Motor drive circuit, control method thereof, and electric appliance

Abstract

The application relates to the field of power electronics, and discloses a motor driving circuit, a control method thereof and an electrical appliance. The motor driving circuit comprises a power supply circuit composed of a main power supply and a plurality of auxiliary power supplies. The main power supply supplies power for normal operation of the motor, and a driving control circuit is arranged to control the connection of the auxiliary power supplies, so that the total power supply voltage of the motor is increased, the torque of the motor is improved, the torque capacity of the motor is ensured when the motor operates under extreme conditions such as locked-rotor, and the input winding of the transformer in the switching power supply does not need to be increased, the efficiency of the overall power supply is further improved, the product manufacturing cost is reduced, the motor operation demand under different conditions is met, and the use experience of users is improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to motor drive circuits and their control methods, and electrical equipment. Background Technology

[0002] As customers continue to demand higher quality of life, the functional requirements for various home appliances driven by electric motors, such as air conditioners, range hoods, and washing machines, are increasing. This means that motors need to face more and more operating conditions, especially short-term extreme conditions such as motor stalling or additional loads. This requires motors to have higher torque capabilities to achieve these conditions.

[0003] In related technologies, the common way to increase motor torque is to increase the input winding of the transformer in the switching power supply of the controller. However, the operating time of the motor under extreme conditions is limited. This method of increasing the switching power supply winding will increase the core loss and coil resistance loss. Especially when operating at high frequency, the winding resistance heats up more, which leads to a decrease in overall power efficiency. In addition, increasing the input winding requires a larger core and heat dissipation space, which increases the product manufacturing cost. Summary of the Invention

[0004] In view of this, the present invention provides a motor drive circuit and its control method, as well as an electrical device, to solve the problem that increasing the motor torque capability by increasing the input winding of the transformer in the switching power supply in the related art increases losses, reduces power efficiency, and increases costs.

[0005] In a first aspect, the present invention provides a motor drive circuit, comprising: a power supply circuit and a drive control circuit, wherein the power supply circuit includes a main power output circuit and at least one auxiliary power output circuit, and the drive control circuit includes: a control sub-circuit configured in a one-to-one correspondence with the auxiliary power output circuit;

[0006] The control sub-circuit includes: a controlled switch and a first diode;

[0007] One end of the main power output circuit is connected to the power supply terminal of the motor, and the other end is connected to the positive terminal of the first diode and the first terminal of the controlled switch, respectively. The negative terminal of the first diode is connected to one end of the auxiliary power output circuit.

[0008] The other end of the auxiliary power supply output circuit is connected to the second end of the controlled switch and then grounded.

[0009] The control terminal of the controlled switch is connected to an external control signal, which is used to control the switching state of the controlled switch.

[0010] This invention establishes a power supply circuit consisting of a main power supply and several auxiliary power supplies. The main power supply provides power for the normal operation of the motor, while a drive control circuit controls the connection of the auxiliary power supplies to increase the total power supply voltage to the motor, thereby improving the motor's torque. This ensures the motor's torque capability even under extreme conditions such as stall. Furthermore, it eliminates the need for an additional transformer input winding in the switching power supply, further improving the overall power supply efficiency, reducing product manufacturing costs, meeting the motor's operating requirements under different conditions, and enhancing the user experience.

[0011] In one optional embodiment, the motor drive circuit further includes a controller and a current sampling circuit. The current sampling circuit includes a sampling resistor and an operational amplifier, wherein one end of the sampling resistor is connected to the negative terminal of the motor and the positive input terminal of the operational amplifier, and the other end is connected to the inverting input terminal of the operational amplifier and then grounded.

[0012] The output terminal of the operational amplifier is connected to the current input terminal of the controller;

[0013] The output terminal of the controller is connected to the control terminal of the controlled switch.

[0014] When the input current at the current input terminal exceeds a preset current threshold, the controller cancels the control signal to control the controlled switch to open, and when the input current at the current input terminal does not exceed a preset voltage threshold, it sends the control signal to control the controlled switch to turn on.

[0015] This invention collects the motor's operating current by setting a current sampling circuit. When the controller determines that the operating current exceeds a preset current threshold, it cancels the control signal to control the controlled switch to open, so that the auxiliary power output circuit and the main power output circuit jointly supply power to the motor, thereby improving the motor's power supply voltage and ensuring the motor's torque capability. When the controller determines that the operating current does not exceed the preset current threshold, it maintains the control signal to control the controlled switch to turn on, so that the main power output circuit supplies power to the motor alone, ensuring the normal operation of the motor and improving power efficiency.

[0016] In one optional embodiment, the motor drive circuit further includes a second diode and a first capacitor, wherein the forward terminal of the second diode is connected to one end of the main power output circuit, and the reverse terminal is connected to the power supply terminal of the motor.

[0017] One end of the first capacitor is connected to one end of the main power output circuit, and the other end is connected to the other end of the main power output circuit.

[0018] This invention provides freewheeling current to the main power output circuit by setting a second diode, and stores and filters the output voltage of the main power output circuit by setting a first capacitor.

[0019] In one optional implementation, the control sub-circuit further includes: a third diode and a second capacitor, wherein the forward terminal of the third diode is connected to one end of the auxiliary power output circuit, and the reverse terminal is connected to the reverse terminal of the first diode.

[0020] One end of the second capacitor is connected to one end of the auxiliary power output circuit, and the other end is connected to the other end of the auxiliary power output circuit.

[0021] This invention provides freewheeling current to the auxiliary power supply output circuit by setting a third diode, and stores and filters the output voltage of the auxiliary power supply output circuit by setting a second capacitor.

[0022] In one alternative implementation, the controlled switch is a MOSFET.

[0023] This invention selects a MOS switch as the controlled switch, which has the advantages of fast switching speed, low conduction loss, flexible control and high reliability.

[0024] In one optional embodiment, the power supply circuit includes a switching power supply and a transformer, the switching power supply being connected to the input winding of the transformer, the transformer including a first output winding and at least one second output winding, the first output winding constituting a main power output circuit, and the second output winding constituting a secondary power output circuit.

[0025] This invention uses a switching power supply composed of a transformer with multiple output windings to power the motor. Without changing the original transformer input winding structure, it improves the motor's torque capability, has low circuit cost, and improves the overall power supply efficiency without increasing manufacturing costs. It can meet the motor's operating needs under different working conditions and enhance the user experience.

[0026] In one optional implementation, the supply voltage of the main power supply output circuit is the first supply voltage required by the motor under normal operating conditions, and the supply voltage of the auxiliary power supply output circuit is the voltage difference between the second supply voltage required by the motor under extreme operating conditions and the first supply voltage.

[0027] This invention sets the auxiliary power supply output voltage based on the voltage difference between the motor's required voltage under actual extreme operating conditions and its required voltage under normal operating conditions. This achieves precise design of the motor's power supply voltage under extreme operating conditions, meeting the motor's power supply needs under extreme conditions while further improving the overall power supply efficiency.

[0028] In a second aspect, the present invention provides a motor drive circuit control method, applied to the motor drive circuit provided in the first aspect or any of its optional embodiments, the method comprising:

[0029] When the motor starts running, a control signal is sent to the control terminal of the controlled switch in the control sub-circuit to turn on the controlled switch, and the motor is driven by the main power output circuit.

[0030] Obtain the operating current of the motor during operation;

[0031] The controlled switch of the control sub-circuit is controlled based on the operating current to adjust the power supply voltage of the motor.

[0032] This invention utilizes a motor drive circuit provided in another embodiment. During motor startup, the motor is controlled by turning on a controlled switch, allowing it to be powered and driven by the main power supply output circuit. Furthermore, the invention monitors the motor's operating current and controls the controlled switch based on this monitoring, automatically adjusting the motor's power supply voltage. This enhances the motor's torque, ensuring torque capability even under extreme conditions such as stall. Moreover, it eliminates the need for an additional transformer input winding in the switching power supply, further improving overall power efficiency, reducing manufacturing costs, meeting motor operating requirements under various conditions, and enhancing the user experience.

[0033] In one optional implementation, when the auxiliary power supply output circuit is single, controlling the controlled switch of the control sub-circuit based on the operating current to adjust the power supply voltage of the motor includes:

[0034] Determine whether the operating current is greater than a preset current threshold;

[0035] When the operating current exceeds a preset current threshold, the control signal sent to the control terminal of the controlled switch is withdrawn to turn off the controlled switch, and the motor is driven by the main power output circuit and the auxiliary power output circuit.

[0036] This invention analyzes the motor's operating current and considers the motor to be in extreme operating conditions when the operating current exceeds a preset current threshold. By controlling the controlled switch to turn off, the auxiliary power supply output circuit is enabled to participate in power supply, thereby increasing the motor's power supply voltage and thus improving the motor's torque capability to meet the motor's operating requirements under extreme conditions.

[0037] In one optional implementation, when there are multiple auxiliary power supply output circuits, controlling the controlled switch of the control sub-circuit based on the operating current to adjust the power supply voltage of the motor includes:

[0038] The current required supply voltage for the motor is determined based on the operating current;

[0039] Based on the current required power supply voltage, determine the target auxiliary power supply output circuits that will participate in power supply from each auxiliary power supply output circuit.

[0040] The control signal sent to the target controlled switch is withdrawn to turn off the target controlled switch, which is the controlled switch of the control sub-circuit corresponding to the target auxiliary power output circuit.

[0041] This invention determines the actual required supply voltage of the motor by utilizing the motor's operating current, thereby identifying the auxiliary power supply output circuit that needs to participate in the power supply. Then, by controlling the controlled switch corresponding to the auxiliary power supply output circuit that needs to participate in the power supply, the invention achieves precise adjustment of the motor's supply voltage, further improving the accuracy of the motor's supply voltage, meeting the functional requirements of the motor under diverse operating conditions, and further enhancing the user experience.

[0042] Thirdly, the present invention provides an electrical device, the electrical device comprising: a motor and a motor drive circuit provided in the first aspect or any optional embodiment thereof, the electrical device further comprising: a main control chip, the main control chip being used to execute the motor drive circuit control method provided in the second aspect or any optional embodiment thereof.

[0043] This invention utilizes a motor drive circuit control method provided in another embodiment. During motor startup, the controlled switch is activated to power the motor from the main power supply output circuit. The method monitors the motor's operating current and adjusts the controlled switch accordingly to automatically regulate the motor's power supply voltage. This enhances the motor's torque, ensuring sufficient torque even under extreme conditions such as stall. Furthermore, it eliminates the need for an additional transformer input winding in the switching power supply, further improving overall power efficiency, reducing manufacturing costs, meeting the operational needs of electrical equipment under various conditions, and enhancing the user experience.

[0044] In one alternative implementation, the electrical appliance is an air conditioner range hood.

[0045] The air-conditioning range hood provided by this invention can adaptively adjust the motor power supply voltage under different operating conditions, which can meet the diverse functional needs of users and improve the user experience. Attached Figure Description

[0046] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the structure of a motor drive circuit according to an embodiment of the present invention;

[0048] Figure 2 This is a flowchart of a motor drive circuit control method according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the structure of an electrical device according to an embodiment of the present invention;

[0050] Figure 4 This is a specific control logic example diagram of a motor drive circuit according to an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram of the structure of the main control chip in an electrical device according to an embodiment of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In related technologies, the common way to increase motor torque is to increase the input winding of the transformer in the switching power supply of the controller. However, the operating time of the motor under extreme conditions is limited. This method of increasing the switching power supply winding will increase the core loss and coil resistance loss. Especially when operating at high frequency, the winding resistance heats up more, which leads to a decrease in overall power efficiency. In addition, increasing the input winding requires a larger core and heat dissipation space, which increases the product manufacturing cost.

[0054] Based on the above problems, this embodiment provides a motor drive circuit. Figure 1 This is a schematic diagram of the structure of a motor drive circuit according to an embodiment of the present invention, as shown below. Figure 1As shown, the motor drive circuit includes a power supply circuit 101 and a drive control circuit. The power supply circuit includes a main power output circuit T1-1 and at least one auxiliary power output circuit T1-2. The drive control circuit includes a control sub-circuit 102 that corresponds to the auxiliary power output circuit.

[0055] The control sub-circuit 102 includes: a controlled switch U3 and a first diode D2;

[0056] One end of the main power output circuit T1-1 is connected to the power supply terminal of the motor M, and the other end is connected to the positive terminal of the first diode D2 and the first terminal of the controlled switch U3 respectively. The negative terminal of the first diode D2 is connected to one end of the auxiliary power output circuit T1-2.

[0057] The other end of the auxiliary power supply output circuit T1-2 is connected to the second end of the controlled switch U3 and then grounded.

[0058] The control terminal of the controlled switch U3 is connected to an external control signal IO-V-MOTOR, which is used to control the switching state of the controlled switch U3.

[0059] Specifically, in this embodiment of the invention, the motor M is a stepper motor as an example. In practical applications, the motor M can also be other motors that use DC power supply, which will not be elaborated here.

[0060] It should be noted that, in Figure 1 The following description uses a secondary power output circuit T1-2 as an example. In practical applications, the secondary power output circuit T1-2 can be flexibly set according to the power supply voltage level required by the motor drive circuit. The more power supply voltage levels required, the more secondary power output circuits T1-2 there are. The power supply voltages of different secondary power output circuits T1-2 can be equal or unequal, and can be flexibly set. This invention is not limited to this. At the same time, the control sub-circuit 102 is set in a one-to-one correspondence with the secondary power output circuit T1-2. The connection relationship between each secondary power output circuit T1-2 and its corresponding control sub-circuit 102 is as follows: Figure 1 The connection relationships shown are the same, and will not be repeated here.

[0061] Specifically, the controlled switch U3 mentioned above can be a switching device such as a transistor, MOSFET, or IGBT, as long as it can realize the connection control between the main power output circuit T1-1 and the ground terminal. This invention is not limited to this. For example, as... Figure 1 As shown, in this embodiment of the invention, the controlled switch U3 is a MOSFET as an example. By selecting a MOSFET as the controlled switch U3, it has the advantages of fast switching speed, low conduction loss, flexible control, and high reliability.

[0062] For example, when the control signal IO-V-MOTOR is connected to the controlled switch U3 (i.e., when IO-V-MOTOR is set to a high level), and the controlled switch U3 is turned on, the aforementioned first diode D2 is reverse-biased and cut off. Figure 1 The voltage at point V- is pulled down to GND. The power supply voltage V-MOTOR of motor M is supplied by the output voltage V0 of the main power output circuit T1-1. When the control signal IO-V-MOTOR is removed, i.e., when IO-V-MOTOR is set to low level, the controlled switch U3 is turned off. Under the action of the output voltage V0 of the main power output circuit T1-1, the first diode D2 is forward-biased, and V- is pulled up to the output voltage +5V of the auxiliary power output circuit T1-2. At this time, the power supply voltage V-MOTOR of motor M = V0 + (+5V), and the total power supply voltage drops by 5V, thereby supplying power to the load of motor M, increasing the running torque of motor M, and enabling motor M to meet the operating conditions under extreme conditions.

[0063] This invention provides a power supply circuit consisting of a main power supply and several auxiliary power supplies. The main power supply provides power to the motor for normal operation, and the auxiliary power supplies are connected by a drive control circuit to increase the total power supply voltage to the motor, thereby improving the motor's torque. This ensures the motor's torque capability even under extreme conditions such as stall. Furthermore, it eliminates the need to add a transformer input winding to the switching power supply, further improving the overall power supply efficiency, reducing product manufacturing costs, meeting the motor's operating requirements under different conditions, and enhancing the user experience.

[0064] In some alternative implementations, such as Figure 1 As shown, the motor drive circuit provided in this embodiment of the invention further includes: a controller ( Figure 1 (not shown in the image) and a current sampling circuit 103, the current sampling circuit 103 includes: a sampling resistor R1 and an operational amplifier U4, wherein one end of the sampling resistor R1 is connected to the negative terminal of the motor M and the positive input terminal of the operational amplifier U4 respectively, and the other end is connected to the inverting input terminal of the operational amplifier U4 and then grounded.

[0065] The output of operational amplifier U4 is connected to the current input of the controller;

[0066] The output of the controller is connected to the control terminal of the controlled switch U3;

[0067] When the current input at the current input terminal exceeds the preset current threshold, the controller cancels the control signal IO-V-MOTOR to control the controlled switch to open, and sends the control signal IO-V-MOTOR to control the controlled switch to turn on when the current input at the current input terminal does not exceed the preset voltage threshold.

[0068] The sampling resistor R1 is used to acquire the operating current signal of motor M, and the operational amplifier U4 is used to amplify the operating current signal before transmitting it to the controller. The specific selection of the sampling resistor R1 and the operational amplifier U4 can be flexibly set according to the actual operating current range of motor M and the signal input requirements of the controller, and will not be elaborated here.

[0069] Specifically, the aforementioned controller can be a separate motor power supply control chip such as an MCU or microprocessor, or it can be the main control chip of an electrical device equipped with a motor M, achieving chip function reuse and saving costs. For example, taking an air conditioner range hood equipped with a stepper motor as an example, this controller is the main control chip for adjusting the range hood; this is merely an example and the invention is not limited thereto.

[0070] In this embodiment of the invention, a current sampling circuit is set up to collect the operating current of the motor. When the controller determines that the operating current exceeds a preset current threshold, the control signal is canceled to control the controlled switch to open, so that the auxiliary power supply output circuit and the main power supply output circuit jointly supply power to the motor, thereby improving the motor's power supply voltage and ensuring the motor's torque capability. When the controller determines that the operating current does not exceed the preset current threshold, the control signal is maintained to control the controlled switch to turn on, and the main power supply output circuit supplies power to the motor alone, ensuring the normal operation of the motor and improving power efficiency.

[0071] In some alternative implementations, such as Figure 1 As shown, the motor drive circuit provided in this embodiment of the invention further includes: a second diode D3 and a first capacitor C1, wherein the forward end of the second diode D3 is connected to one end of the main power output circuit T1-1, and the reverse end is connected to the power supply end of the motor M.

[0072] One end of the first capacitor C1 is connected to one end of the main power output circuit T1-1, and the other end is connected to the other end of the main power output circuit T1-1.

[0073] In this embodiment of the invention, a second diode is used to provide freewheeling current to the main power output circuit, and a first capacitor is used to store energy and filter the output voltage of the main power output circuit.

[0074] In some alternative implementations, such as Figure 1 As shown, the control sub-circuit 102 further includes: a third diode D1 and a second capacitor C3, wherein the forward end of the third diode D1 is connected to one end of the auxiliary power supply output circuit T1-2, and the reverse end is connected to the reverse end of the first diode D2.

[0075] One end of the second capacitor C3 is connected to one end of the auxiliary power output circuit T1-2, and the other end is connected to the other end of the auxiliary power output circuit T1-2.

[0076] In this embodiment of the invention, a third diode is used to provide freewheeling current to the auxiliary power supply output circuit, and a second capacitor is used to store energy and filter the output voltage of the auxiliary power supply output circuit.

[0077] For example, the first capacitor C1 and the second capacitor C3 mentioned above are electrolytic capacitors.

[0078] In some alternative implementations, such as Figure 1 As shown, the power supply circuit 101 includes: a switching power supply ( Figure 1 (not shown) and transformer T1, the switching power supply is connected to the input winding of transformer T1, transformer T1 includes a first output winding and at least one second output winding, the first output winding constitutes the main power output circuit T1-1, and the second output winding constitutes the auxiliary power output circuit T1-2.

[0079] For example, such as Figure 1 As shown, the switching power supply consists of a switching chip U1, a switching device U2, and a bus electrolytic capacitor C2. Its circuit connection structure and working principle are existing technologies and will not be described in detail here.

[0080] This invention provides power to the motor by using a switching power supply composed of a transformer with multiple output windings. Without changing the original transformer input winding structure, it improves the motor's torque capability, reduces circuit costs, and increases the overall power supply efficiency without increasing manufacturing costs. It can meet the motor's operating requirements under different working conditions and enhance the user experience.

[0081] In some optional implementations, the supply voltage of the main power output circuit T1-1 is the first supply voltage required by the motor M under normal operating conditions, and the supply voltage of the auxiliary power output circuit T1-2 is the voltage difference between the second supply voltage required by the motor M under extreme operating conditions and the first supply voltage.

[0082] For example, taking a common household appliance equipped with a motor M as an example, the first power supply voltage can be 6V, 12V, 24V, 36V, etc., and the second power supply voltage can be 11V, 17V, 29V, 41V, etc. This is just an example and is not a limitation.

[0083] This invention sets the auxiliary power supply output voltage based on the voltage difference between the motor's required voltage under extreme operating conditions and its required voltage under normal operating conditions. This achieves precise design of the motor's power supply voltage under extreme operating conditions, meeting the motor's power supply needs under extreme conditions while further improving the overall power supply efficiency.

[0084] This invention also provides a motor drive circuit control method, applied to a motor drive circuit provided in another embodiment of this invention. This method can be applied to motor controllers such as MCUs, microprocessors, etc. Figure 2 As shown, the method includes:

[0085] Step S201: When the motor starts running, a control signal is sent to the control terminal of the controlled switch in the control sub-circuit to turn on the controlled switch.

[0086] Specifically, such as Figure 1 Taking the motor drive circuit shown as an example, the motor is powered and driven by the main power output circuit.

[0087] Step S202: Obtain the operating current of the motor during operation.

[0088] Specifically, the aforementioned current sampling circuit can be used to obtain the operating current of the motor during operation.

[0089] Step S203: Control the controlled switch of the control sub-circuit based on the operating current to adjust the power supply voltage of the motor.

[0090] This invention utilizes a motor drive circuit provided in another embodiment to control the motor's operation by turning on a controlled switch during startup. This controls the motor to be powered by the main power output circuit. During motor operation, the circuit monitors the motor's operating current and controls the controlled switch based on the current readings, automatically adjusting the motor's power supply voltage. This improves the motor's torque, ensuring torque capability even under extreme conditions such as stall. Furthermore, it eliminates the need for an additional transformer input winding in the switching power supply, further improving overall power efficiency, reducing manufacturing costs, meeting motor operating requirements under different conditions, and enhancing the user experience.

[0091] Furthermore, when the auxiliary power supply output circuit is a single circuit, step S203 above includes:

[0092] Step a1: Determine whether the operating current is greater than the preset current threshold.

[0093] The preset current threshold is the operating current value corresponding to when the motor reaches its rated torque, which can be obtained through test calibration and will not be elaborated here.

[0094] Step a2: When the operating current is greater than the preset current threshold, cancel the control signal sent to the control terminal of the controlled switch to turn off the controlled switch.

[0095] Specifically, canceling the control signal sent to the control terminal of the controlled switch means that the control terminal of the controlled switch is at a low level, and the controlled switch is turned off. At this time, the motor is driven by both the main power output circuit and the auxiliary power output circuit.

[0096] Specifically, taking a stepper motor as an example, the torque of a stepper motor is directly proportional to the supply voltage. The higher the voltage, the greater the operating current and the greater the torque capacity. When the stepper motor is stalled, the greater the force, the greater the stall current. Therefore, by analyzing the motor's operating current, it can be determined whether the motor is in a stalled extreme condition, and thus whether the supply voltage needs to be adjusted to improve the motor's torque capacity. For example, when the motor's operating current exceeds the current threshold corresponding to the motor's rated torque, the controlled switch is turned off, thereby supplying power to the motor through both the main power output circuit and the auxiliary power output circuit, increasing the supply voltage and improving the motor's torque capacity.

[0097] This invention analyzes the motor's operating current. When the operating current exceeds a preset current threshold, the motor is considered to be in extreme operating conditions. By controlling the controlled switch to turn off, the auxiliary power supply output circuit is made to participate in power supply, thereby increasing the motor's power supply voltage and thus improving the motor's torque capability to meet the motor's operating requirements under extreme conditions.

[0098] In some alternative embodiments, when there are multiple auxiliary power supply output circuits, step S203 above includes:

[0099] Step b1: Determine the current required supply voltage for the motor based on the operating current.

[0100] Specifically, the required supply voltage for the motor in different operating current ranges can be pre-defined to obtain the mapping relationship between the operating current and the required supply voltage. The current required supply voltage can be determined by judging the operating current range in which the real-time operating current is located. The specific mapping relationship can be obtained by relevant experiments or manual experience, and will not be elaborated here.

[0101] Step b2: Based on the current required supply voltage, determine the target auxiliary power supply output circuits that will participate in the power supply from the auxiliary power supply output circuits.

[0102] For example, suppose the motor drive circuit has three auxiliary power output circuits, and the output voltage of each auxiliary power output circuit is +5V, and the output voltage of the main power output circuit is 12V. If the current required power supply voltage is 22V, then any two of the auxiliary power output circuits are selected as the target auxiliary power output circuits. If the current required power supply voltage is 17V, then any one of the auxiliary power output circuits is selected as the target auxiliary power output circuit. This is just an example, and the present invention is not limited thereto.

[0103] Step b3: Cancel the control signal sent to the target controlled switch to turn off the target controlled switch.

[0104] The target controlled switch is the controlled switch of the control sub-circuit corresponding to the target auxiliary power supply output circuit. The specific working process of each target auxiliary power supply output circuit is similar to the relevant description in the circuit embodiment above, and will not be repeated here.

[0105] This invention utilizes the motor's operating current to determine the actual required supply voltage for the motor, thereby identifying the auxiliary power supply output circuit that needs to participate in the power supply. Then, by controlling the controlled switch corresponding to the auxiliary power supply output circuit that needs to participate in the power supply, the precise adjustment of the motor's supply voltage is achieved, further improving the accuracy of the motor's supply voltage, meeting the functional requirements of the motor under diverse operating conditions, and further enhancing the user experience.

[0106] This invention also provides an electrical device, such as... Figure 3 As shown, the electrical device includes: a motor M and a motor drive circuit 301 provided in another embodiment of the present invention. The electrical device also includes: a main control chip 302, which is used to execute the motor drive circuit control method provided in another embodiment of the present invention.

[0107] Specifically, taking the stepper motor M of an air conditioner range hood as an example, by monitoring the stepper motor current, the main control chip 302 determines whether the stepper motor has entered its extreme operating condition by setting a threshold and making logical judgments, and then activates the aforementioned auxiliary power supply output circuit. Thus, without increasing the switching power supply winding of the controller, the motor drive circuit 301 can promptly provide the stepper motor with a higher supply voltage and output greater motor torque.

[0108] Specifically, operational amplifier devices are used to monitor the stepper motor's current data and provide it to the main control chip 302. The main control chip 302 determines whether the stepper motor has entered its extreme operating condition by setting thresholds and making logical judgments, thereby controlling the auxiliary power supply output circuit to connect to the power supply. Without needing to adjust the switching power supply windings, the motor drive circuit 301 is used according to the stepper motor current and logical judgments to provide the stepper motor with a higher supply voltage and output greater motor torque in a timely manner, thus meeting the voltage requirements of the stepper motor when it enters its extreme operating condition.

[0109] This invention utilizes a motor drive circuit control method provided in another embodiment of the invention. During motor startup, the controlled switch is activated to power the motor from the main power supply output circuit. The method monitors the motor's operating current and adjusts the controlled switch accordingly to automatically regulate the motor's power supply voltage. This enhances the motor's torque, ensuring sufficient torque even under extreme conditions such as stall. Furthermore, it eliminates the need for an additional transformer input winding in the switching power supply, further improving overall power efficiency, reducing manufacturing costs, meeting the operational needs of electrical equipment under various conditions, and enhancing the user experience.

[0110] In some optional embodiments, the electrical device is an air conditioner and range hood. The air conditioner and range hood provided in this embodiment of the invention can adaptively adjust the motor power supply voltage under different operating conditions, meeting diverse user needs and improving the user experience. Furthermore, this electrical device can also be a washing machine, range hood, or other electrical device with a motor; the invention is not limited thereto.

[0111] Taking the stepper motor in an air conditioner range hood as an example, the motor drive circuit and control method provided in this embodiment of the invention, without increasing the input winding in the adjusting power supply, adds a dual-level control circuit, namely the aforementioned motor drive circuit. The main control chip of the air conditioner range hood monitors the stepper motor current. To address the increased torque demand under extreme operating conditions, the main control chip controls the dual-level control circuit to superimpose two voltages, increasing the stepper motor's supply voltage and thus its operating torque to cope with extreme conditions. This solves the problem of insufficient stepper motor torque without increasing the winding of the adjusting power supply. Combined with... Figure 1 As shown, the specific working logic of the range hood is as follows: Figure 4 As shown.

[0112] For example, during the start-up and operation phase of an air conditioner range hood, it is necessary to activate the stepper motor load, such as... Figure 1 As shown, the main control chip sets the default IO-V-MOTOR to high level. At this time, U3 is in the conducting state, D2 is reverse cut off, V- is pulled down to GND, and the stepper motor's power supply voltage V-MOTOR is the voltage V0 output by the switching power supply winding, which directly supplies power to the stepper motor.

[0113] When the stepper motor is running, the main control chip uses R1 to collect the motor's operating current, and uses U4 to amplify the motor current signal and output the MOTOR-AD signal to the main control chip. Based on actual working conditions, the threshold value is set when the stepper current reaches the rated torque.

[0114] The main control chip monitors MOTOR-AD to determine whether the stepper motor has entered its extreme operating condition. When the stepper motor enters its extreme operating condition, it checks whether the MOTOR-AD signal is greater than a set threshold. When the MOTOR-AD signal is less than the set threshold, the voltage V0 output by the winding can meet the requirements for driving the stepper motor. When the MOTOR-AD signal is greater than the set threshold, the stepper motor is stalled under extreme operating conditions, requiring an increase in the stepper motor voltage to improve the stepper motor torque. At this time, the main control chip sets IO-V-MOTOR to a low level, U3 is turned off, and U3 is in a cutoff state. Under the action of V-MOTOR voltage, D2 is forward-biased, and V- is pulled up to +5V. At this time, V-MOTOR = V0 + (+5V), and the voltage will increase by 5V. The boosted supply voltage V-MOTOR supplies power to the stepper motor load of the air conditioner range hood, thereby improving the operating torque of the stepper motor and enabling the stepper motor to meet the operating conditions under extreme conditions.

[0115] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of the main control chip of the electrical device provided in an optional embodiment of the present invention, such as... Figure 5 As shown, the main control chip includes one or more processors 10, a memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components communicate with each other using different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interface). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 5 Take a processor 10 as an example.

[0116] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0117] The memory 20 stores instructions executable by at least one processor 10 to cause at least one processor 10 to perform the method shown in the above embodiments.

[0118] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0119] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0120] The main control chip also includes a communication interface 30 for the controller to communicate with other devices or communication networks.

[0121] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0122] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A motor drive circuit, characterized in that, include: The power supply circuit includes a power supply circuit, a drive control circuit, a second diode, and a first capacitor. The power supply circuit includes a main power output circuit and at least one auxiliary power output circuit. The drive control circuit includes a control sub-circuit that corresponds one-to-one with the auxiliary power output circuit. The control sub-circuit includes: a controlled switch, a first diode, a third diode, and a second capacitor; One end of the main power output circuit is connected to the forward terminal of the second diode, and the reverse terminal of the second diode is connected to the power supply terminal of the motor. The other end of the main power output circuit is connected to the forward terminal of the first diode and the first terminal of the controlled switch, respectively. The reverse terminal of the first diode is connected to the reverse terminal of the third diode, and the forward terminal of the third diode is connected to one end of the auxiliary power output circuit. The other end of the auxiliary power supply output circuit is connected to the second end of the controlled switch and then grounded. The control terminal of the controlled switch is connected to an external control signal, which is used to control the switching state of the controlled switch. One end of the first capacitor is connected to the reverse terminal of the second diode, and the other end is connected to the forward terminal of the first diode; One end of the second capacitor is connected to the reverse terminal of the third diode, and the other end is connected to the other end of the auxiliary power supply output circuit.

2. The motor drive circuit according to claim 1, characterized in that, Also includes: The controller and current sampling circuit, wherein the current sampling circuit includes: a sampling resistor and an operational amplifier, wherein, One end of the sampling resistor is connected to the negative terminal of the motor and the positive input terminal of the operational amplifier, and the other end is connected to the inverting input terminal of the operational amplifier and then grounded. The output terminal of the operational amplifier is connected to the current input terminal of the controller; The output terminal of the controller is connected to the control terminal of the controlled switch; When the input current at the current input terminal exceeds a preset current threshold, the controller cancels the control signal to control the controlled switch to open, and when the input current at the current input terminal does not exceed the preset current threshold, it sends the control signal to control the controlled switch to turn on.

3. The motor drive circuit according to claim 1, characterized in that, The controlled switch is a MOSFET.

4. The motor drive circuit according to claim 1, characterized in that, The power supply circuit includes a switching power supply and a transformer. The switching power supply is connected to the input winding of the transformer. The transformer includes a first output winding and at least one second output winding. The first output winding constitutes a main power output circuit, and the second output winding constitutes a secondary power output circuit.

5. The motor drive circuit according to claim 1, characterized in that, The main power supply output circuit provides the first power supply voltage required by the motor under normal operating conditions, and the auxiliary power supply output circuit provides the voltage difference between the second power supply voltage required by the motor under extreme operating conditions and the first power supply voltage.

6. A method for controlling a motor drive circuit, characterized in that, The method, applied to the motor drive circuit as described in any one of claims 1-5, comprises: When the motor starts running, a control signal is sent to the control terminal of the controlled switch in the control sub-circuit to turn on the controlled switch, and the motor is driven by the main power output circuit. Obtain the operating current of the motor during operation; The controlled switch of the control sub-circuit is controlled based on the operating current to adjust the power supply voltage of the motor.

7. The method according to claim 6, characterized in that, When the auxiliary power supply output circuit is a single circuit, the control of the controlled switch of the control sub-circuit based on the operating current to adjust the power supply voltage of the motor includes: Determine whether the operating current is greater than a preset current threshold; When the operating current exceeds a preset current threshold, the control signal sent to the control terminal of the controlled switch is withdrawn to turn off the controlled switch, and the motor is driven by the main power output circuit and the auxiliary power output circuit.

8. The method according to claim 6, characterized in that, When there are multiple auxiliary power supply output circuits, the control of the controlled switch of the control sub-circuit based on the operating current to adjust the power supply voltage of the motor includes: The current required supply voltage for the motor is determined based on the operating current; Based on the current required power supply voltage, determine the target auxiliary power supply output circuits that will participate in power supply from each auxiliary power supply output circuit. The control signal sent to the target controlled switch is withdrawn to turn off the target controlled switch, which is the controlled switch of the control sub-circuit corresponding to the target auxiliary power output circuit.

9. An electrical appliance, characterized in that, The electrical device includes: a motor and a motor drive circuit as described in any one of claims 1-5, and the electrical device further includes: a main control chip, the main control chip being used to perform the method as described in any one of claims 6-8.

10. The electrical equipment according to claim 9, characterized in that, The electrical equipment mentioned is an air conditioner and a range hood.

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