S ₅ is turned off, the buck circuit 2 works, the inductor current starts to rise linearly, and supplies power to the load R.

Working Mode IV: As shown in Figure 2(d), the second power triode switch S ₂ and the third power triode S ₃ are normally open, the first power triode S ₁ , the fourth power three _The pole switch S4 is normally closed, the sixth power triode switch _S6 is turned off, the _fifth power triode switch S5 is turned off, and the inductor current freewheels from the _second freewheeling diode D2 and decreases linearly.

In order to realize the above working principle, the adopted control scheme is shown in Figure 3: the output voltage feedback u _of and the voltage loop reference u _r are adjusted by the voltage loop PI to obtain the current loop reference i _r . The output current feedback i _of and the current loop reference i _r are regulated by the current loop PI, and then the driving signals drv5 and drv6 of the _fifth and _sixth power triode switch tubes S5 and S6 are obtained through SPWM modulation and driving circuit. _The reference u _{r of} the voltage loop is calculated by the zero comparator and then the driving and dead zone circuit to obtain the driving signals _drv1 , _drv1 , drv2, drv3, and drv4, because these four switching tubes only switch once in the entire power frequency cycle, and the influence of the dead zone is negligible.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principle of the present invention, and these improvements should also be regarded as the invention. protected range.

Claims (1)

1. the double Buck full-bridge inverter of single inductance, including external power supply (U), circuit for reversing (1) and double Buck Circuit (2), it is characterised in that: described circuit for reversing (1) includes the first power triple-pole switch pipe (S₁), the second power Triple-pole switch pipe (S₂), the 3rd power triple-pole switch pipe (S₃) and the 4th power triple-pole switch pipe (S₄), described couple of Buck Circuit (2) includes the 5th power triple-pole switch pipe (S₅), the 6th power triple-pole switch pipe (S₆), the first fly-wheel diode (D₁), the second fly-wheel diode (D₂), output inductor (L), output filter capacitor (C) and load (R), Described first power triple-pole switch pipe (S₁) drain electrode be connected with the positive pole of external power supply (U)；First power three pole is opened Close pipe (S₁) source electrode and the 3rd power triple-pole switch pipe (S₃) drain electrode, be connected to the 5th power triple-pole switch pipe (S₅) Drain electrode；3rd power triple-pole switch pipe (S₃) source electrode be connected with the negative pole of external power supply (U)；Second power three Pole switching tube (S₂) drain electrode be connected with the positive pole of external power supply (U)；4th power triple-pole switch pipe (S₄) source Pole is connected with the negative pole of external power supply (U)；Second power triple-pole switch pipe (S₂) source electrode and the 4th power three pole open Close pipe (S₄) drain electrode, be connected to output filter capacitor (C) and load (R) one end of being connected；Output filter capacitor (C) other end with load (R) is also connected, and is connected to one end of output inductor (L)；First afterflow two pole Pipe (D₁) negative electrode and the second fly-wheel diode (D₂) anode, be connected to the other end of output inductor (L)； First fly-wheel diode (D₁) anode be connected with the negative pole of external power supply (U)；Second fly-wheel diode (D₂) Negative electrode is connected with the positive pole of external power supply (U)；6th power triple-pole switch pipe (S₆) drain electrode be connected to the first afterflow Diode (D₁) negative electrode and the second fly-wheel diode (D₂) the junction point of anode；6th power triple-pole switch pipe (S₆) Source electrode and the 5th power triple-pole switch pipe (S₅) source electrode connect.