Boost circuit, switching power supply and air conditioner

Abstract

The embodiment of the utility model provides a boost circuit, a switching power supply and an air conditioner. The boost circuit comprises a boost module and an output module, the boosting module is connected with the output module, and the boosting module is used for amplifying the input direct-current voltage according to the control signal and continuously supplying power to the output module. Through the design of the boost module in the boost circuit, on the basis of amplifying the DC voltage, the current change speed in the circuit can be reduced, and the effect of continuously supplying power to the output module is realized, so that the output current ripple of the circuit can be reduced, and the service life of a capacitor is prolonged.

Description

Technical Field

[0001] This application belongs to the field of air conditioner technology, and particularly relates to a boost circuit, a switching power supply, and an air conditioner. Background Technology

[0002] Power factor correction technology can not only significantly improve energy utilization efficiency, but also effectively reduce harmonic pollution of the power grid, ensuring the stability and reliability of power supply, making it a frequently used technology in home appliances such as air conditioners.

[0003] As a core topology for achieving power factor correction, boost circuits convert input voltage into a higher output voltage while simultaneously correcting the power factor. However, in practical applications, such as air conditioning systems with stringent power quality requirements, traditional boost circuits still face the problem of large output ripple. Output ripple not only affects system stability but may also lead to performance degradation of electrical equipment, increase electromagnetic interference, and adversely affect the lifespan of capacitors. Utility Model Content

[0004] This application provides a boost circuit, a switching power supply, and an air conditioner that can reduce circuit output ripple and extend the lifespan of capacitors.

[0005] In a first aspect, embodiments of this application provide a boost circuit, including:

[0006] Boost module and output module;

[0007] The boost module is connected to the output module. The boost module is used to amplify the input DC voltage according to the control signal and continuously supply power to the output module.

[0008] Optionally, the boost module includes a first boost unit, a second boost unit, a first switching unit, a second switching unit, and an energy storage unit; the input terminal of the first boost unit is used to connect to the DC voltage, the output terminal of the first boost unit is connected to the input terminal of the second boost unit through the first switching unit, the output terminal of the second boost unit is connected to the output module, the energy storage unit is connected to the input terminal of the second boost unit, the energy storage unit is also connected to the second switching unit, and the second switching unit is also connected to the output terminal of the first boost unit;

[0009] The first switching unit and the second switching unit are used to alternately turn on according to the control signal;

[0010] The first boost unit is used to charge the energy storage unit when the first switching unit is turned on, and to supply power to the output module via the second boost unit;

[0011] The first boost unit is also used to store electrical energy according to the DC voltage when the second switching unit is turned on; the energy storage unit is used to supply power to the output module via the second boost unit when the second switching unit is turned on.

[0012] Optionally, the first switching unit includes:

[0013] A first switching transistor, the first end of which is connected to the input terminal of the second boost unit and one end of the energy storage unit, the second end of which is connected to the output terminal of the first boost unit, and the gate of which is used to receive the control signal.

[0014] Optionally, the second switching unit includes:

[0015] The second switch has a first end connected to the other end of the energy storage unit, a second end connected to the second end of the first switch, and a gate for receiving the control signal.

[0016] The third switch has a first terminal grounded, a second terminal connected to the second terminal of the second switch, and a gate for receiving the control signal.

[0017] A first diode, the anode of which is connected to the second terminal of the third switching transistor, and the cathode of which is connected to the second terminal of the second switching transistor;

[0018] The second diode has its anode connected to the first terminal of the second switching transistor, and its cathode connected to the first terminal of the third switching transistor.

[0019] Optionally, the energy storage unit includes:

[0020] A first capacitor, one end of which is connected to the first terminal of the first switching transistor, and the other end of which is connected to the first terminal of the second switching transistor and the positive terminal of the second diode.

[0021] Optionally, the first boost unit includes:

[0022] A first inductor, one end of which is connected to the DC voltage, and the other end of which is connected to the second terminal of the first switching transistor.

[0023] Optionally, the second boost unit includes:

[0024] The second inductor has one end connected to the first terminal of the first switching transistor and the other end connected to the output module.

[0025] Optionally, the boost circuit further includes a rectifier module, the rectifier module comprising:

[0026] A rectifier bridge, wherein the first and third ends of the rectifier bridge are used to connect to AC power, the second end of the rectifier bridge is connected to the boost module, and the fourth end of the rectifier bridge is grounded;

[0027] The third capacitor has one end connected to the second end of the rectifier bridge and the boost module, and the other end grounded.

[0028] A first resistor, one end of which is connected to the second end of the rectifier bridge, and the other end of which is grounded.

[0029] Secondly, embodiments of this application also provide a switching power supply, including the boost circuit described in any of the preceding claims.

[0030] Thirdly, embodiments of this application also provide an air conditioner, including the switching power supply described above.

[0031] In the boost circuit, switching power supply, and air conditioner of this application embodiment, by designing the boost module in the boost circuit, the rate of current change in the circuit can be reduced while amplifying the DC voltage, thereby achieving the effect of continuous power supply to the output module. This can reduce the output current ripple of the circuit and extend the service life of the capacitor. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0034] Figure 1 This is a first structural block diagram of a boost circuit provided in an embodiment of this application.

[0035] Figure 2 This is a second structural block diagram of the boost circuit provided in the embodiments of this application.

[0036] Figure 3 This is a third structural block diagram of the boost circuit provided in the embodiments of this application.

[0037] Figure 4 This is a structural block diagram of the boost module in the boost circuit provided in the embodiments of this application.

[0038] Figure 5 A circuit diagram of a boost circuit provided in an embodiment of this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0040] In today's society, with the increasingly severe global energy crisis and rising environmental awareness, efficient and green power electronics technology has become a key force driving sustainable development in both industrial and civilian sectors. Power electronics technology, especially power factor correction (PFC) technology, is undeniably important as a cornerstone for improving energy efficiency and reducing environmental pollution. PFC technology not only significantly improves energy utilization efficiency but also effectively reduces harmonic pollution in the power grid, ensuring stable grid operation and thus contributing to the construction of a greener and more efficient energy system.

[0041] Especially in home appliances such as air conditioners, the application of PFC circuits can not only significantly improve system energy efficiency, but also effectively improve power grid quality, reduce harmonic pollution, and ensure the stability and reliability of power supply. As one of the core topologies for implementing PFC functionality, the optimization and improvement of the performance of Boost circuits has always been a hot topic and a challenge in the industry. Boost circuits can convert input voltage into a higher output voltage while achieving power factor correction. However, in practical applications, especially in air conditioning systems with strict power quality requirements, traditional Boost circuits still face the significant challenge of output ripple.

[0042] Output ripple not only affects system stability and reliability but can also degrade the performance of electrical equipment, increase electromagnetic interference (EMI), and adversely affect the lifespan of electrolytic capacitors. Electrolytic capacitors are indispensable components in PFC circuits, used to filter high-frequency components from the output voltage and ensure its stability. However, excessive current ripple increases the workload on electrolytic capacitors, accelerates their aging process, and shortens their lifespan. Therefore, exploring innovative circuit structures and technical solutions to effectively reduce PFC circuit output ripple has become crucial for improving the energy efficiency ratings and user experience of home appliances such as air conditioners.

[0043] It should be noted that current ripple in PFC circuits is mainly caused by the following reasons: First, PFC circuits are typically based on switching power supply technology, where the switching devices switch between on and off at a certain frequency. When the switching device is on, current begins to flow into the inductor, storing energy; when the switching device is off, the inductor releases energy into the circuit. This process causes rapid changes in current, thus generating ripple. Second, during a switching cycle, the inductor stores energy during the on-state of the switching device and releases it to the load or capacitor during the off-state. Because the storage and release of energy are discontinuous processes, this also leads to current fluctuations. Third, according to the formula for calculating the lifespan of electrolytic capacitors, current ripple significantly affects the lifespan of electrolytic capacitors.

[0044] To address the aforementioned issues, this application provides a boost circuit, a switching power supply, and an air conditioner to reduce the output ripple of the boost circuit and extend the lifespan of the capacitor.

[0045] Please see Figure 1 As shown, Figure 1 This is a first structural block diagram of a boost circuit provided in an embodiment of this application. The embodiment of this application provides a boost circuit 100, which includes a boost module 110 and an output module 120. The boost module 110 is connected to the output module 120, and is used to amplify the input DC voltage according to a control signal and continuously supply power to the output module 120.

[0046] In the boost circuit 100 provided in this application embodiment, by designing the boost module 110 in the boost circuit 100, the rate of change of current in the circuit can be reduced on the basis of amplifying DC voltage, so as to achieve the effect of continuously supplying power to the output module 120. This can reduce the output current ripple of the circuit and improve the service life of the capacitor.

[0047] It should be noted that the input to the boost circuit 100 is alternating current (AC), which needs to be converted to direct current (DC) before amplification. Please refer to [link / reference]. Figure 2 and Figure 3 As shown, Figure 2 This is a second structural block diagram of the boost circuit provided in the embodiments of this application. Figure 3 This is a third structural block diagram of the boost circuit provided in the embodiments of this application. For example, the boost circuit 100 further includes a rectifier module 130, which is used to rectify the alternating current to obtain direct current.

[0048] The rectifier module 130 includes a rectifier bridge DB1, a third capacitor C3, and a first resistor R1.

[0049] The rectifier bridge DB1 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first and third terminals of the rectifier bridge DB1 are used to connect to AC power. The second terminal of the rectifier bridge DB1 is connected to the boost module 110, and the fourth terminal of the rectifier bridge DB1 is grounded to GND.

[0050] One end of the third capacitor C3 is connected to the second terminal of the rectifier bridge DB1 and the boost module 110, and the other end of the third capacitor C3 is grounded to GND. The third capacitor C3 can be a polyester capacitor. The third capacitor C3 is a high-frequency current bypass capacitor, which plays a role in suppressing electromagnetic interference (EMI) and reducing the loss of the rectifier bridge DB1.

[0051] One end of the first resistor R1 is connected to the second terminal of the rectifier bridge DB1, and the other end of the first resistor R1 is grounded to GND. The first resistor R1 is a varistor, which plays a role in surge suppression and prevents the rectifier bridge from being damaged by surge breakdown.

[0052] Please combine Figures 1 to 3 And see Figure 4 As shown, Figure 4 This is a structural block diagram of a boost module in a boost circuit provided in an embodiment of this application. The boost module 110 includes a first boost unit 111, a second boost unit 112, a first switching unit 113, a second switching unit 114, and an energy storage unit 115.

[0053] The input terminal of the first boost unit 111 is used to connect to a DC voltage. The output terminal of the first boost unit 111 is connected to the input terminal of the second boost unit 112 through the first switching unit 113. The output terminal of the second boost unit 112 is connected to the output module 120. The energy storage unit 115 is connected to the input terminal of the second boost unit 112, and the energy storage unit 115 is also connected to the second switching unit 114. The second switching unit 114 is also connected to the output terminal of the first boost unit 111.

[0054] The first switching unit 113 and the second switching unit 114 are alternately switched on and off according to a control signal. The first boost unit 111 charges the energy storage unit 115 when the first switching unit 113 is on, and supplies power to the output module 120 via the second boost unit 112. The first boost unit 111 also stores electrical energy based on a DC voltage when the second switching unit 114 is on; the energy storage unit 115 supplies power to the output module 120 via the second boost unit 112 when the second switching unit 114 is on.

[0055] Therefore, the alternating conduction of the first switching unit 113 and the second switching unit 114, combined with the cooperation of the first boost unit 111, the second boost unit 112 and the energy storage unit 115, can continuously supply power to the output module 120, thereby reducing the rate of change of current in the circuit and thus reducing the output current ripple.

[0056] Please combine Figure 4 And see Figure 5 As shown, Figure 5 This is a circuit diagram of a boost circuit provided in an embodiment of this application. For example, the first switching unit 113 includes a first switching transistor Q1. The first end of the first switching transistor Q1 is connected to the input end of the second boost unit 112 and one end of the energy storage unit 115, the second end of the first switching transistor Q1 is connected to the output end of the first boost unit 111, and the gate of the first switching transistor Q1 is used to receive a control signal.

[0057] The first switching transistor Q1 can be an Insulated Gate Bipolar Transistor (IGBT), a composite fully controllable voltage-driven power semiconductor device composed of a BJT (Bipolar Junction Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It combines the advantages of a MOSFET's high input impedance and a GTR's low on-state voltage drop. GTRs have a low saturation voltage drop and high current density, but require a large drive current; MOSFETs have very low drive power and fast switching speed, but a large on-state voltage drop and low current density. IGBTs combine the advantages of both devices, offering low drive power and a low saturation voltage drop. Of course, the first switching transistor Q1 can also be other types of switching transistors; the above is merely illustrative and should not be construed as a limitation on Q1. It should be noted that the control signal is the signal that controls the first switching transistor Q1 to turn on and off.

[0058] For example, the second switching unit 114 includes a second switching transistor Q2, a third switching transistor Q3, a first diode D1, and a second diode D2.

[0059] The first end of the second switch Q2 is connected to the other end of the energy storage unit 115, the second end of the second switch Q2 is connected to the second end of the first switch Q1, and the gate of the second switch Q2 is used to receive control signals.

[0060] The first terminal of the third switch Q3 is grounded to GND, the second terminal of the third switch Q3 is connected to the second terminal of the second switch Q2, and the gate of the third switch Q3 is used to receive control signals.

[0061] It should be noted that the second switch Q2 and the third switch Q3 can be of the same type as the first switch Q1, for example, both can be insulated-gate bipolar transistors (IGBTs). The on and off states of the second switch Q2 and the third switch Q3 are the same, and opposite to the on and off states of the first switch Q1. Based on this, the control signals can be designed to be uniform; for example, the on and off states of the first switch Q1, the second switch Q2, and the third switch Q3 can be controlled separately based on the high and low levels of a single control signal. Alternatively, a drive circuit can be designed to drive the first switch Q1, the second switch Q2, and the third switch Q3. In this case, the first switch Q1 can have a first drive signal, and the second switch Q2 and the third switch Q3 can have second drive signals.

[0062] The positive terminal of the first diode D1 is connected to the second terminal of the third switch Q3, and the negative terminal of the first diode D1 is connected to the second terminal of the second switch Q2.

[0063] The positive terminal of the second diode D2 is connected to the first terminal of the second switch Q2, and the negative terminal of the second diode D2 is connected to the first terminal of the third switch Q3.

[0064] The energy storage unit 115 includes a first capacitor C1. One end of the first capacitor C1 is connected to the first terminal of the first switching transistor Q1, and the other end of the first capacitor C1 is connected to the first terminal of the second switching transistor Q2 and the positive terminal of the second diode D2. For example, the first capacitor C1 can be an electrolytic capacitor. An electrolytic capacitor is a type of capacitor where the metal foil is the positive electrode (aluminum or tantalum), the oxide film (aluminum oxide or tantalum pentoxide) in close contact with the metal is the dielectric, and the cathode is composed of conductive material, electrolyte (which can be liquid or solid), and other materials. Because the electrolyte is the main component of the cathode, it is named an electrolytic capacitor.

[0065] The first boost unit 111 includes a first inductor L1, one end of which is connected to a DC voltage, and the other end of which is connected to the second terminal of the first switching transistor Q1.

[0066] The second boost unit 112 includes a second inductor L2, one end of which is connected to the first terminal of the first switching transistor Q1, and the other end of which is connected to the output module 120.

[0067] For example, the output module 120 includes a second capacitor C2 and a load N1. One end of the second capacitor C2 is connected to the other end of the second inductor L2, and the other end of the second capacitor C2 is connected to the first end of the third switching transistor Q3. The second capacitor C2 can be of the same type as the first capacitor C1, such as both being electrolytic capacitors. The load N1 is connected in parallel with the second capacitor C2.

[0068] The boost circuit 100 includes two operating states, such as a first operating state and a second operating state. An external signal is connected to the gates of the first switch Q1, the second switch Q2, and the third switch Q3. By adjusting the duty cycle, the first switch Q1, the second switch Q2, and the third switch Q3 are controlled to be turned on or off, thereby switching between the first and second operating states.

[0069] In the first operating state, the first switch Q1 is off, while the second switch Q2 and the third switch Q3 are simultaneously on. The current, after being rectified and filtered by the rectifier module 130, flows through the first inductor L1, then through the second switch Q2 and the second diode D2, before returning to the rectifier module 130, forming a loop. At this time, the first inductor L1 is charged; the first capacitor C1 is discharged, and the emitted current flows sequentially through the second inductor L2, the second capacitor C2, the load N1, the third switch Q3, and the second switch Q2, finally returning to the negative terminal of the first capacitor C1. At this time, the second inductor L2 is charged, and the second capacitor C2 is also charged.

[0070] In the second operating state, the first switch Q1 is turned on, while the second switch Q2 and the third switch Q3 are turned off simultaneously. After being rectified and filtered by the rectifier module 130, the current passes through the first inductor L1 and the first switch Q1. A current shunt occurs at the emitter of the first switch Q1. Part of the current flows through the first capacitor C1, through the second diode D2, and back to the rectifier module 130, forming a loop, and the first capacitor C1 is charged. The other part of the current flows through the second inductor L2 to the second capacitor C2 and the load N1, returning to the rectifier module 130 to form a loop, at which point the second capacitor C2 is charged.

[0071] In current PFC circuits, the boost circuit works as follows: when the IGBT is closed and conducting, the inductor charges, the diode is effectively open, and the electrolytic capacitor discharges to the load; when the IGBT is open, the inductor and the power supply voltage are combined to charge the electrolytic capacitor and simultaneously supply power to the load. It is precisely because of the repeated switching of the IGBT that the output current fluctuates.

[0072] In this embodiment, the boost module 110 uses two inductors (first inductor L1 and second inductor L2), three IGBT switches (first switch Q1, second switch Q2 and third switch Q3), and a first capacitor C1 to work together to reduce the rate of change of current within one turn-on and turn-off cycle, thus effectively reducing the output current ripple of the electrolytic capacitor.

[0073] By optimizing the structure of the boost module 110 in the boost circuit 100, output ripple is effectively suppressed, the stress on the second capacitor C2 is reduced, and its service life is extended. Furthermore, this solution is not only suitable for the air conditioning industry but can also be widely applied to all electrical equipment using PFC circuits, such as refrigerators, washing machines, and lighting systems, demonstrating broad application prospects and market potential.

[0074] This application also provides a switching power supply, including the above-described boost circuit. The specific structure of the boost circuit is as described in the above embodiments. Since this switching power supply adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0075] This application also provides an air conditioner, which includes the switching power supply described above. The specific structure of the switching power supply is as described in the above embodiments. Since this air conditioner adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0076] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0077] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0078] The boost circuit, switching power supply, and air conditioner provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A boost circuit, characterized by comprising: Comprising: a boost module and an output module; the boost module is connected with the output module, and is used for amplifying an input direct current voltage according to a control signal and continuously supplying power for the output module; and a rectifier module, comprising: a rectifier bridge, a first end and a third end of the rectifier bridge are used for accessing alternating current, a second end of the rectifier bridge is connected with the boost module, and a fourth end of the rectifier bridge is grounded; a third capacitor, one end of the third capacitor is connected with the second end of the rectifier bridge and the boost module, and the other end of the third capacitor is grounded; a first resistor, one end of the first resistor is connected with the second end of the rectifier bridge, and the other end of the first resistor is grounded.

2. The boost circuit of claim 1, wherein, The boost module comprises a first boost unit, a second boost unit, a first switch unit, a second switch unit and an energy storage unit; an input end of the first boost unit is used for accessing the direct current voltage, an output end of the first boost unit is connected with an input end of the second boost unit through the first switch unit, an output end of the second boost unit is connected with the output module, the energy storage unit is connected with the input end of the second boost unit, the energy storage unit is also connected with the second switch unit, and the second switch unit is also connected with the output end of the first boost unit; the first switch unit and the second switch unit are used for alternatingly conducting according to the control signal; the first boost unit is used for charging the energy storage unit when the first switch unit is conducted, and supplying power for the output module through the second boost unit; the first boost unit is also used for storing electric energy according to the direct current voltage when the second switch unit is conducted, and the energy storage unit is used for supplying power for the output module through the second boost unit when the second switch unit is conducted.

3. The boost circuit of claim 2, wherein, The first switch unit comprises: a first switch tube, a first end of the first switch tube is connected with the input end of the second boost unit and one end of the energy storage unit, a second end of the first switch tube is connected with the output end of the first boost unit, and a gate of the first switch tube is used for accessing the control signal.

4. The boost circuit of claim 3, wherein, The second switch unit comprises: a second switch tube, a first end of the second switch tube is connected with the other end of the energy storage unit, a second end of the second switch tube is connected with the second end of the first switch tube, and a gate of the second switch tube is used for accessing the control signal; a third switch tube, a first end of the third switch tube is grounded, a second end of the third switch tube is connected with the second end of the second switch tube, and a gate of the third switch tube is used for accessing the control signal; a first diode, a positive electrode of the first diode is connected with the second end of the third switch tube, and a negative electrode of the first diode is connected with the second end of the second switch tube; a second diode, a positive electrode of the second diode is connected with the first end of the second switch tube, and a negative electrode of the second diode is connected with the first end of the third switch tube.

5. The boost circuit of claim 4, wherein, The energy storage unit comprises: A first capacitor, one end of the first capacitor is connected to the first end of the first switch tube, and the other end of the first capacitor is connected to the first end of the second switch tube and the positive electrode of the second diode.

6. The boost circuit of claim 3, wherein, The first voltage boosting unit comprises: A first inductor, one end of the first inductor is connected to the direct current voltage, and the other end of the first inductor is connected to the second end of the first switch tube.

7. The boost circuit of claim 6, wherein, The second voltage boosting unit comprises: A second inductor, one end of the second inductor is connected to the first end of the first switch tube, and the other end of the second inductor is connected to the output module.

8. A switching power supply, characterized by comprising: The voltage boosting circuit comprises any one of claims 1-7.

9. An air conditioner characterized by comprising: The switching power supply comprises claim 8.

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