CN218850630U

CN218850630U - Non-isolated hybrid single-phase crossing direct current conversion circuit

Info

Publication number: CN218850630U
Application number: CN202222998460.0U
Authority: CN
Inventors: 李伦全; 周涛; 谭魏明; 时金林; 王健
Original assignee: Nanjing Panda Electronics Co Ltd
Current assignee: Nanjing Panda Electronics Co Ltd
Priority date: 2022-11-10
Filing date: 2022-11-10
Publication date: 2023-04-11
Anticipated expiration: 2032-11-10

Abstract

The utility model discloses a non-isolated form hybrid single-phase crossing direct current converting circuit, including input interchange source, input filter unit, interchange rectifier unit, switch transform unit, output filter unit, the control unit, input interchange source is connected to the input of input filter unit, and the AC input end of interchange rectifier unit is connected to the output of input filter unit, the input of interchange rectifier unit's rectifier output end linked switch transform unit, output filter unit is connected to switch transform unit output, carries out direct current output. The utility model discloses can realize the step-up and bigger step-down duty cycle of wideer scope to better satisfying the use of full voltage range's medium and small power electronic product, obtaining better price/performance ratio.

Description

Non-isolated hybrid single-phase direct current conversion circuit

Technical Field

The utility model relates to a switching power supply, concretely relates to non-isolated form hybrid single phase crossing direct current converting circuit.

Background

With the development of electronic informatization, more and more devices need to be supplied with direct current, and particularly, the popularization of IT devices and the wide application of illumination in various places need a medium-and-small-power electronic converter to complete conversion from alternating current to direct current. These applications place high demands on the size, weight and portability of the power supply (such as adapters, electronic ballasts, etc.), and therefore further increase in power density of the power supply is required. Meanwhile, in order to reduce harmonic pollution of the power converter to the power grid, a plurality of related international standards such as IEC61000-3-2 and the like exist, so that the power supply not only needs to meet the explicit requirements (volume, weight, appearance and the like) of customers, but also needs to meet the legal requirements of related countries. For the power supply, the most important factor limiting the improvement of the power density is the efficiency (or loss), if the overall conversion efficiency of the power supply is low, the loss is inevitably large (the calorific value is inevitably large), the volume of the power supply is difficult to reduce, otherwise, the heat is difficult to dissipate; on the other hand, if the efficiency is high, the loss is small (the amount of heat generation is small), and the required heat dissipation space is also small. In order to achieve the purpose of increasing the power density of a power supply, the efficiency of the power supply is improved by thousands of degrees, for example, the purpose of reducing the volume is achieved through optimized core power components (conventional silicon devices are replaced by novel low-loss silicon carbide devices and the like) and heat dissipation and the like. In addition, the application scenarios of the aforementioned ac/dc converter such as the adapter generally require the power supply to have the capability of wide-range input, and therefore, a Buck (Buck) type Power Factor Correction (PFC) circuit is also gradually introduced to replace the conventional Boost (Boost) type PFC circuit. To achieve greater volume, efficiency, cost, etc.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: the utility model aims to provide a non-isolated hybrid single-phase direct current conversion circuit to satisfy the current input wide-range alternating current-direct current conversion and satisfy the power factor correction function; meanwhile, the control method of the single-phase non-isolated hybrid AC/DC conversion circuit is capable of controlling the conversion circuit to work in a soft start mode, a boost mode or a buck mode.

The technical scheme is as follows: a non-isolation type hybrid single-phase direct current conversion circuit comprises an input alternating current source, an input filtering unit, an alternating current rectifying unit, a switch conversion unit, an output filtering unit and a control unit, wherein the input end of the input filtering unit is connected with the input alternating current source, the output end of the input filtering unit is connected with the alternating current input end of the alternating current rectifying unit, the rectifying output end of the alternating current rectifying unit is connected with the input end of the switch conversion unit, and the output end of the switch conversion unit is connected with the output filtering unit for direct current output.

Further, the switch conversion unit comprises a first switch tube Q1, a second switch tube Q2, a first diode D1, a second diode D2, a third diode D3, and an inductor L1, wherein the inductor L1 comprises two coupling windings L1-1 and L1-2, a first filter capacitor C1, and a second filter capacitor C2; one end of the first filter capacitor C1 is connected with the positive end of the alternating current rectifying unit, and the other end of the first filter capacitor C1 is connected with the negative end of the alternating current rectifying unit; the first switching tube Q1 is serially connected to a positive end loop of the rectification power supply, the source electrode of the first switching tube Q1 is connected with the positive end of the alternating current rectification unit, and the drain electrode of the first switching tube Q1 is connected with the cathode of the first diode D1 and one end of the first winding L1-1 of the inductor L1; the source electrode of the second switching tube Q2 is connected with the anode of the second diode D2 and the dotted terminal of the first winding L1-1 of the inductor L1, and the drain electrode of the second switching tube Q2 is connected with the cathode of the third diode D3 and the negative terminal of the alternating current rectifying unit; the cathode of the second diode D2 is connected with the positive end of the second filter capacitor C2 and is also the output positive end of the switch conversion unit, the anode of the third diode D3 is connected with the dotted end of the second winding L1-2 of the inductor L1, and the other end of the second winding L1-2 of the inductor L1 is connected with the negative end of the second filter capacitor C2 and is also the output negative end of the switch conversion unit.

Further, the first switching tube Q1 in the switching conversion unit may also be placed in the negative terminal loop of the rectification power supply in series, the source is connected to the negative terminal of the ac rectification unit and the negative terminal of the first filter capacitor C1, and the drain is connected to the drain of the second switching tube Q2 and the cathode of the third diode D3.

Furthermore, a first filter capacitor C1 and a second filter capacitor C2 in the switching conversion unit are small-capacity high-frequency nonpolar capacitors.

Further, an inductor L1 in the switching conversion unit has two coupling windings L1-1 and L1-2 or equivalently two coupling windings L1-1 and L1-2, the two windings are highly tightly coupled, the number of turns is the same, and the inductance is close to the same.

The same-name ends of the coupling inductors are only used for conveniently determining the connection sequence of the two inductor windings in the loop, and under the condition that the consistency of the series connection directions of the two coupling inductors is not changed, the other end of the coupling inductors can be taken as the same-name end or the same-name end can be marked at the other end.

Further, the first switching tube Q1 and the second switching tube Q2 are switching tubes capable of being turned on and off at a high frequency and provided with antiparallel diodes, and the antiparallel diodes may be integrated or parasitic diodes, or additional separate diodes.

Further, the input filtering unit is a conventional non-polar capacitor filtering or pi-type filtering with a common-mode inductor, and the output filtering unit is a conventional energy storage capacitor filtering or pi-type filtering with a differential-mode inductor.

A control method of a non-isolated hybrid single-phase direct current conversion circuit comprises the following steps:

(1) The control unit processes the voltage signal or the external communication command;

(2) The control unit judges whether the circuit needs to work in a soft start mode, a boosting mode or a voltage reduction mode;

(3) After the mode is determined, the control unit applies corresponding driving control signals to the first switch tube Q1 and the second switch tube Q2, and the switch conversion unit works according to the mode.

Further, when Q1 and Q2 work in the boost mode, Q1 is applied with the driving signal and is completely conducted, and Q2 is applied with the PWM driving signal, so that Q2 is boosted; when Q1 and Q2 work in the voltage reduction mode, a PWM driving signal is applied to Q1, and Q2 does not apply the PWM driving signal or applies a closing signal, so that Q1 carries out voltage reduction work.

Under the boost mode, two coupling windings pass through the energy storage coupling of inductance, in the time of releasing energy, two inductance winding constitute the series relation in the circuit, thereby can improve the boost ratio, under the step-down mode, two coupling windings pass through the energy storage coupling of inductance, in the time of releasing energy, two inductance winding can constitute the parallel relation in the circuit, thereby can reduce the step-down attenuation ratio, thereby can realize the effective extension of the boost ratio or the step-down ratio in the wide range, thereby compare traditional step-down PFC and avoided under the boost mode or the very big duty cycle restriction under the step-down mode, also effectively changed the loss under these two modes, realize efficiency promotion and energy-conservation.

Furthermore, the control unit comprises an arithmetic processing unit, a signal sampling unit, an auxiliary power supply and a driving unit.

Has the advantages that: compared with the prior art, the utility model, its beneficial effect lies in: (1) The voltage stabilizing circuit can realize wider range of boosting (larger gain) by changing the switch conversion unit and controlling the switch conversion unit so as to output stable voltage; (2) Through the change of the switch conversion unit and the control of the switch conversion unit, the voltage reduction (attenuation ratio) realized by the voltage stabilizing circuit is reduced, so that the larger duty ratio conduction can be realized, the inductance follow current ripple current is reduced, the follow current loss is reduced, and the high efficiency is realized. (3) The wide-range work of the switch conversion unit is utilized, so that the conversion circuit is smaller in size and higher in cost performance compared with a traditional voltage stabilizer needing two stages.

Drawings

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a circuit diagram of the switch converter unit of FIG. 1;

FIG. 3 is a block diagram of a control unit of FIG. 1;

FIG. 4 is a schematic diagram of a conventional series hybrid PFC;

FIG. 5 is a schematic illustration of the interval division of the hybrid operation mode;

FIG. 6 is a schematic diagram of the buck mode operation of the converter cell of FIG. 2;

fig. 7 is a schematic diagram of the boost mode operation of the converter unit of fig. 2.

Detailed Description

The technical solution of the present invention will be further described with reference to the following detailed description and the accompanying drawings.

As shown in fig. 1, the utility model discloses a single-phase interchange source, input filter unit, interchange rectifier unit, switch transform unit, output filter unit, the control unit, the input interchange source is connected to the input of input filter unit, and the ac input end of interchange rectifier unit is connected to the output of input filter unit, the input of interchange rectifier unit is connected to the rectifier output end of interchange rectifier unit, but switch transform unit output termination output filter capacitance and load or equivalent load's converter.

As shown in FIG. 2, the first to second switching tubes (Q1-Q2), the first to third diodes (D1-D3), the inductor L1 with two coupled windings (L1-1, L1-2), the first to second filter capacitors (C1-C2) of the switching conversion unit. One end of the first filter capacitor C1 is connected with the positive end of the alternating current rectifying unit, and the other end of the first filter capacitor C1 is connected with the negative end of the alternating current rectifying unit; the source electrode of the first switch tube Q1 is connected with the positive end of the alternating current rectifying unit, and the drain electrode of the first switch tube Q1 is connected with the cathode of the first diode D1 and one end of a first winding (L1-1) of the inductor L1; the source electrode of the second switching tube Q2 is connected with the anode of the second diode D2 and the same name end of the first winding (L1-1) of the inductor L1, and the drain electrode of the second switching tube Q2 is connected with the cathode of the third diode D3 and the negative end of the alternating current rectifying unit; the cathode of the second diode D2 is connected with the positive end of the second filter capacitor C2 and is also the output positive end of the switch conversion unit, the anode of the third diode D3 is connected with the dotted end of the second winding (L1-2) of the inductor L1, and the other end of the second winding (L1-2) of the inductor L1 is connected with the negative end of the second filter capacitor C2 and is also the output negative end of the switch conversion unit.

As shown in fig. 2, the first to second filter capacitors in the switching conversion unit are small-capacity high-frequency electrodeless capacitors; two coupled windings (L1-1, L1-2) of the inductor L1 are highly tightly coupled, the number of turns is the same, and the inductance is close to the same. The first to second switching tubes are MOS and IGBT switching tubes having antiparallel diodes and capable of switching on and off at high frequency. The switch tube reverse diode can be an integrated or parasitic diode, and can also be an additional independent diode.

As shown in fig. 3, the control unit includes an arithmetic processing unit, a signal sampling unit, an auxiliary power supply, and a driving unit. Meanwhile, the control unit can also comprise a communication unit which can communicate with the outside.

Fig. 4 is a schematic diagram of a conventional series hybrid PFC;

the utility model discloses still include a control method of non-isolated form single phase alternating current constant voltage power supply conversion equipment, including following step:

1) The control unit processes the voltage signal or the external communication command;

2) The control unit judges whether the conversion device needs to work in a soft start mode, a boosting mode or a voltage reduction mode; as shown in fig. 5, which is a schematic diagram of a mixed mode operating range, when the half-wave rectified output voltage is greater than the set output voltage reference, the half-wave rectified output voltage needs to operate in a step-down mode; when the half-wave rectification output voltage is smaller than the set output voltage reference, the system needs to work in a boosting mode; when the output voltage is zero or far lower than the half-wave rectified output voltage at the moment of starting up, a soft start mode is required to be executed to gradually raise the output voltage to the normal output voltage.

3) The control unit controls the first switch tube Q1 and the second switch tube Q2 in the switch conversion unit to work according to the mode. That is, the control unit applies a driving control signal to the first switch Q1 and the second switch Q2 of the switching conversion unit, so that the switching conversion unit operates in an equivalent boost circuit mode or an equivalent buck circuit mode.

When the judgment is in the boosting interval, Q1 and Q2 work in a boosting mode, namely Q1 is applied with a driving signal and is completely conducted all the time, and Q2 is applied with a PWM driving signal, so that Q2 is boosted;

when the judgment is in the voltage reduction interval, Q1 and Q2 work in a voltage reduction mode, namely the PWM driving signal is applied to Q1, and the PWM driving signal is not applied to Q2 or the closing signal is applied to Q2, so that the voltage reduction of Q1 is carried out;

under the boost mode, two coupling windings pass through the energy storage coupling of inductance, in the time of releasing energy, two inductance winding constitute the series relation in the circuit, thereby can improve the boost ratio, under the step-down mode, two coupling windings pass through the energy storage coupling of inductance, in the time of releasing energy, two inductance winding can constitute the parallel relation in the circuit, thereby can reduce the step-down ratio, thereby can realize the effective extension of the boost ratio or the step-down ratio in the wide range, thereby compare traditional step-down PFC and avoided under the boost mode or the very big duty cycle restriction under the step-down mode, also effectively changed the loss under these two modes, realize efficiency promotion and energy-conservation.

The control method is further described below by taking the circuit of the first embodiment as an example:

when the control unit judges that the circuit needs to work in a voltage reduction mode by a voltage signal sampled by the sampling circuit or a command obtained by external communication through program operation in the operation processor unit according to the basic principle of fig. 5, as shown in fig. 6 (a), the second switching tube Q2 has a freewheeling function, and can be regarded as a freewheeling diode without applying a driving signal, or apply a driving signal to perform synchronous rectification work when the anti-parallel diode is conducted; the first switch tube Q1 is a voltage-reducing switch tube, and a PWM signal is applied to make it perform voltage-reducing conversion. At this time, according to the characteristics of the aforementioned L1 inductor, L1-1 and L1-2 can be set to be equal, the inductance is L, the rectified input voltage is higher than the conversion output part, and is stepped down on L1-1 and L1-2 respectively to store energy, the electromotive force direction is as shown in fig. 6 (a), and the current passes through Q1, L1-1 and D2 from the rectifying positive end, outputs equivalent load back to L1-2, D3, and then returns to the rectifying negative end. When the driving signal of Q1 is turned off, the original connection and conduction of Q1 are cut off, and the current cannot change suddenly due to the action of the inductor L1In the reverse direction, follow current flows through a feasible channel, so that D1 is subjected to bias voltage of L1-1 to conduct follow current, and D3 and Q2 are subjected to bias voltage of L1-2 to conduct follow current, so that a rectification power supply end is replaced to form a complete follow current channel; the relevant circuit is shown in fig. 6 (b). Assuming that the load is sufficient to make the inductor current continuous or critical, it can be seen from the above analysis that the duty cycle is D, vl when storing energy _1-1 +Vl _1-2 = Vin-Vo =2Vl, the duty cycle being 1-D, vl when the follow current is de-energized _1-1 ＝Vl _1-2 And (1) obtaining the voltage by using a voltage-second balance principle, wherein the voltage is (Vin-Vo) < DT/2) = Vo (1-D) < T, so that Vo = Vin × D/(2-D), and since 1 > D > 0, D/(2-D) < D is obtained, so that in a voltage reduction mode, compared with a traditional circuit, the voltage reduction attenuation coefficient is reduced, the duty ratio is effectively increased, the follow current time is reduced, and the current ripple is also favorably reduced.

When the basic principle of fig. 5 is referred to determine that the circuit needs to operate in the boost mode, as shown in fig. 7 (a), the first switching tube Q1 must be constantly turned on, and a through signal is applied to it, which can be regarded as a conducting wire; the second switch tube Q2 is a boost switch tube, and a PWM signal is applied to perform boost conversion. At this time, according to the characteristics of the inductance L1, L1-1 and L1-2 can be set to be equal, the inductance is L, the rectified input voltage is directly applied to L1-1 (L1) for energy storage, the electromotive force direction is as shown in FIG. 7 (a), and the current flows from the positive rectifying end, through Q1, L1-1, Q2, and then back to the negative rectifying end. When the driving signal of Q2 is cut off, the original connection and conduction of Q2 are cut off, the current can not change suddenly and reversely due to the action of the inductor L1, but the L1-1 and the L1-2 have close coupling, so that the L1-1 and the L1-2 both have reverse electromotive force, D2 and D3 are biased by the L1-1 and the L1-2 together to conduct follow current, and the current passes through the Q1, the L1-1 and the D2 from the rectification positive end, outputs equivalent load to return to the L1-2 and the D3 and then returns to the rectification negative end; the relevant energy release free-wheeling circuit is shown in fig. 7 (b). Assuming that the load is sufficient to make the inductor current continuous or critical, it can be seen from the above analysis that the duty ratio is D, vl _1-1 = Vin = Vl, with a duty cycle of 1-D, vin + (Vl) when the follow current is de-energized _1-1+ Vl _1-2 )＝Vo，Vl _1-1 ＝Vl _1-2 According to the volt-second balance theorem, vin DT = (Vo-Vin) ((1-D) × T/2), so Vo = Vin (1+D)/(1-D), and since 1 > D > 0, accordingly (1+D)/(1-D) > 1/(1-D) can be known, in the boost mode, compared with the traditional circuit, the same voltage can be obtained by a slightly smaller duty ratio, namely, the boost ratio is effectively increased, the energy storage time is reduced, and the boost range is expanded.

Therefore, as shown in fig. 5, according to the operation mode interval judgment, based on the operation principle, the controller modulates the duty ratio based on the operation principle to make the current and the voltage have the same phase, thereby realizing the Power Factor Correction (PFC), and performing the control and the operation in cycles according to the operation frequency of the voltage. The working effect of the control method is consistent with that of the well-known series hybrid PFC circuit, so that the in-phase buck conversion of the alternating-current input voltage is realized.

If the output voltage is zero or far lower than the half-wave rectified output voltage at the moment of starting up, the step-by-step soft start must be executed to gradually raise the output voltage to the normal output voltage. The specific working principle is also consistent with that of the single phase. The instantaneous output voltage is compared with the input rectified half-wave voltage, and the boost mode is performed when the instantaneous output voltage is higher than the input rectified half-wave voltage, and the buck mode is performed when the instantaneous output voltage is lower than the input rectified half-wave voltage, so that the specific working principle analysis as shown in fig. 6 and 7 is not introduced one by one.

To sum up, the utility model discloses a control unit is according to preset or to the judgement of other external voltage, current signal, the switch tube of control switch transform unit switches on and cuts off, cooperates the real-time voltage demand of input/output simultaneously and can make this alternating current circuit work in step-up, step-down or start three kinds of mode of soft start; meanwhile, the voltage boosting (or the larger voltage boosting gain) in a wider range and the voltage reduction duty ratio (or the smaller voltage reduction attenuation) can be realized, so that the use of middle and small power electronic products in a full voltage range is better met, and the better cost performance is obtained.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-isolated hybrid single-phase direct current conversion circuit is characterized in that: the input alternating current source is connected with the input filtering unit, the output end of the input filtering unit is connected with the alternating current input end of the alternating current rectifying unit, the rectifying output end of the alternating current rectifying unit is connected with the input end of the switch converting unit, and the output end of the switch converting unit is connected with the output filtering unit to output direct current.

2. The non-isolated hybrid single-phase-crossing direct-current conversion circuit according to claim 1, characterized in that: the switch conversion unit comprises a first switch tube Q1, a second switch tube Q2, a first diode D1, a second diode D2, a third diode D3 and an inductor L1, wherein the inductor L1 comprises two coupling windings L1-1 and L1-2, a first filter capacitor C1 and a second filter capacitor C2; one end of the first filter capacitor C1 is connected with the positive end of the alternating current rectifying unit, and the other end of the first filter capacitor C1 is connected with the negative end of the alternating current rectifying unit; the first switch tube Q1 is serially connected to a positive end loop of the rectification power supply, the source electrode of the first switch tube Q1 is connected with the positive end of the alternating current rectification unit, and the drain electrode of the first switch tube Q1 is connected with the cathode of the first diode D1 and one end of the first winding L1-1 of the inductor L1; the source electrode of the second switching tube Q2 is connected with the anode of the second diode D2 and the dotted terminal of the first winding L1-1 of the inductor L1, and the drain electrode of the second switching tube Q2 is connected with the cathode of the third diode D3 and the negative terminal of the alternating current rectifying unit; the cathode of the second diode D2 is connected with the positive end of the second filter capacitor C2 and is also the output positive end of the switch conversion unit, the anode of the third diode D3 is connected with the dotted end of the second winding L1-2 of the inductor L1, and the other end of the second winding L1-2 of the inductor L1 is connected with the negative end of the second filter capacitor C2 and is also the output negative end of the switch conversion unit.

3. The non-isolated hybrid single-phase-crossing direct-current conversion circuit according to claim 2, wherein: the first switch tube Q1 in the switch conversion unit may also be placed in the negative end loop of the rectification power supply in series, the source is connected to the negative end of the ac rectification unit and the negative end of the first filter capacitor C1, and the drain is connected to the drain of the second switch tube Q2 and the cathode of the third diode D3.

4. The non-isolated hybrid single-phase-crossing direct-current conversion circuit according to claim 2, wherein: and a first filter capacitor C1 and a second filter capacitor C2 in the switch conversion unit are small-capacity high-frequency non-polar capacitors.

5. The non-isolated hybrid single-phase-crossing direct-current conversion circuit according to claim 2, wherein: an inductor L1 in the switch conversion unit is provided with two coupling windings L1-1 and L1-2 or equivalently two coupling windings L1-1 and L1-2, the two windings are highly tightly coupled, and the number of turns of the two windings is the same.

6. The non-isolated hybrid single-phase-crossing direct-current conversion circuit according to claim 2, wherein: the first switch tube Q1 and the second switch tube Q2 are switch tubes capable of being switched on and off at high frequency and provided with antiparallel diodes, and the antiparallel diodes can be integrated or parasitic diodes or additional independent diodes.

7. The non-isolated hybrid single-phase-crossing DC converter circuit according to claim 1, wherein: the input filtering unit is conventional non-polar capacitor filtering or pi-type filtering with a common-mode inductor, and the output filtering unit is conventional energy storage capacitor filtering or pi-type filtering with a differential-mode inductor.