Switching power supply circuit of air conditioner, circuit board and air conditioner

Abstract

The invention discloses a switching power supply circuit of an air conditioner, a circuit board and the air conditioner, and the switching power supply circuit comprises a power supply input end which is used for obtaining an external power supply; the transformer comprises a primary winding and a secondary winding; the power output end is used for supplying power to a plurality of loads, and the secondary winding is connected to the power output end; the power supply input end, the primary winding and a switch pin of the switch tube are connected in sequence; the starting driving unit is connected with a control pin of the switching tube and is used for outputting a first pulse signal to the switching tube when the switching power supply circuit is started; and the micro-control unit is connected with a control pin of the switching tube and is used for outputting a second pulse signal to the switching tube after the switching power supply circuit is started and adjusting the carrier frequency of the second pulse signal according to the starting condition of the load. The output power of the switching power supply is flexibly adjusted, so that the operation energy efficiency and the operation stability of the air conditioner are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a switching power supply circuit, a circuit board and an air conditioner of an air conditioner. Background Art

[0002] At present, the existing air conditioner switching power supply control method mainly adopts the fixed output power control method, that is, by setting a fixed power value for the IC driver chip (starting drive unit) to control the operating frequency of the switching power supply. The fixed output power control method has the advantages of simplicity and easy implementation. By setting a fixed power value, the stable output of the switching power supply can be ensured to a certain extent, so that the air conditioner has reliable working performance and relatively low cost, which is suitable for most ordinary household air conditioners.

[0003] However, the existing fixed output power control method of the switching power supply means that the operating frequency of the switching power supply can only be adjusted according to the maximum power, making it impossible for the air conditioner to flexibly adjust the output power according to actual needs, thereby affecting the operating energy efficiency and operating stability of the air conditioner. For example, when the air conditioner is in a low load state, the switching power supply still operates at the maximum power, thereby reducing the operating energy efficiency of the air conditioner; when the air conditioner is in a high load state, the switching power supply still operates at a fixed power and may not be able to provide sufficient power, thereby affecting the normal operation of the air conditioner. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a switching power supply circuit, a circuit board and an air conditioner for an air conditioner, which can realize flexible adjustment of the output power of the switching power supply by taking over the control of the starting drive unit through a micro control unit, so as to improve the operating energy efficiency and operating stability of the air conditioner.

[0005] In the first aspect, an embodiment of the present invention provides a switching power supply circuit of an air conditioner, comprising: a power input end for obtaining an external power supply; a transformer, comprising a primary winding and a secondary winding; a power output end for supplying power to multiple loads, the secondary winding being connected to the power output end; a switch tube, the power input end, the primary winding and the switch pins of the switch tube being connected in sequence; a start drive unit connected to the control pin of the switch tube, for outputting a first pulse signal to the switch tube when the switching power supply circuit is started; a micro control unit connected to the control pin of the switch tube, for outputting a second pulse signal to the switch tube after the switching power supply circuit is started, and adjusting the carrier frequency of the second pulse signal according to the start-up status of the load.

[0006] The switching power supply circuit of the air conditioner according to the embodiment of the present invention has at least the following beneficial effects: the switching power supply circuit of the air conditioner in the present invention obtains external power through the power input terminal, and is connected in sequence through the power input terminal, the primary winding of the transformer and the switch pin of the switch tube, and the secondary winding of the transformer is connected to the power output terminal, so that when the switch tube is connected, the primary winding of the transformer can store the electric energy of the external power supply, and when the switch tube is disconnected, the secondary winding of the transformer releases the electric energy to the power output terminal, so that the power output terminal supplies power to multiple loads, and the starting drive unit connected to the control pin of the switch tube can output a first pulse signal to the switch tube when the switching power supply circuit is started, so as to control the switch tube The carrier frequency (on-off frequency) is controlled to a fixed frequency to start the switching power supply circuit, and a micro control unit is connected to the control pin of the switching tube, which is used to output a second pulse signal to the switching tube after the switching power supply circuit is started, so as to replace the start drive unit to control the carrier frequency of the switching tube, and adjust the carrier frequency of the second pulse signal according to the start-up status of the load, so that the switching tube switches the on-off state with the carrier frequency of the second pulse signal, thereby realizing flexible adjustment of the output power of the switching power supply, and can realize the functions of predicting the load size, pre-adjusting according to the load characteristics, operating according to the optimal efficiency, and performing the modulation wave method according to the electromagnetic interference requirements, so as to improve the operating energy efficiency and operating stability of the air conditioner.

[0007] In some embodiments, the micro control unit is also connected to the start drive unit, and the micro control unit is further used to output a control signal to the start drive unit after the switching power supply circuit is started, so as to control the start drive unit to stop running.

[0008] In some embodiments, the circuit also includes a rectification and filtering unit, which includes a diode and a capacitor, the positive terminal of the diode is connected to the positive terminal of the secondary winding, and the negative terminal is connected to the power supply output terminal; one end of the capacitor is connected to the power supply output terminal, and the other end is connected to the negative terminal of the secondary winding.

[0009] In some embodiments, the circuit also includes a sampling unit, the input end of the sampling unit is respectively connected to the secondary winding and the power supply output end, and is used to sample the output current and output voltage of the switching power supply circuit respectively; the output end of the sampling unit is connected to the micro control unit, and is used to output a current sampling signal and a voltage sampling signal to the micro control unit.

[0010] In some embodiments, the power output terminal is also used to supply power to the micro control unit to start the micro control unit.

[0011] In some embodiments, the load includes a turned-on load and a turned-off load, and adjusting the carrier frequency of the second pulse signal according to the turning-on status of the load includes:

[0012] When the start control signal of the unturned load or the shut down control signal of the turned on load is not received within the first preset time period, the frequency of the second pulse signal is gradually adjusted within a preset frequency range, and the frequency corresponding to the minimum value of the output power at the output end of the power supply is used as the carrier frequency of the second pulse signal.

[0013] In some embodiments, adjusting the carrier frequency of the second pulse signal according to the start-up status of the load further includes:

[0014] When the start control signal of the non-starting load is received, the carrier frequency of the second pulse signal is increased.

[0015] In some embodiments, increasing the carrier frequency of the second pulse signal includes:

[0016] Obtaining a first target power according to the output power and the rated power of the non-turned-on load;

[0017] Before the unactivated load is activated, the carrier frequency of the second pulse signal is increased to increase the output power to the first target power.

[0018] In some embodiments, adjusting the carrier frequency of the second pulse signal according to the start-up status of the load further includes:

[0019] When a shutdown control signal of the turned-on load is received, the carrier frequency of the second pulse signal is reduced.

[0020] In a second aspect, an embodiment of the present invention provides a circuit board, comprising a switching power supply circuit of an air conditioner as described in any one of the first aspects above.

[0021] In a third aspect, an embodiment of the present invention provides an air conditioner, comprising a circuit board as described in any one of the second aspects above.

[0022] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0025] Figure 1 is a schematic diagram of a switching power supply circuit of an air conditioner provided by an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of a switching power supply circuit of an air conditioner provided by another embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a switching power supply circuit of an air conditioner with a rectifier and filter unit provided by another embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of a switching power supply circuit of an air conditioner with a sampling unit provided by another embodiment of the present invention;

[0029] Figure 5 is a specific topological diagram of a switching power supply circuit of an air conditioner provided by another embodiment of the present invention;

[0030] Figure 6 is a startup timing diagram of a switching power supply circuit of an air conditioner provided by another embodiment of the present invention;

[0031] Figure 7 is a block diagram of a power-off load provided by another embodiment of the present invention;

[0032] Figure 8 Another embodiment of the present invention provides a flow chart for adjusting the carrier frequency;

[0033] Fig. 9 is another flow chart of adjusting the carrier frequency provided by another embodiment of the present invention;

[0034] Figure numerals: 110, power input terminal; 120, transformer; 121, primary winding; 122, secondary winding; 130, switch tube; 140, start drive unit; 150, micro control unit; 160, power output terminal; 310, rectifier filter unit; 410, sampling unit; 510, IC driver chip; 520, current sampling unit. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] In current air conditioners, the existing switching power supply control method mainly adopts a fixed output power control method, that is, by setting a fixed power value for the IC driver chip (start-up drive unit) to control the operating frequency of the switching power supply. The fixed output power control method has the advantages of being simple and easy to implement. By setting a fixed power value, the stable output of the switching power supply can be ensured to a certain extent, so that the air conditioner has reliable working performance and relatively low cost, and is suitable for most ordinary household air conditioners; however, the existing switching power supply fixed output power control method causes the operating frequency of the switching power supply to be adjusted only according to the maximum power, so that the air conditioner cannot flexibly adjust the output power according to actual needs, thereby affecting the operating energy efficiency and operating stability of the air conditioner. For example, when the air conditioner is in a low load state, the switching power supply still works at the maximum power, thereby reducing the operating energy efficiency of the air conditioner; when the air conditioner is in a high load state, the switching power supply still works at a fixed power, and may not be able to provide sufficient power, thereby affecting the normal operation of the air conditioner.

[0040] Based on the above situation, an embodiment of the present invention provides a switching power supply circuit, a circuit board and an air conditioner for an air conditioner, wherein the switching power supply circuit in the present invention obtains an external power supply through a power input terminal, and is connected in sequence through the power input terminal, the primary winding of the transformer and the switch pin of the switch tube, and the secondary winding of the transformer is connected to the power output terminal, so that when the switch tube is connected, the primary winding of the transformer can store the electric energy of the external power supply, and when the switch tube is disconnected, the secondary winding of the transformer releases the electric energy to the power output terminal, so that the power output terminal supplies power to multiple loads, and the starting drive unit connected to the control pin of the switch tube can output a first pulse signal to the switch tube when the switching power supply circuit is started, so as to control the switch tube The carrier frequency (on-off frequency) is controlled to a fixed frequency to start the switching power supply circuit, and a microcontroller unit is connected to the control pin of the switching tube, which is used to output a second pulse signal to the switching tube after the switching power supply circuit is started, so as to replace the starting drive unit to control the carrier frequency of the switching tube, and adjust the carrier frequency of the second pulse signal according to the opening condition of the load, so that the switching tube switches the on-off state with the carrier frequency of the second pulse signal, thereby realizing flexible adjustment of the output power of the switching power supply, and can realize the functions of predicting the load size, pre-adjusting according to the load characteristics, operating according to the optimal efficiency, and performing modulation wave methods according to the requirements of electromagnetic interference, so as to improve the operating energy efficiency and operating stability of the air conditioner.

[0041] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0042] Reference Figure 1 , Figure 1 1 is a schematic diagram of a switching power supply circuit of an air conditioner provided by an embodiment of the present invention. The first aspect of the present invention provides a switching power supply circuit of an air conditioner, including: a power input terminal 110, used to obtain an external power supply; a transformer 120, including a primary winding 121 and a secondary winding 122; a power output terminal 160, used to supply power to multiple loads, and the secondary winding 122 is connected to the power output terminal 160; a switch tube 130, wherein the power input terminal 110, the primary winding 121 and the switch pins of the switch tube 130 are connected in sequence; a start drive unit 140, connected to the control pin of the switch tube 130, and used to output a first pulse signal to the switch tube 130 when the switching power supply circuit is started; a micro control unit 150, connected to the control pin of the switch tube 130, and used to output a second pulse signal to the switch tube 130 after the switching power supply circuit is started, and adjust the carrier frequency of the second pulse signal according to the start-up status of the load.

[0043] In some embodiments, the present invention provides a switching power supply circuit for an air conditioner, which mainly includes a power input terminal 110 (Vout), a transformer 120 , a switch tube 130 and a power output terminal 160 . In this switching power supply circuit, a microcontroller unit 150 (MCU) is used to replace the start-up drive unit 140 to control the output power of the switching power supply in real time, so that the air conditioner has higher energy efficiency, wherein the power input terminal 110 is used to obtain an external power supply to supply the entire switching power supply circuit; the transformer 120 includes a primary winding 121 and a secondary winding 122, which are used to convert the voltage and current of the power supply, the primary winding 121 is connected to the power input terminal 110, and the secondary winding 122 is connected to the power output terminal 160; the switch tube 130 (such as IGBT) is located between the power input terminal 110 and the primary winding 121, and plays a role in controlling and regulating the output power of the power supply circuit, and the microcontroller unit 150 realizes the active switching function by controlling the switch tube 130; the start-up drive unit 140 is connected to the control pin of the switch tube 130, and outputs a first pulse signal to the switch tube 130 when the switching power supply circuit is started, so as to start the circuit normally and enable the microcontroller unit 150 to start powering on; the control unit is connected to the control pin of the switch tube 130. When the switching power supply circuit is started, the microcontroller unit 150 is powered on and starts running. The microcontroller unit 150 outputs a second pulse signal to the switch tube 130, and adjusts the carrier frequency of the second pulse signal according to the load (various loads inside the air conditioner) being turned on, so that the switch tube 130 switches the on and off state with the carrier frequency of the second pulse signal, thereby realizing flexible adjustment of the output power of the switching power supply to improve the operating energy efficiency and operating stability of the air conditioner.

[0044] In some embodiments, the power input terminal 110, the transformer 120, the switch tube 130, and the power output terminal 160 constitute a flyback switching power supply. The power input to the power input terminal 110 is a DC power supply, so that the switching power supply in the present invention transfers energy through the mutual inductance of the primary winding 121 and the secondary winding 122 of the transformer 120. When the switch tube 130 is turned on, the current in the primary winding 121 generates magnetic flux to store energy; when the switch tube 130 is turned off, the energy stored in the magnetic flux is released to the load through the secondary winding 122, thereby realizing high-efficiency and low-cost power conversion in the air conditioner; at the same time, the output to the switch can be adjusted to The carrier frequency of the second pulse signal of the switch tube 130 is used to control the rate or frequency of the switch tube 130 being turned on and off, thereby affecting the output power of the flyback switching power supply, so that the micro control unit 150 in the present invention can effectively control the output power of the switching power supply circuit by adjusting the carrier frequency according to the start-up status of the load to meet the load requirements of different air conditioners and optimize the system performance of the air conditioner. For example, within a certain range, a higher carrier frequency can improve the dynamic response of the switching power supply, so that it can adapt to load changes more quickly, thereby increasing the output power of the switching power supply circuit, while a lower carrier frequency may reduce the output power of the switching power supply circuit.

[0045] In some embodiments, the power input terminal 110 is connected to the power load in the air conditioner to provide an operating voltage for the power load in the air conditioner. The switching power supply circuit in the present invention makes the output power of the power input terminal 110 flexible and controllable, so that the switching power supply circuit can determine whether the load is operating normally according to the shutdown status of the connected load. Then, when the power supply voltage meets the requirements, the carrier frequency of the second pulse signal is adjusted to control the switching frequency of the switch tube 130, so that the output current changes. Since the switching frequency can obtain a similar output current within a certain range, the switching frequency is the optimal carrier frequency when the current just meets the load requirements. The above process determines the minimum output current that meets the conditions, and controls the operation of the switch tube 130 according to the carrier frequency corresponding to the minimum output current, thereby realizing the function of making the power input terminal 110 operate at the best efficiency, effectively improving the operating energy efficiency of the air conditioner; at the same time, the micro control unit 150 can determine which loads are to be turned on or off according to the corresponding air conditioning algorithm logic, and then adjust the output power by controlling the switching frequency of the switch tube 130 so that the output current changes, thereby realizing the adjustment of the output power of the switching power supply through the pre-set logic, which has better adapted to the sudden change of the load and effectively avoided the current spike caused by the sudden change of the system.

[0046] refer to Figure 1The power input terminal 110 includes a positive terminal and a negative terminal, the switch tube 130 includes a first switch pin and a second switch pin, one end of the primary winding 121 of the transformer 120 is connected to the positive terminal of the power input terminal 110, and the other end is connected to the first switch pin of the switch tube 130, and the second switch pin of the switch tube 130 is connected to the negative terminal of the power input terminal 110.

[0047] In some embodiments, the switch tube 130 is an IGBT (Insulated Gate Bipolar Transistor). Transistor), the first switch pin is the collector of the insulated gate bipolar transistor, the first switch pin is the emitter of the insulated gate bipolar transistor, and the control pin is the emitter of the insulated gate bipolar transistor. The insulated gate bipolar transistor is a semiconductor device that combines the advantages of MOSFET (metal oxide semiconductor field effect transistor) and BJT (bipolar junction transistor), and has high input impedance, fast switching speed, high voltage tolerance and large current driving capability. Among them, the metal oxide semiconductor field effect transistor has the advantage of fast switching speed, but is not suitable for high voltage scenarios; bipolar transistors are suitable for high voltage scenarios, but have slow switching speeds, and the insulated gate bipolar transistor combines the advantages of both, and realizes the characteristics of fast switching speed in high voltage and high current scenarios, so that the switching power supply circuit in this embodiment can still effectively control the frequency of the switch tube 130 by the micro control unit 150 instead of the start drive unit 140 in the high voltage and high current scenarios, so as to realize flexible adjustment of the output power of the switching power supply, so as to improve the energy efficiency and stability of the air conditioner.

[0048] Reference Figure 2 , Figure 21 is a schematic diagram of a switching power supply circuit of an air conditioner provided by another embodiment of the present invention. In some embodiments, the micro control unit 150 is further used to output a control signal to the start drive unit 140 after the switching power supply circuit is started, so as to control the start drive unit 140 to stop running; specifically, the start drive unit 140 is used to control the switch tube 130 to run according to a preset carrier frequency when the switching power supply circuit is in an off state and the micro control unit 150 is in an unpowered state, so as to turn on the switching power supply circuit and gradually increase the output voltage of the switching power supply circuit; after the output voltage of the power output terminal 160 is stable, the micro control unit 150 starts to start after power is supplied stably with the output voltage, and takes over the control of the carrier frequency of the switch tube 130 by the start drive unit 140, so as to adjust the output power of the power output terminal 160. It can be imagined that the power consumption of the start drive unit 140 is relatively high. When the micro control unit takes over the control of the carrier frequency of the switch tube 130 by the start drive unit 140, the start drive unit 140 is controlled to stop running by the control signal, which can effectively reduce the energy consumption of the switching power supply circuit and further improve the output energy efficiency.

[0049] Among them, since the power supply of the switch tube 130 in the present invention is a flyback power supply, it will automatically establish a voltage under the control of the start-up drive unit 140, and the micro control unit 150 will be powered on and started after the output voltage of the switch power supply is stable, so the micro control unit 150 does not need external power supply.

[0050] In some embodiments, the power output terminal 160 is also used to supply power to the micro control unit 150 to start the micro control unit 150, that is, when the starting drive unit 140 is output, the first pulse signal is output to the switch tube 130, so that when the circuit is started normally, the output voltage of the power output terminal 160 continues to increase and stabilizes to an initial output voltage corresponding to the carrier frequency of the first pulse signal. After the output voltage reaches the temperature, the power output terminal 160 is used to provide the micro control unit 150 with the stable output voltage to power the micro control unit 150 and start the micro control unit 150. It can be imagined that if the output voltage of the switching power supply is not stable, the power supply of the micro control unit 150 is unstable and cannot take over the starting drive unit 140 to continue control. Therefore, the micro control unit 150 in the present invention will only start after a stable output voltage environment is established at the power output terminal 160 to ensure the stability and reliability of the switching power supply circuit.

[0051] Reference Figure 3 , Figure 3It is a schematic diagram of a switching power supply circuit of an air conditioner with a rectifier and filter unit 310 provided by another embodiment of the present invention. In some embodiments, the circuit also includes a rectifier and filter unit 310, and the rectifier and filter unit 310 includes a diode and a capacitor. The positive terminal of the diode is connected to the positive terminal of the secondary winding 122, and the negative terminal is connected to the power output terminal 160; one end of the capacitor is connected to the power output terminal 160, and the other end is connected to the negative terminal of the secondary winding 122. It can be imagined that even a DC power supply may have a certain degree of ripple and noise, and these ripples and noise may come from interference generated by power conversion, switching power supply and other links. Therefore, the rectifier and filter unit 310 can be used to reduce the ripple and noise in the circuit, so that the DC output is smoother and more stable, so as to ensure the operating stability of the switching power supply circuit.

[0052] Reference Figure 4 , Figure 4 1 is a schematic diagram of a switching power supply circuit of an air conditioner with a sampling unit 410 provided in another embodiment of the present invention. In some embodiments, the circuit further includes a sampling unit 410, wherein the input end of the sampling unit 410 is respectively connected to the secondary winding 122 and the power output end 160, for respectively sampling the output current and the output voltage of the switching power supply circuit; the output end of the sampling unit 410 is connected to the micro control unit 150, for outputting a current sampling signal and a voltage sampling signal to the micro control unit 150, wherein the input end of the sampling unit 410 is respectively connected to the secondary winding 122 and the power output end 160, such a connection The connection mode enables the sampling unit 410 to monitor and sample the output current and output voltage of the switching power supply circuit in real time; the output end of the sampling unit 410 is connected to the micro control unit 150, which is used to transmit the collected current sampling signal and voltage sampling signal to the micro control unit 150, so that the micro control unit 150 can understand the actual current and voltage of the power supply output according to the sampling signal, and through the setting of the sampling unit 410, the real-time monitoring and sampling of the output current and voltage of the switching power supply circuit are realized, so that the micro control unit 150 can more accurately adjust the carrier frequency of the second pulse signal. In this way, more accurate power output control can be achieved according to the actual needs of the load, the working efficiency of the power supply can be improved, the energy consumption can be reduced, and the stability of the output voltage and current can be guaranteed to meet the normal working needs of various load devices.

[0053] Among them, the microcontroller unit 150 can obtain the output current and output voltage of the switching power supply circuit according to the received current sampling signal and voltage sampling signal, and then determine the current output power of the power output terminal 160 in the switching power supply circuit according to the output current and the output voltage, and in the subsequent process, adjust the carrier frequency of the second pulse signal in reverse according to the current output power, so that the switch tube 130 switches the on-off state with the carrier frequency of the second pulse signal, thereby realizing flexible adjustment of the output power of the switching power supply.

[0054] In some embodiments, the sampling unit 410 may include the following components: a current sampling resistor: connected between the secondary winding 122 and the power output terminal 160, used to convert the output current into a corresponding voltage signal. Selecting an appropriate resistance value can reduce the impact on circuit performance; a voltage divider: composed of a group of resistors, connected to the power output terminal 160, used to divide the output voltage so that the sampling voltage falls within the input range of the sampling unit 410; an analog / digital converter (ADC): converts the analog voltage signal into a digital signal, and the accuracy, sampling rate, resolution and other parameters of the ADC should be selected according to the actual application requirements; an amplifier and a filter (optional): if the sampling signal needs to be amplified or filtered, an operational amplifier and related filtering circuits can be added; the sampling unit 410 composed of the above components can realize real-time monitoring and sampling of the output current and voltage of the switching power supply circuit. In actual applications, the specific implementation method and parameter selection of the sampling unit 410 will be adjusted according to actual needs and design considerations.

[0055] Reference Figure 5 , Figure 51 is a specific topological diagram of a switching power supply circuit of an air conditioner provided by another embodiment of the present invention, wherein the switch tube 130 is an insulated gate bipolar transistor, the start drive unit 140 is an IC drive chip 510, and the sampling unit 410 includes a current sampling unit 520, which specifically includes: a DC power supply having a positive terminal and a negative terminal; a transformer 120, including a primary winding 121 and a secondary winding 122; an insulated gate bipolar transistor, including a collector, an emitter and a gate, the collector is connected to one end of the primary winding 121, and the other end of the primary winding 121 is connected to the positive terminal of the DC power supply; the emitter is connected to the negative terminal of the DC power supply; the current sampling unit 520, one end of the current sampling unit 520 is connected to the negative terminal of the secondary winding 122, and the positive terminal of the secondary winding 122 is connected to the positive terminal of the power output terminal 160; the current sampling unit The other end of the element 520 is connected to the negative terminal of the power output terminal 160; the IC driving chip 510 is connected to the gate and the current sampling unit 520 respectively; the micro control unit 150 is connected to the gate, the current sampling unit 520, the IC driving chip 510 and the power output terminal 160 respectively; when the switching power circuit is in the off state, the micro control unit 150 is in the off state, and the IC driving chip 510 is used to control the insulated gate bipolar transistor to operate at a preset carrier frequency, so that the switching power circuit is turned on and the output voltage of the power output terminal 160 increases; after the output voltage of the power output terminal 160 is stable, the micro control unit 150 is powered on and the IC driving chip 510 stops running, and the micro control unit 150 is used to control the carrier frequency of the insulated gate bipolar transistor to adjust the output power of the power output terminal 160.

[0056] Among them, the IC driver chip 510 and the micro control unit 150 obtain the output current of the switching power supply circuit through the current sampling unit 520. In addition, the micro control unit 150 also obtains the output voltage of the switching power supply circuit by directly connecting to the positive terminal of the power output terminal 160, so that the micro control unit 150 can determine the output power of the power output terminal 160 based on the output current and the output voltage.

[0057] In some embodiments, the switching power supply circuit also includes a rectifier and filter circuit, which includes a diode and a capacitor. The positive terminal of the diode is connected to the positive terminal of the secondary winding 122, and the negative terminal is connected to the positive terminal of the power supply output terminal 160; the two ends of the capacitor are respectively connected to the positive terminal and negative terminal of the load resistor, which plays a rectifying and filtering role.

[0058] Reference Figure 6 , Figure 6It is a startup timing diagram of the switching power supply circuit of an air conditioner provided by another embodiment of the present invention, wherein the pulse timing of the IC (first pulse signal) corresponds to the operating state of the IC driver chip, the MCU active pulse (second pulse signal) corresponds to the operating state of the microcontroller, and the output voltage Vout of the switching power supply is the output voltage of the power output end. It can be seen that when the switching power supply circuit of the air conditioner is just started, the startup drive unit is in an activated state, and outputs a first pulse signal to the switch tube so that the switch tube operates at the carrier frequency of the first pulse signal. At the same time, the output voltage of the switching power supply gradually increases to a fixed value. After the output voltage of the switching power supply is stable, the microcontroller is powered on and starts to send a second pulse signal to the switch tube so that the switch tube switches the on-off state at the carrier frequency of the second pulse signal. At the same time, the IC driver chip is controlled to stop running through a control signal, so that the pulse timing of the IC is terminated, thereby achieving the effect of the microcontroller taking over the IC driver chip to flexibly adjust the output power of the switching power supply, so as to improve the operating energy efficiency and operating stability of the air conditioner.

[0059] Reference Figure 7 , Figure 7 It is a power-off load block diagram provided by another embodiment of the present invention; in some embodiments, the load includes a turned-on load and an unturned load in the air conditioner, and the microcontroller is also connected to each load to control the turning on and off of each load according to the air conditioning algorithm logic, thereby adjusting the carrier frequency of the second pulse signal according to the turning-on status of the load.

[0060] Reference Figure 8 , Figure 8 Another embodiment of the present invention provides a flowchart for adjusting the carrier frequency; however, after the microcontroller is started, the microcontroller begins to adjust the carrier frequency of the second pulse signal according to the start-up status of the load, including the following steps: when no start-up control signal for an unturned load or a shutdown control signal for an turned-on load is received within a first preset time period, the frequency of the second pulse signal is gradually adjusted within a preset frequency range, and the frequency corresponding to the minimum value of the output power at the output end of the power supply is used as the carrier frequency of the second pulse signal.

[0061] Specifically, after the microcontroller unit is started, the output voltage and output current of the switching power supply are sampled to determine whether the output power is stable. The judgment rules are as follows: if a start control signal of a non-turned-on load or a shut-down control signal of a turned-on load is not received within the first preset time, it means that the current output power is stable, and the subsequent steps of adjusting the IGBT carrier frequency are performed; if a start control signal of a non-turned-on load or a shut-down control signal of a turned-on load is received within the first preset time, it means that the current output power is unstable, and the output voltage and output current of the switching power supply are continuously obtained to determine whether the output power is stable; after determining that the output power is stable, since the switching frequency is Similar currents can be obtained within a certain range, and when the voltage meets the requirements, the output current will change by adjusting the switching frequency. When the current just meets the load requirements, the switching frequency is the optimal carrier frequency. Therefore, the microcontroller unit in the present invention can gradually adjust the frequency of the second pulse signal within a preset frequency range to adjust the IGBT carrier frequency, and use the frequency corresponding to the minimum value of the output power at the output end of the power supply as the carrier frequency of the second pulse signal to adjust the IGBT carrier frequency, determine the minimum extreme value of the output current, and record the control carrier at this time for fixed operation, so as to realize automatic optimization control of the switching power supply, so that the air conditioner can operate at optimal efficiency.

[0062] Reference Fig. 9 , Fig. 9 Another embodiment of the present invention provides another flow chart for adjusting the carrier frequency; in some embodiments, in addition to being able to determine the current extreme value and record the control carrier at this time for fixed operation, the microcontroller can also adjust the IGBT carrier frequency and control the output power when the microcontroller determines that the load is to be turned on or off. Among them, because each low-voltage load is turned on by the air-conditioning algorithm logic, the microcontroller can monitor the switching status of the air-conditioning load and determine the expected state of the load. When the load is not moving, it enters the switching power supply efficiency optimization mode, corresponding to the above-mentioned IGBT carrier frequency adjustment and the process of determining the minimum extreme value of the output current; when the load is to be turned on, the output power of the switching power supply is increased to turn on the load; when the load is to be turned off, the output power of the switching power supply is reduced to turn off the load.

[0063] For example, when a start control signal is received for a load that is not turned on, the carrier frequency of the second pulse signal is increased and the output power of the switching power supply is increased; when a stop control signal is received for a load that is turned on, the carrier frequency of the second pulse signal is reduced and the output power of the switching power supply is reduced, so as to better adapt to sudden changes in load, avoid current spikes caused by system mutations when the load changes, and improve the stability of the air-conditioning system.

[0064] In some embodiments, when a start-up control signal of an unturned load is received, a first target power is obtained based on the output power and the rated power of the unturned load, and before the unturned load is turned on, the carrier frequency of the second pulse signal is increased to increase the output power to the first target power.

[0065] In some embodiments, when a shutdown control signal of an already turned on load is received, a second target power is obtained based on the output power and the rated power of the already turned on load, and before the already turned on load is turned off, the carrier frequency of the second pulse signal is reduced to reduce the output power to the second target power.

[0066] The second aspect of the present invention provides a circuit board, including a switching power supply circuit of an air conditioner as described in any one of the first aspects above, so as to achieve flexible adjustment of the output power of the switching power supply to improve the operating energy efficiency and operating stability of the circuit board.

[0067] A third aspect of the present invention provides an air conditioner, comprising a circuit board as described in any one of the second aspects above, so as to achieve flexible adjustment of the output power of the switching power supply, so as to improve the operating energy efficiency and operating stability of the air conditioner.

[0068] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed methods above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium or a non-transitory medium and a communication medium or a temporary medium. As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier frequency or other transport mechanism, and may include any information delivery media.

[0069] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A switching power supply circuit for an air conditioner, characterized in that: include: Power input terminal, used to obtain external power; A transformer, including a primary winding and a secondary winding; A power output terminal, used to supply power to a plurality of loads, the secondary winding being connected to the power output terminal; A switch tube, wherein the power input terminal, the primary winding and the switch pin of the switch tube are connected in sequence; A start-up drive unit connected to the control pin of the switch tube and configured to output a first pulse signal to the switch tube when the switch power supply circuit is started; A micro control unit is connected to the control pin of the switch tube, and is used to output a second pulse signal to the switch tube after the switch power circuit is started, and adjust the carrier frequency of the second pulse signal according to the start-up status of the load.

2. The switching power supply circuit of the air conditioner according to claim 1, characterized in that: The micro control unit is also connected to the start drive unit, and the micro control unit is also used to output a control signal to the start drive unit after the switch power supply circuit is started, so as to control the start drive unit to stop running.

3. The switching power supply circuit of the air conditioner according to claim 1, characterized in that: The circuit also includes a rectification and filtering unit, which includes a diode and a capacitor. The positive terminal of the diode is connected to the positive terminal of the secondary winding, and the negative terminal is connected to the power supply output terminal; one end of the capacitor is connected to the power supply output terminal, and the other end is connected to the negative terminal of the secondary winding.

4. The switching power supply circuit of the air conditioner according to claim 1, characterized in that: The circuit further comprises a sampling unit, the input end of the sampling unit is respectively connected to the secondary winding and the power supply output end, and is used to sample the output current and output voltage of the switching power supply circuit respectively; The output end of the sampling unit is connected to the micro control unit and is used to output a current sampling signal and a voltage sampling signal to the micro control unit.

5. The switching power supply circuit of the air conditioner according to claim 1, characterized in that: The power output terminal is also used to supply power to the micro control unit so as to start the micro control unit.

6. The switching power supply circuit of the air conditioner according to claim 1, characterized in that: The load includes a turned-on load and a turned-off load, and the adjusting the carrier frequency of the second pulse signal according to the turning-on status of the load includes: When the start control signal of the unturned load or the shut down control signal of the turned on load is not received within the first preset time period, the frequency of the second pulse signal is gradually adjusted within a preset frequency range, and the frequency corresponding to the minimum value of the output power at the output end of the power supply is used as the carrier frequency of the second pulse signal.

7. The switching power supply circuit of the air conditioner according to claim 6, characterized in that: The method of adjusting the carrier frequency of the second pulse signal according to the start-up status of the load further includes: When the start control signal of the non-starting load is received, the carrier frequency of the second pulse signal is increased.

8. The switching power supply circuit of the air conditioner according to claim 7, characterized in that: Increasing the carrier frequency of the second pulse signal comprises: Obtaining a first target power according to the output power and the rated power of the non-turned-on load; The carrier frequency of the second pulse signal is increased to increase the output power to the first target power.

9. The switching power supply circuit of the air conditioner according to claim 6, characterized in that: The method of adjusting the carrier frequency of the second pulse signal according to the start-up status of the load further includes: When a shutdown control signal of the turned-on load is received, the carrier frequency of the second pulse signal is reduced.

10. The switching power supply circuit of the air conditioner according to claim 9, characterized in that: The reducing the carrier frequency of the second pulse signal comprises: Obtaining a second target power according to the output power and the rated power of the turned-on load; The carrier frequency of the second pulse signal is reduced to reduce the output power to the second target power.

11. A circuit board, characterized in that: A switching power supply circuit for an air conditioner comprising the switching power supply circuit as claimed in any one of claims 1 to 10.

12. An air conditioner, characterized in that: Comprising the circuit board as claimed in claim 11.

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