Staggered parallel BUCK circuit and electrical equipment

Abstract

The utility model discloses a staggered parallel BUCK circuit and electrical equipment, and relates to the technical field of power conversion. According to the technical key points, two half-bridge circuits are adopted for voltage reduction processing; the step-down part comprises a first half-bridge circuit, a second half-bridge circuit, a first inductor and a second inductor; the positive end of the first half-bridge circuit is connected with the positive end of the second half-bridge circuit and is connected to the positive electrode of the bus capacitor, and the negative end of the first half-bridge circuit is connected with the negative end of the second half-bridge circuit and is connected to the negative electrode of the bus capacitor; the middle output point of the first half-bridge circuit is connected with one end of the first inductor, the middle output point of the second half-bridge circuit is connected with one end of the second inductor, the other end of the first inductor is connected with the other end of the second inductor to serve as the output end of the voltage reduction part, and voltage reduction signals are output to the output filter capacitor. DC-DC conversion is carried out through alternate wave generation of the two half-bridges, alternate energy storage of the two inductors is achieved, output current is formed by superposition of currents of the two inductors, and therefore output ripples are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power conversion, in particular to an interleaved parallel BUCK circuit and electrical equipment. Background Art

[0002] The BUCK circuit is a DC-DC converter based on the principle of inductive energy storage. It converts the DC voltage provided by the input power supply into an adjustable low-voltage output by controlling the on-off state of the switch tube by controlling the input PWM wave with a variable duty cycle, thereby meeting the power supply requirements of different circuits. It is widely used in systems such as the power supply of electronic equipment and battery management of electric vehicles.

[0003] Currently, the commonly used buck circuit uses a single power transistor plus a freewheeling diode to convert a high-voltage input into a stable low-voltage DC output. This method is technically mature, but in systems with high-voltage input and low-voltage, high-current output, the power transistor is subjected to significant current stress, resulting in severe heating, large output ripple, and a large power inductor and output filter capacitor. Utility Model Content

[0004] The utility model provides an interleaved parallel buck circuit and electrical equipment to solve the problems of severe heating, large output ripple, and large size of power inductors and output filter capacitors in traditional buck circuits in a system with high voltage input and low voltage and high current output.

[0005] The utility model is achieved through the following technical solutions:

[0006] In a first aspect, the utility model provides an interleaved parallel BUCK circuit, comprising an input part, a step-down part, and an output part;

[0007] The input part includes a bus capacitor, and two ends of the bus capacitor are respectively connected to the positive line and the negative line of the bus;

[0008] The step-down part includes a first half-bridge circuit, a second half-bridge circuit, a first inductor and a second inductor;

[0009] The positive end of the first half-bridge circuit is connected to the positive end of the second half-bridge circuit and is also connected to the positive electrode of the bus capacitor; the negative end of the first half-bridge circuit is connected to the negative end of the second half-bridge circuit and is also connected to the negative electrode of the bus capacitor;

[0010] The middle output point of the first half-bridge circuit is connected to one end of the first inductor, the middle output point of the second half-bridge circuit is connected to one end of the second inductor, and the other end of the first inductor is connected to the other end of the second inductor and serves as the output end of the step-down part;

[0011] The output part includes an output filter capacitor, the positive electrode of the output filter capacitor is connected to the output end of the step-down part, and the negative electrode is connected to the negative electrode of the bus capacitor, for outputting low-voltage direct current.

[0012] This utility model employs two half-bridge circuits for step-down processing, utilizing alternating ripples of the two half-bridges for DC-DC conversion. When one half-bridge is operating as a loop, the other is closed, allowing the two inductors to alternately store energy and charge the output capacitor. Because the inductor current cannot change suddenly, a freewheeling current is generated during the on-off state. When the two half-bridges alternately generate ripples, an interleaved buck circuit is formed, resulting in an output current waveform that is a superposition of the two inductor current waveforms, thereby reducing output ripple. Simultaneously, the power transistors of the two half-bridges alternate within their respective half-cycles, reducing current stress and heat generation, thereby increasing device life. This approach also reduces the size of the energy storage inductor by making the output current the sum of the two currents.

[0013] In some embodiments, the first half-bridge circuit includes a first IGBT tube and a second IGBT tube, the collector of the first IGBT tube is connected to the positive electrode of the bus capacitor, the emitter of the first IGBT tube is connected to the collector of the second IGBT tube, and serves as an intermediate output point to output a step-down signal, the emitter of the second IGBT tube is connected to the negative electrode of the bus capacitor, and the gate of the first IGBT tube and the gate of the second IGBT tube are connected to a drive switch.

[0014] In some embodiments, the second IGBT has a body diode.

[0015] In some embodiments, the second half-bridge circuit includes a third IGBT tube and a fourth IGBT tube, the collector of the third IGBT tube is connected to the positive electrode of the bus capacitor, the emitter of the third IGBT tube is connected to the collector of the fourth IGBT tube, and serves as an intermediate output point to output a step-down signal, the emitter of the fourth IGBT tube is connected to the negative electrode of the bus capacitor, and the gate of the third IGBT tube and the gate of the fourth IGBT tube are connected to a drive switch.

[0016] In some embodiments, the fourth IGBT has a body diode.

[0017] In some embodiments, the first half-bridge circuit includes a first MOS transistor and a second MOS transistor, the source of the first MOS transistor is connected to the positive electrode of the bus capacitor, the drain of the first MOS transistor is connected to the source of the second MOS transistor and serves as an intermediate output point to output a step-down signal, the drain of the second MOS transistor is connected to the negative electrode of the bus capacitor, and the gates of the first MOS transistor and the second MOS transistor are connected to a drive switch.

[0018] In some embodiments, the second half-bridge circuit includes a third MOS transistor and a fourth MOS transistor, the source of the third MOS transistor is connected to the positive electrode of the bus capacitor, the drain of the third MOS transistor is connected to the source of the fourth MOS transistor and serves as an intermediate output point to output a step-down signal, the drain of the fourth MOS transistor is connected to the negative electrode of the bus capacitor, and the gates of the third MOS transistor and the fourth MOS transistor are connected to a drive switch.

[0019] In some embodiments, the bus capacitor is an active capacitor.

[0020] In some embodiments, the first inductor and the second inductor have the same inductance value.

[0021] In a second aspect, the present invention provides an electrical device, comprising the interleaved parallel BUCK circuit described in any one embodiment of the first aspect.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: DC-DC conversion is performed by alternately generating waves of two half-bridges. When one half-bridge is used as a loop, the other half-bridge is in a closed state, so that the two inductors alternately store energy to charge the output capacitor. Since the inductor current cannot change suddenly, a loop freewheeling current is formed when the switch state is switched, so that the output current waveform is the superposition of the two inductor current waveforms, thereby reducing output ripple.

[0023] The power tubes of the two half-bridges work alternately in half a cycle, thereby reducing the current stress of a single half-bridge and the heat generation, thereby increasing the service life of the device.

[0024] The output current is the sum of the two currents, which can reduce the volume of the energy storage inductor.

[0025] When the two half-bridges transmit waves at an angle of 180°, an interleaved BUCK circuit is formed. When the two half-bridges transmit waves at the same time, a parallel BUCK circuit is formed. The circuit can operate in different modes as needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0027] Figure 1This is a system block diagram of an interleaved parallel BUCK circuit according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of an interleaved parallel BUCK circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The schematic implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0030] It should be noted that the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to other steps or units inherent in the device.

[0031] The terms used in the various embodiments of the application are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments of the application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meaning generally understood by those of ordinary skill in the art of the application. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having idealized meaning or too formal meaning, unless clearly defined in the various embodiments of the application.

[0032] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not necessarily required to practice the present invention. In other embodiments, well-known structures, circuits, materials, or methods are not described in detail to avoid obscuring the present invention.

[0033] The utility model provides an interleaved parallel buck circuit and electrical equipment, which are suitable for power supply systems or battery management systems of various electronic devices. By alternately generating waves through two half-bridges, the output current waveform is the superposition of two inductor current waveforms, which reduces output ripple, current stress, and heat generation, thereby facilitating the output of stable low-voltage current and extending service life.

[0034] See also Figure 1-2As shown, the staggered parallel BUCK circuit provided by the present invention is different from the conventional BUCK topology in that it uses two half-bridges for step-down processing. The two half-bridges alternately generate waves to form a DC-DC conversion circuit, converting high-voltage DC input into a stable low-voltage DC output. Figure 2 As shown in the circuit schematic diagram, the interleaved parallel BUCK circuit includes an input part, a step-down part and an output part.

[0035] The input section primarily consists of a bus capacitor C3, with its two ends connected to the bus's positive and negative lines, BUS+ and BUS-, respectively. The output section includes an output filter capacitor C4. The positive electrode of filter capacitor C4 is connected to the output of the step-down section, receiving the stepped-down signal. The negative electrode of filter capacitor C4 is connected to the negative electrode of bus capacitor C3. Both points of filter capacitor C4 can also be connected to a load, outputting low-voltage DC power to power the load.

[0036] The innovation of this utility model lies in the use of two half-bridge circuits in the step-down circuit. A half-bridge circuit is a circuit structure in which two power switching devices are connected in a totem pole pattern, with the midpoint serving as the output, to provide a square wave signal. In this embodiment, the step-down circuit comprises a first half-bridge circuit, a second half-bridge circuit, a first inductor, and a second inductor. The first and second half-bridge circuits each include two power switching devices, with the point between the two power switching devices serving as the output point, stepping down the voltage and outputting it to the two inductors.

[0037] Specifically, the positive end of the first half-bridge circuit is connected to the positive end of the second half-bridge circuit, serving as the positive end of the entire step-down section and connected to the positive electrode of bus capacitor C3. The negative end of the first half-bridge circuit is connected to the negative end of the second half-bridge circuit and serves as the negative end of the entire step-down section and connected to the negative electrode of bus capacitor C3. The area between the two power switching devices in the first half-bridge circuit serves as the intermediate output point of the first half-bridge, connected to one end of the first inductor L2. The area between the two power switching devices in the second half-bridge circuit serves as the intermediate output point of the second half-bridge, connected to one end of the second inductor L3. Furthermore, the other end of the first inductor L2 is connected to the other end of the second inductor L3, serving as the output end of the entire step-down section and outputting a voltage drop signal to the output filter capacitor C4 of the output section.

[0038] In some embodiments, the bus capacitor C3 is an active capacitor.

[0039] In some embodiments, the first inductor and the second inductor have the same inductance value.

[0040] In some embodiments, insulated gate bipolar transistors (IGBTs) are used as power switching devices. Specifically, the first half-bridge circuit includes a first IGBT Q1 and a second IGBT Q2. The collector of the first IGBT is connected to the positive electrode of bus capacitor C3, and the emitter of the first IGBT is connected to the collector of the second IGBT. The voltage-step-down signal is output from an intermediate point between the first and second IGBTs, and the emitter of the second IGBT is connected to the negative electrode of bus capacitor C3. The gates of the first and second IGBTs are connected to a drive switch. The drive switch generates a PWM wave to turn the power switching devices on or off, thereby achieving step-down conversion.

[0041] Furthermore, the second half-bridge circuit includes a third IGBT Q3 and a fourth IGBT Q4. The collector of the third IGBT is connected to the positive electrode of bus capacitor C3, and the emitter of the third IGBT is connected to the collector of the fourth IGBT. The area between the third and fourth IGBTs serves as an intermediate output point for outputting a step-down signal. The emitter of the fourth IGBT is connected to the negative electrode of bus capacitor C3. The gates of the third and fourth IGBTs are connected to a drive switch. The drive switch transmits a PWM wave to turn the power switching device on or off, thereby achieving step-down conversion.

[0042] In the above implementation, the first IGBT tube, the second IGBT tube, the third IGBT tube and the fourth IGBT tube can be respectively provided with a drive switch to control the conduction or shutdown of the four power switch devices respectively, or they can share a drive switch to generate four PWM waves to control the four power switch devices respectively.

[0043] In some embodiments, the first IGBT Q1, the second IGBT Q2, the third IGBT Q3, and the fourth IGBT Q4 all have body diodes, or the first and second IGBTs do not have body diodes, while only the third and / or fourth IGBTs have body diodes. The body diodes of the third and fourth IGBTs serve as freewheeling diodes in the buck circuit.

[0044] When the two IGBTs Q1 and Q2 act as a buck circuit, the two IGBTs Q3 and Q4 are in the off state. When Q1 is turned on, the first inductor L2 begins to store energy and the current increases, charging the output capacitor and providing energy to the load. When Q1 is turned off, the inductor current cannot change suddenly, so the body diode of Q2 acts as a circuit for freewheeling.

[0045] When the two IGBTs Q3 and Q4 act as a buck circuit, the two IGBTs Q1 and Q2 are in the off state. When Q3 is turned on, the second inductor L3 begins to store energy and the current increases, charging the output capacitor and providing energy to the load. When Q3 is turned off, the inductor current cannot change suddenly, so the body diode of Q4 acts as a circuit for freewheeling.

[0046] In some embodiments, MOSFETs are used as power switching devices. Specifically, the first half-bridge circuit includes a first MOS transistor and a second MOS transistor. The source of the first MOS transistor is connected to the positive electrode of bus capacitor C3, the drain of the first MOS transistor is connected to the source of the second MOS transistor, and serves as an intermediate output point to output a step-down signal. The drain of the second MOS transistor is connected to the negative electrode of bus capacitor C3, and the gates of the first MOS transistor and the second MOS transistor are connected to a drive switch. The drive switch transmits a PWM wave to turn the power switching device on or off, thereby achieving the purpose of step-down conversion.

[0047] Furthermore, the second half-bridge circuit includes a third MOS transistor and a fourth MOS transistor. The source of the third MOS transistor is connected to the positive electrode of the bus capacitor C3. The drain of the third MOS transistor is connected to the source of the fourth MOS transistor, serving as an intermediate output point to output a step-down signal. The drain of the fourth MOS transistor is connected to the negative electrode of the bus capacitor C3. The gates of the third and fourth MOS transistors are connected to a drive switch. The drive switch transmits a PWM wave to turn the power switching device on or off, thereby achieving the purpose of step-down conversion.

[0048] The voltage reduction principle of the interleaved parallel BUCK circuit proposed in this utility model is:

[0049] When the two power switching devices of the first half-bridge serve as a buck circuit, the two power switching devices of the second half-bridge are in the off state. When the upper tube is turned on, the first inductor L2 begins to store energy and the current increases, charging the output capacitor and providing energy to the load. When the upper tube is turned off, the inductor current cannot change suddenly, forming a loop freewheeling current.

[0050] When the two power switching devices of the second half-bridge serve as a buck circuit, the two power switching devices of the first half-bridge are in the off state. When the upper tube is turned on, the second inductor L3 starts to store energy and the current increases, charging the output capacitor and providing energy to the load. When the upper tube is turned off, the inductor current cannot change suddenly, forming a loop freewheeling current.

[0051] The two half-bridges generate power waves at a 180° staggered frequency. The current in one inductor is added to the freewheeling current in the other inductor. The output current waveform is a superposition of the two inductor current waveforms, reducing output ripple. Simultaneously, both power transistors operate in only half a cycle, reducing current stress and heat generation. The superposition of the switching frequencies of the two power transistors also reduces the size of the inductor.

[0052] In addition, the two half-bridges can also generate waves at the same time and be used as a parallel BUCK circuit.

[0053] The present invention also provides an electrical device using any of the above-mentioned interleaved parallel buck circuits. The electrical device can be a DC power supply device for electronic devices, a battery management device / system, or various electronic devices, including home electronic devices, portable electronic devices, and electric vehicles.

[0054] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only a specific implementation method of the utility model and is not intended to limit the scope of protection of the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model should be included in the scope of protection of the utility model.

Claims

1. An interleaved parallel BUCK circuit, characterized in that: Including input part, step-down part and output part; The input part includes a bus capacitor, and two ends of the bus capacitor are respectively connected to the positive line and the negative line of the bus; The step-down part includes a first half-bridge circuit, a second half-bridge circuit, a first inductor and a second inductor; The positive end of the first half-bridge circuit is connected to the positive end of the second half-bridge circuit and is also connected to the positive electrode of the bus capacitor; the negative end of the first half-bridge circuit is connected to the negative end of the second half-bridge circuit and is also connected to the negative electrode of the bus capacitor; The middle output point of the first half-bridge circuit is connected to one end of the first inductor, the middle output point of the second half-bridge circuit is connected to one end of the second inductor, and the other end of the first inductor is connected to the other end of the second inductor and serves as the output end of the step-down part; The output part includes an output filter capacitor, the positive electrode of the output filter capacitor is connected to the output end of the step-down part, and the negative electrode is connected to the negative electrode of the bus capacitor, for outputting low-voltage direct current.

2. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The first half-bridge circuit includes a first IGBT tube and a second IGBT tube. The collector of the first IGBT tube is connected to the positive electrode of the bus capacitor, the emitter of the first IGBT tube is connected to the collector of the second IGBT tube, and serves as an intermediate output point to output a step-down signal. The emitter of the second IGBT tube is connected to the negative electrode of the bus capacitor, and the gate of the first IGBT tube and the gate of the second IGBT tube are connected to a drive switch.

3. The interleaved parallel BUCK circuit according to claim 2, characterized in that: The second IGBT has a body diode.

4. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The second half-bridge circuit includes a third IGBT tube and a fourth IGBT tube, the collector of the third IGBT tube is connected to the positive electrode of the bus capacitor, the emitter of the third IGBT tube is connected to the collector of the fourth IGBT tube, and serves as an intermediate output point to output a step-down signal, the emitter of the fourth IGBT tube is connected to the negative electrode of the bus capacitor, and the gate of the third IGBT tube and the gate of the fourth IGBT tube are connected to a drive switch.

5. The interleaved parallel BUCK circuit according to claim 4, characterized in that: The fourth IGBT tube has a body diode.

6. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The first half-bridge circuit includes a first MOS transistor and a second MOS transistor. The source of the first MOS transistor is connected to the positive electrode of the bus capacitor, the drain of the first MOS transistor is connected to the source of the second MOS transistor and serves as an intermediate output point to output a step-down signal. The drain of the second MOS transistor is connected to the negative electrode of the bus capacitor, and the gates of the first MOS transistor and the second MOS transistor are connected to a drive switch.

7. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The second half-bridge circuit includes a third MOS transistor and a fourth MOS transistor. The source of the third MOS transistor is connected to the positive electrode of the bus capacitor, the drain of the third MOS transistor is connected to the source of the fourth MOS transistor and serves as an intermediate output point to output a step-down signal. The drain of the fourth MOS transistor is connected to the negative electrode of the bus capacitor, and the gates of the third MOS transistor and the fourth MOS transistor are connected to a drive switch.

8. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The bus capacitor is an active capacitor.

9. The interleaved parallel BUCK circuit according to claim 1, characterized in that: The first inductor and the second inductor have the same inductance value.

10. An electrical device, characterized in that: The electrical device includes the interleaved parallel BUCK circuit according to any one of claims 1 to 9.

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