Motor control method, control device, computer readable storage medium and air conditioner

Abstract

The present invention discloses a motor control method, a control device, a computer-readable storage medium and an air conditioner, wherein the method comprises: controlling the motor according to a preset duty cycle and obtaining a sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor; determining the actual current of the motor according to the sampling voltage; and determining that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds a preset threshold. The method determines whether the sampling resistor or the sampling circuit is damaged based on the actual current and the theoretical current determined by the sampling voltage, and automatically identifies and determines whether the sampling resistor or the sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of household electrical appliances, and in particular to a motor control method, a computer-readable storage medium, an air conditioner, and a motor control device. Background Art

[0002] In air conditioners, non-inductive resistors are generally used for motor current sampling, such as using non-inductive resistors to sample the operating current of compressors and DC fans. However, due to the heat generation of non-inductive resistors, for high current application scenarios, it is generally necessary to connect multiple non-inductive resistors in parallel as the total sampling resistor to solve the problem of high heat generation and difficulty in heat dissipation of non-inductive resistors.

[0003] However, in the application process of multiple sampling resistors in parallel, if one of the sampling resistors is damaged or open, the actual equivalent resistance of multiple parallel non-inductive resistors will change. The motor control of compressors and DC fans is based on the detection and feedback of the motor current based on the resistance value of the equivalent resistor, and then the motor control is based on the detection feedback current. If the resistance value of the equivalent resistor is wrong, then when the motor current is small, the difference between the detection feedback current and the actual current is small, and closed-loop operation can be achieved; however, when the motor current is large, the detection feedback current is seriously inconsistent with the actual current, and stable control of the motor cannot be achieved, which will cause the air conditioner to malfunction, require maintenance, and reduce user experience. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to propose a motor control method, which determines whether the sampling resistor or sampling circuit is damaged by comparing the actual current determined by the sampling voltage with the theoretical current, and automatically identifies and determines whether the sampling resistor or sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or sampling circuit, and ensuring user experience.

[0005] A second object of the present invention is to provide a computer-readable storage medium.

[0006] The third object of the present invention is to provide an air conditioner.

[0007] A fourth objective of the present invention is to provide a motor control device.

[0008] To achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a motor control method, which includes: controlling the motor according to a preset duty cycle and obtaining a sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor; determining the actual current of the motor based on the sampling voltage; and determining that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds a preset threshold.

[0009] According to the motor control method of the embodiment of the present invention, first, the motor is controlled according to the preset duty cycle, and a sampling voltage is obtained, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor, and the actual current of the motor is determined according to the sampling voltage, and when the difference between the actual current and the theoretical current exceeds a preset threshold, it is determined that the sampling resistor or the sampling circuit is damaged. Thus, the method determines whether the sampling resistor or the sampling circuit is damaged by the actual current and the theoretical current determined by the sampling voltage, and automatically identifies and determines whether the sampling resistor or the sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0010] In addition, the motor control method according to the above embodiment of the present invention may also have the following additional technical features:

[0011] According to an embodiment of the present invention, determining the actual current of the motor according to the sampled voltage includes: obtaining the product of the sampled voltage and the sampling gain coefficient to obtain the actual current of the motor.

[0012] According to an embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the motor control method further includes: adjusting the sampling gain coefficient according to the actual current and the theoretical current.

[0013] According to one embodiment of the present invention, the sampling gain coefficient is adjusted according to the actual current and the theoretical current, including: obtaining the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtaining the ratio of the sampling gain coefficient to the adjustment coefficient to obtain the adjusted sampling gain coefficient.

[0014] According to an embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the motor control method further includes: controlling the motor to operate with limited power.

[0015] According to an embodiment of the present invention, controlling the motor to operate with limited power includes: controlling the motor to operate with limited power according to actual current and theoretical current.

[0016] According to one embodiment of the present invention, the motor is controlled to operate with limited power based on the actual current and the theoretical current, including: obtaining the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtaining the ratio of the current maximum allowable operating power of the motor to the adjustment coefficient to obtain the adjusted maximum allowable operating frequency of the motor.

[0017] According to one embodiment of the present invention, the theoretical current is calculated based on a preset duty cycle, a DC bus voltage of the motor, a phase resistance of the motor, a sampling voltage when the sampling resistor and the sampling circuit are not damaged, and a sampling gain coefficient.

[0018] According to one embodiment of the present invention, the theoretical current is calculated by the following formula:

[0019]

[0020] Among them, I 理论 is the theoretical current, V dc is the DC bus voltage of the motor, duty is the preset duty cycle, R is the phase resistance of the motor, V ad is the sampling voltage when the sampling circuit is not damaged, k 采样增益 is the sampling gain factor.

[0021] To achieve the above-mentioned purpose, a second aspect of the present invention provides a computer-readable storage medium on which a motor control program is stored. When the motor control program is executed by a processor, the above-mentioned motor control method is implemented.

[0022] According to the computer-readable storage medium of an embodiment of the present invention, the above-mentioned motor control method is implemented when the motor control program stored thereon is executed by a processor. Based on the above-mentioned motor control method, it is automatically identified and determined whether the sampling resistor or the sampling circuit has damaged resistors without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0023] To achieve the above objectives, a third aspect of the present invention provides an air conditioner, comprising a memory, a processor, and a motor control program stored in the memory and executable on the processor. When the processor executes the motor control program, the above motor control method is implemented.

[0024] According to the air conditioner of the embodiment of the present invention, when the motor control program is executed by the processor, the above-mentioned motor control method is implemented. Based on the above-mentioned motor control method, whether the sampling resistor or the sampling circuit is damaged is determined by the actual current and the theoretical current determined by the sampling voltage. Without adding hardware, it is automatically identified and determined whether the sampling resistor or the sampling circuit is damaged, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, reducing the failure rate and maintenance cost of the air conditioner, and improving the user experience.

[0025] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a motor control device, which includes: a control unit, used to control the motor according to a preset duty cycle; an acquisition unit, used to acquire a sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor; a first determination unit, used to determine the actual current of the motor based on the sampling voltage; and a second determination unit, used to determine that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds a preset threshold.

[0026] According to the motor control device of the embodiment of the present invention, the control unit controls the motor according to the preset duty cycle, and the acquisition unit acquires the sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through the sampling resistor and the sampling circuit connected to the sampling resistor, the first determination unit determines the actual current of the motor according to the sampling voltage, and the second determination unit determines that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds the preset threshold. Thus, the device determines whether the sampling resistor or the sampling circuit is damaged by the actual current and the theoretical current determined by the sampling voltage, and automatically identifies and determines whether the sampling resistor or the sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of a motor control method according to an embodiment of the present invention;

[0029] Figure 2 A motor control circuit diagram according to an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of motor control according to an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a change in the duty cycle of the upper bridge arm of the U phase according to an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of motor control according to another embodiment of the present invention;

[0033] Figure 6 is a flow chart of a motor control method according to a specific embodiment of the present invention;

[0034] Figure 7 is a block diagram of an air conditioner according to an embodiment of the present invention;

[0035] Figure 8 FIG. 4 is a block diagram of a motor control device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] The motor control method, computer-readable storage medium, air conditioner, and motor control device provided in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0038] Figure 1 is a flow chart of a motor control method according to an embodiment of the present invention.

[0039] like Figure 1 As shown, the motor control method of the embodiment of the present invention may include:

[0040] S1, controlling the motor according to a preset duty cycle and obtaining a sampled voltage, wherein the sampled voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor;

[0041] S2, determining the actual current of the motor according to the sampled voltage;

[0042] S3, when the difference between the actual current and the theoretical current exceeds a preset threshold, it is determined that the sampling resistor or the sampling circuit is damaged. The preset threshold can be set according to actual conditions.

[0043] The motor can be a DC motor or an AC motor. The sampling voltage can be obtained through a single sampling resistor or based on three sampling resistors. The specific arrangement of the sampling resistors can be applied according to actual conditions and is not limited here.

[0044] Below Figure 2 The motor control method of the present application is described by taking FIG.

[0045] like Figure 2 As shown, this embodiment uses a single sampling resistor to obtain the actual current of the motor. Among them, the three-phase inverter circuit 1 is composed of six switch tubes, wherein the six switch tubes are represented by U+, U-, V+, V-, W+, and W-, respectively. A node U is formed between the switch tubes U+ and U-, and the node U is connected to the U phase of the motor 20; a node V is formed between the switch tubes V+ and V-, and the node V is connected to the V phase of the motor 20; a node W is formed between the switch tubes W+ and W-, and the node W is connected to the W phase of the motor 20. The input end of the three-phase inverter circuit 1 is connected to the DC power supply Vdc, and the sampling resistor Rs is connected in series between the input end of the three-phase inverter circuit 1 and the negative pole of the DC power supply Vdc. During the motor driving process, the control unit controls the six switch tubes in the three-phase inverter circuit 1 by outputting six PWM (Pulse Width Modulation) signals, so that the three-phase inverter circuit 1 outputs a three-phase electrical signal to drive the motor 2. At the same time, the control unit detects the current of the motor 2 in real time through the sampling resistor Rs to achieve closed-loop control of the motor 2. In addition, Figure 2 In the figure, the three-phase winding of the motor 2 is equivalent to a series resistor-inductor model, and the resistance R and inductance L are equal between the three phases.

[0046] In the motor control process, the control unit is connected to the sampling resistor Rs through the sampling circuit, and the control unit collects the voltage on the sampling resistor Rs through the sampling circuit to reconstruct the motor current. In order to reduce the energy consumption of the sampling resistor Rs, the resistance of the sampling resistor Rs is usually small. Therefore, in order to ensure the detection accuracy, the sampling circuit is provided with an amplifier circuit. The input end of the amplifier circuit is connected to the sampling resistor Rs to amplify the voltage on the sampling resistor Rs, and the amplified voltage is sent to the control unit as the sampling voltage. The control unit reconstructs the actual current of the motor according to the sampling voltage obtained after the amplification process, and controls the motor according to the actual current obtained by the reconstruction. In addition, since the voltage on the sampling resistor Rs corresponds to the direction of the current flowing through, when the motor current flowing through the sampling resistor Rs is a positive current, the voltage on the sampling resistor Rs is a positive voltage, and when the motor current flowing through the sampling resistor Rs is a negative current, the voltage on the sampling resistor Rs is a negative voltage. In order to ensure that the sampling voltage input to the control unit is always positive, a bias circuit can also be set in the sampling circuit, and a positive bias voltage is provided by the bias circuit, and the voltage of the sampling resistor Rs is biased to obtain a positive voltage, which is not limited here.

[0047] After the motor is produced or actually used for a period of time, the resistance of the sampling resistor Rs changes. Assume that the resistance of the sampling resistor Rs changes from the original R1 to 2R1. Since the sampling resistor Rs is very small relative to the phase resistance R of the motor 20, even if the resistance of the sampling resistor Rs doubles, under the same DC bus voltage and duty cycle, the current in the motor circuit remains approximately unchanged.

[0048] However, doubling the resistance of the sampling resistor Rs will cause a huge change in the voltage of the sampling resistor Rs, and further under the amplification effect of the sampling circuit, it will cause a very large change in the sampling voltage input to the control unit. Since the reconstructed model remains unchanged, the reconstructed current will be much larger than the current in the motor circuit, which will have an adverse effect on motor control.

[0049] In order to ensure the stability of motor control, the present application controls the motor based on a preset duty cycle to ensure that the voltage is consistent with that when the theoretical current is obtained, and then reconstructs the actual current of the motor based on the sampled voltage obtained in real time. If the difference between the actual current obtained by reconstruction and the theoretical current exceeds the preset threshold, it is considered that there is a large difference between the actual current and the theoretical current, indicating that there is a problem with the current sampling resistor Rs or the sampling circuit. If the difference between the actual current obtained by reconstruction and the theoretical current is less than or equal to the preset threshold, it means that the current sampling resistor Rs and the sampling circuit are both in normal state, and the motor can be controlled based on the actual current obtained by current reconstruction.

[0050] Therefore, the method can automatically evaluate whether the sampling resistor or the sampling circuit is damaged based on the existing motor control circuit without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0051] In one embodiment of the present invention, determining the actual current of the motor according to the sampled voltage includes: obtaining the product of the sampled voltage and the sampling gain coefficient to obtain the actual current of the motor.

[0052] Specifically, when the sampling circuit includes a bias circuit and an amplifier circuit, the voltage across the sampling resistor is output to the sampling voltage of the control unit through the sampling circuit, which can be expressed by formula (1):

[0053] V ad =V 偏置 +β*i*R s (1)

[0054] Among them, V ad is the sampling voltage, V 偏置 is the DC bias voltage provided by the bias circuit, β is the amplification factor provided by the amplifier circuit, i is the current flowing through the sampling resistor Rs, Rs It should be noted that the above DC bias voltage can be set according to actual conditions and is not mandatory.

[0055] The reconstruction model set by the control unit can be expressed by formula (2):

[0056] I 实际 =V ad *k 采样增益 (2)

[0057] Among them, I 实际 is the actual current, V ad is the sampling voltage, k 采样增益 is the sampling gain factor.

[0058] It should be noted that the sampling gain coefficient in formula (2) is determined by the preset hardware amplifier circuit, the actual sampling resistor, and the voltage conversion relationship in the control unit. It is preset in the software or parameters and will not change with the change of the resistance value of the actual sampling resistor. 采样增益 In a one-to-one correspondence, the actual current sampled should be equal to the theoretical current.

[0059] During the operation of the motor, the control unit substitutes the real-time sampled voltage into formula (2) to calculate the actual current, and compares the actual current with the theoretical current to determine whether the sampling resistor or the sampling circuit is damaged.

[0060] It should be noted that the above theoretical current can be determined when the sampling resistor and the sampling circuit are normal, so as to be used for subsequent judgment.

[0061] In one embodiment of the present invention, the theoretical current is calculated based on a preset duty cycle, a DC bus voltage of the motor, a phase resistance of the motor, a sampling voltage when the sampling resistor and the sampling circuit are not damaged, and a sampling gain coefficient.

[0062] According to one embodiment of the present invention, the theoretical current is calculated by the following formula:

[0063]

[0064] Among them, I 理论 is the theoretical current, V dc is the DC bus voltage of the motor, duty is the preset duty cycle, R is the phase resistance of the motor, V ad is the sampling voltage when the sampling circuit is not damaged, k 采样增益 is the sampling gain factor.

[0065] Specifically, combined Figures 2 to 4 As shown, taking the upper and lower bridge arms of any two phases in the three-phase as an example, the conduction mode of the U-phase bridge arm is as follows: Figure 3 As shown, the duty cycle of conduction increases from small to large until it reaches a preset duty cycle, and then it is stably turned on and off at the preset duty cycle. The duty cycle change can be achieved not only through amplitude modulation output but also through frequency modulation output, and ultimately the bus voltage duty cycle modulation can be satisfied.

[0066] In the process of simultaneously conducting the upper and lower bridge arms of any two phases in the three-phase in the form of pulses, the upper bridge arms and lower bridge arms of any two phases in the three-phase and any two phases of the motor form a loop. Taking the U+ and V- in the three-phase inverter circuit 2 as an example, Figure 2 As shown, the loop forms the following formula (4):

[0067]

[0068] Among them, I is the total circuit current and also the current flowing through the resistor Rs, V dc is the DC bus voltage of the motor, duty is the preset duty cycle, R is the phase resistance of the motor, and Virbt is the on-state voltage drop of the switch tube.

[0069] Since the sampling resistor Rs is very small compared to the sum of the two-phase resistance of the motor (2R), it can be ignored. The switch tube conduction voltage drop Virbt is relative to the modulation voltage (V dc *duty) is also small. After ignoring it, the above formula (4) can be simplified to formula (5):

[0070]

[0071] According to formula (5), after the preset duty cycle is fixed, the actual DC bus voltage can be measured in real time as a known item, and the motor phase resistance is a known item as a motor control parameter, so the actual loop current I is a fixed value. The actual current collected by the control unit at this time needs to satisfy the relationship of formula (5), that is, the actual current calculated by formula (2) should be equal to the current value calculated by formula (5), that is, the theoretical current, and formula (3) is constructed. In other words, the current value calculated based on the preset duty cycle, the DC bus voltage of the motor, the phase resistance of the motor, and the sampling resistance is equal to the sampling voltage when the sampling circuit is not damaged, and the current value calculated by the sampling gain coefficient, and the current value is the theoretical current.

[0072] It should be noted that the above formula (3) is set based on the technical solution of controlling the upper and lower bridge arms of any two phases in the three-phase to be turned on simultaneously in the form of pulses. In the technical solution of controlling the upper and lower bridge arms of any three phases in the three-phase to be turned on simultaneously in the form of pulses, taking U+, V-, and W- in the three-phase inverter circuit 2 as an example, Figure 5 As shown, after ignoring the sampling resistor Rs and the on-state voltage drop of the switch tube, the following formula (6) can be obtained:

[0073]

[0074] The theoretical current is calculated by the following formula:

[0075]

[0076] For details, reference may be made to the above formula derivation process in the process of controlling the upper and lower bridge arms of any two phases in the three phases to be simultaneously turned on in a pulse form, and no limitation is made here.

[0077] Furthermore, due to the sampling gain factor k 采样增益 It is jointly determined by the preset hardware amplifier circuit, the actual sampling resistor, and the voltage conversion relationship of the control unit, and will not change with the change of the actual sampling resistor. At the same time, the theoretical current is calculated based on the preset duty cycle, the DC bus voltage of the motor, the phase resistance of the motor, the sampling resistor and the sampling voltage when the sampling circuit is not damaged, and the sampling gain coefficient. Therefore, when the preset duty cycle, the DC bus voltage of the motor, the actual sampling resistor of the circuit, the amplification factor, and the sampling gain coefficient correspond one by one, the actual current I sampled by the control unit is 实际 Equal to the theoretical current I 理论 .

[0078] When the control unit is produced or actually used for a period of time, the resistance of the sampling resistor changes, causing the I reconstructed by the control unit to 实际 >>I 理论 Therefore, when the control unit outputs a fixed duty cycle, the sampled I 实际 with I 理论 If there is a large difference, it means that there is a problem with the current sampling resistor or sampling circuit. At this time, the control unit can send a corresponding alarm signal to remind the user.

[0079] In one embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the motor control method further includes: adjusting the sampling gain coefficient according to the actual current and the theoretical current.

[0080] That is to say, in order to reduce the impact of damage to the sampling resistor or sampling circuit on motor control, after determining that the sampling resistor or sampling circuit is damaged, the sampling gain coefficient is adjusted to reduce or eliminate the current deviation between the actual current and the theoretical current to eliminate the fault, thereby achieving the purpose of users being able to continue using it in the short term.

[0081] Specifically, when the difference between the actual current and the theoretical current exceeds a preset threshold, the sampling gain coefficient is adjusted according to the actual current and the theoretical current, and the adjusted sampling gain coefficient is substituted into formula (2) as a new reconstruction model, and the control unit calculates the actual current with the adjusted sampling gain coefficient within a preset time period thereafter. This embodiment adjusts the reconstruction model of the actual current by adjusting the sampling gain coefficient to ensure that the current difference between the actual current output by the reconstruction model and the theoretical current meets the requirements of motor control stability, thereby achieving stable control of the motor within a preset time period. For example, when the difference between the actual current and the theoretical current exceeds a preset threshold, the sampling gain coefficient is adjusted according to the deviation between the difference between the actual current and the theoretical current and the preset threshold. For example, multiple adjustment parameters can be pre-set, and the corresponding adjustment parameters are selected according to the deviation between the difference and the preset threshold, so that the sampling gain coefficient is adjusted according to the adjustment parameters.

[0082] The above preset duration can be set according to the actual situation. When the adjustment time of the sampling gain coefficient exceeds the preset time, if the staff still does not perform the corresponding fault alarm processing, it is considered that the current damage time is too long, and the motor can be controlled to stop, or a higher-level alarm reminder can be issued. If before the adjustment time of the sampling gain coefficient exceeds the preset time, if the corresponding fault processing signal, recovery signal, etc. are received to indicate that the sampling resistor or sampling circuit has returned to normal, the original sampling gain coefficient is adjusted, and the actual current is calculated according to the original reconstruction model.

[0083] In one embodiment of the present invention, the sampling gain coefficient is adjusted according to the actual current and the theoretical current, including: obtaining the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtaining the ratio of the sampling gain coefficient to the adjustment coefficient to obtain the adjusted sampling gain coefficient.

[0084] That is, when the difference between the actual current and the theoretical current exceeds the preset threshold, the actual current and the theoretical current are substituted into the following formula:

[0085]

[0086] Among them, α is the adjustment coefficient, I 实际 is the actual current, I 理论 is the theoretical current.

[0087] Substitute the adjustment coefficient calculated by formula (8) into the following formula (9) to calculate the adjusted sampling gain coefficient:

[0088]

[0089] Among them, k' 采样增益is the adjusted sampling gain coefficient, α is the adjustment coefficient, k 采样增益 is the sampling gain factor.

[0090] The adjusted sampling gain coefficient is substituted into formula (2) to serve as a new reconstruction model to determine the actual current within a preset time period.

[0091] In one embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the motor control method further includes: controlling the motor to operate with limited power.

[0092] When multiple resistors are connected in parallel to form a sampling resistor, the increase in the resistance of the sampling resistor may be due to the burning of one or more of the resistors. If the original power is maintained, the remaining resistors in normal state will burn out quickly. Therefore, when it is determined that the sampling resistor or the sampling circuit is damaged, the operating power of the motor is limited synchronously. The power limit control of the motor can be to reduce the maximum operating power of the motor or the current operating power of the motor, which is not limited here.

[0093] In one embodiment of the present invention, controlling the motor to operate with limited power includes: controlling the motor to operate with limited power according to actual current and theoretical current.

[0094] That is to say, the power adjustment parameter is determined according to the actual current and the theoretical current, so as to adjust the motor power. For example, the corresponding power adjustment parameter can be determined according to the range of the difference between the actual current and the theoretical current, and then the motor power is adjusted according to the corresponding power adjustment parameter. For example, when the difference between the actual current and the theoretical current is in (I1, I2], the power adjustment parameter is a1, and the maximum operating power of the motor is controlled to be reduced by a1; when the difference between the actual current and the theoretical current is in (I2, I3], the power adjustment parameter is a2, and the maximum operating power of the motor is controlled to be reduced by a2.

[0095] In one embodiment of the present invention, the motor is controlled to operate with limited power according to the actual current and the theoretical current, including: obtaining the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtaining the ratio of the current maximum allowable operating power of the motor to the adjustment coefficient to obtain the adjusted maximum allowable operating frequency of the motor.

[0096] That is, when the difference between the actual current and the theoretical current exceeds the preset threshold, the actual current and the theoretical current are substituted into formula (8) to calculate the adjustment coefficient. Then, the calculated adjustment coefficient is substituted into the following formula to calculate the maximum allowable operating power of the motor after adjustment:

[0097]

[0098] Wherein, P' is the maximum allowable operating power of the motor after adjustment, α is the adjustment coefficient, and P is the maximum allowable operating power of the current motor.

[0099] This embodiment adjusts the maximum allowable operating power of the motor according to the ratio between the actual current and the theoretical current. When it is determined that the sampling resistor or the sampling circuit is damaged, the maximum allowable operating power of the motor is synchronously limited, and the power reduced by α times is used as the maximum allowable operating limit power. When this embodiment detects that the sampling resistor or the sampling circuit is damaged, the maximum allowable operating limit power of the motor is automatically changed, so as to achieve short-term reliable operation of the motor and reduce the impact on customers.

[0100] As a specific embodiment of the present application, Figure 6 As shown, the motor control method of the embodiment of the present invention may include the following steps:

[0101] S601, determining a theoretical current.

[0102] S602, controlling the motor according to a preset duty cycle and obtaining a sampled voltage.

[0103] S603, obtaining the product of the sampled voltage and the sampling gain coefficient to obtain the actual current of the motor.

[0104] S604, determine whether the difference between the actual current and the theoretical current exceeds a preset threshold. If yes, execute step S605; if no, execute step S602.

[0105] S605, obtaining the ratio of the actual current to the theoretical current to obtain the adjustment coefficient.

[0106] S606, obtaining the ratio of the current maximum allowable operating power of the motor to the adjustment coefficient, and obtaining the adjusted maximum allowable operating frequency of the motor to control the motor to operate with limited power.

[0107] S607, obtaining the ratio of the sampling gain coefficient to the adjustment coefficient to obtain the adjusted sampling gain coefficient. Execute step S603.

[0108] In summary, according to the motor control method of the embodiment of the present invention, first, the motor is controlled according to the preset duty cycle, and a sampling voltage is obtained, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor, and the actual current of the motor is determined according to the sampling voltage. When the difference between the actual current and the theoretical current exceeds a preset threshold, it is determined that the sampling resistor or the sampling circuit is damaged. Therefore, the method determines whether the sampling resistor or the sampling circuit is damaged by the actual current and the theoretical current determined by the sampling voltage, and automatically identifies and determines whether the sampling resistor or the sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0109] Corresponding to the above embodiment, the present invention also proposes a computer-readable storage medium.

[0110] The computer-readable storage medium of the embodiment of the present invention stores a motor control program, and the motor control program implements the above motor control method when executed by a processor.

[0111] According to the computer-readable storage medium of an embodiment of the present invention, the above-mentioned motor control method is implemented when the motor control program stored thereon is executed by a processor. Based on the above-mentioned motor control method, it is automatically identified and determined whether the sampling resistor or the sampling circuit has damaged resistors without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0112] Corresponding to the above embodiment, the present invention also proposes an air conditioner.

[0113] like Figure 7 As shown, the air conditioner 100 of the embodiment of the present invention includes a memory 110, a processor 120, and a motor control program stored in the memory 110 and executable on the processor 120. When the processor 120 executes the motor control program, the above-mentioned motor control method is implemented.

[0114] According to the air conditioner of the embodiment of the present invention, when the motor control program is executed by the processor, the above-mentioned motor control method is implemented. Based on the above-mentioned motor control method, whether the sampling resistor or the sampling circuit is damaged is determined by the actual current and the theoretical current determined by the sampling voltage. Without adding hardware, it is automatically identified and determined whether the sampling resistor or the sampling circuit is damaged, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, reducing the failure rate and maintenance cost of the air conditioner, and improving the user experience.

[0115] Corresponding to the above embodiment, the present invention further proposes a motor control device.

[0116] like Figure 8 As shown, the motor control device according to the embodiment of the present invention may include: a control unit 10 , an acquisition unit 20 , a first determination unit 30 and a second determination unit 40 .

[0117] The control unit 10 is used to control the motor according to a preset duty cycle. The acquisition unit 20 is used to acquire a sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor. The first determination unit 30 is used to determine the actual current of the motor according to the sampling voltage. The second determination unit 40 is used to determine that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds a preset threshold.

[0118] According to an embodiment of the present invention, the first determination unit 30 determines the actual current of the motor according to the sampled voltage, and is specifically used to obtain the product of the sampled voltage and the sampling gain coefficient to obtain the actual current of the motor.

[0119] According to an embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the control unit 10 is further configured to: adjust the sampling gain coefficient according to the actual current and the theoretical current.

[0120] According to an embodiment of the present invention, the control unit 10 is specifically used to: obtain the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtain the ratio of the sampling gain coefficient to the adjustment coefficient to obtain the adjusted sampling gain coefficient.

[0121] According to an embodiment of the present invention, after determining that the sampling resistor or the sampling circuit is damaged, the control unit 10 is further used to: control the motor to operate with limited power.

[0122] According to an embodiment of the present invention, the control unit 10 controls the motor to operate with limited power, specifically, to control the motor to operate with limited power according to the actual current and the theoretical current.

[0123] According to one embodiment of the present invention, the control unit 10 controls the motor to operate with limited power according to the actual current and the theoretical current, and is specifically used to: obtain the ratio of the actual current to the theoretical current to obtain the adjustment coefficient; obtain the ratio of the current maximum allowable operating power of the motor to the adjustment coefficient to obtain the adjusted maximum allowable operating frequency of the motor.

[0124] According to one embodiment of the present invention, the theoretical current is calculated based on a preset duty cycle, a DC bus voltage of the motor, a phase resistance of the motor, a sampling voltage when the sampling resistor and the sampling circuit are not damaged, and a sampling gain coefficient.

[0125] According to one embodiment of the present invention, the theoretical current is calculated by the following formula:

[0126]

[0127] Among them, I 理论 is the theoretical current, V dc is the DC bus voltage of the motor, duty is the preset duty cycle, R is the phase resistance of the motor, V ad is the sampling voltage when the sampling circuit is not damaged, k 采样增益 is the sampling gain factor.

[0128] It should be noted that for details not disclosed in the motor control device of the embodiment of the present invention, please refer to the details disclosed in the motor control method of the above embodiment of the present invention, and the details will not be repeated here.

[0129] According to the motor control device of the embodiment of the present invention, the control unit controls the motor according to the preset duty cycle, and the acquisition unit acquires the sampling voltage, wherein the sampling voltage is obtained by sampling the actual current of the motor through the sampling resistor and the sampling circuit connected to the sampling resistor, the first determination unit determines the actual current of the motor according to the sampling voltage, and the second determination unit determines that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds the preset threshold. Thus, the device determines whether the sampling resistor or the sampling circuit is damaged by the actual current and the theoretical current determined by the sampling voltage, and automatically identifies and determines whether the sampling resistor or the sampling circuit is damaged without adding hardware, thereby avoiding the situation where the motor cannot be stably controlled due to damage to the sampling resistor or the sampling circuit, and ensuring user experience.

[0130] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0131] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0132] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0133] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0134] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0135] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A motor control method, characterized in that: The method comprises: Controlling the motor according to a preset duty cycle and obtaining a sampled voltage, wherein the sampled voltage is obtained by sampling an actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor; Determine the actual current of the motor according to the sampled voltage; When the difference between the actual current and the theoretical current exceeds a preset threshold, it is determined that the sampling resistor or the sampling circuit is damaged.

2. The method according to claim 1, characterized in that The step of determining the actual current of the motor according to the sampled voltage comprises: The product of the sampled voltage and the sampling gain coefficient is obtained to obtain the actual current of the motor.

3. The method according to claim 2, characterized in that After determining that the sampling resistor or the sampling circuit is damaged, the method further includes: The sampling gain coefficient is adjusted according to the actual current and the theoretical current.

4. The method according to claim 3, characterized in that The step of adjusting the sampling gain coefficient according to the actual current and the theoretical current includes: Obtaining a ratio of the actual current to the theoretical current to obtain a regulation coefficient; The ratio of the sampling gain coefficient to the adjustment coefficient is obtained to obtain an adjusted sampling gain coefficient.

5. The method according to any one of claims 1 to 4, characterized in that: After determining that the sampling resistor or the sampling circuit is damaged, the method further includes: The motor is controlled to operate with limited power.

6. The method according to claim 5, characterized in that The controlling the motor to operate with limited power includes: The motor is controlled to operate at limited power according to the actual current and the theoretical current.

7. The method according to claim 6, characterized in that The controlling the motor to operate with limited power according to the actual current and the theoretical current includes: Obtaining a ratio of the actual current to the theoretical current to obtain a regulation coefficient; The ratio of the current maximum allowable operating power of the motor to the adjustment coefficient is obtained to obtain the adjusted maximum allowable operating frequency of the motor.

8. The method according to claim 2, characterized in that: The theoretical current is calculated based on the preset duty cycle, the DC bus voltage of the motor, the phase resistance of the motor, the sampling voltage when the sampling resistor and the sampling circuit are not damaged, and a sampling gain coefficient.

9. The method according to claim 8, characterized in that The theoretical current is calculated by the following formula: Among them, I 理论 is the theoretical current, V dc is the DC bus voltage of the motor, duty is the preset duty cycle, R is the phase resistance of the motor, V ad is the sampling voltage when the sampling circuit is not damaged, k 采样增益 is the sampling gain coefficient.

10. A computer-readable storage medium, characterized in that: A motor control program is stored thereon, and when the motor control program is executed by a processor, the motor control method according to any one of claims 1-9 is implemented.

11. An air conditioner, characterized in that: The invention comprises a memory, a processor and a motor control program stored in the memory and executable on the processor. When the processor executes the motor control program, the motor control method according to any one of claims 1 to 9 is implemented.

12. A motor control device, characterized in that: The device comprises: A control unit, used for controlling the motor according to a preset duty cycle; An acquisition unit, used for acquiring a sampled voltage, wherein the sampled voltage is obtained by sampling an actual current of the motor through a sampling resistor and a sampling circuit connected to the sampling resistor; A first determining unit, configured to determine an actual current of the motor according to the sampled voltage; The second determining unit is used to determine that the sampling resistor or the sampling circuit is damaged when the difference between the actual current and the theoretical current exceeds a preset threshold.

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