Voltage state detection method for air conditioner and zero-crossing circuit

Abstract

The present invention provides a method for detecting the voltage state of an air conditioner and a zero-crossing circuit. The air conditioner includes: a zero-crossing detection module; a motor drive module; and a controller for obtaining a target zero-crossing dead-band time and a target dead-band interval of an input voltage in the zero-crossing detection circuit; determining the frequency of the input voltage based on the target dead-band interval; determining the voltage zero-crossing dead-band interval based on the frequency of the input voltage; determining the state of the motor based on the target zero-crossing dead-band time and the voltage zero-crossing dead-band interval, and adjusting the input voltage based on the motor state. By determining the corresponding relationship between the target zero-crossing dead-band time and the input voltage, the present invention determines the operating state of the motor, i.e., whether the motor is operating in an overvoltage or undervoltage state. If it is determined that the motor is operating in an overvoltage or undervoltage state, the input voltage is adjusted to protect the motor. This protects the motor without increasing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a method for detecting the voltage state of an air conditioner and a zero-crossing circuit. Background Art

[0002] At present, AC motors are widely used in household appliances. Generally, the zero-crossing signal of the zero-crossing detection circuit is used as the reference for controlling the motor, and the motor speed is adjusted by changing the opening angle of the thyristor.

[0003] However, when detecting whether the motor is in an overvoltage or undervoltage state, a special sampling circuit needs to be set up to collect the overvoltage value of the voltage to determine whether the motor is in an overvoltage or undervoltage state, which makes the circuit structure complex and the cost high. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, the first object of the present invention is to provide an air conditioner, which judges the operating state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state, by determining the corresponding relationship between the target zero-crossing dead time and the input voltage, and adjusts the input voltage when it is determined that the motor is operating in an overvoltage or undervoltage state to protect the motor, thereby achieving protection of the motor without increasing the cost.

[0006] Therefore, a second object of the present invention is to provide a method for detecting the voltage state of a zero-crossing circuit.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes an air conditioner, which includes: a zero-crossing detection module for outputting a zero-crossing signal; a motor drive module for driving a motor to operate; and a controller, wherein the controller is configured to: obtain a target zero-crossing dead-zone time and a target dead-zone interval time of an input voltage in the zero-crossing detection module; determine a frequency of the input voltage according to the target dead-zone interval time; determine a voltage zero-crossing dead-zone interval according to the frequency of the input voltage; determine an operating state of the motor according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval, and adjust the input voltage according to the operating state of the motor.

[0008] According to an embodiment of the present invention, the air conditioner determines the corresponding relationship between the target zero-crossing dead-band time and the input voltage, thereby judging the operating state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state. When it is determined that the motor is operating in an overvoltage or undervoltage state, the input voltage is adjusted to protect the motor, thereby achieving protection of the motor without increasing costs.

[0009] In some embodiments, the controller is specifically used to: when the frequency of the input voltage is a first frequency, determine the upper limit time of the first voltage zero-crossing dead zone and the lower limit time of the first voltage zero-crossing dead zone; when the frequency of the input voltage is a second frequency, determine the upper limit time of the second voltage zero-crossing dead zone and the lower limit time of the second voltage zero-crossing dead zone, wherein the first frequency is less than the second frequency.

[0010] In some embodiments, the controller is specifically used to: determine that the motor is operating in an overvoltage state when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time; determine that the motor is operating in an undervoltage state when the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time; and determine that the motor is operating at normal voltage when the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time.

[0011] In some embodiments, the controller is specifically used to: determine that the motor is operating in an overvoltage state when the target zero-crossing dead zone time is greater than the second voltage zero-crossing dead zone upper limit time; determine that the motor is operating in an undervoltage state when the target zero-crossing dead zone time is less than the second voltage zero-crossing dead zone lower limit time; and determine that the motor is operating at normal voltage when the target zero-crossing dead zone time is between the second voltage zero-crossing dead zone lower limit time and the second voltage zero-crossing dead zone upper limit time.

[0012] In some embodiments, the controller is specifically used to: obtain the zero-crossing dead-zone time of multiple input voltages and the multiple dead-zone interval times; calculate the average value of the zero-crossing dead-zone time of multiple input voltages and the average value of the multiple dead-zone interval times, and use the average value of the zero-crossing dead-zone time as the target zero-crossing dead-zone time, and use the average value of the dead-zone interval time as the target dead-zone interval time.

[0013] In order to achieve the above-mentioned purpose, an embodiment of the second aspect of the present invention proposes a voltage state detection method for a zero-crossing circuit, the method comprising: obtaining a target zero-crossing dead-zone time and a target dead-zone interval time of the input voltage; determining the frequency of the input voltage based on the target dead-zone interval time; determining the voltage zero-crossing dead-zone interval based on the frequency of the input voltage; determining the state of the input voltage based on the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval, and controlling the motor to perform corresponding actions based on the state of the input voltage.

[0014] According to the voltage state detection method of the zero-crossing circuit in an embodiment of the present invention, the operating state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state, is judged by determining the corresponding relationship between the target zero-crossing dead time and the input voltage. When it is determined that the motor is operating in an overvoltage or undervoltage state, the input voltage is adjusted to protect the motor, thereby achieving protection of the motor without increasing costs.

[0015] In some embodiments, the voltage zero-crossing dead zone interval is determined according to the frequency of the input voltage, including: when the frequency of the input voltage is a first frequency, determining the first voltage zero-crossing dead zone upper limit time and the first voltage zero-crossing dead zone lower limit time; when the frequency of the input voltage is a second frequency, determining the second voltage zero-crossing dead zone upper limit time and the second voltage zero-crossing dead zone lower limit time, wherein the first frequency is less than the second frequency.

[0016] In some embodiments, the state of the motor is determined based on the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, including: when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time, determining that the motor is operating in an overvoltage state; when the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time, determining that the motor is operating in an undervoltage state; when the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time, determining that the motor is operating at normal voltage.

[0017] In some embodiments, the state of the motor is determined based on the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, including: when the target zero-crossing dead zone time is greater than the second voltage zero-crossing dead zone upper limit time, determining that the motor is operating in an overvoltage state; when the target zero-crossing dead zone time is less than the second voltage zero-crossing dead zone lower limit time, determining that the motor is operating in an undervoltage state; when the target zero-crossing dead zone time is between the second voltage zero-crossing dead zone lower limit time and the second voltage zero-crossing dead zone upper limit time, determining that the motor is operating at normal voltage.

[0018] In some embodiments, obtaining the target zero-crossing dead-zone time and target dead-zone interval time of the input voltage in the zero-crossing detection module includes: obtaining the zero-crossing dead-zone time of multiple input voltages and the multiple dead-zone interval times; calculating the average value of the zero-crossing dead-zone time of multiple input voltages and the average value of the multiple dead-zone interval times, and using the average value of the zero-crossing dead-zone time as the target zero-crossing dead-zone time, and using the average value of the dead-zone interval time as the target dead-zone interval time.

[0019] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 is a circuit structure diagram of a zero-crossing detection circuit according to an embodiment of the present invention;

[0022] Figure 2 is a timing diagram of a zero-crossing detection circuit according to an embodiment of the present invention;

[0023] Figure 3 is a graph showing a corresponding relationship between input voltage and zero-crossing dead time according to an embodiment of the present invention;

[0024] Figure 4 is a block diagram of an air conditioner according to an embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of the zero-crossing dead time when the DC half-wave voltage is low according to one embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of the zero-crossing dead time when the DC half-wave voltage is high according to one embodiment of the present invention;

[0027] Figure 7 4 is a flow chart of a method for detecting a voltage state of a zero-crossing circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0029] like Figure 1FIG. 1 is a schematic diagram of the circuit structure of a zero-crossing detection circuit according to an embodiment of the present invention. After the AC voltage is half-wave rectified by diodes V500 and V501, the input voltage passes through optocoupler B510. When the voltage at point A is greater than the forward voltage drop of 0.7V between pins 1 and 2 of optocoupler B510, the emitter diode of optocoupler B510 is turned on. At the same time, pins 3 and 4 of the secondary of optocoupler B510 are turned on, transistor V514 is turned on, and the zero-crossing detection signal ZERO SI is in a low state. When the voltage at point A is lower than the forward voltage drop of 0.7V between pins 1 and 2 of optocoupler B510, the diode between pins 1 and 2 of the emitter of optocoupler B510 is cut off, transistor V514 is cut off, and the zero-crossing detection signal ZERO SI is in a high state. After the controller detects the zero-crossing signal, it calculates the required turn-on time based on the zero-crossing signal. At the calculated time point, it controls the PG DRIVER signal to output a high level to control the length of time the thyristor is turned on in each AC half-wave cycle, thereby achieving the purpose of adjusting the speed of the PG motor.

[0030] like Figure 2 FIG. 1 is a timing diagram of a zero-crossing detection circuit according to an embodiment of the present invention. Figure 2 It can be seen that there is a corresponding relationship between the input voltage and the zero-crossing dead zone. By determining the zero-crossing dead zone time, it can be determined whether the input voltage is normal, so that the motor can be controlled to take corresponding actions according to the input voltage. Among them, the zero-crossing dead zone time is the zero-crossing pulse width.

[0031] The following combination Figure 1 and Figure 2 The relationship between the input voltage and the zero-crossing dead time in the embodiment of the present invention is described.

[0032] After the AC voltage is rectified by the diode, the input voltage is output. The amplitude of the input voltage remains unchanged, but the frequency is doubled. The AC voltage can be expressed as V = √2VrmsSin(wt), where Vrms is the effective value.

[0033] The input voltage after rectification can be expressed as VA=√2Vrms Sin(2wt), where w is the angular frequency, which can be written as w=2πf, and f is the frequency of the input voltage, such as 50HZ or 60HZ, resulting in: V=√2VrmsSin(4πft). When the input voltage is less than the optocoupler B510 diode conduction voltage of 0.7V, the optocoupler B510 diode is cut off, and ZERO SI outputs a high level. In addition, when the two adjacent half-waves are lower than 0.7V, ZERO SI outputs a high-level pulse width signal, such as Figure 2 As shown, the high-level pulse width is: t2-t1, t4-t3, and the high-level pulse width signal t2-t1, t4-t3 is recorded as the zero-crossing dead zone time.

[0034] When the trigger voltage V=0.7V, t=Tdeadzone / 2, we get 0.7=√2VrmsSin(4πft),

[0035] Vrms = 0.7 / √2Sin(2πfT dead zone)… (1)

[0036] The triggering time interval between the front and back half-waves entering the dead zone is the half-wave period of the input power supply, that is, the half-wave period T after rectification, such as Figure 2 As shown, the dead zone interval T = t3-t1, the frequency of the input voltage f = 2 / T dead zone interval = 2 / (t3-t1), and the frequency of the input voltage f is substituted into the above Vrms formula to obtain:

[0037] Vrms = 0.7 / √2 Sin(4πT dead zone interval T dead zone) …(2)

[0038] From this, we can know that when the dead zone time T is obtained, the interval between the two dead zone triggers before and after T dead zone interval can be calculated. The relationship between the effective value Vrms and T dead zone is as follows: Figure 3 shown.

[0039] like Figure 3 FIG. 1 is a diagram showing the corresponding relationship between the input voltage and the zero-crossing dead time according to an embodiment of the present invention. Figure 3 It can be seen that there is a functional relationship between the input voltage and the dead-band interval. After determining the dead-band interval, the frequency of the input voltage can be determined based on the dead-band interval.

[0040] An air conditioner according to an embodiment of the present invention is described by way of example based on the above zero-crossing detection circuit.

[0041] Reference below Figure 4 An air conditioner according to an embodiment of the present invention is described. Figure 4 As shown, an air conditioner 1 according to an embodiment of the present invention includes: a zero-crossing detection module 10, a motor drive module 11, and a controller 12. The zero-crossing detection module 10 is configured to output a zero-crossing signal; the motor drive module 11 is configured to drive the motor to operate; and the controller 12 is configured to: obtain a target zero-crossing dead-band time and a target dead-band interval of the input voltage in the zero-crossing detection circuit; determine the frequency of the input voltage based on the target dead-band interval; determine the voltage zero-crossing dead-band interval based on the frequency of the input voltage; determine the state of the input voltage based on the target zero-crossing dead-band time and the voltage zero-crossing dead-band interval, and control the motor drive module to perform corresponding actions based on the voltage state. Thus, by determining the corresponding relationship between the input voltage and the target zero-crossing dead-band time, it is determined whether the input voltage is in an overvoltage or undervoltage state, so that the input voltage can be adjusted to protect the motor.

[0042] In the embodiment, when adjusting the input voltage, the target dead zone interval is recorded as T 目标死区间隔时间 , in determining T 目标死区间隔时间 Then, the frequency of the input voltage is judged according to the target dead zone interval time. The frequency of the input voltage is recorded as f, for example. After determining the frequency of the input voltage, the relationship between the frequency and the voltage zero-crossing dead zone interval is judged. Different frequencies correspond to different voltage zero-crossing dead zone intervals. For example, when the frequency is 50HZ, the corresponding voltage zero-crossing dead zone interval is different from the voltage zero-crossing dead zone interval corresponding to the frequency of 60HZ. After determining the voltage zero-crossing dead zone interval corresponding to the frequency, the target zero-crossing dead zone time is compared with the voltage zero-crossing dead zone interval. By comparing the relationship between the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, it is determined whether the DC half-wave voltage is in an overvoltage or undervoltage state. The size of the DC half-wave voltage is adjusted according to the overvoltage or undervoltage state to avoid damage to the motor caused by overvoltage or undervoltage, thereby performing corresponding protection on the motor.

[0043] According to an embodiment of the present invention, the air conditioner determines the corresponding relationship between the target zero-crossing dead-band time and the input voltage, thereby judging the operating state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state. When it is determined that the motor is operating in an overvoltage or undervoltage state, the input voltage is adjusted to protect the motor, thereby achieving protection of the motor without increasing costs.

[0044] In some embodiments, the controller is specifically used to: when the frequency of the input voltage is a first frequency, determine the upper limit time of the first voltage zero-crossing dead zone and the lower limit time of the first voltage zero-crossing dead zone; when the frequency of the input voltage is a second frequency, determine the upper limit time of the second voltage zero-crossing dead zone and the lower limit time of the second voltage zero-crossing dead zone, wherein the first frequency is less than the second frequency.

[0045] In an embodiment, the voltage zero-crossing dead zone interval includes the voltage zero-crossing dead zone upper limit time and the voltage zero-crossing dead zone lower limit time. When the frequency of the input voltage is a first frequency, such as 50HZ, the voltage zero-crossing dead zone interval includes the first voltage zero-crossing dead zone upper limit time and the first voltage zero-crossing dead zone lower limit time, wherein the first voltage zero-crossing dead zone upper limit time is, for example, recorded as T 死区_50Hz_280v , the first voltage zero-crossing dead zone lower limit time is recorded as T 死区_50Hz_150v , the first voltage zero-crossing dead zone upper limit time T 死区_50Hz_280v The corresponding zero-crossing dead zone time when overvoltage occurs, the first voltage zero-crossing dead zone lower limit time T 死区_50Hz_150v It is the corresponding zero-crossing dead time during undervoltage.

[0046] When the frequency of the input voltage is the second frequency, for example, 60 Hz, the voltage zero-crossing dead zone interval includes the second voltage zero-crossing dead zone upper limit time and the second voltage zero-crossing dead zone lower limit time, wherein the second voltage zero-crossing dead zone upper limit time is, for example, recorded as T死区_60Hz_280v , the lower limit time of the second voltage zero-crossing dead zone is recorded as T 死区_60Hz_150v , the second voltage zero-crossing dead zone upper limit time T 死区_60Hz_280v The corresponding zero-crossing dead zone time when overvoltage occurs, and the lower limit time of the second voltage zero-crossing dead zone T 死区_60Hz_150v It is the corresponding zero-crossing dead time during undervoltage.

[0047] Table 1 is a comparison table of target dead zone interval time and input voltage frequency according to an embodiment of the present invention.

[0048] Table 1

[0049]

[0050] It is understandable that the overvoltage value and the undervoltage value are preset. After determining the input frequency of the DC half-wave voltage, the voltage zero-crossing dead zone interval is determined by looking up the table according to the frequency. The determination method is simple and easy to implement.

[0051] like Figure 5 FIG. 1 is a schematic diagram of the zero-crossing dead time when the DC half-wave voltage is low according to an embodiment of the present invention. Figure 5 It can be seen that when the DC half-wave voltage is low, the corresponding zero-crossing dead zone time is longer.

[0052] like Figure 6 FIG. 1 is a schematic diagram of the zero-crossing dead time when the DC half-wave voltage is high according to an embodiment of the present invention. Figure 6 It can be seen that when the DC half-wave voltage is higher, the corresponding zero-crossing dead time is shorter. From this, it can be seen that the zero-crossing dead time is different under different input voltages. When the DC half-wave voltage increases, the zero-crossing dead time decreases. The input voltage and the zero-crossing dead time are inversely proportional.

[0053] In some embodiments, the controller is specifically used to: determine that the motor is operating in an overvoltage state when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time; determine that the motor is operating in an undervoltage state when the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time; and determine that the motor is operating at normal voltage when the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time.

[0054] In an embodiment, whether the DC half-wave voltage is overvoltage or undervoltage is determined by comparing the target zero-crossing dead zone time with the relationship between the first voltage zero-crossing dead zone upper limit time and the first target zero-crossing dead zone lower limit time.

[0055] Specifically, when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time, that is, T 目标死区间隔时间 <T 死区_50Hz_280v, it is considered that the DC half-wave voltage is high and is in an overvoltage state. At this time, it is determined that the motor is running in an overvoltage state, an overvoltage fault will occur, and the corresponding protection strategy is implemented for the motor;

[0056] When the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time, that is, T 目标死区间隔时间 >T 死区_50Hz_150v , it is determined that the motor is running in an overvoltage state, and it is considered that the DC half-wave voltage is low and is in an undervoltage state. At this time, it is determined that the motor is running in an undervoltage state, an undervoltage fault will occur, and the corresponding protection strategy will be executed for the motor;

[0057] When the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time, that is, T 死区_50Hz_150v < T 目标死区间隔时间 <T 死区_50Hz_150v , it is considered that the DC half-wave voltage is normal and in a normal state. At this time, it is determined that the motor is running in a normal state.

[0058] In some embodiments, the controller is specifically used to: determine that the input voltage is in an overvoltage state when the target zero-crossing dead zone time is greater than the second voltage zero-crossing dead zone upper limit time; determine that the input voltage is in an undervoltage state when the target zero-crossing dead zone time is less than the second voltage zero-crossing dead zone lower limit time; and determine that the input voltage is in a normal state when the target zero-crossing dead zone time is between the second voltage zero-crossing dead zone lower limit time and the second voltage zero-crossing dead zone upper limit time.

[0059] In an embodiment, whether the DC half-wave voltage is overvoltage or undervoltage is determined by comparing the target zero-crossing dead zone time with the second voltage zero-crossing dead zone upper limit time and the second target zero-crossing dead zone lower limit time.

[0060] Specifically, when the target zero-crossing dead zone time is greater than the second voltage zero-crossing dead zone upper limit time, that is, T 目标死区间隔时间 >T 死区_60Hz_280v , it is considered that the DC half-wave voltage is high and is in an overvoltage state. At this time, it is determined that the motor is running in an overvoltage state, an overvoltage fault will occur, and the corresponding protection strategy is implemented for the motor;

[0061] When the target zero-crossing dead zone time is less than the second voltage zero-crossing dead zone lower limit time, that is, T 目标死区间隔时间 <T 死区_60Hz_150v , it is determined that the motor is running in an overvoltage state, and it is considered that the DC half-wave voltage is low and is in an undervoltage state. At this time, it is determined that the motor is running in an undervoltage state, an undervoltage fault will occur, and the corresponding protection strategy will be executed for the motor;

[0062] When the target zero-crossing dead zone time is between the second voltage zero-crossing dead zone lower limit time and the second voltage zero-crossing dead zone upper limit time, that is, T 死区_60Hz_150v < T目标死区间隔时间 <T 死区_60Hz_150v , it is considered that the DC half-wave voltage is normal and in a normal state. At this time, it is determined that the motor is running in a normal state.

[0063] In some embodiments, the controller is specifically used to: obtain the zero-crossing dead-zone time and multiple dead-zone interval times of multiple input voltages; calculate the average value of the zero-crossing dead-zone time and the average value of the multiple dead-zone interval times of the multiple input voltages, and use the average value of the zero-crossing dead-zone time as the target zero-crossing dead-zone time, and use the average value of the dead-zone interval time as the target dead-zone interval time.

[0064] In an embodiment, when collecting the zero-crossing dead time and multiple dead interval times of the input voltage, in order to improve the accuracy of subsequent motor state control, it is necessary to collect multiple zero-crossing dead time and multiple dead interval times, and calculate the average value of the multiple zero-crossing dead time to obtain the target zero-crossing dead time, and calculate the average value of the multiple dead interval times to obtain the average value of the dead interval time.

[0065] According to an embodiment of the present invention, the air conditioner determines the corresponding relationship between the target zero-crossing dead-band time and the input voltage, thereby judging the operating state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state. When it is determined that the motor is operating in an overvoltage or undervoltage state, the input voltage is adjusted to protect the motor, thereby achieving protection of the motor without increasing costs.

[0066] The following describes a method for detecting a voltage state of a zero-crossing circuit according to an embodiment of the present invention.

[0067] like Figure 7 As shown, the voltage state detection method of the zero-crossing circuit according to the embodiment of the present invention at least includes steps S1 to S4.

[0068] Step S1, obtaining a target zero-crossing dead-zone time and a target dead-zone interval time of an input voltage in a zero-crossing detection circuit.

[0069] In the embodiment, when adjusting the input voltage, the target dead zone interval is recorded as T 目标死区间隔时间 , in determining T 目标死区间隔时间 .

[0070] Step S2: determining the frequency of the input voltage according to the target dead zone interval.

[0071] In an embodiment, the frequency of the input voltage is determined according to the target dead-zone interval time, and the frequency of the input voltage is, for example, denoted as f.

[0072] Step S3: determining a voltage zero-crossing dead zone interval according to the frequency of the input voltage.

[0073] In an embodiment, after determining the frequency of the input voltage, the relationship between the frequency and the voltage zero-crossing dead zone interval is determined. Different frequencies correspond to different voltage zero-crossing dead zone intervals. For example, when the frequency is 50HZ, the corresponding voltage zero-crossing dead zone interval is different from the voltage zero-crossing dead zone interval corresponding to the frequency of 60HZ.

[0074] Step S4, determining the state of the motor according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval, and adjusting the input voltage according to the state of the motor.

[0075] In an embodiment, after determining the voltage zero-crossing dead zone interval corresponding to the frequency, the target zero-crossing dead zone time is compared with the voltage zero-crossing dead zone interval. By comparing the relationship between the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, it is determined whether the DC half-wave voltage is in an overvoltage or undervoltage state. The magnitude of the DC half-wave voltage is adjusted according to the overvoltage or undervoltage state to avoid damage to the motor caused by overvoltage or undervoltage, thereby performing corresponding protection on the motor.

[0076] According to the voltage state detection method of the zero-crossing circuit in an embodiment of the present invention, the state of the motor, that is, whether the motor is operating in an overvoltage or undervoltage state, is judged by determining the corresponding relationship between the target zero-crossing dead time and the input voltage. When it is determined that the input voltage is overvoltage or undervoltage, the input voltage is adjusted to protect the motor, thereby achieving protection of the motor without increasing costs.

[0077] In some embodiments, the voltage zero-crossing dead zone interval is determined according to the frequency of the input voltage, including: when the frequency of the input voltage is a first frequency, determining the first voltage zero-crossing dead zone upper limit time and the first voltage zero-crossing dead zone lower limit time; when the frequency of the input voltage is a second frequency, determining the second voltage zero-crossing dead zone upper limit time and the second voltage zero-crossing dead zone lower limit time, wherein the first frequency is less than the second frequency.

[0078] In an embodiment, the voltage zero-crossing dead zone interval includes the voltage zero-crossing dead zone upper limit time and the voltage zero-crossing dead zone lower limit time. When the frequency of the input voltage is a first frequency, such as 50HZ, the voltage zero-crossing dead zone interval includes the first voltage zero-crossing dead zone upper limit time and the first voltage zero-crossing dead zone lower limit time, wherein the first voltage zero-crossing dead zone upper limit time is, for example, recorded as T 死区_50Hz_280v , the first voltage zero-crossing dead zone lower limit time is recorded as T 死区_50Hz_150v , the first voltage zero-crossing dead zone upper limit time T 死区_50Hz_280v The corresponding zero-crossing dead zone time when overvoltage occurs, the first voltage zero-crossing dead zone lower limit time T 死区_50Hz_150v It is the corresponding zero-crossing dead time during undervoltage.

[0079] When the frequency of the input voltage is the second frequency, for example, 60 Hz, the voltage zero-crossing dead zone interval includes the second voltage zero-crossing dead zone upper limit time and the second voltage zero-crossing dead zone lower limit time, wherein the second voltage zero-crossing dead zone upper limit time is, for example, recorded as T 死区_60Hz_280v , the lower limit time of the second voltage zero-crossing dead zone is recorded as T 死区_60Hz_150v , the second voltage zero-crossing dead zone upper limit time T 死区_60Hz_280v The corresponding zero-crossing dead zone time when overvoltage occurs, and the lower limit time of the second voltage zero-crossing dead zone T 死区_60Hz_150v It is the corresponding zero-crossing dead time during undervoltage.

[0080] In some embodiments, the state of the motor is determined based on the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, including: when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time, determining that the motor is operating in an overvoltage state; when the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time, determining that the motor is operating in an undervoltage state; when the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time, determining that the motor is operating at normal voltage.

[0081] In some embodiments, the state of the motor is determined based on the target zero-crossing dead zone time and the voltage zero-crossing dead zone interval, including: when the target zero-crossing dead zone time is greater than the second voltage zero-crossing dead zone upper limit time, determining that the motor is operating in an overvoltage state; when the target zero-crossing dead zone time is less than the second voltage zero-crossing dead zone lower limit time, determining that the motor is operating in an undervoltage state; when the target zero-crossing dead zone time is between the second voltage zero-crossing dead zone lower limit time and the second voltage zero-crossing dead zone upper limit time, determining that the motor is operating at normal voltage.

[0082] In an embodiment, whether the DC half-wave voltage is overvoltage or undervoltage is determined by comparing the target zero-crossing dead zone time with the relationship between the first voltage zero-crossing dead zone upper limit time and the first target zero-crossing dead zone lower limit time.

[0083] Specifically, when the target zero-crossing dead zone time is less than the first voltage zero-crossing dead zone upper limit time, that is, T 目标死区间隔时间 <T 死区_50Hz_280v , it is considered that the DC half-wave voltage is high and is in an overvoltage state. At this time, it is determined that the motor is running in an overvoltage state, an overvoltage fault will occur, and the corresponding protection strategy is implemented for the motor;

[0084] When the target zero-crossing dead zone time is greater than the first voltage zero-crossing dead zone lower limit time, that is, T 目标死区间隔时间 >T 死区_50Hz_150v , it is determined that the motor is running in an overvoltage state, and it is considered that the DC half-wave voltage is low and is in an undervoltage state. At this time, it is determined that the motor is running in an undervoltage state, an undervoltage fault will occur, and the corresponding protection strategy will be executed for the motor;

[0085] When the target zero-crossing dead zone time is between the first voltage zero-crossing dead zone lower limit time and the first voltage zero-crossing dead zone upper limit time, that is, T 死区_50Hz_150v < T 目标死区间隔时间 <T 死区_50Hz_150v , it is considered that the DC half-wave voltage is normal and in a normal state. At this time, it is determined that the motor is running in a normal state.

[0086] In some embodiments, obtaining the target zero-crossing dead-zone time and target dead-zone interval time of the input voltage in the zero-crossing detection module includes: obtaining the zero-crossing dead-zone time and multiple dead-zone interval times of multiple input voltages; calculating the average value of the zero-crossing dead-zone time and the average value of the multiple dead-zone interval times of the multiple input voltages, and using the average value of the zero-crossing dead-zone time as the target zero-crossing dead-zone time, and using the average value of the dead-zone interval time as the target dead-zone interval time.

[0087] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0088] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that: include: A zero-crossing detection module, used for outputting a zero-crossing signal; Motor drive module, used to drive the motor to operate; A controller configured to: Obtaining a target zero-crossing dead zone time and a target dead zone interval time of an input voltage in the zero-crossing detection module; determining the frequency of the input voltage according to the target dead-band interval; Determining a voltage zero-crossing dead zone interval according to the frequency of the input voltage; The operating state of the motor is determined according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval, and the input voltage is adjusted according to the operating state of the motor.

2. The air conditioner according to claim 1, characterized in that The controller is specifically used for: When the frequency of the input voltage is the first frequency, determining the upper limit time of the first voltage zero-crossing dead zone and the lower limit time of the first voltage zero-crossing dead zone; When the frequency of the input voltage is a second frequency, a second voltage zero-crossing dead zone upper limit time and a second voltage zero-crossing dead zone lower limit time are determined, wherein the first frequency is less than the second frequency.

3. The air conditioner according to claim 2, characterized in that The controller is specifically used for: When the target zero-crossing dead-band time is less than the first voltage zero-crossing dead-band upper limit time, determining that the motor is operating in an overvoltage state; When the target zero-crossing dead-zone time is greater than the first voltage zero-crossing dead-zone lower limit time, determining that the motor is operating in an undervoltage state; When the target zero-crossing dead-band time is between the first voltage zero-crossing dead-band lower limit time and the first voltage zero-crossing dead-band upper limit time, it is determined that the motor is operating at a normal voltage.

4. The air conditioner according to claim 2, characterized in that The controller is specifically used for: When the target zero-crossing dead-band time is less than the second voltage zero-crossing dead-band upper limit time, determining that the motor is operating in an overvoltage state; When the target zero-crossing dead-zone time is greater than the lower limit time of the second voltage zero-crossing dead-zone, determining that the motor is operating in an undervoltage state; When the target zero-crossing dead-band time is between the second voltage zero-crossing dead-band lower limit time and the second voltage zero-crossing dead-band upper limit time, it is determined that the motor is operating at a normal voltage.

5. The air conditioner according to claim 1, characterized in that The controller is specifically used for: Acquire a plurality of zero-crossing dead-zone times of the input voltages and a plurality of dead-zone interval times; An average value of the zero-crossing dead-zone times of the input voltages and an average value of the dead-zone intervals are calculated, and the average value of the zero-crossing dead-zone times is used as the target zero-crossing dead-zone time, and the average value of the dead-zone intervals is used as the target dead-zone interval time.

6. A method for detecting the voltage state of a zero-crossing circuit, characterized in that: include Obtaining a target zero-crossing dead-zone time and a target dead-zone interval time of an input voltage in a zero-crossing detection circuit; determining the frequency of the input voltage according to the target dead-band interval; Determining a voltage zero-crossing dead zone interval according to the frequency of the input voltage; The state of the motor is determined according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval, and the input voltage is adjusted according to the state of the motor.

7. The method for detecting the voltage state of a zero-crossing circuit according to claim 6, wherein: Determining a voltage zero-crossing dead zone interval according to the frequency of the input voltage includes: When the frequency of the input voltage is the first frequency, determining the upper limit time of the first voltage zero-crossing dead zone and the lower limit time of the first voltage zero-crossing dead zone; When the frequency of the input voltage is a second frequency, a second voltage zero-crossing dead zone upper limit time and a second voltage zero-crossing dead zone lower limit time are determined, wherein the first frequency is less than the second frequency.

8. The method for detecting the voltage state of a zero-crossing circuit according to claim 7, wherein: Determining the state of the motor according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval includes: When the target zero-crossing dead-band time is less than the first voltage zero-crossing dead-band upper limit time, determining that the motor is operating in an overvoltage state; When the target zero-crossing dead-zone time is greater than the first voltage zero-crossing dead-zone lower limit time, determining that the motor is operating in an undervoltage state; When the target zero-crossing dead-band time is between the first voltage zero-crossing dead-band lower limit time and the first voltage zero-crossing dead-band upper limit time, it is determined that the motor is operating at a normal voltage.

9. The method for detecting the voltage state of a zero-crossing circuit according to claim 7, wherein: Determining the state of the motor according to the target zero-crossing dead-zone time and the voltage zero-crossing dead-zone interval includes: When the target zero-crossing dead-band time is less than the second voltage zero-crossing dead-band upper limit time, determining that the motor is operating in an overvoltage state; When the target zero-crossing dead-zone time is greater than the lower limit time of the second voltage zero-crossing dead-zone, determining that the motor is operating in an undervoltage state; When the target zero-crossing dead-band time is between the second voltage zero-crossing dead-band lower limit time and the second voltage zero-crossing dead-band upper limit time, it is determined that the motor is operating at a normal voltage.

10. The method for detecting the voltage state of a zero-crossing circuit according to claim 6, wherein: Obtaining a target zero-crossing dead-zone time and a target dead-zone interval time of an input voltage in the zero-crossing detection module includes: Acquire a plurality of zero-crossing dead-zone times of the input voltages and a plurality of dead-zone interval times; An average value of the zero-crossing dead-zone times of the input voltages and an average value of the dead-zone intervals are calculated, and the average value of the zero-crossing dead-zone times is used as the target zero-crossing dead-zone time, and the average value of the dead-zone intervals is used as the target dead-zone interval time.

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