Hybrid power supply system, control method thereof and air conditioner

Abstract

The application discloses a hybrid power supply system, a control method thereof and an air conditioner. The system comprises a photovoltaic positive electrode of a solar photovoltaic assembly, which is connected to a first input end of a first voltage boosting module through a first switch module; an output end of the first voltage boosting module is connected to a first input end of a second voltage boosting module; a photovoltaic negative electrode of the solar photovoltaic assembly is connected to a second input end of the first voltage boosting module; an alternating current commercial power is connected to the first input end of the second voltage boosting module through a second switch module and a rectifier module; a first output end of the rectifier module is connected to a first input end of the second voltage boosting module; a first output end of the second voltage boosting module is connected to a positive electrode of a bus capacitor unit; a second output end of the rectifier module is connected to a first input end of the second voltage boosting module on one hand and connected to a negative electrode of the bus capacitor unit and grounded on the other hand. According to the scheme, the voltage boosting circuit of the solar photovoltaic power supply is connected in series with the voltage boosting circuit of the commercial power supply system, so that the utilization rate of the voltage boosting circuit of the alternating current commercial power supply is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of power supply, and particularly relates to a hybrid power supply system, a control method thereof and an air conditioner. BACKGROUND

[0002] With the increasingly prominent contradiction between energy shortage and energy demand in production and life, the development and application of new energy have gradually attracted the attention of countries around the world. Under the background of carbon neutrality, clean and environmentally friendly photovoltaic power generation and its application have become a relatively popular research field in China, and the market prospect of the photovoltaic related field is relatively broad.

[0003] In order to protect the environment and save energy, clean and renewable solar energy is applied to air conditioners. In related schemes, there are many air conditioner technologies that use hybrid power supply of commercial power and photovoltaic power. The hybrid power supply method used in these schemes is to directly integrate a photovoltaic power generation grid-connected system into the direct current side of a mature air conditioner power supply system to form a hybrid power supply system with commercial power.

[0004] However, in the above scheme, the commercial power and the solar photovoltaic power source each have a separate boost circuit. In the scenario where the solar power supply energy is sufficient and the air conditioner only needs to be powered by solar power and does not need to be powered by alternating commercial power, the boost circuit of the alternating commercial power source is idle and does not work, and at least there is a problem of low utilization rate of the boost circuit of the alternating commercial power source.

[0005] The above content is only used to assist in understanding the technical solutions of the present application and does not represent an acknowledgement that the above content is prior art. SUMMARY

[0006] The present application aims to provide a hybrid power supply system, a control method thereof and an air conditioner to solve the problem that in the scheme of hybrid power supply of commercial power and solar photovoltaic power, a photovoltaic power generation grid-connected system is directly integrated into the direct current side of a commercial power supply system to form a hybrid power supply system with commercial power, in the scenario where the air conditioner does not need to be powered by alternating commercial power, the boost circuit of the alternating commercial power source is idle and does not work, and at least there is a problem of low utilization rate of the boost circuit of the alternating commercial power source. The effect of at least improving the utilization rate of the boost circuit of the alternating commercial power source is achieved by connecting the boost circuit of the solar photovoltaic power source and the boost circuit of the commercial power supply system in series to form a two-stage boost circuit of the solar photovoltaic power source.

[0007] The application provides a hybrid power supply system, comprising: a solar photovoltaic power supply, an alternating current mains power supply and a bus capacitor unit; the solar photovoltaic power supply comprises: a solar photovoltaic assembly, a first switch module and a first voltage boosting module; the alternating current mains power supply comprises: a rectifier module, a second switch module and a second voltage boosting module; wherein the photovoltaic positive pole of the solar photovoltaic assembly is connected to the first input end of the first voltage boosting module through the first switch module; the output end of the first voltage boosting module is connected to the first input end of the second voltage boosting module, so that the first voltage boosting module and the second voltage boosting module are connected in series to form a two-stage voltage boosting module of the solar photovoltaic power supply; the photovoltaic negative pole of the solar photovoltaic assembly is connected to the second input end of the first voltage boosting module; the first output end of the rectifier module is connected to the first input end of the second voltage boosting module after alternating current mains passes through the second switch module and the rectifier module; the first output end of the second voltage boosting module is connected to the positive pole of the bus capacitor unit; the second output end of the second voltage boosting module is connected to the negative pole of the bus capacitor unit; the second output end of the rectifier module is connected to the first input end of the second voltage boosting module on one hand and to the negative pole of the bus capacitor unit and to the ground on the other hand.

[0008] In some embodiments, the first voltage boosting module comprises: a first inductor module, a first diode module and a first switch tube module; wherein the photovoltaic voltage output by the solar photovoltaic assembly is converted into a first voltage boosting voltage after passing through the first switch module and the first inductor module; the first voltage boosting voltage is input into the collector of the first switch tube module in the first voltage boosting module and also input into the anode of the first diode module; a second voltage boosting voltage, i.e., a photovoltaic voltage boosting voltage, is obtained after passing through the first diode module; the photovoltaic voltage boosting voltage is output from the cathode of the first diode module to the second voltage boosting module, and is output to the positive pole of the bus capacitor unit after being boosted again by the second voltage boosting module, thereby obtaining a direct current bus voltage of the hybrid power supply system.

[0009] In some embodiments, the second voltage boosting module comprises a second inductor module, a second diode module and a second switch tube module; wherein, when the second switch module is closed, the AC mains, after passing through the second switch module and the rectifier module, outputs a rectified voltage; when there is the photovoltaic voltage boosted by the first voltage boosting module, the rectified voltage and the photovoltaic voltage boosted by the first voltage boosting module, after passing through the second inductor module, are input to the collector of the second switch tube module in the second voltage boosting module and to the anode of the second diode module; after passing through the second diode module, the cathode of the second diode module outputs a DC bus voltage of the hybrid power supply system to the positive electrode of the bus capacitor unit; when there is no photovoltaic voltage boosted by the first voltage boosting module, the rectified voltage, after passing through the second inductor module, is input to the collector of the second switch tube module in the second voltage boosting module and to the anode of the second diode module; after passing through the second diode module, the cathode of the second diode module outputs a DC bus voltage of the hybrid power supply system to the positive electrode of the bus capacitor unit; when the second switch module is closed, when there is the photovoltaic voltage boosted by the first voltage boosting module, the photovoltaic voltage boosted by the first voltage boosting module, after passing through the second inductor module, is input to the collector of the second switch tube module in the second voltage boosting module and to the anode of the second diode module; after passing through the second diode module, the cathode of the second diode module outputs a DC bus voltage of the hybrid power supply system to the positive electrode of the bus capacitor unit.

[0010] In another aspect, the present application provides an air conditioner, which comprises the hybrid power supply system described above.

[0011] With the above air conditioner, the present application further provides a control method of a hybrid power supply system of an air conditioner, comprising: in the case that the hybrid power supply system of the air conditioner is started, controlling the second switch module to be closed to start the AC mains power supply; acquiring the photovoltaic voltage output by the solar photovoltaic assembly; determining whether the photovoltaic voltage output by the solar photovoltaic assembly is greater than a set voltage threshold; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold, controlling the first switch module to be closed to start the solar photovoltaic power supply; controlling at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module to boost the photovoltaic voltage output by the solar photovoltaic assembly to a first boost voltage; at the same time, controlling at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module to boost the rectified voltage output by the rectifier module and the second boost voltage output by the second boost module based on the first boost voltage to the DC bus voltage of the hybrid power supply system to supply the power consumption load of the air conditioner; at this time, the hybrid power supply system works in the working state of being commonly supplied by the AC mains power supply and the solar photovoltaic power supply; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold, maintaining the second switch module to be closed and maintaining the first switch module to be disconnected, and controlling at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module to boost the rectified voltage output by the rectifier module to the DC bus voltage of the hybrid power supply system to supply the power consumption load of the air conditioner; at this time, the hybrid power supply system works in the working state of being supplied only by the AC mains power supply.

[0012] In some embodiments, further comprising: determining the load demand power of the air conditioner after the hybrid power supply system of the air conditioner is started; controlling at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module by using the MPPT algorithm, so that the solar photovoltaic assembly outputs the set maximum power point output power; determining the maximum power that the solar photovoltaic assembly can output, denoted as photovoltaic power, when the solar photovoltaic assembly outputs the maximum power point output power; determining whether the photovoltaic power of the solar photovoltaic assembly is greater than the set power threshold; if it is determined that the photovoltaic power of the solar photovoltaic assembly is less than or equal to the power threshold, controlling the first switch module to be disconnected when the first switch module is closed, so as to control at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module, so that the rectification voltage output by the rectification module is boosted to the DC bus voltage of the hybrid power supply system to supply the power load of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered only by the alternating mains power supply; if it is determined that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, controlling the operation process of the hybrid power supply system according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the alternating mains power supply and the solar photovoltaic power supply.

[0013] In some embodiments, when the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, the operation process of the hybrid power supply system is controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, including: determining whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, then after the second switch tube module in the second boost module stops working in the case that the second switch tube module in the second boost module works, the second switch module is controlled to be opened, so that the second boosted voltage of the first boost module is supplied to the DC bus voltage of the hybrid power supply system, and the second boosted voltage is supplied to the power load of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the solar photovoltaic power supply alone; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, then the first switch module is maintained to be closed, and the second switch module is maintained to be closed, the power supply of the AC power supply is determined, and at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module and the second switch tube module in the second boost module is controlled to be coordinated, so that the sum of the photovoltaic power of the solar photovoltaic assembly and the power supply of the AC power supply is greater than or equal to the load demand power of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the AC power supply and the solar photovoltaic power supply.

[0014] In some embodiments, further comprising: determining the load demand power of the air conditioner after the hybrid power supply system of the air conditioner is started; using the MPPT algorithm, controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module, so that the solar photovoltaic assembly outputs the set maximum power point output power; determining the maximum power that the solar photovoltaic assembly can output, denoted as photovoltaic power, when the solar photovoltaic assembly outputs the maximum power point output power; determining whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner when the solar photovoltaic assembly outputs the maximum power point output power; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, then when the first switching module and the second switching module are both turned on, controlling the second switching module to be turned off, and at the same time, controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module, so that the first boost module outputs a second boost voltage based on the photovoltaic voltage of the solar photovoltaic assembly, and controlling at least one of the switching frequency and the duty cycle of the second switching tube module in the second boost module, so that the second boost module boosts the second boost voltage output by the first boost voltage to the DC bus voltage of the hybrid power supply system, to supply the electrical load of the air conditioner; at this time, the hybrid power supply system works in a working state powered by the solar photovoltaic power supply alone; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, then further controlling the operation process of the hybrid power supply system according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner.

[0015] In some embodiments, in the case that the solar photovoltaic assembly outputs the maximum power at the maximum power point, and the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, the operation process of the hybrid power supply system is further controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, including: controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module, so that the first boost module outputs a second boost voltage based on the boost voltage of the photovoltaic voltage of the solar photovoltaic assembly, which is greater than the rectified voltage output by the rectifier module, and then controls the second switching module to be closed in the case that the second switching module is opened; controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module, so that the first boost module outputs a second boost voltage based on the boost voltage of the photovoltaic voltage of the solar photovoltaic assembly, which can increase the rectified current output by the rectifier module in a set manner, and determine the mains power of the AC mains power supply; coordinating and controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module and the second switching tube module in the second boost module, so that the sum of the photovoltaic power of the solar photovoltaic assembly and the mains power of the AC mains power supply is greater than or equal to the load demand power of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the AC mains power supply and the solar photovoltaic power supply.

[0016] In some embodiments, further comprising: determining the load demand power of the air conditioner after the hybrid power supply system of the air conditioner is started; obtaining the photovoltaic voltage output by the solar photovoltaic assembly; determining whether the photovoltaic voltage output by the solar photovoltaic assembly is greater than a set voltage threshold; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold, controlling the first switching module to be closed in the case that the first switching module is opened, and controlling at least one of the switching frequency and the duty cycle of the first switching tube module in the first boost module, so that the photovoltaic voltage output by the solar photovoltaic assembly is boosted to a first boost voltage, so that the second boost voltage output by the first boost module based on the first boost voltage is greater than or equal to the rectified voltage output by the rectifier module; at this time, the hybrid power supply system works in the working state of being powered by the AC mains power supply and the solar photovoltaic power supply; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold, controlling at least one of the switching frequency and the duty cycle of the second switching tube module in the second boost module, so that the rectified voltage output by the rectifier module is boosted to the DC bus voltage of the hybrid power supply system, which is supplied to the electrical load of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the AC mains power supply alone.

[0017] Thus, the scheme of the present application, for the first Boost circuit of the solar photovoltaic power supply and the second Boost circuit of the AC power supply, the first Boost circuit connected to the solar photovoltaic power supply is connected to the rectifier bridge of the AC power supply and before the second Boost circuit, to connect the first Boost circuit and the second Boost circuit in series, forming a two-stage Boost circuit of the photovoltaic power supply, when only the solar photovoltaic power supply is powered, the first Boost circuit first boosts the lower solar photovoltaic voltage VDC1 to a suitable voltage VDC2, and then the voltage VDC2 is boosted to the DC bus voltage VDC4 through the second Boost circuit; when the solar photovoltaic power supply and the AC power supply are powered at the same time, the first Boost circuit boosts the solar photovoltaic voltage VDC1 to the voltage VDC2, and the voltage VDC2 needs to be equal to the voltage VDC3 after the AC power rectification, and the second Boost circuit boosts the voltage VDC3 to the DC bus voltage VDC4; thereby, by connecting the boost circuit of the solar photovoltaic power supply and the boost circuit of the power supply system in series, a two-stage boost circuit of the solar photovoltaic power supply is formed, which can at least improve the utilization rate of the boost circuit of the AC power supply. At the same time, it is also beneficial to reduce the boost ratio of the boost circuit of the solar photovoltaic power supply and save costs.

[0018] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application.

[0019] The technical solutions of the present application will be further described in detail below by means of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structure schematic diagram of an embodiment of the hybrid power supply system of the present application;

[0021] Figure 2 The topological structure schematic diagram of an embodiment of the AC and photovoltaic hybrid power supply circuit proposed by the present application;

[0022] Figure 3 The hybrid power supply startup working process schematic diagram of an embodiment of the AC and photovoltaic hybrid power supply circuit proposed by the present application;

[0023] Figure 4 The hybrid power supply running working process schematic diagram of an embodiment of the AC and photovoltaic hybrid power supply circuit proposed by the present application;

[0024] Figure 5Flowchart of an embodiment of a control method for the hybrid power supply system of the air conditioner of the present application;

[0025] Figure 6 Flowchart of an embodiment of a first process of running the hybrid power supply system of the air conditioner after starting in the method of the present application;

[0026] Figure 7 Flowchart of an embodiment of a process of controlling power supply according to photovoltaic power and load demand power in the method of the present application when photovoltaic power is greater than a power threshold;

[0027] Figure 8 Flowchart of an embodiment of a second process of running the hybrid power supply system of the air conditioner after starting in the method of the present application;

[0028] Figure 9 Flowchart of an embodiment of a process of controlling power supply according to photovoltaic power and load demand power in the method of the present application when the maximum power point output power of the solar photovoltaic assembly and the photovoltaic power is less than or equal to the load demand power;

[0029] Figure 10 Flowchart of an embodiment of a third process of running the hybrid power supply system of the air conditioner after starting in the method of the present application. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in connection with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0031] It is considered that, in the related scheme of the hybrid power supply air conditioner technology of the mains and photovoltaic, the photovoltaic power generation grid-connected system is directly incorporated into the direct current side of the mature air conditioner power supply system, and the hybrid power supply system is composed of the mains. However, since the mains and the solar photovoltaic power source have their own separate boost circuits, in the scene where the solar power supply energy is sufficient and the air conditioner only needs solar power supply and does not need alternating current mains power supply, the boost circuit of the alternating current mains power supply is idle and does not work, at least there is a problem of low utilization rate of the boost circuit of the alternating current mains power supply.

[0032] Moreover, the solar photovoltaic power supply is limited by the number of photovoltaic components, connection mode, sunlight intensity and other factors, and the voltage range of the solar photovoltaic power supply output fluctuates greatly, and the minimum may be below 50V. The boost ratio is large when boosting from 50V to the voltage required to drive the air conditioner compressor (generally about 380V), and the inductance of the boost circuit needs to be large inductance, and the duty cycle of the switch tube will also be large, which will increase the conduction power consumption, affecting the cost and reliability.

[0033] Therefore, the scheme of the present application provides a hybrid power supply system, in particular a hybrid power supply circuit of a hybrid power supply system applied to solar air conditioners and variable frequency air conditioners, which can at least improve the utilization rate of the boost circuit of the alternating current mains power supply.

[0034] According to an embodiment of the present application, a hybrid power supply system is provided. Referring to Figure 1 The hybrid power supply system can include a solar photovoltaic power supply, an alternating current mains power supply and a bus capacitor unit such as a bus capacitor C. The solar photovoltaic power supply includes a solar photovoltaic component, a first switch module such as a switch K1 and a first boost module such as a first Boost boost circuit, and the boost ratio of the first boost module can be less than a set boost ratio. The alternating current mains power supply includes a rectifier module, a second switch module such as a switch K2 and a second boost module such as a second Boost boost circuit.

[0035] The photovoltaic positive electrode of the solar photovoltaic component is connected to the first input end of the first boost module after passing through the first switch module. The output end of the first boost module is connected to the first input end of the second boost module to make the first boost module and the second boost module in series to form a two-stage boost module of the solar photovoltaic power supply. The photovoltaic negative electrode of the solar photovoltaic component is connected to the second input end of the first boost module.

[0036] The alternating current mains is connected to the first input end of the second boost module after passing through the second switch module and the rectifier module. The first output end of the rectifier module is connected to the first input end of the second boost module. The first output end of the second boost module is connected to the positive electrode of the bus capacitor unit, and the second output end of the second boost module is connected to the negative electrode of the bus capacitor unit and grounded. The second output end of the rectifier module is connected to the first input end of the second boost module on one hand, and to the negative electrode of the bus capacitor unit and grounded on the other hand.

[0037] For the hybrid power supply air conditioning system of the mains and solar power, in the scene that only needs solar power supply and does not need alternating current mains power supply, the boost circuit of the alternating current mains power supply is idle, so that the utilization rate of the boost circuit of the alternating current mains power supply is not high. The scheme of the present application provides a hybrid power supply system, in particular, a hybrid power supply circuit of a hybrid power supply system applied to a solar air conditioner and a variable frequency air conditioner. The two-stage boost circuit of the solar photovoltaic power supply is formed by connecting the boost circuit (such as the first boost circuit) of the solar photovoltaic power supply and the boost circuit (such as the second boost circuit) of the mains power supply in series, so as to at least solve the problem that in the hybrid power supply scheme of the mains and the solar photovoltaic power supply, the photovoltaic power generation grid-connected system is directly connected to the DC side of the mains power supply system to form a hybrid power supply system with the mains. In the scene that does not need alternating current mains power supply, the boost circuit of the alternating current mains power supply is idle and does not work, and the utilization rate of the boost circuit of the alternating current mains power supply is not high.

[0038] At the same time, before the boost circuit (such as the first boost circuit) of the solar photovoltaic power supply is connected in series with the boost circuit (such as the second boost circuit) of the mains power supply, when the output voltage of the solar photovoltaic power supply is low, the boost ratio of the boost circuit of the solar photovoltaic power supply needs to be set high, and there is a problem that the boost circuit of the solar photovoltaic power supply needs a large inductance and the switching tube has a large conduction power consumption. In the scheme of the present application, the boost circuit (such as the first boost circuit) of the solar photovoltaic power supply is connected in series with the boost circuit (such as the second boost circuit) of the mains power supply, so as to form a two-stage boost circuit of the solar photovoltaic power supply, so that the boost ratio of the boost circuit of the solar photovoltaic power supply does not need to be large, thereby reducing the cost and improving the reliability of the boost circuit of the solar photovoltaic power supply.

[0039] In some embodiments, the first boost module comprises a first inductor module, a first diode module and a first switching tube module, the first inductor module is an inductor L1, the first diode module is a diode D1, and the first switching tube module is a switching tube Q1.

[0040] The photovoltaic voltage (such as voltage VDC1) output by the solar photovoltaic assembly is input into the collector of the first switch tube module in the first boost module and also input into the anode of the first diode module. After the first diode module, a second boost voltage is obtained, which is denoted as a photovoltaic boost voltage. The photovoltaic boost voltage is output from the cathode of the first diode module to the second boost module, and after being boosted again by the second boost module, is output to the positive electrode of the bus capacitor unit, thereby obtaining the DC bus voltage (such as voltage VDC4) of the hybrid power supply system.

[0041] In some embodiments, the second boost module comprises a second inductor module, a second diode module and a second switch tube module, such as inductor L2, diode D2 and switch tube Q2.

[0042] In the case where the second switch module is closed, the AC mains is input into the second switch module and the rectifier module, and a rectified voltage (such as voltage VDC3) is output.

[0043] In the case where the photovoltaic boost voltage is obtained by the first boost module, the rectified voltage and the photovoltaic boost voltage obtained by the first boost module are input into the collector of the second switch tube module in the second boost module and also input into the anode of the second diode module. After the second diode module, the photovoltaic boost voltage is output from the cathode of the second diode module to the positive electrode of the bus capacitor unit, thereby obtaining the DC bus voltage (such as voltage VDC4) of the hybrid power supply system.

[0044] In the case where the photovoltaic boost voltage is not obtained by the first boost module, the rectified voltage is input into the collector of the second switch tube module in the second boost module and also input into the anode of the second diode module. After the second diode module, the photovoltaic boost voltage is output from the cathode of the second diode module to the positive electrode of the bus capacitor unit, thereby obtaining the DC bus voltage (such as voltage VDC4) of the hybrid power supply system.

[0045] When the second switch module is off, and with the photovoltaic boost voltage obtained from the first boost module present, the photovoltaic boost voltage obtained from the first boost module, after passing through the second inductor module, is input to the collector of the second switch module in the second boost module, and also to the anode of the second diode module. After passing through the second diode module, it is output from the cathode of the second diode module to the positive terminal of the bus capacitor unit, thus obtaining the DC bus voltage (e.g., voltage VDC4) of the hybrid power supply system.

[0046] Figure 2 This is a schematic diagram of the topology of an embodiment of the AC and photovoltaic hybrid power supply circuit proposed in this invention. Figure 2 As shown, the AC / PV hybrid power supply circuit includes: a solar photovoltaic power source, an AC mains power source, and a bus capacitor C. The DC bus voltage VDC4 output from the bus capacitor C powers the motor in the compressor via an inverter.

[0047] The solar photovoltaic power supply includes: a solar photovoltaic module, a switch K1, and a first boost converter circuit. The first boost converter circuit includes: an inductor L1, a switch Q1, and a diode D1. The AC mains power supply includes: a switch K2, a rectifier bridge, and a second boost converter circuit. The second boost converter circuit includes: an inductor L2, a switch Q2, and a diode D2. The solar photovoltaic module and the AC mains power supply are external power sources.

[0048] exist Figure 2 In the example shown, the solar photovoltaic (PV) module supplies power to the air conditioner. The PV voltage output by the solar PV module is VDC1. This PV voltage first passes through switch K1, which can be a DC contactor, DC relay, etc. The other end of switch K1 (i.e., the end of switch K1 furthest from the solar PV module) is connected to the first Boost converter circuit. The first Boost converter circuit includes inductor L1, diode D1, and switching transistor Q1. The function of the first Boost converter circuit is to boost the PV voltage VDC1 to voltage VDC2, while simultaneously executing the maximum power point tracking (MPPT) algorithm.

[0049] The AC mains power supplies the air conditioner. The AC mains power first passes through switch K2, which can be an AC contactor, AC relay, etc. The other end of switch K2 (the end furthest from the AC mains power) is connected to the rectifier bridge. The rectifier bridge outputs DC power, with a voltage of VDC3. The other end of the rectifier bridge (the end furthest from switch K2) is connected to the second boost converter circuit. The second boost converter circuit includes inductor L2, diode D2, and switching transistor Q2. The function of the second boost converter circuit is to boost the rectified voltage VDC3 output from the rectifier bridge to the DC bus voltage VDC4. The DC bus uses the DC bus voltage VDC4 to power the internal load of the air conditioner, such as the motor in the compressor. A large-value capacitor (DC bus capacitor C) is connected between the positive and negative terminals of the DC bus. The DC bus capacitor C serves to store energy, stabilize voltage, and filter. The cathode of diode D1 in the first boost converter circuit is connected to the positive terminal ("+") of the rectifier bridge output.

[0050] Thus, see Figure 2 The example shown connects the first and second boost circuits in series to form a two-stage boost circuit for the solar photovoltaic power supply. Specifically, the first boost circuit connected to the solar photovoltaic power supply is connected after the rectifier bridge of the AC mains power supply and before the second boost circuit, thus forming a two-stage boost topology for the solar photovoltaic power supply.

[0051] When only solar photovoltaic power is supplied, the first boost circuit first boosts the lower solar photovoltaic voltage VDC1 to a suitable voltage VDC2 (e.g., 200VDC), and then the second boost circuit boosts VDC2 to the DC bus voltage VDC4 (typically 380VDC). In this operating state, the boost factor (or boost ratio) of both the first and second boost circuits is lower than the boost factor when only the first boost circuit is used to boost the solar photovoltaic voltage VDC1 to the DC bus voltage VDC4, thereby improving the reliability of the hybrid power supply circuit.

[0052] When both solar photovoltaic (PV) power and AC mains power are supplied simultaneously, the first boost circuit boosts the solar PV voltage VDC1 to VDC2. VDC2, after passing through diode D1, must equal the rectified AC mains voltage VDC3 (typically 260VDC~320VDC). The second boost circuit then boosts VDC3 to the DC bus voltage VDC4. In this operating state, the boost factor of the first boost circuit is lower than that of using only the first boost circuit to boost the PV voltage VDC1 to the DC bus voltage VDC4, thus improving the reliability of the hybrid power supply circuit.

[0053] According to the technical scheme, the first Boost circuit of the solar photovoltaic power supply and the second Boost circuit of the AC power supply are connected in series, the first Boost circuit of the solar photovoltaic power supply is connected to the rectifier bridge of the AC power supply and before the second Boost circuit, and a two-stage Boost circuit of the photovoltaic power supply is formed. When only the solar photovoltaic power supply is used for power supply, the first Boost circuit first boosts the lower solar photovoltaic voltage VDC1 to a suitable voltage VDC2, and then the second Boost circuit boosts the voltage VDC2 to the DC bus voltage VDC4. When the solar photovoltaic power supply and the AC power supply are used for power supply at the same time, the first Boost circuit boosts the solar photovoltaic voltage VDC1 to the voltage VDC2, the voltage VDC2 after passing through the diode D1 needs to be equal to the voltage VDC3 after the AC power supply is rectified, and the second Boost circuit boosts the voltage VDC3 to the DC bus voltage VDC4. Therefore, by connecting the Boost circuit of the solar photovoltaic power supply and the Boost circuit of the power supply system in series, a two-stage Boost circuit of the solar photovoltaic power supply is formed, and the utilization rate of the Boost circuit of the AC power supply can be improved. At the same time, it is also beneficial to reduce the Boost ratio of the Boost circuit of the solar photovoltaic power supply and save costs.

[0054] According to the embodiment of the present application, an air conditioner corresponding to the hybrid power supply system is also provided. The air conditioner can include the hybrid power supply system described above.

[0055] Since the processing and functions realized by the air conditioner of the present embodiment are basically corresponding to the embodiments, principles and examples of the system, the description of the present embodiment will not be described in detail, and the related description in the foregoing embodiments can be referred to, which will not be described herein.

[0056] According to the technical scheme, the first Boost voltage increasing circuit of the solar photovoltaic power supply and the second Boost voltage increasing circuit of the AC mains power supply are connected in series, the first Boost voltage increasing circuit connected to the solar photovoltaic power supply is connected after a rectifier bridge of the AC mains power supply and before the second Boost voltage increasing circuit, and a two-stage voltage increasing circuit of the photovoltaic power supply is formed, when only the solar photovoltaic power supply supplies power, the first Boost voltage increasing circuit first increases the lower solar photovoltaic voltage VDC1 to a proper voltage VDC2, and then the second Boost voltage increasing circuit increases the voltage VDC2 to a DC bus voltage VDC4, when the solar photovoltaic power supply and the AC mains power supply supply power simultaneously, the first Boost voltage increasing circuit increases the solar photovoltaic voltage VDC1 to the voltage VDC2, the voltage VDC2 after passing through a diode D1 needs to be equal to a voltage VDC3 of the AC mains after rectification, and the second Boost voltage increasing circuit increases the voltage VDC3 to the DC bus voltage VDC4, the first Boost voltage increasing circuit can reduce the voltage increasing multiple of the photovoltaic voltage, and the use rate of the second Boost voltage increasing circuit is improved, and the reliability of the hybrid power supply circuit is improved.

[0057] According to the embodiment of the application, a control method of a hybrid power supply system of an air conditioner corresponding to the air conditioner is also provided, as shown in the flowchart of an embodiment of the method of the application. Figure 5 The control method of the hybrid power supply system of the air conditioner can include the process of controlling the starting of the hybrid power supply system of the air conditioner, and specifically can include steps S110 to S150.

[0058] In step S110, when the hybrid power supply system of the air conditioner starts, the second switch module is controlled to be closed to start the AC mains power supply.

[0059] In step S120, the photovoltaic voltage (such as voltage VDC1) output by the solar photovoltaic module is acquired.

[0060] In step S130, it is determined whether the photovoltaic voltage output by the solar photovoltaic module is greater than a set voltage threshold (such as voltage threshold Vst).

[0061] At step S140, if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold, the first switch module is controlled to be closed to start the solar photovoltaic power supply. At least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled to boost the photovoltaic voltage output by the solar photovoltaic assembly to a first boost voltage, where the first boost voltage is greater than the photovoltaic voltage output by the solar photovoltaic assembly and less than the DC bus voltage of the hybrid power supply system. At the same time, at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled to boost the rectified voltage output by the rectifier module and the second boost voltage output by the second boost module based on the first boost voltage to the DC bus voltage of the hybrid power supply system, to supply the electrical load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system operates in a working state powered by the AC mains power supply and the solar photovoltaic power supply.

[0062] At step S150, if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold, the second switch module is maintained closed and the first switch module is maintained open, and at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled to boost the rectified voltage output by the rectifier module to the DC bus voltage of the hybrid power supply system, to supply the electrical load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system operates in a working state powered only by the AC mains power supply.

[0063] Figure 3 The hybrid power supply starting process of an embodiment of the AC and photovoltaic hybrid power supply circuit is shown in the flowchart. The hybrid power supply control method of the AC and photovoltaic hybrid power supply circuit will be described below with reference to the examples shown in Figure 2 and Figure 3 The AC and photovoltaic hybrid power supply circuit shown in Figure 3 and Figure 2 The hybrid power supply control method when starting the AC and photovoltaic hybrid power supply circuit includes:

[0064] Step 11, when starting, the switch K2 is closed, and the output voltage VDC1 of the solar photovoltaic assembly is detected by the voltage detection circuit and recorded as the photovoltaic voltage VDC1.

[0065] Step 12, determine whether the photovoltaic voltage VDC1 is greater than the set voltage threshold Vst: if yes, execute step 13, if no, execute step 14.

[0066] Step 13, when photovoltaic voltage VDC1 > set voltage threshold Vst, the solar photovoltaic assembly can supply power, and the switch K1 is closed. The solar photovoltaic voltage VDC1 is boosted to the voltage VDC2 by controlling the switching frequency and duty cycle of the switch tube Q1. The voltage VDC3 is obtained by subtracting the voltage drop of the diode D1 from the voltage VDC2. The voltage VDC3 should be equal to or higher than the voltage after the AC mains is rectified by the rectifier bridge. The voltage VDC3 is boosted to the DC bus voltage VDC4 by controlling the switching frequency and duty cycle of the switch tube Q2.

[0067] Step 14, when photovoltaic voltage VDC1 < set voltage threshold Vst, the solar photovoltaic assembly cannot supply power, and the switch K1 is opened. The rectified voltage VDC3 is obtained by rectifying the AC mains by the rectifier bridge. The rectified voltage VDC3 supplies power to the DC bus through the second Boost circuit, and the DC bus voltage VDC4 of the hybrid power supply system is obtained. The DC bus voltage VDC4 is output by controlling the switching frequency and duty cycle of the switch tube Q2.

[0068] In some embodiments, the control method of the hybrid power supply system of the air conditioner according to the scheme of the present application further comprises: controlling the first process of the hybrid power supply system of the air conditioner after starting to run, specifically the process of controlling whether to switch states in state 1.

[0069] The following will be described in detail with reference to the accompanying drawings. Figure 6 An embodiment flowchart of the method of the present application for controlling the first process of the hybrid power supply system of the air conditioner after starting to run is shown in the accompanying drawings, and the specific process of controlling the first process of the hybrid power supply system of the air conditioner after starting to run is further described, which includes steps S210 to S250.

[0070] Step S210, after the hybrid power supply system of the air conditioner is started, the load demand power of the air conditioner is determined. For example, according to the target frequency of the compressor in the air conditioner, the power Pout required by the air conditioner is calculated, which is recorded as the load demand power Pout.

[0071] Step S220, using the MPPT algorithm, control at least one of the switching frequency and duty cycle of the first switch tube module in the first boost module, so that the solar photovoltaic assembly outputs at the set maximum power point output power. In the case of the solar photovoltaic assembly at the maximum power point output power, the maximum power that the solar photovoltaic assembly can output is determined, denoted as photovoltaic power (such as power Pdc). Specifically, determining the maximum power that the solar photovoltaic assembly can output, denoted as photovoltaic power (such as power Pdc), includes: in the case of the solar photovoltaic assembly at the maximum power point output power, obtaining the photovoltaic voltage (such as voltage VDC1) output by the solar photovoltaic assembly, and obtaining the photovoltaic current (such as current I1) output by the solar photovoltaic assembly. In the case of the solar photovoltaic assembly at the maximum power point output power, according to the photovoltaic voltage output by the solar photovoltaic assembly and the photovoltaic current output by the solar photovoltaic assembly, the maximum power that the solar photovoltaic assembly can output is determined, denoted as photovoltaic power (such as power Pdc).

[0072] Step S230, determine whether the photovoltaic power of the solar photovoltaic assembly is greater than the set power threshold.

[0073] Step S240, if it is determined that the photovoltaic power of the solar photovoltaic assembly is less than or equal to the power threshold, then in the case of the first switch module being closed, the first switch module is controlled to be opened, to control at least one of the switching frequency and duty cycle of the second switch tube module in the second boost module, so that the rectifier voltage output by the rectifier module is boosted to the DC bus voltage of the hybrid power supply system, to supply the electrical load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system works in a working state powered only by the alternating current mains power supply.

[0074] Step S250, if it is determined that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, then according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, control the operation process of the hybrid power supply system. At this time, the hybrid power supply system works in a working state powered by the alternating current mains power supply and the solar photovoltaic power supply.

[0075] Figure 4 The hybrid power supply operation flowchart of an embodiment of the alternating current and photovoltaic hybrid power supply circuit proposed by the present application. In Figure 2 The alternating current and photovoltaic hybrid power supply circuit shown in the figure works, Figure 2The AC and photovoltaic hybrid power supply circuit shown can work in any one of state 1, state 2 and state 3. Among them, state 1 is a state in which the solar photovoltaic power supply and the AC power supply supply power simultaneously. State 2 is a state in which the solar photovoltaic power supply supplies power alone, and the solar photovoltaic power supply supplies power to the DC bus through the first Boost circuit and the second Boost circuit. State 3 is a state in which the AC power supply supplies power alone, and the AC power supply supplies power to the DC bus through the second Boost circuit.

[0076] As shown in Figure 4 As shown in Figure 2 The AC and photovoltaic hybrid power supply circuit shown, the hybrid power supply control method in operation, comprising:

[0077] Step 21, in Figure 2 As shown in the AC and photovoltaic hybrid power supply circuit, in the case that the power load of the air conditioner (such as a variable frequency air conditioner) is calculated according to the target frequency of the compressor in the variable frequency air conditioner, the power required by the air conditioner is recorded as the load demand power Pout.

[0078] Step 22, according to the working state of the switch tube Q1 and the switch tube Q2, it is judged whether the air conditioner runs in state 1 or state 2 or state 3: when the air conditioner runs in state 1 (i.e. the state in which the solar photovoltaic power supply and the AC power supply supply power simultaneously), steps 23 to 28 are entered. When the air conditioner runs in state 2 (i.e. the state in which the solar photovoltaic power supply supplies power alone), steps 29 to 35 are entered. When the air conditioner runs in state 3 (i.e. the state in which the AC power supply supplies power alone), steps 36 to 39 are entered.

[0079] As shown in Figure 4 As shown in Figure 2 The AC and photovoltaic hybrid power supply circuit shown, the hybrid power supply control method in operation, further comprising:

[0080] When the air conditioner runs in state 1 (i.e. the state in which the solar photovoltaic power supply and the AC power supply supply power simultaneously), steps 23 to 28 are executed. Step 23, the maximum power point tracking algorithm is used to control the switching frequency and duty cycle of the switch tube Q1, so that the photovoltaic module outputs power at the maximum power point. According to the photovoltaic voltage VDC1 and the current I1 output by the solar photovoltaic module, the maximum power Pdc that the solar photovoltaic module can output is calculated, which is recorded as the photovoltaic power Pdc.

[0081] Step 24, compare the photovoltaic power Pdc with the set power threshold Pst, specifically to judge whether the photovoltaic power Pdc is less than the set power threshold Pst: if yes, execute step 25, if not, execute step 26.

[0082] Step 25, if the photovoltaic power Pdc is less than the set power threshold Pst, it is judged that the output energy of the solar photovoltaic power supply is insufficient, and the solar photovoltaic power supply needs to be turned off. First, the switch tube Q1 is controlled to be not working, then the switch K1 is turned off, and the state 3 (i.e. the state of the AC mains power supply alone) is entered to run. The switching frequency and duty cycle of the switch tube Q2 are controlled, and the rectified voltage VDC3 output by the AC mains after rectification by the rectifier bridge is boosted to the DC bus voltage VDC4.

[0083] Step 26, if the photovoltaic power Pdc is greater than or equal to the set power threshold Pst, the photovoltaic power Pdc is compared with the load demand power Pout.

[0084] In some embodiments, in the case that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold in step S250, the specific process of the operation process of the hybrid power supply system is controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, see the following exemplary description.

[0085] The following Figure 7 An embodiment flowchart of controlling the power supply process according to the photovoltaic power and the load demand power in the case that the photovoltaic power is greater than the power threshold in the method of the present application is shown in the following figure, which further illustrates the specific process of controlling the power supply process according to the photovoltaic power and the load demand power in the case that the photovoltaic power is greater than the power threshold in step S250, including steps S310 to S330.

[0086] Step S310, in the case that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, it is determined whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner.

[0087] Step S320, in the case that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, after the second switch tube module in the second boost module is controlled to stop working, the second switch module is controlled to be turned off, so that the second boost voltage after the boost of the first boost module is used as the DC bus voltage of the hybrid power supply system to supply the electrical load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system works in the working state of being powered by the solar photovoltaic power supply alone.

[0088] Step S330, in the case that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold, if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, the first switch module is maintained to be closed, and the second switch module is maintained to be closed, the power supply of the alternating current commercial power is determined, and at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module and the second switch tube module in the second boost module is coordinated and controlled, so that the sum of the photovoltaic power of the solar photovoltaic assembly and the power supply of the alternating current commercial power is greater than or equal to the load demand power of the air conditioner. At this time, the hybrid power supply system works in the working state of being powered by the alternating current commercial power supply and the solar photovoltaic power supply.

[0089] As shown in Figure 4 As shown in Figure 2 The alternating current and photovoltaic hybrid power supply circuit shown in the figure, the hybrid power supply control method in operation, further comprises:

[0090] In step 26, specifically, it is judged whether the photovoltaic power Pdc is greater than the load demand power Pout: if yes, step 27 is executed, otherwise step 28 is executed.

[0091] Step 27, if the photovoltaic power Pdc is greater than the load demand power, only the solar photovoltaic power supply is needed, and the alternating current commercial power supply is not needed, first control the switch tube Q2 to be inoperative, then disconnect the switch K2, and turn to state 2 (i.e. the state of the solar photovoltaic power supply alone).

[0092] Step 28, if the photovoltaic power Pdc is less than or equal to the load demand power, state 1 is maintained (i.e. the state of the solar photovoltaic power supply and the alternating current commercial power supply at the same time). According to the rectified voltage VDC3 output by the alternating current commercial power after the rectifier bridge and the current I2 output by the alternating current commercial power after the rectifier bridge, the power Pac output by the alternating current commercial power supply is calculated, which is recorded as the commercial power Pac. By coordinating and controlling the switching frequency and the duty cycle of the switch tube Q1 and the switch tube Q2, the photovoltaic power Pdc plus the commercial power Pac is equal to or greater than the load demand power Pout.

[0093] In some embodiments, the control method of the hybrid power supply system of the air conditioner according to the scheme of the present application further comprises: a second process of controlling the hybrid power supply system of the air conditioner to run after starting, specifically a process of controlling whether to switch states in state 2.

[0094] The following will be combined Figure 8 The embodiment flowchart of the second process of controlling the hybrid power supply system of the air conditioner to run after starting in the method of the present application shown in the figure will be further described to illustrate the specific process of controlling the hybrid power supply system of the air conditioner to run after starting, including steps S410 to S450.

[0095] Step S410, determining the load demand power of the air conditioner after the hybrid power supply system of the air conditioner is started. For example, according to the target frequency of the compressor in the air conditioner, the power Pout required by the air conditioner is calculated, which is recorded as the load demand power Pout.

[0096] Step S420, using the MPPT algorithm, controlling at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module, so that the solar photovoltaic assembly outputs the set maximum power point output power. In the case that the solar photovoltaic assembly outputs the maximum power point output power, the maximum power that the solar photovoltaic assembly can output is determined, which is recorded as the photovoltaic power (such as the power Pdc). Specifically, the maximum power that the solar photovoltaic assembly can output is determined, which is recorded as the photovoltaic power (such as the power Pdc), including: in the case that the solar photovoltaic assembly outputs the maximum power point output power, the photovoltaic voltage (such as the voltage VDC1) output by the solar photovoltaic assembly is obtained, and the photovoltaic current (such as the current I1) output by the solar photovoltaic assembly is obtained. In the case that the solar photovoltaic assembly outputs the maximum power point output power, according to the photovoltaic voltage output by the solar photovoltaic assembly and the photovoltaic current output by the solar photovoltaic assembly, the maximum power that the solar photovoltaic assembly can output is determined, which is recorded as the photovoltaic power (such as the power Pdc).

[0097] Step S430, in the case that the solar photovoltaic assembly outputs the maximum power point output power, determining whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner.

[0098] Step S440, in the case that the solar photovoltaic assembly outputs the maximum power point output power, if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, in the case that the first switch module and the second switch module are both turned on, the second switch module is controlled to be turned off, at the same time, at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled, so that the first boost module outputs a second boost voltage based on the photovoltaic voltage of the solar photovoltaic assembly, and at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled, so that the second boost module boosts the second boost voltage output based on the first boost voltage to the DC bus voltage of the hybrid power supply system, to supply the power load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system works in the working state of being powered by the solar photovoltaic power supply alone. In this case, the second boost voltage, such as VDC3 based on VDC2, is between the photovoltaic voltage VDC1 and the DC bus voltage VDC4.

[0099] Step S450, if the photovoltaic frequency of the solar photovoltaic assembly is determined to be less than or equal to the load demand power of the air conditioner, the operation process of the hybrid power supply system is further controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, when the solar photovoltaic assembly outputs power at the maximum power point.

[0100] As shown in Figure 4 As shown in Figure 2 The hybrid power supply circuit and the hybrid power supply control method in operation shown in the alternating current and photovoltaic hybrid power supply circuit further comprise:

[0101] When the air conditioner operates in state 2 (i.e. the state of solar photovoltaic power supply alone), steps 29 to 35 are executed. Step 29, the switching frequency and duty cycle of the switching tube Q1 are controlled by using the maximum power point tracking algorithm, so that the solar photovoltaic assembly outputs power at the maximum power point. The maximum power Pdc that can be output by the photovoltaic assembly is calculated according to the photovoltaic voltage VDC1 and the current I1 output by the solar photovoltaic assembly, and is recorded as the photovoltaic power Pdc.

[0102] Step 30, compare the photovoltaic power Pdc with the load demand power Pout, specifically, determine whether the photovoltaic power Pdc is greater than the load demand power Pout: if yes, execute step 31, if no, execute step 33.

[0103] Step 31, if the photovoltaic power Pdc is greater than the load demand power Pout, the switch K2 is opened, and state 2 is maintained. The photovoltaic voltage VDC1 is boosted to the voltage VDC3 by controlling the switching frequency and duty cycle of the switching tube Q1. In the operating state 2, the voltage VDC3 is a value between the photovoltaic voltage VDC1 and the direct current bus voltage VDC4, which is set by the control logic. For example, when the photovoltaic voltage VDC1 is 50VDC and the direct current bus voltage VDC4 is 380VDC, the voltage VDC3 can be set to 150VDC. Or when the photovoltaic voltage VDC1 is 200VDC and the direct current bus voltage VDC4 is 380VDC, the voltage VDC3 can be set to 300VDC, and then step 32 is executed.

[0104] Step 32, the voltage VDC3 is boosted to the direct current bus voltage VDC4 by controlling the switching frequency and duty cycle of the switching tube Q2.

[0105] In some embodiments, in step S450, when the solar photovoltaic module is outputting power at the maximum power point, and the photovoltaic power of the solar photovoltaic module is less than or equal to the load demand power of the air conditioner, the specific process of controlling the operation process of the hybrid power supply system is further controlled according to the photovoltaic power of the solar photovoltaic module and the load demand power of the air conditioner, as described in the following examples.

[0106] The following describes an embodiment of the method of the application shown in Figure 9 The following describes an embodiment of the method of the application shown in

[0107] In step S510, at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled to enable the first boost module to output a second boost voltage based on the boost voltage of the photovoltaic voltage of the solar photovoltaic module, and the rectified current output by the rectifier module can be increased in a set manner to determine the mains power of the AC mains power supply.

[0108] In step S520, at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled to enable the first boost module to output a second boost voltage based on the boost voltage of the photovoltaic voltage of the solar photovoltaic module, and the rectified current output by the rectifier module can be increased in a set manner to determine the mains power of the AC mains power supply.

[0109] In step S530, at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module and the second switch tube module in the second boost module is controlled to enable the sum of the photovoltaic power of the solar photovoltaic module and the mains power of the AC mains power supply to be greater than or equal to the load demand power of the air conditioner. At this time, the hybrid power supply system is operating in a working state in which the AC mains power supply and the solar photovoltaic power supply are jointly supplying power.

[0110] As Figure 4 As Figure 2 The AC and photovoltaic hybrid power supply circuit shown in the hybrid power supply control method further comprises:

[0111] Step 33, when the air conditioner runs in state 2 (i.e. the state of solar photovoltaic power supply alone), compare the photovoltaic power Pdc with the load demand power Pout, specifically to determine whether the photovoltaic power Pdc is greater than the load demand power Pout, after which, if the photovoltaic power Pdc is less than or equal to the load demand power Pout, the solar photovoltaic power supply and the AC mains power supply need to be powered simultaneously. First, control the switching frequency and duty cycle of the switching tube Q1 to make the first Boost voltage VDC3 higher than the AC mains rectified voltage, and then close the switch K2, and then execute step 34.

[0112] For example: the photovoltaic power supply is 100VDC, running in state 2, the first boost module boosts 100VDC to 200VDC, and the second boost module boosts 200VDC to the bus voltage 360VDC. At this time, the switching speed and duty cycle of the switching tube Q2 of the second boost module are suitable for boosting 200VDC to 360VDC. If the switch K2 is closed directly at this time, then the AC mains rectified voltage 308VDC will replace the 200VDC voltage output by the first boost module instantaneously, and the switching speed and duty cycle of the switching tube Q2 will not be adjusted in time, resulting in the loss of control of the second boost module (the output voltage of the second boost module is too high).

[0113] Step 34, control the switching frequency and duty cycle of the switching tube Q1 to make the first Boost voltage VDC2 output a suitable voltage, which can gradually increase the current I2 output by the AC mains power supply, and then execute step 35.

[0114] For example: first, the first boost module boosts the photovoltaic voltage to 310VDC, which is higher than the AC mains rectified voltage 308VDC, and then the switch K2 is closed, the AC mains is powered, but at this time 308VDC is still lower than 310VDC, and the current I2 is still 0. Reduce the switching speed and duty cycle of the switching tube Q1 of the first boost module to make the output voltage of the first boost module drop to 308VDC, and then gradually drop to 300VDC. During this process, the current I2 gradually increases. The purpose of increasing the current I2 is that the current I1 is the current provided by the photovoltaic power supply, and the current I2 is the current provided by the AC mains. Because the photovoltaic power Pdc is less than or equal to the load demand power Pout, the solar photovoltaic power supply and the AC mains power supply need to be powered simultaneously, so increasing I2 is to increase the power Pac provided by the AC mains to the load.

[0115] Step 35, calculate the power Pac output by the AC mains power supply according to the voltage VDC3 and the current I2, and record it as the AC mains power Pac. By coordinating the switching frequency and duty cycle of the switching tube Q1 and the switching tube Q2, the photovoltaic power Pdc plus Pac is equal to or greater than the load demand power Pout, at which time it runs in state 1.

[0116] In some embodiments, the method for controlling the hybrid power supply system of the air conditioner further comprises: controlling a third process of the hybrid power supply system of the air conditioner after starting, specifically, a process of controlling whether to switch states in state 3.

[0117] The following will be described in detail with reference to the accompanying drawings. Figure 10 The following will be described in detail with reference to the accompanying drawings.

[0118] In step S610, after the hybrid power supply system of the air conditioner is started, the load demand power of the air conditioner is determined. For example, the power Pout required by the air conditioner is calculated according to the target frequency of the compressor in the air conditioner, and is recorded as the load demand power Pout.

[0119] In step S620, the photovoltaic voltage (such as voltage VDC1) output by the solar photovoltaic assembly is obtained.

[0120] It is determined whether the photovoltaic voltage output by the solar photovoltaic assembly is greater than a set voltage threshold (such as voltage threshold Vst).

[0121] In step S630, if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold, the first switch module is controlled to be closed in the case that the first switch module is opened, and at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled, so that the photovoltaic voltage output by the solar photovoltaic assembly is boosted to a first boost voltage, and the second boost voltage output by the first boost module based on the first boost voltage is greater than or equal to the rectified voltage output by the rectifier module. At this time, the hybrid power supply system works in a working state of being commonly powered by the alternating current mains power supply and the solar photovoltaic power supply.

[0122] In step S640, if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold, at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled, so that the rectified voltage output by the rectifier module is boosted to the DC bus voltage of the hybrid power supply system, and is supplied to the power load (such as the motor in the compressor) of the air conditioner. At this time, the hybrid power supply system works in a working state of being powered by the alternating current mains power supply alone.

[0123] As shown in the above, Figure 4 As shown in the above, Figure 2 The hybrid power supply circuit of alternating current and photovoltaic power supply, the hybrid power supply control method in operation, comprises:

[0124] When the air conditioner operates in state 3 (i.e. the state of AC power supply alone), steps 36 to 39 are executed.

[0125] Step 36, the output voltage VDC1 of the solar photovoltaic assembly is detected by the voltage detection circuit, recorded as the photovoltaic voltage VDC1.

[0126] Step 37, whether the photovoltaic voltage VDC1 is greater than the set voltage threshold Vst is compared: if yes, step 38 is executed, otherwise step 39 is executed.

[0127] Step 38, if the photovoltaic voltage VDC1 > the set voltage threshold Vst, the solar photovoltaic power supply can supply power, the switch K1 is closed, the switching frequency and duty cycle of the switch tube Q1 are controlled, the photovoltaic voltage VDC1 is boosted to the voltage VDC2, and the voltage VDC2 minus the voltage drop of the diode D1 is equal to or greater than the voltage VDC3, at this time state 1 is entered for operation.

[0128] Step 39, when the photovoltaic voltage VDC1 ≤ the set voltage threshold Vst, state 3 is maintained, the switching frequency and duty cycle of the switch tube Q2 are controlled, and the voltage VDC3 is boosted to the DC bus voltage VDC4.

[0129] The scheme of the present application connects the diode D1 of the first Boost circuit to the rectifier bridge and before the inductor L2 of the second Boost circuit, forming a series connection with the second Boost circuit. Instead of connecting the diode D1 of the first Boost circuit to the DC bus and forming a parallel connection with the second Boost circuit. In this way, a series connection is formed between the first Boost circuit and the second Boost circuit, forming a two-stage boost circuit for the solar photovoltaic power supply, which first boosts the photovoltaic power supply VDC1 to VDC3 through the first Boost circuit, and then boosts it to VDC4 through the second Boost circuit, which is a sequential boosting process. This can reduce the boost ratio of the first Boost circuit to the photovoltaic voltage and improve the reliability of the hybrid power supply circuit. Moreover, the second Boost circuit is reused for the DC voltage VDC3 after AC power rectification and the DC voltage VDC2 after photovoltaic power supply boosting, improving the utilization rate of the second Boost circuit.

[0130] Since the method implemented by the present embodiment basically corresponds to the aforementioned air conditioner embodiments, principles and examples, the description of the present embodiment will not be described in detail, and the relevant description in the aforementioned embodiments can be referred to herein.

[0131] According to the technical scheme of the embodiment, the first Boost voltage increasing circuit of the solar photovoltaic power supply and the second Boost voltage increasing circuit of the AC mains power supply are connected in series, the first Boost voltage increasing circuit connected to the solar photovoltaic power supply is connected after the rectifier bridge of the AC mains power supply and before the second Boost voltage increasing circuit, when only the solar photovoltaic power supply is used for power supply, the first Boost voltage increasing circuit first increases the lower solar photovoltaic voltage VDC1 to a proper voltage VDC2, and then the second Boost voltage increasing circuit increases the voltage VDC2 to the DC bus voltage VDC4, when the solar photovoltaic power supply and the AC mains power supply are used for power supply at the same time, the first Boost voltage increasing circuit increases the solar photovoltaic voltage VDC1 to the voltage VDC2, the voltage VDC2 after passing through the diode D1 needs to be equal to the voltage VDC3 after the AC mains power supply is rectified, and the second Boost voltage increasing circuit increases the voltage VDC3 to the DC bus voltage VDC4, thereby reducing the voltage increasing multiple of the first Boost voltage increasing circuit, saving the cost, and improving the reliability of the hybrid power supply circuit.

[0132] In summary, those skilled in the art can easily understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0133] The above only describes the embodiments of the present application and is not used to limit the present application, and those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A hybrid power supply system characterized by comprising: The application relates to a hybrid power supply system of an air conditioner. The hybrid power supply system comprises a solar photovoltaic power supply, an alternating-current commercial power supply and a bus capacitor unit. The solar photovoltaic power supply comprises a solar photovoltaic assembly, a first switch module and a first voltage-boosting module; the alternating-current commercial power supply comprises a rectifier module, a second switch module and a second voltage-boosting module; wherein the photovoltaic positive pole of the solar photovoltaic assembly is connected to the first input end of the first voltage-boosting module through the first switch module; the output end of the first voltage-boosting module is connected to the first input end of the second voltage-boosting module, so that the first voltage-boosting module and the second voltage-boosting module are connected in series to form two-stage voltage-boosting modules of the solar photovoltaic power supply; and the photovoltaic negative pole of the solar photovoltaic assembly is connected to the second input end of the first voltage-boosting module; the first output end of the rectifier module is connected to the first input end of the second voltage-boosting module after the alternating-current commercial power supply passes through the second switch module and the rectifier module; the first output end of the second voltage-boosting module is connected to the positive pole of the bus capacitor unit; the second output end of the second voltage-boosting module is connected to the negative pole of the bus capacitor unit; and the second output end of the rectifier module is connected to the first input end of the second voltage-boosting module on one hand and connected to the negative pole of the bus capacitor unit and grounded on the other hand; The application further relates to a control method of the hybrid power supply system of the air conditioner. In the case that the hybrid power supply system of the air conditioner is started, the second switch module is controlled to be closed to start the alternating-current commercial power supply to supply power; The photovoltaic voltage output by the solar photovoltaic assembly is acquired; It is determined whether the photovoltaic voltage output by the solar photovoltaic assembly is greater than a set voltage threshold value; If it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold value, the first switch module is controlled to be closed to start the solar photovoltaic power supply to supply power; at least one of the switching frequency and the duty cycle of the first switch tube module in the first voltage-boosting module is controlled to make the photovoltaic voltage output by the solar photovoltaic assembly be boosted to a first voltage-boosting voltage; meanwhile, at least one of the switching frequency and the duty cycle of the second switch tube module in the second voltage-boosting module is controlled to make the rectified voltage output by the rectifier module and the second voltage-boosting voltage output by the second voltage-boosting module based on the first voltage-boosting voltage be boosted to the direct-current bus voltage of the hybrid power supply system to supply the power load of the air conditioner; at this time, the hybrid power supply system works in the working state of being commonly supplied with power by the alternating-current commercial power supply and the solar photovoltaic power supply; If it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold value, the second switch module is maintained to be closed, the first switch module is maintained to be disconnected, and at least one of the switching frequency and the duty cycle of the second switch tube module in the second voltage-boosting module is controlled to make the rectified voltage output by the rectifier module be boosted to the direct-current bus voltage of the hybrid power supply system to supply the power load of the air conditioner; at this time, the hybrid power supply system works in the working state of being supplied with power only by the alternating-current commercial power supply.

2. The hybrid power supply system of claim 1, wherein, The first boost module comprises a first inductor module, a first diode module and a first switch tube module; wherein, The photovoltaic voltage output by the solar photovoltaic assembly is subjected to the first switch module and the first inductor module to obtain a first boost voltage; the first boost voltage is input to the collector of the first switch tube module in the first boost module and also input to the anode of the first diode module; after being subjected to the first diode module, a second boost voltage, i.e. a photovoltaic boost voltage, is obtained; the photovoltaic boost voltage is output from the cathode of the first diode module to the second boost module, is subjected to the second boost module again to be boosted, and is then output to the positive electrode of the bus capacitor unit to obtain the DC bus voltage of the hybrid power supply system.

3. The hybrid power supply system according to claim 1 or 2, characterized by, The second boost module comprises a second inductor module, a second diode module and a second switch tube module; wherein, In the case where the second switch module is closed, the AC mains is subjected to the second switch module and the rectifier module to output a rectified voltage: In the case where the photovoltaic boost voltage obtained by the first boost module is present, the rectified voltage and the photovoltaic boost voltage obtained by the first boost module are subjected to the second inductor module to be input to the collector of the second switch tube module in the second boost module and also input to the anode of the second diode module; after being subjected to the second diode module, the photovoltaic boost voltage is output from the cathode of the second diode module to the positive electrode of the bus capacitor unit to obtain the DC bus voltage of the hybrid power supply system; In the case where the photovoltaic boost voltage obtained by the first boost module is absent, the rectified voltage is subjected to the second inductor module to be input to the collector of the second switch tube module in the second boost module and also input to the anode of the second diode module; after being subjected to the second diode module, the photovoltaic boost voltage is output from the cathode of the second diode module to the positive electrode of the bus capacitor unit to obtain the DC bus voltage of the hybrid power supply system; In the case where the second switch module is closed, in the case where the photovoltaic boost voltage obtained by the first boost module is present, the photovoltaic boost voltage obtained by the first boost module is subjected to the second inductor module to be input to the collector of the second switch tube module in the second boost module and also input to the anode of the second diode module; after being subjected to the second diode module, the photovoltaic boost voltage is output from the cathode of the second diode module to the positive electrode of the bus capacitor unit to obtain the DC bus voltage of the hybrid power supply system.

4. The hybrid power supply system of claim 1, wherein, The control method of the hybrid power supply system of the air conditioner further comprises: After the hybrid power supply system of the air conditioner is started, the load demand power of the air conditioner is determined; The MPPT algorithm is used to control at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module so that the solar photovoltaic assembly outputs the maximum power point output power; in the case where the solar photovoltaic assembly outputs the maximum power point output power, the maximum power that can be output by the solar photovoltaic assembly is determined, i.e. a photovoltaic power; determining whether the photovoltaic power of the solar photovoltaic assembly is greater than a set power threshold value; if it is determined that the photovoltaic power of the solar photovoltaic assembly is less than or equal to the power threshold value, then in the case that the first switch module is closed, the first switch module is controlled to be disconnected, at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled, so that the rectified voltage output by the rectifier module is boosted to the DC bus voltage of the hybrid power supply system, and is supplied to the power load of the air conditioner; at this time, the hybrid power supply system works in a working state powered only by the alternating current mains power supply; if it is determined that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold value, then according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, the operation process of the hybrid power supply system is controlled; at this time, the hybrid power supply system works in a working state powered by the alternating current mains power supply and the solar photovoltaic power supply.

5. The hybrid power supply system of claim 4, wherein, In the case that the photovoltaic power of the solar photovoltaic assembly is greater than the power threshold value, according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, the operation process of the hybrid power supply system is controlled, including: determining whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, then in the case that the second switch tube module in the second boost module works, the second switch tube module in the second boost module is controlled to stop working, then the second switch module is controlled to be disconnected, so that the second boosted voltage of the first boost module is supplied to the DC bus voltage of the hybrid power supply system, and is supplied to the power load of the air conditioner; at this time, the hybrid power supply system works in a working state powered only by the solar photovoltaic power supply; if it is determined that the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, then the first switch module is maintained to be closed, and the second switch module is maintained to be closed, the mains power of the alternating current mains power supply is determined, and at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module and the second switch tube module in the second boost module is controlled, so that the sum of the photovoltaic power of the solar photovoltaic assembly and the mains power of the alternating current mains power supply is greater than or equal to the load demand power of the air conditioner; at this time, the hybrid power supply system works in a working state powered by the alternating current mains power supply and the solar photovoltaic power supply.

6. The hybrid power supply system of any one of claims 1, 4, 5, wherein, The control method of the hybrid power supply system of the air conditioner further includes: after the hybrid power supply system of the air conditioner is started, the load demand power of the air conditioner is determined; The MPPT algorithm is used to control at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module, so that the solar photovoltaic assembly outputs at the set maximum power point output power; when the solar photovoltaic assembly outputs at the maximum power point output power, the maximum power that the solar photovoltaic assembly can output is determined, which is recorded as photovoltaic power; When the solar photovoltaic assembly outputs at the maximum power point output power, it is determined whether the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner; If it is determined that the photovoltaic frequency of the solar photovoltaic assembly is greater than the load demand power of the air conditioner, when the first switch module and the second switch module are both turned on, the second switch module is controlled to be turned off, and at least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled, so that the first boost module outputs a second boost voltage based on the photovoltaic voltage boost voltage of the solar photovoltaic assembly, and at least one of the switching frequency and the duty cycle of the second switch tube module in the second boost module is controlled, so that the second boost module boosts the second boost voltage output by the first boost voltage to the DC bus voltage of the hybrid power supply system, and supplies the power load of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the solar photovoltaic power supply alone; If it is determined that the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, the operation process of the hybrid power supply system is further controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner.

7. The hybrid power supply system of claim 6, wherein, When the solar photovoltaic assembly outputs at the maximum power point output power, and the photovoltaic frequency of the solar photovoltaic assembly is less than or equal to the load demand power of the air conditioner, the operation process of the hybrid power supply system is further controlled according to the photovoltaic power of the solar photovoltaic assembly and the load demand power of the air conditioner, including: At least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled, so that the first boost module outputs a second boost voltage based on the photovoltaic voltage boost voltage of the solar photovoltaic assembly, and after the rectified voltage output by the rectifier module, the second switch module is controlled to be closed when the second switch module is turned off; At least one of the switching frequency and the duty cycle of the first switch tube module in the first boost module is controlled, so that the first boost module outputs a second boost voltage based on the photovoltaic voltage boost voltage of the solar photovoltaic assembly, and the rectified current output by the rectifier module can be increased in a set manner, and the mains power of the AC mains power supply is determined. coordinating at least one of a switching frequency and a duty cycle of the first switch module in the first boost module and the second switch module in the second boost module to make a sum of the photovoltaic power of the solar photovoltaic assembly and the mains power of the AC mains power supply greater than or equal to the load demand power of the air conditioner; at this time, the hybrid power supply system works in a working state of being powered by the AC mains power supply and the solar photovoltaic power supply together.

8. The hybrid power supply system of any one of claims 1, 4-7, wherein, The control method of the hybrid power supply system of the air conditioner further includes: determining the load demand power of the air conditioner after the hybrid power supply system of the air conditioner is started; obtaining the photovoltaic voltage output by the solar photovoltaic assembly; determining whether the photovoltaic voltage output by the solar photovoltaic assembly is greater than a set voltage threshold; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is greater than the voltage threshold, controlling the first switch module to be closed in the case that the first switch module is opened, controlling at least one of the switching frequency and the duty cycle of the first switch module in the first boost module to make the photovoltaic voltage output by the solar photovoltaic assembly boosted to a first boosted voltage, to make the second boosted voltage output by the first boost module based on the first boosted voltage greater than or equal to the rectified voltage output by the rectifier module; at this time, the hybrid power supply system works in the working state of being powered by the AC mains power supply and the solar photovoltaic power supply together; if it is determined that the photovoltaic voltage output by the solar photovoltaic assembly is less than or equal to the voltage threshold, controlling at least one of the switching frequency and the duty cycle of the second switch module in the second boost module to make the rectified voltage output by the rectifier module boosted to the DC bus voltage of the hybrid power supply system to supply the power consumption load of the air conditioner; at this time, the hybrid power supply system works in the working state of being powered by the AC mains power supply alone.

9. An air conditioner characterized by comprising: comprise: The hybrid power supply system according to any one of claims 1 to 8.

Images