CN201348340Y - Speed regulating device and air conditioning system using the speed regulating device - Google Patents

Abstract

The utility model relates to a low-temperature speed regulating device and an air-conditioning system applied to an air-conditioning system. The speed regulating device includes a pressure switch, which is installed on the exhaust pipeline of the compressor of the air conditioning system; the chopper speed regulating board, which further includes a main controller and a pressure switch signal input interface connected to the main controller, a power circuit, 485 The communication module, the zero-crossing detection circuit and the motor control signal output module, the chopper speed control board communicates with the external unit main board of the air conditioning system through the 485 communication module; the chopper speed control board receives the status information of the pressure switch through the pressure switch signal input interface; A logic program is stored in the main controller, and the logic program controls the speed of the outdoor fan according to the pressure switch signal, the operating time and the operating mode of the air conditioning system, and the power circuit is connected to the main board of the external unit of the air conditioning system. The novel low-temperature refrigeration speed regulating device is characterized by low cost and low failure rate.

Description

Speed regulating device and air conditioning system using the speed regulating device

technical field

The utility model relates to a low-temperature speed regulating device and an air-conditioning system applied to an air-conditioning system.

Background technique

In many regions such as Europe, some bakeries, kitchens and high-end restaurants still need to maintain the comfort of indoor air in winter when the outdoor weather is very cold. They cannot meet the indoor constant temperature and humidity requirements by simply turning on the heater. Ordinary air conditioners cannot operate safely and reliably in low temperature environments, so it is necessary to develop a low temperature refrigeration air conditioner to adjust indoor comfort in low temperature environments. At present, the low-temperature refrigeration speed control devices commonly used in China use pressure sensors and temperature sensors to jointly adjust the air volume of the external fan by detecting the exhaust pressure value of the air conditioner compressor and the outdoor ambient temperature to achieve low-temperature refrigeration. The cost of a pressure sensor At more than two hundred yuan, the cost is relatively expensive; the cost of a pressure switch is only more than ten yuan, which not only greatly reduces the cost, but also has stronger reliability.

Chopper speed regulation is a relatively common motor speed regulation method, which is widely used in occasions where the accuracy requirement is not very high. This speed control method has a short development cycle and low cost, and has been widely used in the air-conditioning industry. In addition, in the refrigeration system, the gear position requirement of the external fan is generally determined indirectly by the main board of the external unit according to the temperature detected by the temperature sensor at a specific point: that is, the higher the temperature detected by the temperature sensor, the higher the air volume required by the external fan. The larger the heat dissipation, the greater the cooling capacity. Conversely, the lower the temperature, the smaller the required air volume and the less cooling capacity, thus determining the gear position requirements of the external fan.

Utility model content

The first purpose of the utility model is to provide a low-cost speed regulating device for an air-conditioning system.

The second purpose of the utility model is to provide an air conditioning system using the above-mentioned speed regulating device.

In order to achieve the above-mentioned first purpose, the utility model provides the following technical solutions:

governor, including

A pressure switch, which is installed on the discharge pipe of the compressor of the air conditioning system;

The chopper speed control board further includes a main controller and a pressure switch signal input interface connected to the main controller, a power circuit, a 485 communication module, a zero-crossing detection circuit and a motor control signal output module. The chopper speed control board passes through the 485 The communication module communicates with the main board of the external unit of the air conditioning system; the chopper speed control board receives the status information of the pressure switch through the pressure switch signal input interface; the logic program is stored in the main controller, and the power circuit is connected to the external unit of the air conditioning system motherboard.

The feature of this new type of low-temperature refrigeration speed regulating device is to adjust the speed of the external fan by detecting the on-off signal of the pressure switch on the compressor exhaust pipe and combining the time and mode of the external fan running at a certain wind speed gear. When it is detected that the pressure switch is disconnected or closed, the logic program set in the speed control device will finally decide to increase, decrease or Maintain the speed of the external fan. Different pressure values can be selected for the disconnection and recovery pressure values of the pressure switch according to different air-conditioning systems. Compared with the current domestic low-temperature speed control device, the cost has been reduced by nearly 200 yuan; the control method is simple and more versatile, and only one pressure switch is used to detect the signal, without the need for a temperature sensor, which also reduces the burden caused by the temperature sensor. to the occurrence of failure rates.

In order to achieve the above-mentioned second purpose, the utility model provides the following technical solutions:

The air-conditioning system includes a compressor connected into a closed circuit, an indoor heat exchanger, an outdoor heat exchanger, an outdoor unit main board, an external fan, and a speed regulating device for regulating the speed of the external fan. The speed regulating device includes:

A pressure switch, which is installed on the discharge pipe of the compressor of the air conditioning system;

The chopper speed control board further includes a main controller and a pressure switch signal input interface connected to the main controller, a power circuit, a 485 communication module, a zero-crossing detection circuit and a motor control signal output module. The chopper speed control board passes through the 485 The communication module communicates with the main board of the external unit of the air-conditioning system; the chopper speed control board receives the status information of the pressure switch through the pressure switch signal input interface; the logic program is stored in the main controller and the power circuit is connected to the main board of the external unit of the air-conditioning system .

The chopper speed control board divides the speed of the outdoor fan into N gears, each gear corresponds to a different percentage of the maximum speed of the outdoor fan, where N is greater than 3.

Compared with the current technology, the speed regulating device of the utility model is specially designed for low-temperature refrigeration and air-conditioning, which satisfies the normal use of the air-conditioning system in a low-temperature environment, and expands the temperature range of the reliable operation environment of the air conditioner to -15°C ≤T≤43°C. The ambient temperature range for reliable cooling operation of ordinary air conditioners is 18°C≤T≤43°C. If the cooling operation is lower than this ambient temperature, the evaporator will be frosted, the system pressure will be low, and the system will be filled with liquid and other abnormal phenomena.

Description of drawings

Fig. 1 is the schematic diagram of the utility model air-conditioning system;

Fig. 2 is the block diagram of the module of the chopper speed control board;

Figure 3 is the circuit diagram of the chopper speed control board.

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Detailed ways

Referring to FIG. 1 , the air conditioning system mainly includes a compressor 1 , an indoor heat exchanger 2 and an outdoor heat exchanger 3 connected in a closed circuit. Both the main board 6 of the outdoor unit and the speed regulating device 5 can regulate the rotating speed of the external fan 4 . Adjusting the rotational speed of the external fan 4 can achieve the purpose of adjusting the heat exchange effect of the outdoor heat exchanger 3 . The speed regulating device 5 includes a pressure switch 51 and a chopper speed regulating plate 52 , and the pressure switch 51 is installed on the discharge pipeline of the compressor 1 . Referring to FIG. 2, the chopper speed control board 52 includes a main controller 521, a pressure switch signal input interface 522 connected to the main controller, a power supply circuit 523, an RS485 communication module 524, a zero-crossing detection circuit 525 and a motor control signal output module 526 , the chopper speed control board 52 communicates with the main board of the external machine of the air conditioning system through the RS485 communication module. The chopper speed control board 52 receives the status information of the pressure switch 51 through the pressure switch signal input interface. A logic program is stored in the main controller 521, and the logic program controls the speed of the external fan according to the pressure switch signal, the running time and the running mode of the air conditioning system. The power supply circuit 523 is connected to the main board 6 of the external unit of the air conditioning system. The main controller 521 includes an MCU, a crystal oscillator, a reset circuit, a pull-up resistor and a switch.

Referring to Fig. 3, the composition and working process of each unit of the chopper speed control board 52 are as follows:

The main controller 521 includes an MCU, a crystal oscillator, a reset circuit, a pull-up resistor and a switch, and the crystal oscillator circuit, the reset circuit, the pull-up resistor and the switch are respectively connected to the corresponding pins of the MCU,

The power supply circuit 523 includes a first filter circuit, a voltage stabilizing circuit, and a second filter circuit connected in sequence. The first filter circuit and the second filter circuit respectively include electrolytic capacitors and ceramic capacitors connected in parallel. The voltage regulator circuit is a 5V voltage regulator chip. The DC 12V power supply is first filtered by the first filter circuit, and then passed through the 5V voltage regulator chip to become 5V stable DC voltage signal, and then output a smooth and stable 5V voltage signal after the second filter.

The pressure switch signal input interface 522 includes a filter circuit and a pull-up resistor. The filter circuit is composed of two electrolytic capacitors. The pressure detection switch signal is output from the pressure detection switch. The level of the output signal is stabilized through the pull-up resistor, and then passed through the filter circuit. The filtered output smooth signal is connected to the corresponding pin of the MCU.

The zero-crossing detection circuit 525 includes a photoelectric coupling circuit. The AC signal is first connected in series with a diode and a resistor to the input port of the photocoupler, and the output port of the photocoupler is connected to the corresponding pin of the MCU. Calculate the number of times the photoelectric coupler conducts to calculate the number of cycles of the sinusoidal AC signal,

The signal output circuit 6 of the motor includes a photoelectric coupling circuit and a thyristor circuit. The photoelectric coupling circuit and the current limiting resistor are connected in series to the MCU port. The first pin of the photoelectric coupling circuit is connected to the +5V power supply; the other pin of the photoelectric coupling circuit is Connect the thyristor, the photoelectric coupling circuit is respectively connected with the forward and reverse embedded pressure diodes; the resistance-capacitance module is connected in parallel between the thyristor pin 1, and the 220V strong power supply positive terminal X1 is connected after the second pin is connected in series with the differential mode inductor L1 ; Between the terminal X1 and the SCR pin 1, the resistance-capacity module RC1 is incorporated, and the SCR pin 1 is connected to the terminal X2 as the positive input of the motor and the live wire of the motor; the terminal X5 is used as the negative pole of the 220V strong power supply And the neutral wire of the motor; a piezoresistor VR1, a filter capacitor C8, and a discharge resistor R13 are incorporated between the live wire and the neutral wire.

The chopper speed control board 52 of the above-mentioned speed control device 5 can be designed separately from the main board 6 of the external machine, as shown in Figure 1, and can also be synthesized and developed on a PCB with the main board of the external machine. The above-mentioned speed regulating device 5 differs from the existing low-temperature speed regulating device in that it does not use traditional expensive pressure sensors and temperature sensors, but uses a common pressure switch 51 commonly used in air-conditioning systems. The off signal is used to adjust the speed of the external fan, so as to realize the low temperature cooling function.

For example, if a low-temperature refrigeration function needs to be added to an air-conditioning system, it is only necessary to weld a pressure switch (YK-XMPa/YMPa) on the compressor exhaust pipe of the air-conditioning system. The pressure switch can be matched according to different systems. The breaking pressure value X and recovery pressure value Y), in general, the breaking pressure of the pressure switch is 1.7-3.2MP, the recovery pressure is 1.2-2.6MP, and the difference between the breaking pressure and the recovery pressure is 0.4-0.7 MP. Then connect the connection line of the pressure switch 51 and the external fan to the chopper speed control board 52. When cooling in low-temperature refrigeration conditions, the chopper speed control board 52 can automatically detect the on-off signal of the pressure switch and the set The fixed program is used to adjust the rotating speed of the external fan 4 to realize the purpose of low-temperature refrigeration.

The working principle of the above-mentioned speed regulating device 5 is: use the main board 6 of the external machine to provide +12V direct current to the chopper speed regulating board 52, output +5V direct current to supply the main controller 521 and each functional circuit after passing through the voltage stabilizing block in the power supply circuit 523 . The zero-crossing detection circuit 525 on the chopper speed control board 52 first detects the zero-crossing point of the voltage of the 220V AC power supply 7, and uses the zero-crossing point as the counting starting point to control the switching of the thyristor, thereby controlling the 220V AC power within one cycle. The action time of the external fan 4, and then achieve the purpose of adjusting the speed of the external fan 4. The chopper speed control board 52 can obtain the gear position requirements of the external machine main board 6 according to the RS485 communication to determine the number of counting points, so that the external fan 4 can work at a predetermined gear position, and realize a single chopper speed control function. The chopper speed control board 52 can also determine the gear position requirement according to the switch state of the pressure switch 51 and the logic program, and then perform the corresponding external fan speed control.

The pressure detection switch signal is processed by the filter circuit and input to the PA4-HS-pin of the main controller 521, and the main controller 521 outputs the PWM signal to control the external fan 4 through the pin -HS-PB4 according to the state of the pressure switch 51. The signal passes through the photoelectric coupler and thyristor circuit to control the speed of the external fan (the AC is connected to the H gear of the motor, and the duty cycle of the PWM signal is changed to control the speed of the external fan), and the time of the main controller is detected by zero-crossing. Circuit 525 to collect the count. For example, the main controller needs to delay 1S, then the main controller needs to detect the number of zero-crossing points N=1/0.02=50 times, which is 1S, and the alternating current is 50HZ. The main controller 521 communicates with the main board 6 of the external machine through the RS485 bus, and the power supply circuit 523 uses a 7805 power chip to output +5V voltage (+12V power is provided by the main board 6 of the external machine).

Hardware requirements of chopper speed control board 52:

RS485 communication mode is adopted between the chopper speed control board 52 and the main board 6 of the external machine, and the main board 6 of the external machine supplies 12V voltage to the chopper speed control board.

The 220V voltage on the chopper speed control board 52 is directly provided by the power supply 7, and the high wind gear (H gear) of the external blower fan 4 is received on the chopping wave speed control board 52, and the middle and low wind gears (M gear and L gear) are not connected.

A fault indicator light can also be added on the chopper governor board.

The control logic of the logic program in the main controller 521 is as follows:

When the communication between the chopper speed control board 52 and the main board 6 of the external machine is normal, the fault indicator light on the chopper speed control board 52 will flash; The external fan 4 stops after 15 seconds after the stop of the compressor 1, and the fault indicator light on the speed control board is always on, (the hand operator reports E6 fault).

When pressing the shutdown key to stop, the external blower 4 stops after a delay of 15 seconds after the compressor 1 stops.

As a preferred example, the chopper speed control board 52 divides the speed of the external fan into 6 gears, that is, 100%, 90%, 70%, 50%, 35%, and 20% of the highest gear speed for air volume output, and the highest gear It is 6, the lowest gear is 1, and from 6th gear to 1st gear, the air volume output keeps decreasing.

In the above example, the chopper speed control board 52 divides the speed of the external fan into 6 gears. In fact, it can also be divided into 4 gears, 5 gears or more gears. The number of specific gears can be set according to needs.

Of course, the utility model can also have other simple deformations. In a word, obvious changes made according to the hints of the above embodiments, and other changes that do not deviate from the essence of the present utility model shall be included in the scope of the claims.

Claims (9)

1. The speed regulating device is characterized in that it comprises A pressure switch, which is installed on the discharge pipe of the compressor of the air conditioning system; The chopper speed control board further includes a main controller and a pressure switch signal input interface connected to the main controller, a power supply circuit, an RS485 communication module, a zero-crossing detection circuit and a motor control signal output module. The chopper speed control board passes through RS485 The communication module communicates with the main board of the external unit of the air conditioning system; the chopper speed control board receives the status information of the pressure switch through the pressure switch signal input interface; the logic program is stored in the main controller, and the power circuit is connected to the external unit of the air conditioning system motherboard. 2. The speed regulating device according to claim 1, It is characterized by: The main controller outputs a PWM signal, and the PWM signal controls the speed of the external fan through the photocoupler and the thyristor circuit. 3. The speed regulating device according to claim 1, It is characterized by: The breaking pressure of the pressure switch is 1.7-3.2MP, the recovery pressure is 1.2-2.6MP, and the difference between the breaking pressure and the recovery pressure is 0.4-0.7MP. 4. The speed regulating device according to claim 1, It is characterized by: The chopper speed control board divides the speed of the outdoor fan into N gears, each gear corresponds to a different percentage of the maximum speed of the outdoor fan, where N is greater than 3. 5. The speed regulating device according to claim 4, It is characterized by: N=6, where 6th gear to 1st gear correspond to 100%, 90%, 70%, 50%, 35% and 20% of the maximum speed of the external fan. 6. The air conditioning system, including the compressor connected into a closed circuit, the indoor heat exchanger, the outdoor heat exchanger, the main board of the outdoor unit, the external fan and the speed regulating device for regulating the speed of the external fan, It is characterized by: The speed regulating device includes: A pressure switch, which is installed on the discharge pipe of the compressor of the air conditioning system; The chopper speed control board further includes a main controller and a pressure switch signal input interface connected to the main controller, a power supply circuit, an RS485 communication module, a zero-crossing detection circuit and a motor control signal output module. The chopper speed control board passes through RS485 The communication module communicates with the main board of the external unit of the air conditioning system; the chopper speed control board receives the status information of the pressure switch through the pressure switch signal input interface; the logic program is stored in the main controller, and the power circuit is connected to the external unit of the air conditioning system motherboard. 7. The air conditioning system according to claim 6, It is characterized by: The breaking pressure of the pressure switch is 1.7-3.2MP, the recovery pressure is 1.2-2.6MP, and the difference between the breaking pressure and the recovery pressure is 0.4-0.7MP. 8. The air conditioning system according to claim 6, It is characterized by: The chopper speed control board divides the speed of the outdoor fan into N gears, each gear corresponds to a different percentage of the maximum speed of the outdoor fan, where N is greater than 3. 9. The air conditioning system according to claim 8, It is characterized by: N=6, where 6th gear to 1st gear correspond to 100%, 90%, 70%, 50%, 35% and 20% of the maximum speed of the external fan.

Images