CN211508909U

CN211508909U - Self-excited staggered parallel Buck converter

Info

Publication number: CN211508909U
Application number: CN201822052371.0U
Authority: CN
Inventors: 谢廉毅; 陈怡�
Original assignee: Hangzhou Bigfish Bio Tech Co ltd
Current assignee: Hangzhou Bigfish Bio Tech Co ltd
Priority date: 2018-04-02
Filing date: 2018-04-02
Publication date: 2020-09-15
Anticipated expiration: 2028-04-02

Abstract

A self-excited staggered parallel Buck converter comprises at least two Buck units and an output capacitor, wherein a main circuit of each Buck unit comprises a triode, a main circuit diode and a main circuit inductor, only one other Buck unit is connected through a self-excited path, and all Buck units form a closed-loop self-excited loop; the self-excitation path comprises a voltage division resistor, a self-excitation capacitor and a self-excitation switch; a self-excited switch is connected between the base electrode and the emitting electrode of each triode; the base electrode of one triode and the collector electrode of the other triode are connected with a divider resistor and a self-excited capacitor in two Buck units connected by a self-excited path; one end of the voltage limiting resistor is connected between the voltage dividing resistor and the self-excitation capacitor, and the other end of the voltage limiting resistor is connected between the main circuit inductor and the output capacitor. The utility model has the characteristics of easily dilatation and start but difficult shut down of shaking, be applicable to the work occasion of high voltage input low voltage output.

Description

Self-excited staggered parallel Buck converter

The application is divided into application cases of a self-excited staggered parallel Buck converter with application number of 2018204516446, wherein the application date is 2018, 4 and 2.

Technical Field

The utility model relates to a step-down type DC-DC converter field, more specifically the saying so, it relates to a crisscross parallelly connected Buck converter of auto-excitation formula.

Background

Compared with a single Buck converter, the Buck converter connected in parallel in an interleaved mode has the advantages of being large in capacity and small in input current ripple and output current ripple. Compared with a separately excited Buck converter, the self-excited Buck converter has the advantages of easiness in starting, high cost performance and the like. The market urgently needs a Buck converter integrating the advantages of the Buck converter and the converter, and the technical scheme for further improving the performance of the Buck converter is achieved.

SUMMERY OF THE UTILITY MODEL

The utility model overcomes the defects of the prior art, and provides a multi-channel 'interlocking' self-excitation unit which is easy to start oscillation and difficult to stop oscillation, so that the self-excitation type staggered parallel Buck converter is easy to expand and the capacity is increased; the device is easy to start oscillation and has low requirements on components participating in self-excitation; and the self-excitation type staggered parallel Buck converter is not easy to stop oscillation and can still work autonomously under the condition of a default control loop.

In order to solve the technical problem, the technical scheme of the utility model as follows:

a self-excited staggered parallel Buck converter is characterized in that: the converter comprises at least two Buck units and an output capacitor, a main circuit of each Buck unit comprises a triode, a main circuit diode Dj _1 and a main circuit inductor Lj _1, emitting electrodes of the triodes of all the Buck units are connected with the positive end of a direct-current power supply, the first end of each main circuit inductor Lj _1 is connected with a collector electrode of the corresponding triode of the Buck unit, and the second ends of all the main circuit inductors Lj _1 are connected together and connected with one end of the output capacitor Co; a resistor Rpl _1 to a resistor Rpn _1, a resistor Rpl _2 to a resistor Rpn _2, a capacitor Cpl _1 to a capacitor Cpn _1, a diode Dpl _1 to a diode Dpn _1, a diode D1_1 to a diode Dn _1, a triode Qpl _1 to a triode Qpn _1 form a closed-loop self-excited unit; a self-excited switch is connected between the base electrode and the emitting electrode of each triode, when the potential of the base electrode of each triode is higher than that of the emitting electrode of each triode, the triodes are conducted, and when the potential of the base electrode of each triode is lower than that of the emitting electrode of each triode, the triodes are cut off; in two Buck units connected by a self-excited path, a voltage division resistor Rpj-1_2 and a self-excited capacitor Cpj _1 are connected to the base electrode of one triode Qpj-1_1 and the collector electrode of the other triode Qpj _ 1; one end of the voltage limiting resistor Rpj _1 is connected between the voltage dividing resistor Rpj _2 and the self-excited capacitor Cpj _1, and the other end is connected between the main circuit inductor Lj _1 and the output capacitor Co; the anodes of all diodes Dj _1 are connected to the negative terminal of the dc power supply.

Furthermore, only one main circuit inductor Lj _1 is provided, and the anode of the main circuit diode Dj _1 is connected with the cathode of the direct-current power supply; the cathode of the main circuit diode Dj _1 is connected with the collector of the triode of the Buck unit.

Compared with the prior art, the utility model the advantage lies in:

1. the main circuit of Buck unit is connected between DC power supply positive pole and output capacitance, links to each other through the self excitation route between the Buck unit, forms closed loop self excitation circuit, and the number of Buck unit easily expands, conveniently increases the capacity.

2. When the triode of one Buck unit is conducted, the other Buck unit is cut off, namely the two Buck units realize interlocking by utilizing the self-excitation path, and the closed-loop self-excitation loop is easy to start.

3. The self-excited closed loop circuit consists of a self-excited path, a triode, a diode and an inductor, has low requirements on self-excited components, is not easy to stop oscillation, and can still work autonomously under the condition of a default control loop.

Drawings

Fig. 1 is a circuit diagram of the present invention, in which 1 main circuit inductor, a voltage limiting resistor and an output capacitor are connected.

Detailed Description

As shown in fig. 1, the self-excited interleaved Buck converter comprises at least two Buck units and an output capacitor, wherein a main circuit of each Buck unit comprises a triode Qpj _1, a main circuit diode Dj _1 and a main circuit inductor Lj _1, emitters of the triodes of all the Buck units are connected with a positive end of a direct-current power supply Vi, first ends of all the main circuit inductors Lj _1 are connected with collectors of the triodes of the Buck units, and second ends of all the main circuit inductors are connected together and connected with one end of the output capacitor Co; the output capacitor is connected in parallel with the load Z.

Each Buck unit is provided with one Buck unit and only one other Buck unit is connected through a self-excitation circuit, and all Buck units form a closed-loop self-excitation circuit; the self-excitation path comprises a voltage division resistor Rpj-1_2, a self-excitation capacitor Cpj _1 and a self-excitation switch; when the electric potential of the base electrode of the triode is higher than the electric potential of the emitting electrode of the triode, the self-excited switch is closed, and when the electric potential of the base electrode of the triode is lower than the electric potential of the emitting electrode of the triode, the self-excited switch is disconnected; in fig. 1, the self-excited switch is realized by a diode Dpj-1_ 1; in two Buck units connected by a self-excited path, a voltage division resistor Rpj-1_2 and a self-excited capacitor Cpj _1 are connected to the base electrode of one triode Qpj-1_1 and the collector electrode of the other triode Qpj _ 1; only 1 main circuit inductor, namely Lj _1, and one end of the voltage limiting resistor Rpj _1 is connected with one end of the output capacitor Co. The capacitor Cpj _1 and the inductor Lj _1 are connected in series, the capacitor Rpj _1 is connected in parallel with the capacitor Cpj _1 and the inductor Lj _1 which are connected in series, the inductor Lj _1 divides the voltage of the capacitor Cpj _1, and the resistor Rpj _1 limits the voltage of the capacitor Cpj _1 and the inductor Lj _1 together, so that the voltage of the capacitor Cpj _1 is limited. The anodes of all diodes Dj _1 are connected to the negative terminal of the power supply. When Dj _1 is turned on, Rpj _1 in the circuit of FIG. 1 will make Cpj _1 have a higher upper limit of charging voltage. The value range of j is 1 to n, Rpj _1 represents the voltage limiting resistance of the jth Buck unit, and n represents the total number of Buck units.

The first and second terminals of the main circuit inductance are only for distinguishing the two terminals of the inductance and are not the first and second in mathematical sense.

In fig. 1, a resistor Rp1_1 to a resistor Rpn _1, a resistor Rp1_2 to a resistor Rpn _2, a capacitor Cp1_1 to a capacitor Cpn _1, a diode Dp1_1 to a diode Dpn _1, a diode D1_1 to a diode Dn _1, and a transistor Qp1_1 to a transistor Qpn _1 form a closed-loop self-excited unit. All triodes are PNP type BJT tubes.

Two Buck units connected by a self-excited path are interlocked. For example, in fig. 1, the jth Buck cell is assumed to be the current-stage cell, and the jth-1 Buck cell is assumed to be the next-stage cell.

An emitter of the PNP BJT Qpj _1 is connected to the positive terminal of the dc power Vi and the cathode of the diode Dpj _1, a base of the PNP BJT Qpj _1 is connected to the anode of the diode Dpj _1 and the one end of the resistor Rpj _2, a collector of the PNP BJT Qpj _1 is connected to the one end of the resistor Rpj _1, the one end of the capacitor Cpj _1, the cathode of the diode Dj _1 and the one end of the inductor Lj _1, the other end of the inductor Lj _1 is connected to the one end of the capacitor Co and the one end of the load Z, the other end of the load Z is connected to the other end of the capacitor Co, the anode of the diode Dj _1 and the negative terminal of the dc power Vi, and j ranges from 1 to n.

The other end of the resistor Rp1_2 is connected to both the other end of the resistor Rp2_1 and the other end of the capacitor Cp2_1, and so on, the other end of the resistor Rpn-1_2 is connected to both the other end of the resistor Rpn _1 and the other end of the capacitor Cpn _1, and the other end of the resistor Rpn _2 is connected to both the other end of the resistor Rp1_1 and the other end of the capacitor Cp1_ 1.

The circuit shown in fig. 1 utilizes the inconsistency of the self-excited cell (mainly PNP BJT Qp1_1 to PNP BJT Qpn _1) to generate the required oscillation. Assuming that Qp1_1 is turned on first, the diode D1_1 is turned off, the inductor L1_1 is charged with magnetism, the current iL1_1 is gradually increased, and the dc power Vi charges the capacitor Cp2_1 through the resistor Rpl _ 2. During the charging process of Cp2_1, the base current of Qp1_1 gradually decreases, while the collector current of Qp1_1 gradually increases, and Qp1_1 gradually exits the saturation state into the cutoff state. When Qp1_1 is turned off, D1_1 is turned on, L1_1 is discharged, and iL1_1 is gradually reduced. Meanwhile, the PNP BJT Qpn _1 is turned on, the diode Dn _1 is turned off, the inductor Ln _1 is charged, the current iLn _1 gradually increases, and the dc power Vi charges the capacitor Cp1_1 through the resistor Rpn _ 2. By analogy, Qpn _1 lags Qpl _1 on and off, Qpk-1_1 lags Qpk _1 on and off, Qp1_1 lags Qp2_1 on and off, and k ranges from 2 to n. In steady state, when Qp1_1 is turned on, Cp1_1 discharges through Rpn _2 and Dpn 1; when Qpk _1 is turned on, Cpk _1 is discharged through Rpk-1_2 and Dpk-1_ 1; when Qpn _1 is turned on, Cpn _1 is discharged through Rpn-1_2 and Dpn-1_ 1. The process is repeated. Dpj _1 is used to protect Qpj _1 and participate in oscillation, and resistor Rpj _1 is used to limit the terminal voltage of Cpj _ 1.

As shown in fig. 1, only one main circuit inductor Lj _1 is provided, and the anode of the main circuit diode Dj _1 is connected with the cathode of the direct-current power supply; the cathode of the main circuit diode Dj _1 is connected with the collector of the triode of the Buck unit.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the concept of the present invention, and these improvements and decorations should also be considered as the protection scope of the present invention.

Claims

1. A self-excited staggered parallel Buck converter is characterized in that: the converter comprises at least two Buck units and an output capacitor, a main circuit of each Buck unit comprises a triode, a main circuit diode Dj _1 and a main circuit inductor Lj _1, emitting electrodes of the triodes of all the Buck units are connected with the positive end of a direct-current power supply, the first end of each main circuit inductor Lj _1 is connected with a collector electrode of the corresponding triode of the Buck unit, and the second ends of all the main circuit inductors Lj _1 are connected together and connected with one end of the output capacitor Co; a resistor Rpl _ l to a resistor Rpn _ l, a resistor Rpl _2 to a resistor Rpn _2, a capacitor Cpl _ l to a capacitor Cpn _ l, a diode Dpl _ l to a diode Dpn _ l, a diode Dl _ l to a diode Dn _ l, and a triode Qpl _ l to a triode Qpn _ l form a closed-loop self-excited unit; a self-excited switch is connected between the base electrode and the emitting electrode of each triode, when the potential of the base electrode of each triode is higher than that of the emitting electrode of each triode, the triodes are conducted, and when the potential of the base electrode of each triode is lower than that of the emitting electrode of each triode, the triodes are cut off; in two Buck units connected by a self-excited path, a voltage division resistor Rpj-1_2 and a self-excited capacitor Cpj _ l are connected to the base electrode of one transistor Qpj-1_ l and the collector electrode of the other transistor Qpj _ l; one end of the voltage limiting resistor Rpj _1 is connected between the voltage dividing resistor Rpj _2 and the self-excited capacitor Cpj _ l, and the other end is connected between the main circuit inductor Lj _1 and the output capacitor Co; the anodes of all diodes Dj _ l are connected to the negative terminal of the dc power supply.

2. The self-excited interleaved Buck converter according to claim 1, further comprising: only one main circuit inductor Lj _1 is provided, and the anode of the main circuit diode Dj _1 is connected with the cathode of the direct-current power supply; the cathode of the main circuit diode Dj _1 is connected with the collector of the triode of the Buck unit.