Current sampling circuit and system and clothes airing machine

Abstract

The utility model provides a current sampling circuit and system and a clothes airing machine, and relates to the technical field of circuit design. The current sampling circuit comprises a driving circuit, a filter circuit and a controller, the driving circuit comprises a sampling resistor and is configured to drive the motor and control the rotating speed of the motor; a first end of the sampling resistor is connected with a first voltage end, and a second end of the sampling resistor is electrically connected with a motor; the first end of the filter circuit is electrically connected with the first end of the sampling resistor, the second end of the filter circuit is electrically connected with the second end of the sampling resistor, and the filter circuit is configured to filter the initial voltage corresponding to the second end of the sampling resistor to obtain sampling voltage; the frequency of the sampling voltage is within a preset frequency range; the first end of the controller is electrically connected with the third end of the filter circuit, and the controller is configured to obtain the sampling voltage and convert the sampling voltage into sampling current. According to the embodiment of the invention, the anti-interference capability of the sampling current is improved, so that the accuracy of the sampling current obtained by sampling is improved.

Description

Technical Field

[0001] The present application relates to the technical field of circuit design, and in particular to a current sampling circuit, system and clothes drying machine. Background Art

[0002] In motor applications, the resistor current sampling method is mostly used. This sampling method is that the controller obtains the voltage corresponding to one end of the sampling resistor as the sampling voltage, and converts the sampling voltage into the sampling current. It has the advantages of low cost and fast response.

[0003] However, this resistance current sampling method also has an obvious defect, that is, the sampling current obtained by sampling has a large error. Utility Model Content

[0004] In view of the shortcomings of the existing methods, the present application proposes a current sampling circuit, system and clothes drying machine to solve the technical problem of large error in the sampled current of the motor obtained by sampling in the related art.

[0005] In a first aspect, an embodiment of the present application provides a current sampling circuit, including:

[0006] The driving circuit includes a sampling resistor, and is configured to drive the motor and control the speed of the motor; a first end of the sampling resistor is connected to the first voltage end, and a second end of the sampling resistor is used to be electrically connected to the motor;

[0007] A filter circuit, wherein the first end is electrically connected to the first end of the sampling resistor, the second end is electrically connected to the second end of the sampling resistor, and is configured to filter the initial voltage corresponding to the second end of the sampling resistor to obtain a sampled voltage; the frequency of the sampled voltage is within a predetermined frequency range;

[0008] The controller has a first terminal electrically connected to the third terminal of the filter circuit and is configured to obtain a sampled voltage and convert the sampled voltage into a sampled current; the sampled current is used to characterize the current passing through the motor.

[0009] In a possible implementation, the filter circuit includes an inductor, a first capacitor, and a second capacitor;

[0010] The first end of the first capacitor and the first end of the second capacitor are electrically connected and serve together as the first end of the filter circuit;

[0011] The first end of the inductor serves as the second end of the filter circuit;

[0012] The second end of the inductor, the second end of the first capacitor, and the second end of the second capacitor are all electrically connected and serve together as the third end of the filter circuit;

[0013] The first capacitor is configured to filter a voltage signal lower than a first voltage frequency; the second capacitor is configured to filter a voltage signal higher than a second voltage frequency; and the predetermined frequency range is a voltage frequency between the first voltage frequency and the second voltage frequency.

[0014] In a possible implementation, the driving circuit further includes a first switch module, a first resistor and a second resistor;

[0015] The control end of the first switch module is electrically connected to the first end of the first resistor and the first end of the second resistor, and the first end and the second end of the first switch module are electrically connected to the motor and the second end of the sampling resistor respectively;

[0016] The second end of the first resistor is electrically connected to the second end of the controller, and the second end of the second resistor is electrically connected to the second end of the sampling resistor;

[0017] The controller is also configured to control the on and off of the first switch module to drive the motor and control the rotation speed of the motor.

[0018] In a possible implementation, the current sampling circuit further includes: a first protection circuit;

[0019] The first protection circuit includes a first diode and a second diode;

[0020] The cathode of the first diode is electrically connected to the motor, and the anode of the first diode, the cathode of the second diode and the first end of the first switch module are all electrically connected;

[0021] The anode of the second diode is electrically connected to the first end of the sampling resistor.

[0022] In a possible implementation, the current sampling circuit further includes: a second protection circuit;

[0023] The second protection circuit includes a third diode, a fourth diode and a third resistor;

[0024] The cathode of the third diode is electrically connected to the second voltage terminal, and the anode of the third diode, the cathode of the fourth diode and the first end of the third resistor are all electrically connected and are commonly electrically connected to the third end of the filter circuit;

[0025] An anode of the fourth diode is electrically connected to the first voltage terminal;

[0026] The second end of the third resistor is electrically connected to the first end of the controller.

[0027] In a possible implementation, the current sampling circuit further includes: a voltage filtering circuit;

[0028] The voltage filtering circuit includes a third capacitor and a fourth capacitor;

[0029] The first end of the third capacitor, the first end of the fourth capacitor, and the third end of the controller are all electrically connected and are commonly electrically connected to the third voltage end; the third end of the controller serves as a voltage input end of the controller;

[0030] The second end of the third capacitor, the second end of the fourth capacitor, and the fourth end of the controller are all electrically connected and are commonly electrically connected to the fourth voltage end.

[0031] In one possible implementation, the controller includes an analog-to-digital conversion unit;

[0032] The analog-to-digital conversion unit includes a comparison voltage generation module and a comparison module;

[0033] A comparison voltage generating module, electrically connected to the comparison module, configured to divide the reference voltage into a set of a first predetermined number of arithmetic progressions increasing from zero to the reference voltage as a plurality of comparison voltages;

[0034] The comparison module is electrically connected to the first end of the controller and is configured to compare each sampling voltage with multiple comparison voltages in sequence to determine a comparison result, and determine a sampling current according to each comparison result; the sampling voltage is an analog signal, the sampling current is a digital signal, and the first voltage end is grounded.

[0035] In a possible implementation, the controller further includes a current determination unit;

[0036] The current determination unit is electrically connected to the comparison module and is configured to use the determined sampling current as the initial sampling current, and in each calculation of the sampling current, determine the current sampling current according to the collected second predetermined number of initial sampling currents and a predetermined algorithm.

[0037] In one possible implementation, the current determination unit is specifically configured to collect initial sampling currents at predetermined time intervals, remove the maximum value and the minimum value of a second predetermined number of collected initial sampling currents, and determine the average value of the remaining initial sampling currents as the average sampling current; and use the average value of the current average sampling current and the previous average sampling current as the current sampling current.

[0038] In a second aspect, an embodiment of the present application provides a current sampling system, comprising: a motor and a current sampling circuit as in the first aspect;

[0039] The motor is electrically connected to the driving circuit of the current sampling circuit.

[0040] In a third aspect, an embodiment of the present application provides a clothes drying machine, comprising: the current sampling system of the second aspect.

[0041] The beneficial technical effects brought about by the technical solution provided by the embodiment of the present application include:

[0042] The current sampling circuit of the embodiment of the present application includes a filtering circuit, wherein the first end and the second end of the filtering circuit are electrically connected to the first end and the second end of the sampling resistor respectively, and the initial voltage corresponding to the second end of the sampling resistor can be filtered to obtain a sampling voltage. The sampling voltage frequency obtained after filtering is within a predetermined frequency range, and low-frequency voltage signals and high-frequency voltage signals are filtered. Since the controller converts the sampling voltage into a sampling current, the irregular high-order harmonics and random interference contained in the sampled phase current can be greatly reduced, the anti-interference ability of the sampling current is improved, and thus the accuracy of the sampled current obtained by sampling is improved.

[0043] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0045] Figure 1 A schematic diagram of the structure of a first current sampling system provided in an embodiment of the present application;

[0046] Figure 2 A schematic diagram of the structure of the connection between a main control board and a motor provided in an embodiment of the present application;

[0047] Figure 3 A schematic diagram of the structure of a second current sampling system provided in an embodiment of the present application;

[0048] Figure 4 A schematic diagram of the structure of a third current sampling system provided in an embodiment of the present application;

[0049] Figure 5 A schematic diagram of the structure of a fourth current sampling system provided in an embodiment of the present application.

[0050] Description of reference numerals:

[0051] 10-current sampling circuit;

[0052] 20-motor;

[0053] 110-driving circuit, 111-sampling resistor;

[0054] 120-filter circuit;

[0055] 130 - controller, 131 - analog-to-digital conversion unit, 1311 - comparison voltage generation module, 1312 - comparison module, 132 - current determination unit;

[0056] 140-first protection circuit;

[0057] 150-second protection circuit;

[0058] 160-voltage filtering circuit;

[0059] 170-reset circuit;

[0060] P1-first voltage terminal, P2-second voltage terminal, P3-third voltage terminal, P4-fourth voltage terminal, P5-fifth voltage terminal, P6-sixth voltage terminal;

[0061] L1-inductor, CE2-first capacitor, C3-second capacitor;

[0062] Q1-first switch device, R1-first resistor, R2-second resistor;

[0063] D1-first diode, D2-second diode;

[0064] D3-third diode, D4-fourth diode, R4-third resistor;

[0065] CE1-third capacitor, C1-fourth capacitor;

[0066] R3-the fourth resistor, C2-the fifth capacitor. DETAILED DESCRIPTION

[0067] The embodiments of the present application are described below in conjunction with the drawings in the present application. It should be understood that the implementation methods described below in conjunction with the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0068] It will be understood by those skilled in the art that, unless specifically stated, the "said" and "the" used herein may also include plural forms. It should be further understood that the wording "including" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the implementation of other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the present technical field. It should be understood that when we say that an element is "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or it may refer to the connection relationship between the element and the other element through an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein refers to at least one of the items defined by the term, for example, "A and / or B" may be implemented as "A", or as "B", or as "A and B".

[0069] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0070] Research has found that the traditional resistance current sampling method has obvious defects. Due to the wide range of speed regulation and high-speed characteristics of the motor, and the motor itself cannot obtain an ideal sinusoidal air gap magnetic field, the phase current sampled during system control contains irregular high-order harmonics and random interference. In addition, the instability of the current sampling circuit and the existence of analog-to-digital conversion unit deviation further increase the actual sampled current error. The use of this method can improve the anti-interference ability of phase current sampling, and combined with the predetermined algorithm, the current value of the current motor can be accurately obtained.

[0071] The current sampling circuit, system and clothes drying machine provided in this application are intended to solve the above technical problems of related technologies.

[0072] The following is a detailed description of the technical solution of the present application and how the technical solution of the present application solves the above technical problems with specific embodiments. It should be noted that the following implementations can refer to, draw on or combine with each other, and the same terms, similar features and similar implementation steps in different implementations will not be described repeatedly.

[0073] The present application embodiment provides a current sampling system, see Figure 1 , a schematic diagram of the structure of a first current sampling system is shown. The current sampling system includes: a motor 20 and a current sampling circuit 10.

[0074] The motor 20 is electrically connected to the driving circuit 110 of the current sampling circuit 10 .

[0075] Specifically, the driving circuit 110 is electrically connected to the motor 20 and can drive the motor 20 to rotate.

[0076] See also Figure 1 As shown, an embodiment of the present application provides a current sampling circuit. The current sampling circuit 10 includes: a driving circuit 110 , a filtering circuit 120 and a controller 130 .

[0077] The driving circuit 110 includes a sampling resistor 111 , and the driving circuit 111 is configured to drive the motor 20 and control the speed of the motor 20 ; a first end of the sampling resistor 111 is connected to the first voltage terminal P1 , and a second end of the sampling resistor 111 is used to be electrically connected to the motor 20 .

[0078] The first voltage terminal P1 may be a fixed voltage terminal or directly grounded.

[0079] A first end of the filter circuit 120 is electrically connected to a first end of the sampling resistor 111, and a second end of the filter circuit 120 is electrically connected to a second end of the sampling resistor 111. The filter circuit 120 is configured to filter an initial voltage corresponding to the second end of the sampling resistor 111 to obtain a sampled voltage; the frequency of the sampled voltage is within a predetermined frequency range.

[0080] Specifically, the filter circuit 120 can filter the initial voltage corresponding to the second end of the sampling resistor 111, filter the low-frequency voltage signal and the high-frequency voltage signal, so that the sampled voltage frequency obtained by sampling is within a predetermined frequency range, that is, the sampled current converted from the sampled voltage is filtered, thereby greatly reducing the irregular high-order harmonics and random interference contained in the sampled phase current.

[0081] The first terminal of the controller 130 is electrically connected to the third terminal of the filter circuit 120 . The controller 130 is configured to obtain a sampled voltage and convert the sampled voltage into a sampled current. The sampled current is used to characterize the current passing through the motor 20 .

[0082] The sampled current obtained in the embodiment of the present application may be a digital signal representing the current passing through the motor 20 . There is no need to calculate the actual current value, and it only needs to be identified in the controller 130 .

[0083] The current sampling circuit 10 of the embodiment of the present application includes a filter circuit 120. The first end and the second end of the filter circuit 120 are electrically connected to the first end and the second end of the sampling resistor 111 respectively. The initial voltage corresponding to the second end of the sampling resistor 111 can be filtered to obtain a sampled voltage. The frequency of the sampled voltage obtained after the filtering process is within a predetermined frequency range, and the low-frequency voltage signal and the high-frequency voltage signal are filtered. Since the controller 130 converts the sampled voltage into a sampled current, the irregular high-order harmonics and random interference contained in the sampled phase current can be greatly reduced, the anti-interference ability of the sampled current is improved, and thus the accuracy of the sampled current obtained by sampling is improved.

[0084] See also Figure 2 The main control board is connected to an AC power supply of AC220V, which is then converted to DC 32V by a switch circuit and provided to the motor 20. The controller 130 can adjust the speed of the motor 20 and collect the current passing through the motor 20.

[0085] In practical applications, the motor 20 may be a 32V DC motor with a full load of about 65W. The speed of the motor 20 can be adjusted by adjusting the input voltage. The maximum speed of the motor 20 is about 70mm / s, and the maximum current is about 2.0A.

[0086] See also Figure 3As shown in FIG. 1 , a schematic diagram of the structure of the second current sampling system is shown. Figure 3 As shown, the controller 130 includes an analog-to-digital conversion unit 131 .

[0087] The analog-to-digital conversion unit 131 includes a comparison voltage generation module 1311 and a comparison module 1312 .

[0088] The comparison voltage generation module 1311 is electrically connected to the comparison module 1312 . The comparison voltage generation module 1311 is configured to divide the reference voltage into a set of a first predetermined number of arithmetic progressions increasing from zero to the reference voltage as a plurality of comparison voltages.

[0089] The comparison module 1312 is electrically connected to the first end of the controller 130. The comparison module 1312 is configured to compare each sampling voltage with multiple comparison voltages in sequence to determine a comparison result, and determine a sampling current according to each comparison result; the sampling voltage is an analog signal, the sampling current is a digital signal, and the first voltage terminal P1 is grounded.

[0090] Optionally, a reference voltage is used as the input voltage VDD, and the input voltage VDD can be the input voltage of the input voltage terminal of the controller 130. The controller 130 divides the input voltage VDD into an arithmetic progression of 4096 equal parts. The sampling voltage is compared with the multiple comparison voltages in sequence according to the arrangement of multiple comparison voltages in ascending order. Each comparison outputs a 0 or 1, and the comparison result obtained is a digital signal, which can be used as a sampling current. The embodiment of the present application uses a successive approximation calculation method, which is equivalent to taking the value closest to the sampled voltage in the 4096 parts as the sampling current, and storing it in the cache of the comparison module 1312. The comparison module 1312 outputs an interrupt signal indicating that the comparison is completed.

[0091] See also Figure 4 As shown in FIG. 1 , a schematic diagram of the structure of the third current sampling system is shown. Figure 4 As shown, the controller 130 further includes a current determination unit 132 .

[0092] The current determination unit 132 is electrically connected to the comparison module 1312 and is configured to use the determined sampling current as the initial sampling current and determine the current sampling current according to the collected second predetermined number of initial sampling currents and a predetermined algorithm in each calculation of the sampling current.

[0093] Specifically, the controller 130 of the embodiment of the present application can continue to perform subsequent operations based on the sampled current determined by the comparison module 1312, so as to accurately collect the current current of the motor 20.

[0094] Optionally, the second predetermined number may be 5, 10, 15, etc. The predetermined algorithm is a calculation rule pre-stored in the current determination unit 132 and may be implemented using a software program.

[0095] In some embodiments, the current determination unit 132 is specifically configured to collect initial sampling currents at predetermined time intervals, remove the maximum value and the minimum value of the second predetermined number of collected initial sampling currents, and determine the average value of the remaining initial sampling currents as the average sampling current; and use the average value of the current average sampling current and the previous average sampling current as the current sampling current.

[0096] Optionally, the initial sampling current is also a digital signal, and the predetermined time interval may be 100 us. The current sampling current is a final value output by the current determination unit 132 , that is, the current current of the motor 20 .

[0097] Optionally, the current determination unit 132 is further configured to determine a third predetermined number of average sampled currents as a group, and sequentially determine the average of the current average sampled current and the previous average sampled current, so that a current sampled current is output at a designed time interval. The third predetermined number may be 5.

[0098] As an example, the calculation process of the current sampling current includes: ① the current determination unit 132 collects the initial sampling current once every 100us; ② after collecting 10 initial sampling currents, start calculating the average value, remove the maximum and minimum values, and take the average value of the remaining 8 initial sampling currents to obtain the average sampling current; ③ take the average value of the obtained average sampling current and the average sampling current collected last time, and obtain the calculated value as the current sampling current. After 5 times, the output calculated value is the final value of AD collection.

[0099] As an example, assume that the 10 initial sampling currents collected are: 2, 7, 4, 8, 5, 6, 4, 6, 8, 9; remove the maximum value 9 and the minimum value 2, and obtain the average value 6; assume that the 5 average values ​​obtained are 6, 8, 9, 8, 6; calculate the final output value: (6+8) / 2=7; (7+9) / 2=8; (8+8) / 2=8; (8+6) / 2=7; repeat the above operations to obtain the next final value, and output a final value in about 5ms.

[0100] See also Figure 5 As shown in FIG. 1 , a schematic diagram of the structure of a fourth current sampling system is shown. Figure 5 As shown, the filter circuit 120 includes an inductor L1, a first capacitor CE2 and a second capacitor C3.

[0101] The first end of the first capacitor CE2 and the first end of the second capacitor C3 are electrically connected and serve together as the first end of the filter circuit 120; the first end of the inductor L1 serves as the second end of the filter circuit 120; the second end of the inductor L1, the second end of the first capacitor CE2, and the second end of the second capacitor C3 are all electrically connected and serve together as the third end of the filter circuit 120.

[0102] The first capacitor CE2 is configured to filter a voltage signal lower than a first voltage frequency; the second capacitor C3 is configured to filter a voltage signal higher than a second voltage frequency; and the predetermined frequency range is a voltage frequency between the first voltage frequency and the second voltage frequency.

[0103] Specifically, the voltage signal of the first voltage frequency is a low-frequency voltage signal, and the voltage signal of the second voltage frequency is a high-frequency voltage signal.

[0104] As an example, the inductance value of the inductor L1 is 3.3μH (microhenry); the first capacitor CE2 is an electrolytic capacitor, the capacitance value of the first capacitor CE2 is 10μF (microfarad), and the withstand voltage is 50v (volt); the second capacitor C3 is a ceramic capacitor, and the capacitance value is 100nF (nanofarad); the sampling resistor 111 is 0.2Ω (ohm) with an accuracy of 1%.

[0105] See also Figure 5 As shown, in some embodiments, the driving circuit 110 further includes a first switch module, a first resistor R1 and a second resistor R2;

[0106] The control end of the first switch module is electrically connected to the first end of the first resistor R1 and the first end of the second resistor R2, and the first end and the second end of the first switch module are electrically connected to the motor 20 and the second end of the sampling resistor 111 respectively;

[0107] The second end of the first resistor R1 is electrically connected to the second end of the controller 130 , and the second end of the second resistor R2 is electrically connected to the second end of the sampling resistor 111 ;

[0108] The controller 130 is further configured to control the on and off of the first switch module to drive the motor 20 and control the rotation speed of the motor 20 .

[0109] As an example, see Figure 5 As shown, the first switch module includes a first switch device Q1. The first switch device Q1 is turned on and off, so that the first end and the second end of the first switch module are turned on and off. The first switch device Q1 is a MOS tube with a maximum withstand voltage of 100V and a current of 30A (ampere); the resistance of the first resistor R1 is 10Ω, and the resistance of the second resistor R2 is 10kΩ.

[0110] See also Figure 5As shown, B1 is a DC motor, the sampling resistor R5 is the sampling resistor 111, and the switching and speed regulation functions are achieved through the first switch device Q1. When the motor 20 is running, the current passes through the motor 20, the first switch device Q1, and the sampling resistor R5 to the negative pole of the power supply. The voltage on the sampling resistor R5 can be collected to calculate the current passing through the motor 20. The inductor L1, the first capacitor CE2 and the second capacitor C3 jointly form a filtering circuit 120 for the voltage of the sampling resistor R5.

[0111] See also Figure 5 As shown, in some embodiments, the current sampling circuit 10 further includes: a first protection circuit 140; the first protection circuit 140 includes a first diode D1 and a second diode D2.

[0112] The cathode of the first diode D1 is electrically connected to the motor 20 , and the anode of the first diode D1 , the cathode of the second diode D2 , and the first end of the first switch module are all electrically connected.

[0113] An anode of the second diode D2 is electrically connected to a first end of the sampling resistor 111 .

[0114] Specifically, when the first switch device Q1 is turned off, the current is instantly cut off, which will impact the motor 20. The first diode D1 can discharge the current to protect the motor 20. The first switch device Q1 is frequently switched on and off, and the external voltage cannot change suddenly. The second diode D2 can discharge the current to protect the circuit.

[0115] As an example, see Figure 5 As shown, the first diode D1 is an M7 diode, model 1N4007, with a maximum withstand voltage of 1000V and a current of 1A. The second diode D2 is a transient absorption diode, which is turned on when the reverse voltage is greater than 36V.

[0116] See also Figure 5 As shown, in some embodiments, the current sampling circuit 10 further includes: a second protection circuit 150. The second protection circuit 150 includes a third diode D3, a fourth diode D4 and a third resistor R4.

[0117] The cathode of the third diode D3 is electrically connected to the second voltage terminal P2 , and the anode of the third diode D3 , the cathode of the fourth diode D4 and the first end of the third resistor R4 are all electrically connected and commonly electrically connected to the third end of the filter circuit 120 .

[0118] An anode of the fourth diode D4 is electrically connected to the first voltage terminal P1 . A second terminal of the third resistor R4 is electrically connected to a first terminal of the controller 130 .

[0119] Specifically, the third diode D3 and the fourth diode D4 can protect the IO (Input / Output) port of the first end of the controller 130 to prevent the voltage on the IO port from exceeding the voltage range. The analog voltage signal of the sampling voltage of the first end of the controller 130 is controlled between 0 and 5V.

[0120] When the controller 130 is connected to a power source, the pin at the first end of the controller 130 is not initialized. The pin is a common input / output port. If there is voltage externally, the pin of the controller 130 has an output voltage, which will cause an instantaneous excessive current and may damage the controller 130. The third resistor R4 is a current limiting resistor, which can protect the pin at the first end of the controller 130.

[0121] As an example, see Figure 5 As shown, the resistance of the third resistor R4 is 1 kΩ. The second voltage terminal P2 is a fixed voltage of 5 v.

[0122] See also Figure 5 As shown, in some embodiments, the current sampling circuit 10 further includes: a voltage filtering circuit 160; the voltage filtering circuit 160 includes a third capacitor CE1 and a fourth capacitor C1.

[0123] The first end of the third capacitor CE1, the first end of the fourth capacitor C1, and the third end of the controller 130 are all electrically connected and are commonly electrically connected to the third voltage end P3; the third end of the controller 130 serves as a voltage input end of the controller 130;

[0124] The second end of the third capacitor CE1 , the second end of the fourth capacitor C1 , and the fourth end of the controller 130 are all electrically connected and commonly electrically connected to the fourth voltage end P4 .

[0125] Specifically, the voltage filter circuit 160 can filter the input voltage of the controller 130, the third terminal and the fourth terminal of the controller 130 are electrically connected to the comparison voltage generation module 1311, and the third terminal of the controller 130 is the input voltage VDD, which serves as the reference voltage of the comparison voltage generation module 1311. The input voltage VDD can be 5V.

[0126] As an example, see Figure 5 As shown, the capacitance value of the third capacitor CE1 is 10μF (microfarad) and the withstand voltage is 50V; the fourth capacitor C1 is a ceramic capacitor with a capacitance value of 100nF (nanofarad). The third voltage terminal P3 is a fixed voltage of 5V, and the fourth voltage terminal P4 can be grounded or a fixed voltage less than 5V.

[0127] See also Figure 5 As shown, in some embodiments, the current sampling circuit 10 further includes: a reset circuit 170. The reset circuit 170 includes a fourth resistor R3 and a fifth capacitor C2.

[0128] The first end of the fourth resistor R3 and the first end of the fifth capacitor C2 are both electrically connected to the fifth end of the controller 130; the second end of the fourth resistor R3 and the second end of the fifth capacitor C2 are electrically connected to the fifth voltage end P5 and the sixth voltage end P6 respectively.

[0129] Specifically, the reset circuit 170 is configured so that the fifth terminal of the controller 130 maintains a high level, so as to reset the circuit in the controller 130 .

[0130] As an example, see Figure 5 As shown, the resistance of the fourth resistor R3 is 10kΩ, the fifth capacitor C2 is a ceramic capacitor, and the capacitance is 100nF. The fifth voltage terminal P5 is a fixed voltage of 5v, and the sixth voltage terminal P6 can be grounded or a fixed voltage less than 5v.

[0131] See also Figure 5 As shown, the acquisition logic of the analog-to-digital conversion unit 131 is as follows: in continuous sampling, the sampling current AD value changes every moment. Since the angles at which the coil in the motor 20 cuts the magnetic flux lines are different, when passing through the filter circuit 120, the amplitude of the current change can be reduced, so that the collected current value is more stable. The P14 pin of the controller 130 serves as the second end of the controller 130, generating a high level to drive the first switch device Q1, and the current passes through the motor B1, the first switch device Q1 and the sampling resistor R5 to the negative pole of the power supply. In this loop, the current passing through the motor B1 is equal to the current of the sampling resistor R5. The voltage on the sampling resistor R5 is collected, and then the current of the motor 20 can be calculated using Ohm's law. The voltage on the sampling resistor R5 passes through the inductor L1, the first capacitor CE2, the second capacitor C3 and the third resistor R4 to the analog-to-digital converter of the controller 130. The division of the analog-to-digital converter can be 4096 parts, and the controller 130 uses the closest division as the current sampling.

[0132] In practical applications, if the current value needs to be displayed, the sampled current can be divided by 4096, multiplied by 5V, and then divided by the resistance value of the sampling resistor R5 0.2Ω to obtain the current value of the motor 20 .

[0133] The current sampling circuit 10 of the embodiment of the present application combines peripheral circuit elements with the calculation method inside the controller 130, and has the advantages of low cost and fast response speed. The current sampling circuit 10 of the embodiment of the present application accurately collects the current value of the motor 20 through hardware filtering and software algorithm, thereby improving product performance.

[0134] Based on the same inventive concept, an embodiment of the present application provides a clothes drying machine, including the current sampling system of the embodiment of the present application.

[0135] The current sampling system of the embodiment of the present application can also be applied to smart home devices such as smart curtains or smart robots.

[0136] Based on the same inventive concept, an embodiment of the present application provides a current sampling method, which is applied to the current sampling circuit 10 of the embodiment of the present application. The method includes:

[0137] Obtaining a sampling voltage; the sampling voltage is obtained by filtering the initial voltage corresponding to the second end of the sampling resistor 111;

[0138] Convert the sampled voltage into sampled current.

[0139] In some embodiments, converting the sampled voltage into the sampled current includes:

[0140] Compare each sampled voltage with a plurality of comparison voltages in sequence to determine a comparison result; the plurality of comparison voltages is a set of a first predetermined number of arithmetic progressions increasing from zero to the reference voltage by dividing the reference voltage; the sampled voltage is an analog signal;

[0141] A sampling current is determined according to each comparison result; the sampling current is a digital signal.

[0142] In some embodiments, after determining a sample current according to each comparison result, the method includes:

[0143] The determined sampling current is used as the initial sampling current, and the initial sampling current is collected at a predetermined time interval;

[0144] Determine an average value of the remaining initial sampling currents after removing the maximum value and the minimum value of the second predetermined number of initial sampling currents collected as the average sampling current;

[0145] The average of the current average sampling current and the previous average sampling current is used as the current sampling current.

[0146] Optionally, taking the average of the current average sampling current and the previous average sampling current as the current sampling current includes: determining a third predetermined number of average sampling currents as a group, and determining the average of the current average sampling current and the previous average sampling current in sequence, so that a current sampling current is output at a designed time interval.

[0147] Those skilled in the art will appreciate that the various operations, methods, steps, measures, and schemes in the processes discussed in this application may be alternated, changed, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and schemes in the related art that are similar to those disclosed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted.

[0148] In the description of the present application, the directions or positional relationships indicated by words such as "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the exemplary directions or positional relationships shown in the accompanying drawings. They are for the convenience of describing or simplifying the description of the embodiments of the present application, and do not indicate or imply that the referred device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0149] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0150] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0151] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0152] The above is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical concept of the scheme of the present application, other similar implementation methods based on the technical ideas of the present application are also within the protection scope of the embodiments of the present application.

Claims

1. A current sampling circuit, characterized in that: include: The driving circuit includes a sampling resistor, configured to drive the motor and control the speed of the motor; a first end of the sampling resistor is connected to a first voltage end, and a second end of the sampling resistor is used to be electrically connected to the motor; a filter circuit, wherein a first end is electrically connected to a first end of the sampling resistor, a second end is electrically connected to a second end of the sampling resistor, and is configured to filter an initial voltage corresponding to the second end of the sampling resistor to obtain a sampled voltage; wherein a frequency of the sampled voltage is within a predetermined frequency range; A controller, a first end of which is electrically connected to a third end of the filter circuit, is configured to obtain the sampled voltage and convert the sampled voltage into a sampled current; the sampled current is used to characterize the current passing through the motor.

2. The current sampling circuit according to claim 1, characterized in that: The filter circuit includes an inductor, a first capacitor and a second capacitor; The first end of the first capacitor and the first end of the second capacitor are electrically connected and serve together as the first end of the filter circuit; The first end of the inductor serves as the second end of the filter circuit; The second end of the inductor, the second end of the first capacitor, and the second end of the second capacitor are all electrically connected and serve together as the third end of the filter circuit; The first capacitor is configured to filter a voltage signal lower than a first voltage frequency; the second capacitor is configured to filter a voltage signal higher than a second voltage frequency; and the predetermined frequency range is a voltage frequency between the first voltage frequency and the second voltage frequency.

3. The current sampling circuit according to claim 1, characterized in that: The driving circuit also includes a first switch module, a first resistor and a second resistor; The control end of the first switch module is electrically connected to the first end of the first resistor and the first end of the second resistor, and the first end and the second end of the first switch module are electrically connected to the motor and the second end of the sampling resistor respectively; The second end of the first resistor is electrically connected to the second end of the controller, and the second end of the second resistor is electrically connected to the second end of the sampling resistor; The controller is further configured to control the on and off of the first switch module to drive the motor and control the rotation speed of the motor.

4. The current sampling circuit according to claim 3, characterized in that: Also includes: a first protection circuit; The first protection circuit includes a first diode and a second diode; The cathode of the first diode is electrically connected to the motor, and the anode of the first diode, the cathode of the second diode and the first end of the first switch module are all electrically connected; An anode of the second diode is electrically connected to a first end of the sampling resistor.

5. The current sampling circuit according to claim 1, characterized in that: Also includes: A second protection circuit; The second protection circuit includes a third diode, a fourth diode and a third resistor; The cathode of the third diode is electrically connected to the second voltage terminal, and the anode of the third diode, the cathode of the fourth diode and the first end of the third resistor are all electrically connected and are commonly electrically connected to the third end of the filter circuit; The anode of the fourth diode is electrically connected to the first voltage end; The second end of the third resistor is electrically connected to the first end of the controller.

6. The current sampling circuit according to claim 1, characterized in that: Also includes: Voltage filtering circuit; The voltage filtering circuit includes a third capacitor and a fourth capacitor; The first end of the third capacitor, the first end of the fourth capacitor, and the third end of the controller are all electrically connected and are commonly electrically connected to the third voltage end; the third end of the controller serves as a voltage input end of the controller; The second end of the third capacitor, the second end of the fourth capacitor, and the fourth end of the controller are all electrically connected and are commonly electrically connected to the fourth voltage end.

7. The current sampling circuit according to claim 1, characterized in that: The controller includes an analog-to-digital conversion unit; The analog-to-digital conversion unit includes a comparison voltage generation module and a comparison module; The comparison voltage generating module is electrically connected to the comparison module and is configured to divide the reference voltage into a set of a first predetermined number of arithmetic progressions increasing from zero to the reference voltage as a plurality of comparison voltages; The comparison module is electrically connected to the first end of the controller and is configured to compare each of the sampled voltages with multiple comparison voltages in sequence to determine a comparison result, and determine a sampling current according to each comparison result; the sampled voltage is an analog signal, the sampled current is a digital signal, and the first voltage end is grounded.

8. The current sampling circuit according to claim 7, characterized in that: The controller further includes a current determination unit; The current determination unit is electrically connected to the comparison module and is configured to use the determined sampling current as the initial sampling current, and in each calculation of the sampling current, determine the current sampling current based on the collected second predetermined number of the initial sampling currents and a predetermined algorithm.

9. A current sampling system, characterized in that: include: A motor and a current sampling circuit as claimed in any one of claims 1 to 8; The motor is electrically connected to the driving circuit of the current sampling circuit.

10. A clothes drying machine, characterized in that: include: The current sampling system as claimed in claim 9.

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