Control method and apparatus for beauty instrument and beauty instrument

Abstract

A control method and apparatus (500) for a beauty instrument, and a beauty instrument. The beauty instrument comprises a switching power supply for controlling an output voltage, and further comprises a controller connected to the switching power supply. The controller of the beauty instrument executes the control method. The controller comprises a cascaded feedback control structure formed by cascading a power loop and a voltage loop. The method comprises: acquiring a current load voltage and a current load power of a beauty instrument, and a reference voltage and a reference power loaded by the beauty instrument (S110); inputting the current load voltage and the reference voltage of the beauty instrument into the voltage loop, and inputting the current load power and the reference power of the beauty instrument into the power loop (S120); and controlling the output voltage on the basis of an output value of the cascaded feedback control structure, so as to limit the load voltage and the load power of the beauty instrument by means of the output voltage (S130), so that the load voltage of the beauty instrument does not exceed a reference voltage within an allowable error range, and the load power does not exceed a reference power within an error allowance range.

Description

A control method and device for a beauty instrument, and a beauty instrument

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202310803571.8, entitled “A control method, device and beauty instrument for a beauty instrument”, filed with the Patent Office of China on June 30, 2023, and application number 202321715768.8, entitled “A beauty instrument and its control circuit”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of beauty care technology, and in particular to a control method and device for a beauty instrument, and a beauty instrument. Background Art

[0004] Radiofrequency beauty devices work by transmitting radiofrequency waves through the skin and affecting the underlying tissue. They are painless, non-invasive, and have no side effects, resulting in excellent results and a widespread popularity among consumers. Within a safe range, the higher the radiofrequency output power, the better the skincare results. However, the higher the radiofrequency output power, the faster the temperature rises at the electrode tip. Leaving the electrode tip attached to a specific area and not moving it there creates a risk of burns.

[0005] Currently, most radio frequency beauty devices are controlled through a voltage loop, a current loop, or a cascaded combination of a voltage loop and a current loop. When the skin impedance of different users is different, the current passing through the skin varies, and the heat generated is also different. For certain people, excessive heat generation may even cause burns, or excessive voltage may cause electric shock. Therefore, existing technologies usually require the installation of complex and expensive impedance monitoring circuits to compensate for this defect.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a control method, device, and beauty instrument for a beauty instrument, while limiting the maximum power and maximum voltage of the beauty instrument, thereby preventing the beauty instrument from causing a burning sensation due to excessive power and an electric shock sensation due to excessive voltage, thereby improving the user's skin care experience.

[0008] The embodiments of this application adopt the following technical solutions:

[0009] In a first aspect, an embodiment of the present application provides a method for controlling a beauty instrument, the beauty instrument including a switching power supply for controlling an output voltage, and a controller connected to the switching power supply. The method is executed by the controller of the beauty instrument, the controller including a cascade feedback control structure formed by cascading a power loop and a voltage loop. The method for controlling the beauty instrument includes:

[0010] Obtaining the current load voltage and load power of the beauty instrument, as well as the reference voltage and reference power of the beauty instrument load;

[0011] Inputting the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and inputting the current load power of the beauty instrument and the reference power into the power loop;

[0012] The output voltage is controlled according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

[0013] In a second aspect, an embodiment of the present application further provides a control device for a beauty instrument, the beauty instrument including a switching power supply for controlling an output voltage, and a controller connected to the switching power supply. The device is applied to the controller of the beauty instrument, the controller including a cascade feedback control structure formed by cascading a power loop and a voltage loop. The control device of the beauty instrument includes:

[0014] a data acquisition unit, configured to acquire the current load voltage and load power of the beauty instrument, as well as the reference voltage and reference power of the load of the beauty instrument;

[0015] a data input unit, configured to input the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and input the current load power of the beauty instrument and the reference power into the power loop;

[0016] A feedback control unit is used to control the output voltage according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

[0017] In a third aspect, an embodiment of the present application further provides a beauty instrument control circuit, comprising: a load voltage detection circuit, a load power detection circuit, a cascade feedback control structure, and a switching power supply, wherein the cascade feedback control structure comprises a power loop and a voltage loop, wherein the power loop and the voltage loop are connected in a cascade manner;

[0018] The load voltage detection circuit is connected to the load of the beauty instrument and the voltage loop respectively, and is used to detect the current load voltage of the beauty instrument and send the current load voltage of the beauty instrument to the voltage loop;

[0019] The load power detection circuit is connected to the load of the beauty instrument and the power ring respectively, and is used to detect the current load power of the beauty instrument and send the current load power of the beauty instrument to the power ring;

[0020] The power loop and the voltage loop are further connected to the controller of the beauty instrument, the power loop receives reference power from the controller, and the voltage loop receives reference voltage from the controller. The cascade feedback control structure is connected to the switching power supply, and is used to send the output value of the cascade feedback control structure to the switching power supply;

[0021] The switching power supply is used to generate a corresponding output voltage according to the output value of the cascade feedback control structure, and limit the load voltage and load power of the beauty instrument through the output voltage.

[0022] In a fourth aspect, embodiments of the present application further provide a beauty instrument, comprising: a switching power supply for controlling an output voltage and a controller connected to the switching power supply, the controller comprising a cascade feedback control structure formed by cascading a power loop and a voltage loop, the controller executing a control method for the beauty instrument via the cascade feedback control structure;

[0023] Alternatively, the beauty instrument includes: a controller and the above-mentioned beauty instrument control circuit.

[0024] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects:

[0025] The embodiment of the present application uses the cascade feedback control structure of the beauty instrument controller as the hardware basis, uses the current load voltage and reference voltage of the beauty instrument as the input of the voltage loop in the cascade feedback control structure, and uses the current load power and reference power of the beauty instrument as the input of the power loop in the cascade feedback control structure, providing reference data and feedback data for the cascade feedback control structure. Since the feedback data includes the load voltage and load power, the load voltage and load power of the beauty instrument can be limited through the cascade feedback control structure, so that the load voltage of the beauty instrument does not exceed the reference voltage within the allowable error range, and the load power does not exceed the reference power within the allowable error range. In this way, the beauty instrument can avoid a burning sensation due to excessive power and an electric shock sensation due to excessive voltage, thereby improving the user's skin care experience.

[0026] In addition, the embodiment of the present application also constructs a closed-loop control loop from the switching power supply to the beauty instrument load, from the beauty instrument load to the cascade feedback control structure, and from the cascade feedback control structure to the switching power supply, thereby improving the control stability and response rate by constructing a closed-loop control loop. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] FIG1 is a schematic flow chart of a control method for a beauty instrument according to an embodiment of the present application;

[0029] FIG2 is a schematic diagram of a circuit principle of a series feedback control structure according to an embodiment of the present application;

[0030] FIG3 is a schematic diagram of a circuit principle of a parallel feedback control structure in an embodiment of the present application;

[0031] FIG4 is a schematic diagram of a PWM signal generation principle according to an embodiment of the present application;

[0032] FIG5 is a schematic diagram of the structure of a control device of a beauty instrument according to an embodiment of the present application;

[0033] FIG6 is a schematic structural diagram of a beauty instrument control circuit according to an embodiment of the present application;

[0034] FIG7 is a schematic structural diagram of a beauty instrument according to an embodiment of the present application;

[0035] FIG8 is a schematic structural diagram of another beauty instrument in an embodiment of the present application. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] The present application provides a method for controlling a beauty instrument. As shown in FIG1 , a flow chart of a method for controlling a beauty instrument according to the present application is provided. The method includes at least the following steps S110 to S130:

[0038] Step S110 , obtaining the current load voltage and load power of the beauty instrument, and the reference voltage and reference power of the beauty instrument load.

[0039] The beauty instrument of an embodiment of the present application includes a switching power supply for controlling the output voltage, and also includes a controller connected to the switching power supply, the controller includes a cascade feedback control structure formed by cascading a power loop and a voltage loop, wherein the cascade mode of the power loop and the voltage loop includes a series mode as shown in Figure 2 and a parallel mode as shown in Figure 3.

[0040] As mentioned above, most of the beauty devices in the existing technology control the electrode head power of the radio frequency beauty device through a voltage loop, a current loop or a cascade solution of a voltage loop and a current loop. They cannot take into account the control of the electrode head voltage, and the control response rate and stability are relatively poor.

[0041] To address the above-mentioned issues, the controller of the embodiment of the present application has been improved at the hardware level, namely, the voltage loop and the power loop are cascaded, and the load voltage and load power of the beauty instrument are controlled through the voltage loop and the power loop. Therefore, in the data acquisition phase, the controller of the embodiment of the present application not only obtains the current load power of the beauty instrument, but also obtains the current load voltage of the beauty instrument, and provides the current load voltage and load power of the beauty instrument as feedback data to the cascade feedback control structure. At the same time, the controller also provides the cascade feedback control structure with corresponding reference data (reference data is reference voltage and reference power), so that the cascade feedback control structure can perform feedback control on the feedback data based on the reference data, so that the feedback data dynamically tends to the reference data. In this way, the maximum value of the load power and the maximum value of the load voltage of the beauty instrument can be limited, thereby avoiding the burning sensation caused by excessive power and the electric shock caused by excessive voltage.

[0042] Among them, the load of the beauty instrument can be understood as the component in the beauty instrument used to contact the skin. Taking the radio frequency beauty instrument as an example, the load of the radio frequency beauty instrument can be understood as the electrode head of the radio frequency beauty instrument, and the load voltage and load power are the electrode head voltage and electrode head power.

[0043] Step S120: inputting the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and inputting the current load power of the beauty instrument and the reference power into the power loop.

[0044] On the one hand, the embodiment of the present application provides the feedback data and reference data required for control for the cascade feedback control structure through this step; on the other hand, it can also realize a closed-loop control loop from the switching power supply to the load, from the load to the cascade feedback control structure, and from the cascade feedback control structure to the switching power supply, thereby improving the control stability and response rate by constructing a closed-loop control loop.

[0045] Step S130 , controlling the output voltage according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

[0046] The control effect of the cascade feedback control structure is related to its feedback data. Since the embodiment of the present application uses the load voltage and load power of the beauty instrument as feedback data, the cascade feedback control structure of the embodiment of the present application can limit the load voltage and load power of the beauty instrument, so that the load voltage of the beauty instrument does not exceed the reference voltage within the allowable error range, and the load power does not exceed the reference power within the allowable error range.

[0047] Referring to the control method of the beauty instrument shown in Figure 1, it can be seen that the embodiment of the present application takes the cascade feedback control structure of the beauty instrument controller as the hardware basis, takes the current load voltage and reference voltage of the beauty instrument as the input of the voltage loop in the cascade feedback control structure, and takes the current load power and reference power of the beauty instrument as the input of the power loop in the cascade feedback control structure, providing reference data and feedback data for the cascade feedback control structure. Since the feedback data includes the load voltage and load power, the load voltage and load power of the beauty instrument can be limited through the cascade feedback control structure, avoiding the burning sensation caused by excessive power and the electric shock sensation caused by excessive voltage, thereby improving the user's skin care experience.

[0048] In addition, the embodiment of the present application also constructs a closed-loop control loop from the switching power supply to the beauty instrument load, from the beauty instrument load to the cascade feedback control structure, and from the cascade feedback control structure to the switching power supply, thereby improving the control stability and response rate by constructing a closed-loop control loop.

[0049] In some embodiments of the present application, obtaining the current load voltage and load power of the beauty device in step S110 specifically includes:

[0050] Performing voltage sampling and current sampling on the beauty instrument load to obtain a sampled voltage and a sampled current;

[0051] Performing amplitude conversion on the sampled voltage and the sampled current to obtain a load voltage and a load current;

[0052] The load power is obtained according to the load voltage and the load current.

[0053] In practical applications, the signal conditioning circuit in the prior art can be used to perform voltage sampling and current sampling on the beauty instrument load and perform amplitude conversion on the sampled voltage and sampled current to obtain the load voltage and load current, and then the load voltage and load current are processed by a multiplier to obtain the load power.

[0054] The cascade connection modes of the power loop and the voltage loop of the cascade feedback control structure of the embodiment of the present application include a series connection mode and a parallel connection mode. The control processes corresponding to the two connection modes are respectively described below.

[0055] In the first case, the cascade feedback control structure is the series feedback control structure shown in FIG2 , where the voltage loop is an outer voltage loop implemented based on the first PI regulator, and the power loop is an inner power loop implemented based on the second PI regulator.

[0056] For the series feedback control structure, in the above step S120, the current load voltage of the beauty instrument and the reference voltage are input into the voltage loop, and the current load power of the beauty instrument and the reference power are input into the power loop, which specifically includes:

[0057] The reference voltage U Vref Input the positive input terminal of the first PI regulator (i.e. the “+” port of the first PI regulator in FIG2 ), and convert the current load voltage U Vsample Input the negative input terminal of the first PI regulator (i.e., the "-" port of the first PI regulator in FIG2 ), and input the output of the first PI regulator into the positive input terminal of the second PI regulator (i.e., the "+" port of the second PI regulator in FIG2 );

[0058] And the reference power U Pref The current load power U of the beauty instrument is input to the positive input terminal of the second PI regulator through the controllable transmission channel. Psample The negative input terminal of the second PI regulator (ie, the "-" port of the second PI regulator in FIG2 ) is input, and the output of the second PI regulator is input into the switching power supply.

[0059] In practical applications, referring to FIG2 , the output end of the first PI regulator is generally connected to the positive input end of the second PI regulator after passing through a current limiting resistor. The current load voltage U Vsample Generally, it is connected to the negative input terminal of the first PI regulator after passing through the current limiting resistor. Psample It is usually connected to the negative input terminal of the second PI regulator after passing through a current limiting resistor.

[0060] It should be noted that, since the power value cannot be directly transmitted in the hardware circuit, the input of the load power (reference power) into the cascade feedback control structure involved in the embodiment of the present application should be understood as inputting the voltage value corresponding to the load power (reference power) into the cascade feedback control structure. Referring to Figures 2 and 3 of the embodiment of the present application, the load power U Psample and reference power U Pref All are expressed by voltage values.

[0061] In some possible implementations of the embodiment, inputting the reference power to the positive input terminal of the second PI regulator through a controllable transmission channel specifically includes:

[0062] Obtaining an output value of the first PI regulator;

[0063] controlling the state of the controllable transmission channel according to the output value of the first PI regulator, where the state of the controllable transmission channel includes a conducting state and a non-conducting state;

[0064] When the state of the controllable transmission channel is the conductive state, the reference power is input into the positive input end of the second PI regulator; when the state of the controllable transmission channel is the non-conductive state, the reference power is not input into the positive input end of the second PI regulator.

[0065] In some application scenarios of the above possible implementation schemes, the controllable transmission channel includes a unidirectional conducting element, which refers to a circuit component with a unidirectional conducting function. Optionally, the unidirectional conducting element includes, for example, the diode D1 shown in Figure 2. The negative end of the unidirectional conducting element receives the reference power, and the positive end of the unidirectional conducting element is connected in parallel with the output end of the first PI regulator and then connected to the forward output end of the second PI regulator.

[0066] The controlling the state of the controllable transmission channel according to the output value of the first PI regulator specifically includes: obtaining a positive electrode voltage value of the unidirectional conductive element according to the output value of the first PI regulator, and comparing the positive electrode voltage value of the unidirectional conductive element with a negative electrode voltage value;

[0067] When the positive electrode voltage value of the unidirectional conductive element is not less than the negative electrode voltage value thereof, the unidirectional conductive element is in the on state, so that the controllable transmission channel can be controlled to be in the on state;

[0068] When the positive electrode voltage value of the unidirectional conductive element is less than the negative electrode voltage value thereof, the unidirectional conductive element is in a cut-off state, thereby controlling the controllable transmission channel to be in a non-conducting state.

[0069] As previously mentioned, in some scenarios, the output of the first PI regulator is connected to the positive input of the second PI regulator via a current-limiting resistor. In this case, the positive terminal of the unidirectional conductive element is connected in parallel with the output of the first PI regulator. This can be understood as the positive terminal of the unidirectional conductive element being connected in parallel with the output of the first PI regulator after passing through the current-limiting resistor. Accordingly, the output value of the first PI regulator after passing through the current-limiting resistor is used as the positive voltage value of the unidirectional conductive element.

[0070] Since the voltage loop in the cascade feedback control structure is used to adjust the load voltage of the beauty instrument at the next moment, and the power loop is used to adjust the load power of the beauty instrument at the next moment, therefore, in the design stage of the series feedback control structure shown in Figure 2, the parameters of the circuit elements of the series feedback control structure should be reasonably designed so that when the diode is in the cut-off state, the second PI regulator enters the saturation state and the first PI regulator enters the feedback control state; and when the diode is in the on state, the second PI regulator enters the feedback control state and the first PI regulator enters the saturation state. In this way, when the power corresponding to the output value of the first PI regulator is less than the reference power, the series feedback control structure can make the load voltage of the beauty instrument in a constant voltage state and the load power in a low power state; and when the power corresponding to the output value of the first PI regulator is close to or exceeds the reference power, the series feedback control structure can make the load voltage of the beauty instrument in a constant power state and the load voltage lower than the reference voltage.

[0071] Specifically, in some embodiments of the present application, when the state of the controllable transmission channel is a non-conducting state, when the output value of the first PI regulator is input into the positive input terminal of the second PI regulator, controlling the output voltage according to the output value of the cascade feedback control structure in step S130 specifically includes:

[0072] The output voltage of the switching power supply is controlled according to the output value of the second PI regulator in a saturated state, so as to control the load voltage of the beauty instrument to be in a constant voltage state through the output voltage.

[0073] In conjunction with the circuit schematic shown in Figure 2, when the state of the controllable transmission channel is non-conductive, the power value corresponding to the output value of the first PI regulator is less than the reference power value, the second PI regulator is in saturation, and the value of the load input terminal of the second PI regulator is close to 0, that is, the load power of the beauty instrument is close to 0, and the load power is in a low-power state. At this time, the first PI regulator is in a feedback control state. In the feedback control state, the first PI regulator is used to make the value of its negative input terminal approach the value of its positive input terminal. Therefore, the load voltage of the beauty instrument will be in a constant voltage state.

[0074] In some other embodiments of the present application, when the controllable transmission channel is in the on state, when the reference power is input to the positive input terminal of the second PI regulator, controlling the output voltage according to the output value of the cascade feedback control structure in step S130 specifically includes:

[0075] The output voltage of the switching power supply is controlled according to the output value of the second PI regulator in the feedback control state, so as to control the load power of the beauty instrument to be in a constant power state through the output voltage.

[0076] In conjunction with the circuit schematic shown in Figure 2, when the controllable transmission channel is in the on state, the power value corresponding to the output value of the first PI regulator approaches or exceeds the reference power value, and the second PI regulator is in a feedback control state. The second PI regulator is used to make the value of its negative input terminal approach the value of its positive input terminal. Therefore, the load power of the beauty instrument will be in a constant power state. At this time, the first PI regulator is in a saturated state. The value of the negative input terminal of the first PI regulator cannot reach the voltage limit reference of the positive input terminal. The value of the negative input terminal is less than the value of the positive input terminal. Therefore, the load voltage of the beauty instrument is less than the reference voltage.

[0077] It can be seen that when the load voltage of the beauty device is in a constant voltage state, its load power is in a low power state, and when the load power of the beauty device is in a constant power state, its load voltage is less than the reference voltage. In other words, at any time, the load voltage and load power of the beauty device are limited by the reference voltage and reference power. Therefore, by setting the reference voltage and reference power, the load voltage and load power of the beauty device can be limited.

[0078] It should be noted that the "constant voltage state" in the embodiments of the present application means that the voltage fluctuation of the load voltage is within the allowable error range. At this time, the waveform trend of the load voltage is consistent with the reference voltage waveform, but the waveform envelope of the load voltage will show slight fluctuations. For example, if the reference voltage waveform is a sine wave, then the waveform trend of the load voltage is also approximately a sine wave, but the load voltage value corresponding to each moment has a slight deviation from the reference voltage value. Similarly, the "constant power state" means that the power fluctuation of the load power is within the allowable error range. At this time, the waveform trend of the load power is consistent with the reference power waveform, but the waveform envelope of the load power will show slight fluctuations. For example, if the reference power waveform is a sine wave, then the waveform trend of the load power is also approximately a sine wave, but the load power value corresponding to each moment has a slight deviation from the reference power value.

[0079] In the second case, the cascade feedback control structure is the parallel feedback control structure shown in FIG3 .

[0080] For the series feedback control structure, in the above step S120, the current load voltage of the beauty instrument and the reference voltage are input into the voltage loop, and the current load power of the beauty instrument and the reference power are input into the power loop, which specifically includes:

[0081] The reference voltage U Vref Input the positive input terminal of the third PI regulator (i.e. the "+" port of the third PI regulator in FIG3 ), and convert the current load voltage U VsampleInput the negative input terminal of the third PI regulator (i.e., the "-" port of the third PI regulator in Figure 3), and input the output of the third PI regulator into the switching power supply through the diode D3; specifically, the positive end of the diode D3 is connected to the switching power supply, and the negative end is connected to the output terminal of the third PI regulator.

[0082] The reference power U Pref Input the positive input terminal of the fourth PI regulator (i.e. the “+” port of the fourth PI regulator in FIG3 ), and convert the current load power U Psample The output of the fourth PI regulator is input to the negative input terminal of the fourth PI regulator (i.e., the "-" terminal of the fourth PI regulator in FIG3 ), and the output of the fourth PI regulator is input to the switching power supply through the diode D4. Specifically, the positive terminal of the diode D4 is connected to the switching power supply, and the negative terminal is connected to the output terminal of the fourth PI regulator.

[0083] In actual application, referring to FIG3 , the current load voltage U Vsample Generally, it is connected to the negative input terminal of the third PI regulator after passing through the current limiting resistor. Psample Generally, it is connected to the negative input terminal of the fourth PI regulator after passing through a current limiting resistor.

[0084] As mentioned above, since the voltage loop in the cascade feedback control structure is used to adjust the load voltage of the beauty instrument at the next moment, and the power loop is used to adjust the load power of the beauty instrument at the next moment, therefore, in the design stage of the parallel feedback control structure shown in FIG3 , the parameters of the circuit elements of the parallel feedback control structure should be reasonably designed, and the working states of the third PI regulator and the fourth PI regulator should be controlled by the conduction and cutoff of the diodes D3 and D4. Specifically,

[0085] When the diode D4 is in the cut-off state, the fourth PI regulator enters the saturation state. At this time, the diode D3 is in the on state, and the third PI regulator enters the feedback control state. In this way, the parallel feedback control structure can keep the load voltage of the beauty instrument in a constant voltage state, and the load power is less than the reference power.

[0086] When the diode D3 is in the cut-off state, the third PI regulator enters the saturation state. At this time, the diode D4 is in the on state, and the fourth PI regulator enters the feedback control state. In this way, the parallel feedback control structure can make the load power of the beauty instrument in a constant power state, and the load voltage is less than the reference voltage.

[0087] Accordingly, the output voltage is controlled according to the output value of the cascade feedback control structure in step S130, which specifically includes:

[0088] When the third PI regulator is in a saturation state and the fourth PI regulator is in a feedback control state, the output voltage of the switching power supply is controlled by the output value of the fourth PI regulator, so as to control the load power of the beauty instrument to be in a constant power state through the output voltage; in the constant power state, the third PI regulator is in a saturation state, and the value of the negative input terminal of the third PI regulator cannot reach the voltage limiting reference of the positive input terminal. The value of the negative input terminal is less than the value of the positive input terminal, so the load voltage of the beauty instrument is less than the reference voltage.

[0089] When the fourth PI regulator is in a saturation state and the third PI regulator is in a feedback control state, the output voltage of the switching power supply is controlled by the output value of the third PI regulator, so as to control the load voltage of the beauty instrument to be in a constant voltage state through the output voltage; in the constant voltage state, the fourth PI regulator is in a saturation state, and the value of the negative input terminal of the fourth PI regulator cannot reach the power limit reference of the positive input terminal. The value of the negative input terminal is less than the value of the positive input terminal, so the load power of the beauty instrument is less than the reference power.

[0090] Referring to the circuit schematic diagram shown in Figure 3, it can be seen that during the switching process of the third PI regulator from saturation to feedback control, the load power is in an uncontrollable state. Similarly, during the switching process of the fourth PI regulator from saturation to feedback control, the load voltage is in an uncontrollable state, which is likely to have a negative impact on the user's physical experience during actual use. Based on this, the present application preferably designs the cascade feedback control structure as a series feedback control structure.

[0091] In some embodiments of the present application, the switching power supply includes a comparator and a voltage-controlled voltage source. The output voltage is controlled according to the output value of the cascade feedback control structure in step S130, specifically including:

[0092] The output value of the cascade feedback control structure is input to the positive input terminal of the comparator to control the PWM (Pulse Width Modulation) signal output by the comparator through the output value, and then the output voltage of the voltage-controlled voltage source is controlled by the PWM signal.

[0093] The comparator receives the output value of the cascaded feedback control structure at its positive input and a sawtooth wave signal at its negative input. The comparator then outputs a PWM signal. Assuming the waveform of the output value of the cascaded feedback control structure is approximately a sine wave, the comparator compares the sine wave with the sawtooth wave and outputs the PWM signal shown in Figure 4.

[0094] The present application also provides a control device 500 for a beauty instrument, the beauty instrument including a switching power supply for controlling an output voltage, and a controller connected to the switching power supply. The device is applied to the controller of the beauty instrument, and the controller includes a cascade feedback control structure formed by cascading a power loop and a voltage loop. As shown in FIG5 , a schematic structural diagram of a control device for a beauty instrument in an embodiment of the present application is provided. The device 500 includes at least: a data acquisition unit 510, a data input unit 520, and a feedback control unit 530, wherein:

[0095] The data acquisition unit 510 is used to acquire the current load voltage and load power of the beauty instrument, as well as the reference voltage and reference power of the beauty instrument load;

[0096] A data input unit 520 is configured to input the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and input the current load power of the beauty instrument and the reference power into the power loop;

[0097] The feedback control unit 530 is configured to control the output voltage according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

[0098] In some embodiments of the present application, the cascade feedback control structure is a series feedback control structure, the voltage loop is a voltage outer loop implemented based on a first PI regulator, and the power loop is a power inner loop implemented based on a second PI regulator;

[0099] The data input unit 520 is specifically used to input the reference voltage into the positive input terminal of the first PI regulator, input the current load voltage of the beauty instrument into the negative input terminal of the first PI regulator, and input the output of the first PI regulator into the positive input terminal of the second PI regulator; and input the reference power into the positive input terminal of the second PI regulator through a controllable transmission channel, input the current load power of the beauty instrument into the negative input terminal of the second PI regulator, and input the output of the second PI regulator into the switching power supply.

[0100] In some embodiments of the present application, the data input unit 520 is specifically used to obtain the output value of the first PI regulator; control the state of the controllable transmission channel according to the output value of the first PI regulator, and the state of the controllable transmission channel includes a conductive state and a non-conductive state; when the state of the controllable transmission channel is a conductive state, input the reference power into the positive input end of the second PI regulator; when the state of the controllable transmission channel is a non-conductive state, input the output value of the first PI regulator into the positive input end of the second PI regulator.

[0101] In some embodiments of the present application, the controllable transmission channel includes a unidirectional conductive element, a negative terminal of the unidirectional conductive element receives the reference power, and a positive terminal of the unidirectional conductive element is connected in parallel to the output terminal of the first PI regulator and then to the positive output terminal of the second PI regulator;

[0102] The data input unit 520 is specifically used to obtain the positive voltage value of the unidirectional conductive element according to the output value of the first PI regulator, and obtain the negative voltage value of the unidirectional conductive element according to the reference power; compare the positive voltage value of the unidirectional conductive element with its negative voltage value; when the positive voltage value of the unidirectional conductive element is not less than its negative voltage value, control the state of the controllable transmission channel to be a conductive state; when the positive voltage value of the unidirectional conductive element is less than its negative voltage value, control the state of the controllable transmission channel to be a non-conductive state.

[0103] In some embodiments of the present application, the feedback control unit 530 is specifically used to control the output voltage of the switching power supply according to the output value of the second PI regulator in a saturation state when the output value of the first PI regulator is input into the positive input terminal of the second PI regulator when the state of the controllable transmission channel is a non-conducting state, so as to control the load voltage of the beauty instrument to be in a constant voltage state through the output voltage; and when the state of the controllable transmission channel is a conductive state, when the reference power is input into the positive input terminal of the second PI regulator, control the output voltage of the switching power supply according to the output value of the second PI regulator in a feedback control state, so as to control the load power of the beauty instrument to be in a constant power state through the output voltage.

[0104] In some embodiments of the present application, the switching power supply includes a comparator and a voltage-controlled voltage source, and the feedback control unit 530 is specifically used to input the output value of the cascade feedback control structure into the positive input terminal of the comparator, so as to control the PWM signal output by the comparator through the output value, and then control the output voltage of the voltage-controlled voltage source through the PWM signal.

[0105] In some embodiments of the present application, the data acquisition unit 510 is specifically used to perform voltage sampling and current sampling on the beauty instrument load to obtain a sampled voltage and a sampled current; perform amplitude conversion on the sampled voltage and the sampled current to obtain a load voltage and a load current; and obtain the load power based on the load voltage and the load current.

[0106] It can be understood that the control device of the above-mentioned beauty instrument can implement each step of the control method of the beauty instrument provided in the aforementioned embodiment. The relevant explanations about the control method of the beauty instrument are applicable to the control device of the beauty instrument and will not be repeated here.

[0107] The present application also provides a beauty instrument control circuit. FIG6 shows a schematic diagram of a beauty instrument control circuit according to the present application. The beauty instrument control circuit includes:

[0108] A load voltage detection circuit, a load power detection circuit, a cascade feedback control structure, and a switching power supply, wherein the cascade feedback control structure includes a power loop and a voltage loop, and the power loop and the voltage loop are connected in a cascade manner;

[0109] The load voltage detection circuit is connected to the load and voltage loop of the beauty instrument respectively, and is used to detect the current load voltage of the beauty instrument and send the current load voltage of the beauty instrument to the voltage loop;

[0110] The load power detection circuit is connected to the load and the power ring of the beauty instrument respectively, and is used to detect the current load power of the beauty instrument and send the current load power of the beauty instrument to the power ring;

[0111] The power loop and the voltage loop are also connected to the controller of the beauty instrument. The power loop receives the reference power from the controller, and the voltage loop receives the reference voltage from the controller. The cascade feedback control structure is connected to the switching power supply to send the output value of the cascade feedback control structure to the switching power supply.

[0112] The switching power supply is used to generate a corresponding output voltage according to the output value of the cascade feedback control structure, and limit the load voltage and load power of the beauty instrument through the output voltage, so that the load voltage of the beauty instrument does not exceed the reference voltage within the allowable error range, and the load power does not exceed the reference power within the allowable error range.

[0113] Among them, the load of the beauty instrument can be understood as the component in the beauty instrument used to contact the skin. Taking the radio frequency beauty instrument as an example, the load of the radio frequency beauty instrument can be understood as the electrode head of the radio frequency beauty instrument, and the load voltage and load power are the electrode head voltage and electrode head power.

[0114] Referring to the beauty instrument control circuit shown in Figure 6, it can be seen that the embodiment of the present application takes the cascade feedback control structure of the beauty instrument controller as the hardware basis, takes the current load voltage and reference voltage of the beauty instrument as the input of the voltage loop in the cascade feedback control structure, and takes the current load power and reference power of the beauty instrument as the input of the power loop in the cascade feedback control structure, providing reference data and feedback data for the cascade feedback control structure. Since the feedback data includes the load voltage and load power, the load voltage and load power of the beauty instrument can be limited through the cascade feedback control structure, avoiding the burning sensation caused by excessive power and the electric shock sensation caused by excessive voltage, thereby improving the user's skin care experience.

[0115] In addition, the embodiment of the present application also constructs a hardware closed-loop control loop from the switching power supply to the beauty instrument load, from the beauty instrument load to the cascade feedback control structure, and from the cascade feedback control structure to the switching power supply, thereby improving the control stability and response rate by constructing a hardware closed-loop control loop.

[0116] In some embodiments of the present application, the load power detection circuit includes: a load current detection circuit and a multiplier, wherein:

[0117] The load current detection circuit is connected to the load of the beauty instrument and the first input terminal of the multiplier respectively, and is used to detect the current load current of the beauty instrument and send the current load current of the beauty instrument to the multiplier;

[0118] The second input end of the multiplier is connected to the output end of the load voltage detection circuit, and the output end of the multiplier is connected to the power ring. The multiplier is used to multiply the current load voltage and load current of the beauty instrument to obtain load power and send the load power to the power ring.

[0119] In some possible application scenarios of this embodiment, the load voltage detection circuit includes: a voltage sampling circuit and a first amplitude conversion circuit, and the load current detection circuit includes: a current sampling circuit and a second amplitude conversion circuit, wherein:

[0120] The voltage sampling circuit is connected to the first amplitude conversion circuit, and is used to sample the voltage of the beauty instrument load and send the sampled voltage to the first amplitude conversion circuit;

[0121] The first amplitude conversion circuit is connected to the second input terminal of the multiplier and the voltage loop respectively, and is used to perform amplitude conversion on the sampled voltage, obtain the load voltage through the amplitude conversion, and send it to the multiplier and the voltage loop;

[0122] The current sampling circuit is connected to the second amplitude conversion circuit, and is used to sample the current of the beauty instrument load and send the sampled current to the second amplitude conversion circuit;

[0123] The second amplitude conversion circuit is connected to the first input terminal of the multiplier and is used for performing amplitude conversion on the sampled current, obtaining the load current through the amplitude conversion and sending the load current to the multiplier.

[0124] In practical applications, the voltage sampling circuit and the first amplitude conversion circuit, as well as the current sampling circuit and the second amplitude conversion circuit can be respectively implemented by signal conditioning circuits in the prior art. For example, as shown in Figures 2 and 3, the voltage sampling circuit and the first amplitude conversion circuit are implemented by the first signal conditioning circuit, and the current sampling circuit and the second amplitude conversion circuit are implemented by the second signal conditioning circuit.

[0125] The cascade connection modes of the power loop and the voltage loop of the cascade feedback control structure of the embodiment of the present application include a series connection mode and a parallel connection mode. The beauty instrument control circuits corresponding to the two cascade connection modes are described below respectively.

[0126] The first cascade method is that the cascade feedback control structure is the series feedback control structure shown in Figure 2. The power loop and the voltage loop are connected in series. At this time, the voltage loop is the voltage outer loop implemented based on the first PI regulator, and the power loop is the power inner loop implemented based on the second PI regulator.

[0127] As shown in Figure 2, the circuit connection method corresponding to the series feedback control structure is as follows:

[0128] The voltage loop includes a first PI regulator, and the power loop includes a second PI regulator, wherein:

[0129] The positive input terminal of the first PI regulator is connected to the first port of the controller, the negative input terminal of the first PI regulator is connected to the load voltage detection circuit, and the output terminal of the first PI regulator is connected to the positive input terminal of the second PI regulator;

[0130] The positive input end of the second PI regulator is also connected to the second port of the controller, the negative input end of the second PI regulator is connected to the output end of the load power detection circuit, and the output end of the second PI regulator is connected to the input end of the switching power supply.

[0131] The first port of the controller in the embodiment of the present application can be understood as a chip pin or an output port of an integrated power supply in the controller that can provide a reference voltage for the first PI regulator. Correspondingly, the second port of the controller can be understood as a chip pin or an output port of an integrated power supply in the controller that can provide a voltage value corresponding to the reference power for the second PI regulator.

[0132] It should be noted that, since the power value cannot be directly transmitted in the hardware circuit, the embodiment of the present application involves sending the load power (reference power) to the power ring should be understood as sending the voltage value corresponding to the load power (reference power) to the power ring. Referring to Figures 2 and 3 of the embodiment of the present application, the load power UPsample and reference power U Pref All are expressed by voltage values.

[0133] In some embodiments of the present application, the beauty instrument control circuit also includes a first unidirectional conducting element, which refers to a circuit component with a unidirectional conducting function. The first unidirectional conducting element, for example, includes the diode D1 shown in Figure 2. The negative end of the first unidirectional conducting element is connected to the second port of the controller, and the positive end of the first unidirectional conducting element is connected in parallel with the output end of the first PI regulator and then connected to the positive input end of the second PI regulator.

[0134] In practical applications, referring to FIG2 , the output end of the first PI regulator is generally connected to the positive input end of the second PI regulator through a current limiting resistor. The current load voltage U Vsample Generally, the current is sent to the negative input terminal of the first PI regulator after passing through the current limiting resistor. Psample Generally, the current is sent to the negative input terminal of the second PI regulator after passing through a current limiting resistor, so as to protect the circuit elements of the series feedback control structure from being damaged due to sudden current increase through the current limiting circuit.

[0135] Those skilled in the art can flexibly design the circuit structures of the first PI regulator and the second PI regulator in the embodiment of the present application, and the circuit structure in FIG2 should not constitute a limitation thereto.

[0136] In addition, since the voltage loop in the cascade feedback control structure is used to adjust the load voltage of the beauty instrument at the next moment, and the power loop is used to adjust the load power of the beauty instrument at the next moment, therefore, in the design stage of the series feedback control structure shown in Figure 2, the parameters of the circuit elements of the series feedback control structure should be reasonably designed so that when the diode is in the cut-off state, the second PI regulator enters the saturation state and the first PI regulator enters the feedback control state; and when the diode is in the on state, the second PI regulator enters the feedback control state and the first PI regulator enters the saturation state. In this way, when the power corresponding to the output value of the first PI regulator is less than the reference power, the series feedback control structure can make the load voltage of the beauty instrument in a constant voltage state and the load power in a low power state; and when the power corresponding to the output value of the first PI regulator is close to or exceeds the reference power, the series feedback control structure can make the load voltage of the beauty instrument in a constant power state and the load voltage lower than the reference voltage.

[0137] In conjunction with the circuit schematic shown in Figure 2, when diode D1 is in the off state, the power value corresponding to the output value of the first PI regulator is less than the reference power value, the second PI regulator is in a saturated state, and the value of the load input terminal of the second PI regulator is close to 0, that is, the load power of the beauty instrument is close to 0, that is, the load power is in a low-power state. At this time, the first PI regulator is in a feedback control state. In this feedback control state, the first PI regulator is used to make the value of its negative input terminal approach the value of its positive input terminal. Therefore, the load voltage of the beauty instrument will be in a constant voltage state.

[0138] When diode D1 is in the on state, the power value corresponding to the output value of the first PI regulator approaches or exceeds the reference power value, and the second PI regulator is in a feedback control state. The second PI regulator is used to make the value of its negative input terminal approach the value of its positive input terminal. Therefore, the load power of the beauty instrument will be in a constant power state. At this time, the first PI regulator is in a saturated state. The value of the negative input terminal of the first PI regulator cannot reach the voltage limit reference of the positive input terminal. The value of the negative input terminal is less than the value of the positive input terminal. Therefore, the load voltage of the beauty instrument is less than the reference voltage.

[0139] It can be seen that when the load voltage of the beauty device is in a constant voltage state, its load power is in a low power state, and when the load power of the beauty device is in a constant power state, its load voltage is less than the reference voltage. In other words, at any time, the load voltage and load power of the beauty device are limited by the reference voltage and reference power. Therefore, by setting the reference voltage and reference power, the load voltage and load power of the beauty device can be limited.

[0140] It should be noted that the "constant voltage state" in the embodiment of the present application means that the voltage fluctuation of the load voltage is within the allowable error range. At this time, the waveform trend of the load voltage is consistent with the reference voltage waveform, but the waveform envelope of the load voltage will show slight fluctuations. For example, if the reference voltage waveform is a sine wave, then the waveform trend of the load voltage is also approximately a sine wave, but the load voltage value corresponding to each moment has a slight deviation relative to the reference voltage value.

[0141] Similarly, the "constant power state" means that the power fluctuation of the load power is within the allowable error range. At this time, the waveform trend of the load power is consistent with the reference power waveform, but the waveform envelope of the load power will show slight fluctuations. For example, if the reference power waveform is a sine wave, then the waveform trend of the load power is also approximately a sine wave, but the load power value corresponding to each moment has a slight deviation from the reference power value.

[0142] The second cascade mode is a cascade feedback control structure, which is a parallel feedback control structure as shown in FIG3 . In this case, the power loop and the voltage loop are connected in parallel.

[0143] As shown in Figure 3, the circuit connection method corresponding to the parallel feedback control structure is as follows:

[0144] The voltage loop includes a third PI regulator, where:

[0145] The positive input end of the third PI regulator is connected to the first port of the controller, the negative input end of the third PI regulator is connected to the output end of the load voltage detection circuit, the output end of the third PI regulator is connected to the negative end of the second unidirectional conducting element, and the positive end of the second unidirectional conducting element is connected to the input end of the switching power supply. Here, the second unidirectional conducting element, for example, includes the diode D3 shown in Figure 3.

[0146] The power loop includes a fourth PI regulator, where:

[0147] The positive input end of the fourth PI regulator is connected to the second port of the controller, the negative input end of the fourth PI regulator is connected to the output end of the load power detection circuit, the output end of the fourth PI regulator is connected to the negative end of the third unidirectional conducting element, and the positive end of the third unidirectional conducting element is connected to the input end of the switching power supply. Here, the third unidirectional conducting element, for example, includes the diode D4 shown in Figure 3.

[0148] In actual application, referring to Figure 3, the current load voltage U Vsample Generally, it is sent to the negative input terminal of the third PI regulator after passing through the current limiting resistor. Psample Generally, the current is sent to the negative input terminal of the fourth PI regulator after passing through a current limiting resistor, so as to protect the circuit elements of the parallel feedback control structure from being damaged due to sudden current increase through the current limiting circuit.

[0149] As mentioned above, since the voltage loop in the cascade feedback control structure is used to adjust the load voltage of the beauty instrument at the next moment, and the power loop is used to adjust the load power of the beauty instrument at the next moment, therefore, in the design stage of the parallel feedback control structure shown in FIG3 , the parameters of the circuit elements of the parallel feedback control structure should be reasonably designed, and the working states of the third PI regulator and the fourth PI regulator should be controlled by the conduction and cutoff of the diodes D3 and D4. Specifically,

[0150] When the diode D4 is in the cut-off state, the fourth PI regulator enters the saturation state. At this time, the diode D3 is in the on state, and the third PI regulator enters the feedback control state. In this way, the parallel feedback control structure can keep the load voltage of the beauty instrument in a constant voltage state, and the load power is less than the reference power.

[0151] When the diode D3 is in the cut-off state, the third PI regulator enters the saturation state. At this time, the diode D4 is in the on state, and the fourth PI regulator enters the feedback control state. In this way, the parallel feedback control structure can make the load power of the beauty instrument in a constant power state, and the load voltage is less than the reference voltage.

[0152] Referring to the circuit schematic diagram shown in Figure 3, it can be seen that during the switching process of the third PI regulator from saturation to feedback control, the load power is in an uncontrollable state. Similarly, during the switching process of the fourth PI regulator from saturation to feedback control, the load voltage is in an uncontrollable state, which is likely to have a negative impact on the user's physical experience during actual use. Based on this, the present application preferably designs the cascade feedback control structure as a series feedback control structure.

[0153] In some embodiments of the present application, a switching power supply includes a comparator and a voltage-controlled voltage source. The output of the cascaded feedback control structure is connected to the positive input of the comparator, and the negative input of the comparator is connected to a reference signal source, such as a sawtooth signal source. In this manner, the comparator can input a PWM (Pulse Width Modulation) signal, which is then transmitted to the voltage-controlled voltage source, thereby controlling the output voltage of the switching power supply.

[0154] The present application also provides a beauty instrument. In some scenarios, as shown in FIG7 , a schematic diagram of the structure of a beauty instrument according to an embodiment of the present application is provided. The beauty instrument according to an embodiment of the present application includes: a switching power supply for controlling the output voltage and a controller connected to the switching power supply. The controller includes a cascaded feedback control structure formed by cascading a power loop and a voltage loop. The controller executes the control method of the beauty instrument described above through the cascaded feedback control structure. In other scenarios, as shown in FIG8 , a schematic diagram of the structure of another beauty instrument according to an embodiment of the present application is provided. The beauty instrument includes: a controller and the beauty instrument control circuit described in the above embodiment.

[0155] In some embodiments of the present application, the beauty instrument control circuit can be integrated on the controller, and the electrical connection between the beauty instrument control circuit and the controller can be achieved through intra-board routing; the beauty instrument control circuit can also be integrated separately on another circuit board, in which case the beauty instrument control circuit and the controller can be electrically connected through inter-board routing.

[0156] Of course, the beauty instrument in the embodiment of the present application may also include other required hardware, which will not be illustrated one by one in the embodiment of the present application.

[0157] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for controlling a beauty instrument, wherein: The beauty instrument includes a switching power supply for controlling an output voltage, and also includes a controller connected to the switching power supply. The method is executed by the controller of the beauty instrument, and the controller includes a cascade feedback control structure formed by cascading a power loop and a voltage loop. The control method of the beauty instrument includes: Obtaining the current load voltage and load power of the beauty instrument, as well as the reference voltage and reference power of the load of the beauty instrument; Inputting the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and inputting the current load power of the beauty instrument and the reference power into the power loop; The output voltage is controlled according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

2. The control method according to claim 1, wherein: The cascade feedback control structure is a series feedback control structure, the voltage loop is a voltage outer loop implemented based on a first PI regulator, and the power loop is a power inner loop implemented based on a second PI regulator; the current load voltage of the beauty instrument and the reference voltage are input into the voltage loop, and the current load power of the beauty instrument and the reference power are input into the power loop, including: Input the reference voltage into the positive input terminal of the first PI regulator, input the current load voltage of the beauty instrument into the negative input terminal of the first PI regulator, and input the output of the first PI regulator into the positive input terminal of the second PI regulator; The reference power is input into the positive input terminal of the second PI regulator through a controllable transmission channel, the current load power of the beauty instrument is input into the negative input terminal of the second PI regulator, and the output of the second PI regulator is input into the switching power supply.

3. The control method according to claim 2, wherein: The step of inputting the reference power into the positive input terminal of the second PI regulator through a controllable transmission channel comprises: Obtaining an output value of the first PI regulator; Controlling the state of the controllable transmission channel according to the output value of the first PI regulator, wherein the state of the controllable transmission channel includes a conducting state and a non-conducting state; When the state of the controllable transmission channel is the conducting state, the reference power is input into the positive input end of the second PI regulator; when the state of the controllable transmission channel is the non-conducting state, the output value of the first PI regulator is input into the positive input end of the second PI regulator.

4. The control method according to claim 3, wherein: The controllable transmission channel includes a unidirectional conductive element, the negative terminal of the unidirectional conductive element receives the reference power, the positive terminal of the unidirectional conductive element is connected in parallel with the output terminal of the first PI regulator and then connected to the positive output terminal of the second PI regulator, and the state of the controllable transmission channel is controlled according to the output value of the first PI regulator, including: obtaining the positive electrode voltage value of the unidirectional conductive element according to the output value of the first PI regulator, and obtaining the negative electrode voltage value of the unidirectional conductive element according to the reference power; Comparing the positive electrode voltage value of the unidirectional conductive element with the negative electrode voltage value; When the positive electrode voltage value of the unidirectional conductive element is not less than the negative electrode voltage value thereof, the state of the controllable transmission channel is controlled to be a conductive state; When the positive electrode voltage value of the unidirectional conductive element is smaller than the negative electrode voltage value thereof, the state of the controllable transmission channel is controlled to be a non-conductive state.

5. The control method according to claim 3, wherein: When the state of the controllable transmission channel is a non-conducting state, when the output value of the first PI regulator is input into the positive input terminal of the second PI regulator, the output voltage is controlled according to the output value of the cascade feedback control structure, including: The output voltage of the switching power supply is controlled according to the output value of the second PI regulator in a saturated state, so as to control the load voltage of the beauty instrument to be in a constant voltage state through the output voltage.

6. The control method according to claim 3, wherein: When the state of the controllable transmission channel is the on state, when the reference power is input into the positive input terminal of the second PI regulator, the output voltage is controlled according to the output value of the cascade feedback control structure, including: The output voltage of the switching power supply is controlled according to the output value of the second PI regulator in the feedback control state, so as to control the load power of the beauty instrument to be in a constant power state through the output voltage.

7. The control method according to any one of claims 1 to 6, wherein: The switching power supply includes a comparator and a voltage-controlled voltage source, and the output voltage is controlled according to the output value of the cascade feedback control structure, including: The output value of the cascade feedback control structure is input to the positive input terminal of the comparator, so as to control the PWM signal output by the comparator through the output value, and further control the output voltage of the voltage-controlled voltage source through the PWM signal.

8. The control method according to claim 7, wherein: The obtaining of the current load voltage and load power of the beauty instrument includes: Performing voltage sampling and current sampling on the beauty instrument load to obtain a sampled voltage and a sampled current; Performing amplitude conversion on the sampled voltage and the sampled current to obtain a load voltage and a load current; The load power is obtained according to the load voltage and the load current.

9. A control device for a beauty instrument, wherein: The beauty instrument includes a switching power supply for controlling an output voltage, and also includes a controller connected to the switching power supply. The device is applied to the controller of the beauty instrument. The controller includes a cascade feedback control structure formed by cascading a power loop and a voltage loop. The control device of the beauty instrument includes: A data acquisition unit is used to obtain the current load voltage and load power of the beauty instrument, and the load The reference voltage and reference power of the load; A data input unit, used for inputting the current load voltage of the beauty instrument and the reference voltage into the voltage loop, and inputting the current load power of the beauty instrument and the reference power into the power loop; A feedback control unit is used to control the output voltage according to the output value of the cascade feedback control structure, so as to limit the load voltage and load power of the beauty instrument through the output voltage.

10. A beauty instrument control circuit, wherein: The beauty instrument control circuit comprises: a load voltage detection circuit, a load power detection circuit, a cascade feedback control structure and a switching power supply, wherein the cascade feedback control structure comprises a power loop and a voltage loop, and the power loop and the voltage loop are connected in a cascade manner; The load voltage detection circuit is connected to the load of the beauty instrument and the voltage loop respectively, and is used to detect the current load voltage of the beauty instrument and send the current load voltage of the beauty instrument to the voltage loop; The load power detection circuit is connected to the load of the beauty instrument and the power ring respectively, and is used to detect the current load power of the beauty instrument and send the current load power of the beauty instrument to the power ring; The power ring and the voltage ring are also connected to the controller of the beauty instrument, the power ring receives reference power from the controller, the voltage ring receives reference voltage from the controller, and the cascade feedback control structure is connected to the switching power supply, for sending the output value of the cascade feedback control structure to the switching power supply; The switching power supply is used to generate a corresponding output voltage according to the output value of the cascade feedback control structure, and to limit the load voltage and load power of the beauty instrument through the output voltage.

11. The beauty instrument control circuit according to claim 10, wherein: The cascade feedback control structure is a series feedback control structure, and the power loop and the voltage loop are connected in series.

12. The beauty instrument control circuit according to claim 11, wherein: The voltage loop includes a first PI regulator, and the power loop includes a second PI regulator; The positive input end of the first PI regulator is connected to the first port of the controller, the negative input end of the first PI regulator is connected to the load voltage detection circuit, and the output end of the first PI regulator is connected to the positive input end of the second PI regulator; The positive input end of the second PI regulator is also connected to the second port of the controller, the negative input end of the second PI regulator is connected to the output end of the load power detection circuit, and the output end of the second PI regulator is connected to the input end of the switching power supply.

13. The beauty instrument control circuit according to claim 12, wherein: The beauty instrument control circuit also includes a first unidirectional conductive element, a negative terminal of the first unidirectional conductive element is connected to the second port of the controller, and a positive terminal of the first unidirectional conductive element is connected in parallel with the output terminal of the first PI regulator and then connected to the positive input terminal of the second PI regulator.

14. The beauty instrument control circuit according to claim 10, wherein: The cascade feedback control structure is a parallel feedback control circuit, and the power loop and the voltage loop are connected in parallel.

15. The beauty instrument control circuit according to claim 14, wherein: The voltage loop includes a third PI regulator; The positive input end of the third PI regulator is connected to the first port of the controller, the negative input end of the third PI regulator is connected to the output end of the load voltage detection circuit, the output end of the third PI regulator is connected to the negative end of the second unidirectional conductive element, and the positive end of the second unidirectional conductive element is connected to the input end of the switching power supply.

16. The beauty instrument control circuit according to claim 14, wherein: The power loop comprises a fourth PI regulator; The positive input end of the fourth PI regulator is connected to the second port of the controller, the negative input end of the fourth PI regulator is connected to the output end of the load power detection circuit, the output end of the fourth PI regulator is connected to the negative end of the third unidirectional conductive element, and the positive end of the third unidirectional conductive element is connected to the input end of the switching power supply.

17. The beauty instrument control circuit according to claim 10, wherein: The load power detection circuit includes a load current detection circuit and a multiplier; The load current detection circuit is connected to the load of the beauty instrument and the first input terminal of the multiplier respectively, and is used to detect the current load current of the beauty instrument and send the current load current of the beauty instrument to the multiplier; The second input end of the multiplier is connected to the output end of the load voltage detection circuit, and the output end of the multiplier is connected to the power ring. The multiplier is used to multiply the current load voltage and load current of the beauty instrument to obtain load power and send the load power to the power ring.

18. The beauty instrument control circuit according to claim 17, wherein: The load voltage detection circuit includes a voltage sampling circuit and a first amplitude conversion circuit, and the load current detection circuit includes a current sampling circuit and a second amplitude conversion circuit; The voltage sampling circuit is connected to the first amplitude conversion circuit, and is used to sample the voltage of the beauty instrument load and send the sampled voltage to the first amplitude conversion circuit; The first amplitude conversion circuit is connected to the second input terminal of the multiplier and the voltage loop respectively, and is used to perform amplitude conversion on the sampled voltage, obtain the load voltage through amplitude conversion and send it to the multiplier and the voltage loop; The current sampling circuit is connected to the second amplitude conversion circuit, and is used to perform current sampling on the beauty instrument load and send the sampled current to the second amplitude conversion circuit; The second amplitude conversion circuit is connected to the first input terminal of the multiplier and is used for performing amplitude conversion on the sampling current, obtaining the load current through the amplitude conversion and sending it to the multiplier.

19. A beauty instrument, wherein: The beauty instrument comprises: a switching power supply for controlling an output voltage and a controller connected to the switching power supply, the controller comprising a cascade feedback control structure formed by cascading a power loop and a voltage loop, and the controller executes the control method of the beauty instrument according to any one of claims 1 to 8 through the cascade feedback control structure; Alternatively, the beauty instrument comprises: a controller and the beauty instrument control circuit according to any one of claims 10 to 18.

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