Alternating current and direct current compatible air conditioner circuit and design method thereof

Abstract

The invention discloses an alternating current and direct current compatible air conditioner circuit and a design method thereof, the circuit comprises a control unit, and a switching circuit and a boost chopper circuit which are respectively connected with the control unit, the switching circuit comprises a first switching circuit and a second switching circuit, and the boost chopper circuit comprises a first boost chopper circuit and a second boost chopper circuit; the first switch circuit and the first boost chopper circuit are respectively connected with a photovoltaic module, the second switch circuit and the second boost chopper circuit are respectively connected with a power system, outputs of the first boost chopper circuit and the second boost chopper circuit are arranged in a matched manner and are connected in parallel to jointly supply power, and the control unit is connected with the photovoltaic module based on dynamic power distribution logic. The first boost chopper circuit boosts the voltage of the photovoltaic module and the second boost chopper circuit boosts the voltage of the power system by controlling the switching on and switching off of the first switching circuit and the second switching circuit respectively.

Description

Technical Field

[0001] The present invention belongs to the technical field of power control, and in particular relates to an AC / DC compatible air-conditioning circuit and a design method thereof. Background Art

[0002] Traditional air conditioning systems have the following core problems, which urgently need to be solved through AC / DC compatibility technology: 1. Unreliable power switching: Reliance on a single power source (AC 220V / 380V) causes air conditioners to shut down when the grid fluctuates or when there is a power outage. This particularly affects the temperature control continuity in critical scenarios such as data centers and industrial cabinet cores.

[0003] 2. Harmonic interference and short device life: Harmonic suppressors in AC input circuits are prone to overheating and damage due to the superposition of resonant current, reducing system stability.

[0004] 3. Energy efficiency loss: The AC / DC hybrid solution converts power through an inverter (such as DC-AC inversion), but there are problems such as energy loss, slow response speed, and complex circuits.

[0005] 4. High size and cost: Traditional photovoltaic air conditioners are directly powered by batteries or photovoltaic systems, but require high-cost DC compressors and large-capacity energy storage equipment, which are complex to maintain. Summary of the Invention

[0006] In order to solve the shortcomings of the existing technology and achieve the purpose of powering photovoltaic modules and mains electricity, the present invention adopts the following technical solutions: An AC / DC compatible air conditioning circuit includes a control unit and a switch circuit and a boost chopper circuit respectively connected to the control unit, the switch circuit including a first switch circuit and a second switch circuit, and the boost chopper circuit including a first boost chopper circuit and a second boost chopper circuit; the first switch circuit and the first boost chopper circuit are respectively connected to a photovoltaic module, the second switch circuit and the second boost chopper circuit are respectively connected to a power system, the outputs of the first boost chopper circuit and the second boost chopper circuit are coordinated and connected in parallel to supply power together, and the control unit, based on dynamic power distribution logic, controls the opening and closing of the first switch circuit and the second switch circuit respectively, so that the first boost chopper circuit boosts the photovoltaic module voltage and the second boost chopper circuit boosts the power system voltage.

[0007] Furthermore, a first DC voltage sampling module and a second DC voltage sampling module are provided at both ends of the first boost chopper circuit, the first boost chopper circuit is also connected to the intelligent power module, a third DC voltage sampling module and a fourth DC voltage sampling module are provided at both ends of the second boost chopper circuit, and the second boost chopper circuit is also connected to the AC voltage detection module and the rectifier bridge respectively; the first DC voltage sampling module collects the voltage of the photovoltaic module, and the first current detection module in the first boost chopper circuit collects the current of the photovoltaic module; the AC voltage collection module collects the AC voltage of the power system, the third DC voltage sampling module collects the distilled DC voltage of the power system, and the second current detection module in the second boost chopper circuit collects the distilled DC current of the power system, and calculates the photovoltaic power and the grid power through the control unit and compares them with the set power; If the photovoltaic power is greater than the set power, the photovoltaic module will supply power, the first switch circuit will be closed, the second switch circuit will be opened, and the first boost chopper circuit will work to boost the output to the specified voltage, and then perform inversion processing through the intelligent power module to run the compressor; If the photovoltaic power is less than the set power, it is distributed proportionally. The first and second switch circuits are both closed, and the first and second boost chopper circuits are both operated. The outputs of the two are connected in parallel and boosted to the specified voltage. The voltages are then output to the intelligent power module for inversion processing to operate the compressor. If the photovoltaic power is equal to zero, it means that the photovoltaic module cannot provide voltage at night or on rainy days. The power system supplies power, the first switch circuit is opened, the second switch circuit is closed, and the second boost chopper circuit works to boost the output to the specified voltage. The intelligent power module performs inversion processing to run the compressor.

[0008] Furthermore, the first boost chopper circuit is also connected to the rechargeable battery pack module. When the photovoltaic power is greater than the set power and the output of the first boost chopper circuit is boosted, if there is no demand for air conditioning at this time, the remaining power is consumed by the rechargeable battery pack module.

[0009] Furthermore, the first DC voltage sampling module collects photovoltaic voltage, the first current detection module collects photovoltaic current, the AC voltage collection module collects the AC voltage of the power system, the third DC voltage sampling module collects the rectified DC voltage of the power system, and the second current detection module collects the rectified DC current of the power system. The control unit compares the collected voltage and current with the set voltage and current. If the comparison with the set value exceeds the limit, overvoltage / undervoltage protection is performed.

[0010] Furthermore, in addition to MCU software protection, there is also hardware protection. The first boost chopper circuit includes a first drive module, a first protection module, and a first current detection module. The first protection module detects the real-time working current through the first current detection module. If the current exceeds the limit, the first protection module lowers the control signal output by the control unit to the first boost chopper circuit, causing the first drive module to stop outputting, thereby stopping the first boost chopper circuit from working, thereby triggering hardware protection. The second boost chopper circuit includes a second drive module, a second protection module and a second current detection module. The second protection module detects the real-time operating current through the second current detection module. If the current exceeds the limit, the control signal output by the control unit to the second boost chopper circuit is lowered, so that the second drive module stops outputting, and then the second boost chopper circuit stops working, thereby triggering hardware protection.

[0011] Furthermore, the first switching circuit 1 includes a first diode, a first positive temperature coefficient thermistor and a first relay. Current passes through the first diode and the first positive temperature coefficient thermistor. The first diode acts as a unidirectional conductor to ensure the correctness of the current direction. The first positive temperature coefficient thermistor has a small resistance at normal temperature, allowing current to pass through, providing working current for the first relay, so that the first relay can be normally attracted, thereby controlling the corresponding circuit.

[0012] Furthermore, the output end of the photovoltaic module is provided with a first electromagnetic compatibility processing module, and the first switching circuit is connected in series after the first electromagnetic compatibility processing module to avoid the impact of excessive surge current on the EMI filter and subsequent circuits, protect the subsequent circuit components, and reduce the impact of the starting current on the entire circuit system, including the impact on the EMI filter and subsequent connected components such as the power module and load, thereby extending the service life of these devices.

[0013] Furthermore, the second switching circuit includes a second positive temperature coefficient thermistor and a second relay. Current passes through the second positive temperature coefficient thermistor. The second positive temperature coefficient thermistor has a small resistance at normal temperature, allowing current to pass through, providing working current to the second relay, so that the second relay can be normally attracted, thereby controlling the corresponding circuit.

[0014] Furthermore, a second electromagnetic compatibility processing module is provided at the output end of the photovoltaic module, and a second switching circuit is connected in series after the second electromagnetic compatibility processing module to avoid the impact of excessive surge current on the EMI filter and subsequent circuits, protect the subsequent circuit components, and reduce the impact of the starting current on the entire circuit system, including the impact on the EMI filter and subsequent connected components such as the power module and load, thereby extending the service life of these devices.

[0015] A method for designing an AC / DC compatible air-conditioning circuit is provided. The method constructs the AC / DC compatible air-conditioning circuit and performs parallel power supply of photovoltaic modules and power systems based on dynamic power allocation logic.

[0016] The advantages and beneficial effects of the present invention are: The present invention discloses an AC / DC compatible air conditioning circuit and design method thereof. By utilizing AC / DC compatible air conditioning circuit technology, an air conditioning system capable of simultaneously adapting to both AC and DC power supplies is generated. A parallel design of photovoltaic Boost and grid PFC is employed to construct a hardware topology with a pure DC bus architecture. A dynamic power allocation algorithm is employed that sequentially performs sampling, calculation, regulation, and output. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 4 is a structural block diagram of an AC / DC compatible air conditioning circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0019] like Figure 1 As shown, an AC / DC compatible air conditioning circuit is used for air conditioning systems that are adapted to both AC and DC power supplies. The main circuit includes: DC power supply: After EMC1 (electromagnetic compatibility) processing, the PV+ and PV- output voltages of the photovoltaic modules are connected at one end to the boost chopper circuit BOOST1 (composed of inductor L1, diode D1, switch S1, driver module 1, protection module 1, and current detection module 1). The other end is connected to the switching circuit 1 (composed of diode DD1, positive temperature coefficient thermistor PTC1), and relay RELAY1. The control signal DC_SOFT_START of the switching circuit 1 is input by the microcontroller unit (MCU). The BOOST1 circuit includes DC voltage acquisition module 1 and DC voltage acquisition module 2. The output VOUT1 of the BOOST1 circuit is connected to the intelligent power module (IPM) for inverter processing to start the compressor COMP, and to the rechargeable battery pack module for charging.

[0020] AC power supply: After EMC2 processing, the AC power output live or phase line (ACL) and the neutral line (ACN) are connected to a switch circuit 2 consisting of a positive temperature coefficient thermistor (PTC2) and a relay (RELAY2). The MCU inputs the control signal AC_SOFT_START of switch circuit 2. Switch circuit 2 is then connected to the AC voltage detection module 1. The other end is connected to a rectifier bridge, and then to the boost chopper circuit BOOST2, which consists of an inductor L2, a diode D2, a switch S2, a driver module 2, a protection module 2, and a current detection module 2. The BOOST2 circuit includes DC voltage acquisition modules 3 and 4 before and after. The output VOUT2 is connected in parallel with VOUT1 to provide power. By controlling the output voltages PV+ and PV- of the photovoltaic module and the opening and closing of the switch circuit 1, the power factor correction (PFC) processing of the BOOST1 circuit is realized, and the voltage of the photovoltaic module is increased to 380V.

[0021] By controlling the opening and closing of the AC mains ACL and ACN and the switch circuit 2, the PFC processing of the BOOST2 circuit is realized, and the voltage of the mains after rectification is increased to 380V.

[0022] The MCU performs real-time power monitoring and controls the opening and closing of the switching circuit according to the dynamic power allocation logic.

[0023] The DC voltage sampling module 1 collects the photovoltaic voltage VPV, the current detection module 1 collects the photovoltaic current IPDC, the AC voltage collection module 1 collects the mains AC voltage VAC, the DC voltage module 3 collects the mains rectified DC voltage VDC, and the current detection module 2 collects the mains rectified DC current ISNS. These are input into the MCU to calculate the photovoltaic power Ppv and the grid power Pgrid, which can be compared with the set power Pload: If Ppv>Pload, the photovoltaic panels will provide 100% power. At this time, switch circuit 1 is closed, switch circuit 2 is open, and BOOST1 circuit works to boost VOUT1 to 380V. VOUT1 is output to the IPM module for inverter processing to run the compressor. If there is no need for air conditioning at this time, the remaining power can be consumed by the rechargeable battery module.

[0024] If Ppv < Pload, it is proportionally distributed. At this time, switch circuit 1 is closed, switch circuit 2 is closed, BOOST1 circuit works, BOOST2 circuit works, VOUT1 is boosted to 380V, VOUT2 is boosted to 380V, VOUT2 and VOUT1 are connected in parallel, and jointly output to the IPM module for inversion processing to operate the compressor.

[0025] If Ppv = 0, it means that it is night or rainy and the photovoltaic module cannot provide voltage. Then it is 100% powered by the mains. At this time, switch circuit 1 is opened, switch circuit 2 is closed, BOOST2 circuit works, VOUT2 is boosted to 380V, output to the IPM module for inversion processing to operate the compressor.

[0026] Protection mechanism: The DC voltage sampling module 1 collects the photovoltaic voltage VPV, the current detection module 1 collects the photovoltaic current IPDC, the AC voltage collection module 1 collects the mains AC voltage VAC, the DC voltage module 3 collects the DC voltage VDC after the mains is rectified, the current detection module 2 collects the DC current ISNS after the mains is rectified, and inputs them to the MCU to compare with the set voltage and current. If it exceeds the limit when compared with the set value, overvoltage / undervoltage protection is performed.

[0027] In addition to the MCU software protection, this embodiment also has hardware protection. The protection module Ⅰ detects the real-time working current through the current detection module Ⅰ. If it exceeds the limit, it pulls down the pulse width modulation PWM (Pulse Width Modulation, a technology that controls power output by adjusting the width of an electrical signal) output by the MCU to BOOST1, the drive module Ⅰ stops outputting, the BOOST1 circuit stops working, and hardware protection is triggered.

[0028] The protection module Ⅱ detects the real-time working current through the current detection module Ⅱ. If it exceeds the limit, it pulls down the PWM output by the MCU to BOOST2, the drive module Ⅱ stops outputting, the BOOST2 circuit stops working, and hardware protection is triggered.

[0029] Harmonic interference and device life: The switch circuit 1 consists of DD1, PTC1, and RELAY1. The current passes through DD1 and PTC1. DD1 plays a role of unidirectional conduction to ensure the correctness of the current direction. PTC1 has a small resistance at normal temperature, allows current to pass through, provides working current for RELAY1, enables the relay to be normally attracted, and thus controls the corresponding circuit. It is connected in series after EMC1 to avoid impact on the EMI filter and subsequent circuits due to excessive surge current, protect the components of the subsequent circuit, and can reduce the impact of the starting current on the entire circuit system, including the impact on components such as the EMI filter and subsequent connected power modules, loads, etc., so the service life of these devices can be extended.

[0030] Switching circuit 2 consists of PTC2 and RELAY2, with current flowing through PTC2. At normal temperatures, PTC2 has a low resistance, allowing current to flow through, providing operating current to RELAY2, enabling the relay to properly close and thus control the corresponding circuit. Connecting it in series after EMC2 prevents excessive inrush current from impacting the EMI filter and subsequent circuitry, protecting downstream circuit components and reducing the impact of startup current on the entire circuit system, including the EMI filter and subsequent connected components such as the power module and load, thereby extending the service life of these devices.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An AC / DC compatible air conditioning circuit, comprising a control unit, a switch circuit and a boost chopper circuit respectively connected to the control unit, characterized in that: The switching circuit includes a first switching circuit and a second switching circuit, and the boost chopper circuit includes a first boost chopper circuit and a second boost chopper circuit; the first switching circuit and the first boost chopper circuit are respectively connected to the photovoltaic component, and the second switching circuit and the second boost chopper circuit are respectively connected to the power system. The outputs of the first boost chopper circuit and the second boost chopper circuit are arranged in coordination and connected in parallel to supply power together. The control unit is based on dynamic power distribution logic, and controls the opening and closing of the first switching circuit and the second switching circuit respectively, so that the first boost chopper circuit increases the voltage of the photovoltaic component and the second boost chopper circuit increases the voltage of the power system.

2. The AC / DC compatible air conditioning circuit according to claim 1, characterized in that: A first DC voltage sampling module and a second DC voltage sampling module are provided at both ends of the first boost chopper circuit. The first boost chopper circuit is also connected to the intelligent power module. A third DC voltage sampling module and a fourth DC voltage sampling module are provided at both ends of the second boost chopper circuit. The second boost chopper circuit is also connected to the AC voltage detection module and the rectifier bridge, respectively. The first DC voltage sampling module collects the voltage of the photovoltaic module, and the first current detection module in the first boost chopper circuit collects the current of the photovoltaic module; the AC voltage collection module collects the AC voltage of the power system, the third DC voltage sampling module collects the distilled DC voltage of the power system, and the second current detection module in the second boost chopper circuit collects the distilled DC current of the power system. The photovoltaic power and the grid power are calculated by the control unit and compared with the set power. If the photovoltaic power is greater than the set power, the photovoltaic module will supply power, the first switch circuit will be closed, the second switch circuit will be opened, and the first boost chopper circuit will work to boost the output to the specified voltage, and then perform inversion processing through the intelligent power module to run the compressor; If the photovoltaic power is less than the set power, it is distributed proportionally. The first and second switch circuits are both closed, and the first and second boost chopper circuits are both operated. The outputs of the two are connected in parallel and boosted to the specified voltage. The voltages are then output to the intelligent power module for inversion processing to operate the compressor. If the photovoltaic power is equal to zero, the power system supplies power, the first switch circuit is opened, the second switch circuit is closed, and the second boost chopper circuit works to boost the output to the specified voltage, and performs inversion processing through the intelligent power module to run the compressor.

3. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The first boost chopper circuit is also connected to the rechargeable battery module. When the photovoltaic power is greater than the set power and the output of the first boost chopper circuit is boosted, if there is no demand for air conditioning at this time, the remaining power is consumed by the rechargeable battery module.

4. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The first DC voltage sampling module collects photovoltaic voltage, the first current detection module collects photovoltaic current, the AC voltage collection module collects the AC voltage of the power system, the third DC voltage sampling module collects the rectified DC voltage of the power system, and the second current detection module collects the rectified DC current of the power system. The control unit compares the collected voltage and current with the set voltage and current. If the comparison with the set value exceeds the limit, overvoltage / undervoltage protection is performed.

5. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The first boost chopper circuit includes a first driving module, a first protection module, and a first current detection module. The first protection module detects the real-time operating current through the first current detection module. If the current exceeds the limit, the first protection module lowers the control signal output by the control unit to the first boost chopper circuit, causing the first driving module to stop outputting, thereby stopping the first boost chopper circuit from operating. The second boost chopper circuit includes a second driving module, a second protection module and a second current detection module. The second protection module detects the real-time operating current through the second current detection module. If the real-time operating current exceeds the limit, the second protection module lowers the control signal output by the control unit to the second boost chopper circuit, causing the second driving module to stop outputting, thereby stopping the second boost chopper circuit from working.

6. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The first switching circuit 1 includes a first diode, a first positive temperature coefficient thermistor and a first relay. Current passes through the first diode and the first positive temperature coefficient thermistor. The first diode acts as a unidirectional conductor. The first positive temperature coefficient thermistor has a small resistance at normal temperature, allowing current to pass through, providing working current for the first relay, so that the first relay can be normally attracted.

7. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The output end of the photovoltaic assembly is provided with a first electromagnetic compatibility processing module, and the first switch circuit is connected in series after the first electromagnetic compatibility processing module.

8. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The second switching circuit includes a second positive temperature coefficient thermistor and a second relay. Current passes through the second positive temperature coefficient thermistor. The second positive temperature coefficient thermistor has a small resistance at normal temperature, allowing current to pass through, providing working current for the second relay, so that the second relay can be normally attracted.

9. The AC / DC compatible air conditioning circuit according to claim 2, characterized in that: The output end of the photovoltaic assembly is provided with a second electromagnetic compatibility processing module, and the second switch circuit is connected in series after the second electromagnetic compatibility processing module.

10. A method for designing an AC / DC compatible air conditioner circuit, characterized by: Construct an AC / DC compatible air conditioning circuit as described in claim 1, and perform parallel power supply of photovoltaic components and power systems based on dynamic power allocation logic.

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