CN220509087U - Temperature controller operating condition detection circuit - Google Patents

Abstract

The application discloses a temperature control working state detection circuit, wherein the temperature controller working state detection circuit is connected with a heating circuit, the heating circuit is powered by input alternating current to work, and the heating circuit comprises a temperature controller for controlling the on state of the heating circuit according to temperature, a heating wire for heating and a silicon controlled rectifier for controlling the heating circuit to work according to a control signal; the temperature controller working state detection circuit comprises a microprocessor and an optocoupler bias circuit which is connected and matched with the controllable silicon and the microprocessor; an output pin of the microprocessor is connected with the controllable silicon in the heating circuit, and sends a control signal to the controllable silicon; the microprocessor detects zero crossing points of the input alternating current through a zero crossing detection circuit; the optocoupler bias circuit is connected with the circuit input end and the circuit output end of the controllable silicon in the heating circuit, and the blocking condition of the air inlet and the air outlet of the equipment can be recognized more rapidly and effectively by detecting the conduction state of the heating circuit and then detecting the working state of the temperature controller. Once the temperature controller is powered off, the technology makes a significant contribution to the stable operation of daily household appliances and the safe use of users.

Description

Temperature controller operating condition detection circuit

Technical Field

The application relates to the field of electric appliance temperature control, in particular to a temperature controller working state detection circuit under alternating current work.

Background

The temperature controller is a device for controlling by using temperature, and is mainly used for maintaining or adjusting the temperature of a specific system. The basic structure comprises a temperature sensor, a control unit and an execution device. The temperature sensor is responsible for detecting the temperature of the current system and converting the temperature into an identifiable signal, and the control unit compares the received signal with a preset temperature threshold value and performs related operations, such as turning on or off a heating element, through the execution device so as to maintain or adjust the temperature of the system.

Because of its simple structure, small volume, safety and reliability, and easy installation and use, the temperature controller is widely used in household appliances such as air blowing tubes, electric heaters, electric kettles, water dispensers and various heating devices. The working temperature of the equipment is controlled, so that the equipment is ensured to run in a preset temperature range, and overheating and supercooling phenomena are avoided, so that the safety of the equipment and internal elements thereof is protected.

In the prior art, the temperature controller mainly monitors the temperature of the environment where the temperature controller is located to judge the working state of the temperature controller. When the equipment normally operates, if the excessive temperature is detected, the temperature controller can be automatically powered off to protect the equipment from being damaged by overheat. However, there are certain limitations to this approach.

Firstly, current thermostats are more focused on the detection of the ambient temperature, whereas the state of the motor inside the device, in particular the heat dissipation conditions during its operation, are not directly monitored. In some special cases, such as blocking the air inlet or the air outlet of the air blower, even if the temperature controller is already powered off due to overheating, the motor may continue to operate at high temperature due to the inability to obtain effective heat dissipation. In this state, the life of the motor and its drive controller is greatly reduced, and burnout or other serious safety problems may occur.

Second, although it is possible to determine whether the device is blocked by detecting the internal temperature of an Intelligent Power Module (IPM) within the controller, this method has some time delay. Because the temperature inside the IPM rises more slowly, the time to detect the wind blocking state may be longer. During this time, if the motor continues to operate at a high temperature, irreversible damage may have occurred.

In addition, this detection method depending on the internal temperature change of the IPM does not accurately reflect the clogging of the air outlet device. This means that the user may not be able to learn about the abnormal state of the device in time, thereby missing the optimal maintenance and repair time.

In addition, in the above problems, it is only needed to additionally increase leads between the temperature controller and the heating wires, and the current working state of the heating wires is judged by detecting the circuit of the flowing temperature controller, so that the conditions of high cost, high production difficulty and circuit space waste exist.

Therefore, aiming at the problems, a detection circuit and a detection method thereof are developed, wherein the detection circuit can detect the working state of the temperature controller in real time and accurately without directly detecting the voltage and the loop current at two ends of the temperature controller, so that the blocking condition of an air port of equipment can be identified more quickly and effectively, the overheat damage of a motor and a driving controller is prevented, and the detection circuit has important practical significance and value.

Disclosure of Invention

The purpose of this application aims at overcoming the at least one point defect that prior art exists, provides one kind and realizes blocking up the wind state through discernment temperature controller operating condition under alternating current operational environment, and motor and drive controller long-time operation lead to the control by temperature change operating condition detection circuit of damage under the effective blocking up wind condition.

In order to achieve the above object, in a first aspect, the present application discloses a temperature controller working state detection circuit, where the temperature controller working state detection circuit is connected with a heating circuit, the heating circuit is powered by input ac power, and the heating circuit includes a temperature controller for controlling an on state of the heating circuit according to temperature, a heating wire for heating, and a silicon controlled rectifier for controlling the heating circuit to work according to a control signal; the temperature controller working state detection circuit comprises a microprocessor and an optocoupler bias circuit which is connected and matched with the controllable silicon and the microprocessor; the output pin of the microprocessor is connected with the silicon controlled rectifier in the heating circuit, and sends a control signal to the silicon controlled rectifier; the microprocessor detects zero crossing points of the input alternating current through a zero crossing detection circuit; the optocoupler bias circuit is connected with the circuit input end and the circuit output end of the controllable silicon in the heating circuit and is used for detecting the conduction state of the heating circuit and inputting the detection structure and the high-low level form into the input pin of the microprocessor so as to judge the opening and closing state of the temperature controller in the heating circuit,

in some embodiments, the input pin of the microprocessor is connected with the grid electrode of the controllable silicon through the optocoupler isolation circuit, so that the work of the controllable silicon is controlled, and the electrical isolation is realized.

In some embodiments, an output pin in the microprocessor outputs a high level at a zero crossing position of the input alternating current, so that the silicon controlled rectifier works, and the heating circuit is controlled to work and heat.

In an embodiment, the input pin of the microprocessor periodically detects the input of the optocoupler bias circuit, and determines the on state of the heating circuit according to the input of the optocoupler bias circuit, that is, detects the on-off state of the temperature controller in the heating circuit, and the optocoupler bias circuit outputs a low level when the heating circuit is on and outputs a high level after the heating circuit is off.

In a second aspect, for achieving the purpose of the present application, the present application further discloses a temperature controller working state detection method based on the temperature control working state detection circuit. The method comprises the following steps:

step one: the microprocessor detects zero crossing points of input alternating current through a zero crossing detection circuit;

step two: the microprocessor adjusts the output pins to output at the zero crossing point of the input alternating current and controls the silicon controlled rectifier to work, so that the heating circuit works;

step three, a step of performing; the microprocessor periodically detects the output of the optocoupler bias circuit, and judges the opening and closing states of the temperature controllers in the heating circuit according to the output of the optocoupler bias circuit.

The application detects the working state of the temperature controller through detecting the conduction state of the heating circuit, and can more quickly and effectively identify the blocking condition of the air inlet and the air outlet of the equipment. Once the temperature controller is powered off, the air inlet of the equipment can be judged to be blocked.

The method can avoid long-time operation of the motor and the driving controller under the condition of wind blockage, further avoid damage caused by overheat, and greatly prolong the service life and the safety of the equipment. In addition, as the method can quickly detect the blockage of the air port, a user can also take measures in time, such as cleaning or replacing the air port, so as to avoid further damage of equipment. This technology makes a significant contribution to the stable operation of daily household appliances and the safe use of users.

Drawings

Various aspects of the present disclosure will be better understood upon reading the following detailed description in conjunction with the drawings, the location, dimensions, and ranges of individual structures shown in the drawings, etc., are sometimes not indicative of actual locations, dimensions, ranges, etc. In the drawings:

FIG. 1 is a block diagram of hardware connections of an embodiment of the present disclosure.

Fig. 2 is a schematic circuit configuration diagram of an embodiment of the present disclosure, based on a simplified representation, without a microprocessor and a zero-crossing detection circuit.

Description of the embodiments

The present disclosure will be described below with reference to the accompanying drawings, which illustrate several embodiments of the present disclosure. It should be understood, however, that the present disclosure may be embodied in many different forms and should not be limited to the embodiments described below, but rather, the embodiments described below are intended to provide a more complete disclosure of the present disclosure and to fully illustrate the scope of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide yet additional embodiments.

It should be understood that throughout the drawings, like reference numerals refer to like elements. In the drawings, the size of certain features may be modified for clarity.

It should be understood that the terminology used in the description is for the purpose of describing particular embodiments only, and is not intended to be limiting of the disclosure. All terms (including technical and scientific terms) used in the specification have the meanings commonly understood by one of ordinary skill in the art unless otherwise defined. For the sake of brevity and/or clarity, techniques, methods and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but the techniques, methods and apparatus should be considered a part of the specification where appropriate.

As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. The use of the terms "comprising," "including," and "containing" in the specification mean that the recited features are present, but that one or more other features are not excluded. The use of the phrase "and/or" in the specification includes any and all combinations of one or more of the associated listed items. The words "between X and Y" and "between about X and Y" used in this specification should be interpreted to include X and Y. The phrase "between about X and Y" as used herein means "between about X and about Y", and the phrase "from about X to Y" as used herein means "from about X to about Y".

In the description, an element is referred to as being "on," "attached" to, "connected" to, "coupled" to, "contacting" or the like another element, and the element may be directly on, attached to, connected to, coupled to or contacting the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly attached to," directly connected to, "directly coupled to, or" directly contacting "another element, there are no intervening elements present. In the specification, one feature is arranged "adjacent" to another feature, which may mean that one feature has a portion overlapping with or located above or below the adjacent feature.

In the specification, spatial relationship words such as "upper", "lower", "left", "right", "front", "rear", "high", "low", and the like may describe the relationship of one feature to another feature in the drawings. It will be understood that the spatial relationship words comprise, in addition to the orientations shown in the figures, different orientations of the device in use or operation. For example, when the device in the figures is inverted, features that were originally described as "below" other features may be described as "above" the other features. The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the relative spatial relationship will be explained accordingly.

Examples

As shown in fig. 1 and 2, the detection circuit 1 disclosed in the present embodiment is matched with a heating circuit 2, where the heating circuit 1 at least includes a temperature controller, a heating wire and a silicon controlled rectifier (SCR 1 in the figure), and the heating circuit 2 is connected with an input alternating current and is driven to work by the input alternating current; temperature controller, heater (F1 in the figure) and SCR1 establish ties in heating circuit 1, and wherein the temperature controller can preset threshold temperature, and when heating circuit 1 is in threshold temperature, the temperature controller disconnection makes the heater close work, prevents further intensification and then causes electrical apparatus damage. In the heating circuit, a current input end (an A pole in the figure) and a circuit output end (a K pole in the figure) of the SCR1 are used for connecting the heating circuit 1 in series, and the work of a heating wire is controlled by controlling the opening and closing states of the heating circuit 1, namely, the heating control is realized.

It should be understood that the temperature controller controls the heating circuit 1 to be opened or closed based on the temperature threshold, and the SCR1 actively controls the heating circuit 1 to be opened, and the working purposes and effects of the two are different.

In this embodiment, as shown in fig. 1 and 2, the microprocessor 4 (MCU in the drawing) in the detection circuit 1 has an output pin mcu_o and an input pin mcu_i, where the output pin mcu_o is connected to a gate electrode (G pole in the drawing) in the SCR1 in the heating circuit, so as to implement the operation control of the MCU on the SCR1, and in order to implement the electrical isolation of the MCU from other electrical devices during operation, the mcu_o is connected to the optocoupler U1, and the specific components of the optocoupler U1 are clearly shown in fig. 1, so that a description thereof will not be given again. Finally, the optocoupler U1 outputs high and low levels to the grid electrode of the SCR1, and the grid electrode acquires signals and then controls the conduction relation of the heating circuit 2 according to the signals.

In this embodiment, as shown in fig. 1 and 2, the output of the pin mcu_o in the microprocessor 4 is guided by the zero-crossing data provided by the zero-crossing detection circuit 5, and the main function of the zero-crossing detection circuit 5 is to detect when the ac signal passes through its zero voltage point, i.e. when it changes from a positive half-cycle to a negative half-cycle, or from a negative half-cycle to a positive half-cycle. Since the zero-crossing detection circuit 5 is a mature circuit, its circuit structure composition and cooperation with the input ac power and detection reasons are well known in the art, only the basic structure and functions of the zero-crossing detection circuit 5 will be briefly described in this embodiment, and the zero-crossing detection circuit 5 will not be described in detail. For example: a basic zero crossing detection circuit 5 may consist of an operational amplifier and some basic resistors and diodes. The working principle of the circuit is as follows: when the input is alternating current, the output of the operational amplifier will change correspondingly when the polarity of the voltage changes (i.e., zero crossing). When the input voltage changes from positive to negative, the output of the operational amplifier changes from high to low; and vice versa. Thus, it is possible to determine when the ac signal passes through the zero point by detecting the change in the output level of the operational amplifier.

It will be appreciated that in order to convert this signal into a digital signal which can be processed by the microprocessor 4, a shaping circuit is added to the output of the zero crossing detection circuit 5 to shape the varying analog signal into a level hopped digital signal. This digital signal can then be received by an input pin of the microprocessor 4, from which the microprocessor 4 can determine the zero crossing of the ac signal.

It will also be appreciated that because the voltage of the input ac power is typically relatively high and the microprocessor 4 is only capable of processing low voltage signals, it is also necessary to divide or otherwise reduce the voltage to a range that the microprocessor 4 can handle before inputting the signal to the microprocessor 4.

In this embodiment, as a core component of the detection circuit, the optocoupler bias circuit 3 substantially connects the a terminal and the K terminal of the SCR1, i.e., substantially detects the substantially open/close state of the heating circuit 2, and sends the result to the mcu_i in the form of high/low level. In the embodiment, the optocoupler bias circuit 3 is a pull-up circuit, and the optocoupler device U2 and the pull-up resistor R5 are connected with an output end of the optocoupler device U2 and MCU_I of the microprocessor 4 respectively at a first end of the pull-up resistor R5; the second terminal of the pull-up resistor R5 is connected to the high level VDD, and when the input terminal of the optocoupler U2 is not receiving a signal, the pull-up resistor R5 pulls the mcu_i high. When a signal exists at the input end of the optocoupler device 2, the photoelectric sensitive element in the optocoupler device U2 is conducted, and the MCU_I is pulled down to be low level.

Further, the other output end of the optocoupler U2 is grounded, and the output end is connected and matched with the first end of the pull-up resistor R5 through a capacitor C2.

In the case of the above hardware configuration, the implementation procedure of this embodiment is as follows:

under the normal working state, the temperature controller is normally closed. Detecting the zero-crossing position of the input alternating current by a zero-crossing detection circuit 5; at the zero crossing time t0 of the alternating current, the MCU_O outputs a high level, the optical coupler device U1 is conducted to work, the bidirectional thyristor SCR1 is triggered to conduct to work, and the heating wire F1 starts to heat; when the SCR1 works normally, the optical coupler device U2 cannot work in a conducting mode due to small conducting voltage drop (negligible), so that the MCU_I is always in a high level; detecting MCU_I voltage at intervals of fixed time t; (since the temperature control is performed with the time of opening and closing again, the time is basically in the second level, so the interval time t can be set in the hundred millisecond level); when the air inlet and the air outlet are abnormally blocked, the heating wire F1 is still heated, the temperature of the temperature controller continuously rises, and when the temperature triggering value of the temperature controller is reached, the temperature controller is disconnected; at interval time t, for example, at the zero crossing time tn0, mcu_o outputs a low level, while at the next zero crossing time tn1 of the same period, mcu_o outputs a high level. If the MCU_I receives a low level between the time tn0 and the time tn1, the temperature controller is indicated to work normally and is in a closed state; if the MCU_I receives a high level from the time tn0 to tn1, the temperature controller is indicated to be over-temperature protection and is in an off state.

It should be understood that, when the SCR1 controlling the heating wire F1 may be designed to be periodically heated (the period time is set to be in the hundreds of milliseconds), the duty ratio received by the trigger pin G of the SCR1 is designed to be less than 100%, that is, the duty ratio of the mcu_o is designed to be less than 100%. In the design, when the SCR1 is turned off, the working state of the temperature controller can be identified by detecting the MCU_I receiving signal.

The duty cycle is a ratio concept, for example, when 50 alternating current half waves are turned on to be 100%, a heating period is 500ms, and when 1 alternating current half wave is turned on to be 98%.

Although exemplary embodiments of the present disclosure have been described, it will be understood by those skilled in the art that various changes and modifications can be made to the exemplary embodiments of the present disclosure without materially departing from the spirit and scope of the disclosure. Accordingly, all changes and modifications are intended to be included within the scope of the present disclosure as defined by the appended claims. The disclosure is defined by the following claims, with equivalents of the claims to be included therein.

Claims (4)

1. The utility model provides a temperature controller operating condition detection circuitry, this temperature controller operating condition detection circuitry links to each other with heating circuit, heating circuit receives the work of input alternating current power supply, including the temperature controller according to temperature control heating circuit on state in the heating circuit, play the heater strip of heating effect and according to the silicon controlled rectifier of control signal control heating circuit work, its characterized in that: the temperature controller working state detection circuit comprises a microprocessor and an optocoupler bias circuit which is connected and matched with the controllable silicon and the microprocessor; an output pin of the microprocessor is connected with the controllable silicon in the heating circuit, and sends a control signal to the controllable silicon; the microprocessor detects zero crossing points of the input alternating current through a zero crossing detection circuit; the optocoupler bias circuit is connected with the circuit input end and the circuit output end of the controllable silicon in the heating circuit and is used for detecting the conduction state of the heating circuit, and inputting the detection structure and the high-low level form into the input pin of the microprocessor, so that the judgment of the opening and closing state of the temperature controller in the heating circuit is realized.

2. A thermostat operating condition detection circuit as claimed in claim 1 wherein: the input pin of the microprocessor is connected with the grid electrode of the controllable silicon through the optocoupler isolation circuit, so that the work of the controllable silicon is controlled, and the electrical isolation is realized.

3. A thermostat operating condition detection circuit as claimed in claim 1 wherein: the output pin in the microprocessor outputs high level at the zero crossing position of the input alternating current, so that the silicon controlled rectifier works, and the heating circuit is controlled to work and heat.

4. A thermostat operating condition detection circuit as claimed in claim 1 wherein: the input pin of the microprocessor periodically detects the input of the optocoupler bias circuit, judges the conduction state of the heating circuit according to the input of the optocoupler bias circuit, namely detects the opening and closing state of a temperature controller in the heating circuit, and outputs a low level when the heating circuit is conducted and a high level after the heating circuit is disconnected.