Central air conditioner multi-path control circuit based on three-relay combinational logic

Abstract

The embodiment of the invention discloses a central air conditioner multi-path control circuit based on three-relay combinational logic. The central air conditioner multi-path control circuit comprises a micro control unit (MCU) and three single-pole double-throw relays driven by three control input / output (IO) ports of the MCU. A specific logic level combination is output through the MCU, the on-off states of the three relays are controlled, and five independent output channels can be formed only through the three relays by means of different connection combinations of normally open contacts of the relays. And the five output channels are respectively used for controlling the high-speed, medium-speed and low-speed wind speeds of a fan of the central air conditioner and the opening and closing of a valve, so that the complete control on the five-path output function of the central air conditioner is realized. According to the invention, the problems of large occupied MCU IO port resources, high system cost and large size of a single-path relay single-path control mode in the prior art are solved, and the IO resources and hardware cost of the controller are remarkably saved on the premise of ensuring complete control functions and stable operation through a simple hardware circuit and logic design.

Description

Technical Field

[0001] This invention relates to the field of circuit control technology, specifically to a central air conditioning multi-channel control circuit based on three-relay combination logic. Background Technology

[0002] Currently, central air conditioning control systems are widely used in homes, offices, schools, and other locations. In existing technologies, a common control method is single-channel relay single-output, where each relay controls one central air conditioning output (such as high-speed, medium-speed, or low-speed fans or valve control). While this method is simple and logically clear, it requires significant MCU I / O port resources.

[0003] In practical applications, especially when MCU I / O port resources are limited (such as when it is necessary to drive LCD displays, peripheral functional circuits, etc.), the traditional single-channel relay control method is difficult to meet the needs of multi-channel output, resulting in problems such as poor system scalability, increased cost, and increased size. Summary of the Invention

[0004] To address this, this invention provides a central air conditioning multi-channel control circuit based on three-relay combinational logic, which solves the technical problem that existing technologies cannot meet the demand for multiple outputs and that there is a contradiction between limited IO resources and functional integrity.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] This invention provides a central air conditioning multi-channel control circuit based on three-relay combinational logic, including a microcontroller unit (MCU), specifically comprising:

[0007] The first relay driver module, the second relay driver module, and the third relay driver module have their input terminals connected to the three control I / O ports of the MCU, respectively.

[0008] The coils of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are driven by the corresponding relay driving module.

[0009] The common terminals of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are respectively connected to a DC power supply, and the first normally open contact and the second normally open contact of each relay are configured to output different logic level combinations.

[0010] The first normally open contact and the second normally open contact of the three single-pole double-throw relays form five output channels. These five output channels are respectively connected to the high-speed fan control terminal, medium-speed fan control terminal, low-speed fan control terminal, valve opening control terminal, and valve closing control terminal of the central air conditioning system. By combining the control signal logic output from the MCU to the three relay drive modules, the on / off state of the three single-pole double-throw relays is controlled, thereby selectively conducting one or more of the five output channels to achieve five-way control function.

[0011] Furthermore, the first relay driving module, the second relay driving module, and the third relay driving module all include a transistor switching circuit. The base of the transistor switching circuit is connected to the control I / O port of the MCU through a current-limiting resistor, the emitter is grounded, the collector is connected to one end of the corresponding relay coil, and the other end of the relay coil is connected to the driving power supply.

[0012] Furthermore, the relay drive module also includes a reverse parallel diode, the positive terminal of which is connected to the collector of the transistor switching circuit, and the negative terminal is connected to the drive power supply, for releasing the induced electromotive force when the relay coil is de-energized.

[0013] Furthermore, the correspondence between the state combinations of the three single-pole double-throw relays and the five-way control functions is as follows:

[0014] When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the control terminal for closing the valve is activated.

[0015] When the first relay is closed, the second relay is open, and the third relay is closed, the high-speed control terminal of the fan and the valve opening control terminal are connected.

[0016] When the first relay is open, the second relay is closed, and the third relay is closed, the control terminal for the medium speed of the fan is connected to the control terminal for the valve opening.

[0017] When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the low-speed control terminal of the fan and the valve opening control terminal are connected.

[0018] Furthermore, at least one of the five output channels is connected in series with a load protection element.

[0019] Furthermore, the MCU generates the control signal logic combination according to the preset temperature control program or the received user instructions.

[0020] Furthermore, the high-speed control terminal, medium-speed control terminal, and low-speed control terminal of the fan are used to control the three-phase tap motor or electronic speed control module of the central air conditioning fan.

[0021] Furthermore, the valve opening control terminal and the valve closing control terminal are used to control the electric two-way valve or three-way valve of the central air conditioning water circuit or refrigerant circuit pipeline.

[0022] The embodiments of the present invention have the following advantages:

[0023] This invention includes a microcontroller unit (MCU) and three single-pole double-throw (SPDT) relays, each driven by one of the MCU's three control I / O ports. By outputting specific logic level combinations from the MCU, the on / off states of the three relays are controlled. Utilizing different connection combinations of their normally open contacts, five independent output channels can be formed using only three relays. These five output channels are used to control the high, medium, and low speed settings of the central air conditioning fan, as well as the opening and closing of valves, thereby achieving complete control of the five-way output function of the central air conditioning system. This invention solves the problems of existing single-channel relay single-channel control methods, which occupy a large number of MCU I / O port resources, resulting in high system cost and large size. With simple hardware circuitry and logic design, it significantly saves controller I / O resources and hardware costs while ensuring complete control functions and stable operation. Attached Figure Description

[0024] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0026] Figure 1 This is a schematic diagram of existing technology;

[0027] Figure 2 A schematic diagram illustrating the application principle of a central air conditioning multi-channel control circuit based on three-relay combination logic, provided for an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the circuit principle of a central air conditioning multi-channel control circuit based on three-relay combination logic, provided for an embodiment of the present invention. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the current era of energy-saving, environmentally friendly, and intelligent building trends, central air conditioning is suitable for homes, office buildings, schools, and other places. However, the vast majority of circuit designs for controlling central air conditioning systems on the market still use single-channel relay control. (Refer to...) Figure 1 This method involves the MCU sending high and low level signals to control relays, with one relay controlling one output of the central air conditioner (high speed, medium speed, low speed, or valve output). The diagram below shows a common relay control circuit. This design consumes a significant number of MCU I / O ports. If the MCU's I / O resources are limited, for example, if the MCU's I / O ports also need to drive an LCD display and peripheral functional circuits, insufficient I / O resources can make it difficult to control multiple outputs of the central air conditioner.

[0031] To address the aforementioned technical issues that make it difficult to meet the demand for multiple outputs, and the contradiction between limited I / O resources and functional completeness.

[0032] refer to Figure 2 Through hardware circuitry, the MCU logic drives the relays, controlling the operation of three single-pole double-throw relays to engage or disengage the relay logic level output, thereby controlling the output of different channels of the central air conditioning system.

[0033] refer to Figure 3 This invention discloses a central air conditioning multi-channel control circuit based on three-relay combinational logic, including a microcontroller unit (MCU), specifically comprising:

[0034] The first relay driver module, the second relay driver module, and the third relay driver module have their input terminals connected to the three control I / O ports of the MCU, respectively.

[0035] The coils of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are driven by the corresponding relay driving module.

[0036] The common terminals of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are respectively connected to a DC power supply, and the first normally open contact and the second normally open contact of each relay are configured to output different logic level combinations.

[0037] The first normally open contact and the second normally open contact of the three single-pole double-throw relays form five output channels. These five output channels are respectively connected to the high-speed fan control terminal, medium-speed fan control terminal, low-speed fan control terminal, valve opening control terminal, and valve closing control terminal of the central air conditioning system. By combining the control signal logic output from the MCU to the three relay drive modules, the on / off state of the three single-pole double-throw relays is controlled, thereby selectively conducting one or more of the five output channels to achieve five-way control function.

[0038] Furthermore, the first relay driving module, the second relay driving module, and the third relay driving module all include a transistor switching circuit. The base of the transistor switching circuit is connected to the control I / O port of the MCU through a current-limiting resistor, the emitter is grounded, the collector is connected to one end of the corresponding relay coil, and the other end of the relay coil is connected to the driving power supply.

[0039] Furthermore, the relay drive module also includes a reverse parallel diode, the positive terminal of which is connected to the collector of the transistor switching circuit, and the negative terminal is connected to the drive power supply, for releasing the induced electromotive force when the relay coil is de-energized.

[0040] Furthermore, the correspondence between the state combinations of the three single-pole double-throw relays and the five-way control functions is as follows:

[0041] When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the control terminal for closing the valve is activated.

[0042] When the first relay is closed, the second relay is open, and the third relay is closed, the high-speed control terminal of the fan and the valve opening control terminal are connected.

[0043] When the first relay is open, the second relay is closed, and the third relay is closed, the control terminal for the medium speed of the fan is connected to the control terminal for the valve opening.

[0044] When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the low-speed control terminal of the fan and the valve opening control terminal are connected.

[0045] refer to Figure 3 Under normal power supply conditions, the MCU sends different high and low level signals to Relay1, Relay2, and Relay3 in different operating modes. The first part of the circuit is a driver circuit for three single-pole double-throw relays, which amplifies the pulse level signals sent by the MCU to drive the relays.

[0046] The second part of the circuit is the logic output circuit of a single-pole double-throw relay. D8, D9, and D10 are inverting diodes with unidirectional conductivity, preventing current from flowing in the reverse direction to the relay coils RL1, RL2, and RL3, thus protecting the relays. By constructing the circuit as shown in the schematic above, different logic level outputs can be achieved.

[0047] The third part of the circuit is a single-pole double-throw relay logic output that controls the central air conditioning system. It provides power to the central air conditioning system to control the opening and closing of the central air conditioning valves and the control of the central air conditioning fan speed (high speed, medium speed, low speed).

[0048]

[0049] This invention uses fewer relays to control multiple central air conditioning outputs, achieving the effect of one relay controlling one central air conditioning output (high-speed, medium-speed, low-speed, or valve output). It relies entirely on hardware circuitry to build three single-pole double-throw (SPDT) relays, driven by an MCU to implement their combined logic outputs. This allows the three SPDT relays to control five central air conditioning outputs with good stability. By building the hardware circuitry and using software to output logic levels to control the three SPDT relays, the product is integrated, saving space and cost, solving the problem of excessive product size, and still achieving the functionality of controlling a central air conditioning system with five relay outputs.

[0050] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A central air conditioning multi-channel control circuit based on three-relay combinational logic, characterized in that, This includes a microcontroller unit (MCU), specifically: The first relay driver module, the second relay driver module, and the third relay driver module have their input terminals connected to the three control I / O ports of the MCU, respectively. The coils of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are driven by the corresponding relay driving module. The common terminals of the first single-pole double-throw relay, the second single-pole double-throw relay, and the third single-pole double-throw relay are respectively connected to a DC power supply, and the first normally open contact and the second normally open contact of each relay are configured to output different logic level combinations. The first normally open contact and the second normally open contact of the three single-pole double-throw relays form five output channels. These five output channels are respectively connected to the high-speed fan control terminal, medium-speed fan control terminal, low-speed fan control terminal, valve opening control terminal, and valve closing control terminal of the central air conditioning system. By combining the control signal logic output from the MCU to the three relay drive modules, the on / off state of the three single-pole double-throw relays is controlled, thereby selectively conducting one or more of the five output channels to achieve five-way control function.

2. The central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, The first relay driving module, the second relay driving module, and the third relay driving module all include a transistor switching circuit. The base of the transistor switching circuit is connected to the control I / O port of the MCU through a current-limiting resistor, the emitter is grounded, the collector is connected to one end of the corresponding relay coil, and the other end of the relay coil is connected to the driving power supply.

3. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 2, characterized in that, The relay drive module also includes a reverse parallel diode, the positive terminal of which is connected to the collector of the transistor switching circuit, and the negative terminal is connected to the drive power supply, for releasing the induced electromotive force when the relay coil is de-energized.

4. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, The correspondence between the state combinations of the three single-pole double-throw relays and the five-way control functions is as follows: When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the control terminal for closing the valve is activated. When the first relay is closed, the second relay is open, and the third relay is closed, the high-speed control terminal of the fan and the valve opening control terminal are connected. When the first relay is open, the second relay is closed, and the third relay is closed, the control terminal for the medium speed of the fan is connected to the control terminal for the valve opening. When the first relay is disconnected, the second relay is disconnected, and the third relay is closed, the low-speed control terminal of the fan and the valve opening control terminal are connected.

5. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, At least one of the five output channels is connected in series with a load protection element.

6. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, The MCU generates the control signal logic combination according to the preset temperature control program or the received user instructions.

7. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, The high-speed control terminal, medium-speed control terminal, and low-speed control terminal of the fan are used to control the three-phase tap motor or electronic speed control module of the central air conditioning fan.

8. A central air conditioning multi-channel control circuit based on three-relay combinational logic as described in claim 1, characterized in that, The valve opening control terminal and valve closing control terminal are used to control the electric two-way valve or three-way valve of the central air conditioning water circuit or refrigerant circuit pipeline.

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