Soft start circuit and motor

Abstract

The soft start circuit comprises a first current detection circuit, a first switch circuit, a comparison circuit, a reference source circuit and a master control circuit, the detection end of the first current detection circuit is electrically connected with a power supply, and the input end of the first switch circuit is electrically connected with the power supply. The output end of the first switching circuit is electrically connected with a power supply end, the first input end of the comparison circuit is electrically connected with the output end of the first current detection circuit, the second input end of the comparison circuit is electrically connected with the reference source circuit, the main control circuit is electrically connected with the output end of the comparison circuit, and the main control circuit is further electrically connected with the controlled end of the first switching circuit. The utility model aims to solve the problem that the conventional motor is easy to impact and damage due to the adoption of a direct starting mode.

Description

Technical Field

[0001] The utility model relates to the technical field of soft start, and particularly relates to a soft start circuit and a motor. Background Art

[0002] The existing starting method of motors is generally direct starting. However, direct starting of motors usually generates large current and large torque. Due to the armature electromotive force and the inductance of the stator coil, the starting current may reach dozens of times the rated current. Such an excessive starting current will not only cause the grid voltage to drop, affecting the normal power consumption of other users on the grid, but also may seriously deteriorate the commutation of the motor, or even burn out the motor. Moreover, the effect of direct starting is relatively rough, and the equipment is prone to mechanical vibration and noise. The mechanical vibration will affect the stability and accuracy of the equipment, and may even cause damage and failure of the equipment, thus shortening its service life. Content of the Utility Model

[0003] The main object of the utility model is to provide a soft start circuit, aiming to solve the problem that the existing direct starting method of motors is easy to cause impact and damage to the motors.

[0004] To achieve the above object, a soft start circuit proposed by the utility model is applied to a motor. The motor includes a power supply terminal, and the soft start circuit includes:

[0005] A first current detection circuit, the detection end of the first current detection circuit is electrically connected to a power supply, and the first current detection circuit is used to detect the current of the power supply and output a corresponding first current detection signal;

[0006] A first switch circuit, the input end of the first switch circuit is electrically connected to the power supply, and the output end of the first switch circuit is electrically connected to the power supply terminal;

[0007] A comparison circuit and a reference source circuit, the first input end of the comparison circuit is electrically connected to the output end of the first current detection circuit, the second input end of the comparison circuit is electrically connected to the reference source circuit, the reference source circuit is used to output a reference voltage signal, and the comparison circuit is used to compare the first current detection signal with the reference voltage and output a corresponding first control signal;

[0008] A main control circuit, the main control circuit is electrically connected to the output end of the comparison circuit, and the main control circuit is also electrically connected to the controlled end of the first switch circuit. The main control circuit is used to adjust the conduction degree of the first switch circuit according to the first control signal.

[0009] Optionally, the first current detection circuit includes:

[0010] A current sensor, the input end of the current sensor is electrically connected to a power supply, and the output end of the current sensor is electrically connected to the first input end of the comparison circuit.

[0011] Optionally, the reference source circuit includes:

[0012] A trimming circuit, the input end of the trimming circuit is used to access a first current, and the output end of the trimming circuit is electrically connected to the second input end of the comparison circuit.

[0013] Optionally, the soft start circuit further includes:

[0014] A voltage follower circuit, a first clamping circuit, a second clamping circuit, a first filtering circuit, and a second filtering circuit. The input end of the voltage follower circuit is electrically connected to the first ends of the first clamping circuit and the first filtering circuit respectively. The output end of the voltage follower circuit is electrically connected to the second clamping circuit, the first ends of the second filtering circuit, and the first input end of the comparison circuit respectively. The input end of the voltage follower circuit is further electrically connected to the output end of the first current detection circuit. The second ends of the first filtering circuit and the second filtering circuit are both grounded;

[0015] A second voltage follower, a third clamping circuit, a fourth clamping circuit, a third filtering circuit, and a fourth filtering circuit. The input end of the second voltage follower is electrically connected to the first ends of the third clamping circuit and the third filtering circuit respectively. The output end of the second voltage follower is electrically connected to the third clamping circuit, the first ends of the third filtering circuit, and the second input end of the comparison circuit respectively. The input end of the second voltage follower is further electrically connected to the output end of the reference source circuit. The second ends of the second filtering circuit and the third filtering circuit are both grounded.

[0016] Optionally, the soft start circuit further includes:

[0017] A second current detection circuit, the detection end of the second current detection circuit is electrically connected to the power supply, the output end of the second current detection circuit is electrically connected to the main control circuit. The second current detection circuit outputs a corresponding second current detection signal according to the current of the power supply, and the main control circuit controls the first switch circuit to be turned on or off according to the second current detection signal.

[0018] Optionally, the second current detection circuit includes an isolation amplifier circuit and a proportional amplifier circuit. The input end of the isolation amplifier circuit is electrically connected to the power supply, the output end of the isolation amplifier circuit is electrically connected to the input end of the proportional amplifier circuit, and the output end of the proportional amplifier circuit is electrically connected to the main control circuit.

[0019] Optionally, the soft start circuit further includes:

[0020] A phase detection circuit. The power supply includes a rectifier bridge circuit. The detection end of the phase detection circuit is electrically connected to the rectifier bridge circuit of the power supply. The output end of the phase detection circuit is electrically connected to the main control circuit. The phase detection circuit outputs a corresponding second control signal to the main control circuit according to the current of the rectifier bridge circuit. The main control circuit controls the first switch circuit to conduct or disconnect according to the second control signal.

[0021] Optionally, the phase detection circuit includes:

[0022] An optocoupler, a comparator circuit and a second switch circuit. The optocoupler includes a photodiode and a phototransistor. The input end of the photodiode is electrically connected to the input end of the rectifier bridge circuit of the power supply. The output end of the photodiode is electrically connected to the output end of the rectifier bridge circuit of the power supply. The first input end of the comparator circuit is used to access a reference voltage. The input end of the phototransistor is electrically connected to the second input end of the comparator circuit. The output end of the comparator circuit is electrically connected to the controlled end of the second switch circuit. The input end of the second switch circuit is electrically connected to the main control circuit. The output end of the second switch circuit is grounded.

[0023] The present utility model also proposes a motor, including a power supply end and the soft start circuit described in any one of the above.

[0024] The technical solution of the present utility model includes a first current detection circuit, a first switch circuit, a comparison circuit, a reference source circuit and a main control circuit. The first current detection circuit is used to detect the current of the power supply and output a corresponding first current detection signal. The reference source circuit is used to provide a reference voltage signal. The comparison circuit is used to compare the first current detection signal with the reference voltage signal and output a corresponding first control signal to the controlled end of the first switch circuit, such as a PWM control signal. The duty cycle of the PWM control signal is proportional to the conduction degree of the first switch circuit, so as to control the current size output from the power supply to the power supply terminal. For example, when the current output by the power supply is too large, the main control circuit outputs a PWM control signal with a relatively low duty cycle to the controlled end of the first switch circuit within the first preset time, that is, at the moment when the motor starts, so that the conduction degree of the first switch circuit becomes lower, avoiding damage to the motor due to excessive starting current at the moment of starting. After the first preset time, the duty cycle of the PWM control signal controlled by the main control circuit gradually increases, so that the conduction degree of the first switch circuit gradually increases, and the power supply normally supplies power to the motor. With such a setting, when the motor starts, the soft start circuit of the present utility model can limit the current size output from the power supply to the motor power supply terminal, thereby avoiding the impact and damage of excessive current on the motor during direct starting and shortening its service life. In practical applications, users can adjust the reference source circuit according to actual needs to output a corresponding reference voltage signal, thereby adjusting the current size that limits the power supply output to the motor at the moment of motor instant start. That is, the soft start circuit of the present utility model can be customized according to the characteristics of the motor, the load situation and system requirements, which not only ensures the smooth start of the motor, but also takes into account the flexibility of the actual application of the soft start circuit of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0026] Figure 1 It is a module schematic diagram of an embodiment of the present utility model;

[0027] Figure 2 It is a circuit structure schematic diagram of another embodiment of the present utility model;

[0028] Figure 3 It is a circuit structure schematic diagram of yet another embodiment of the present utility model;

[0029] Figure 4Schematic diagram of the circuit structure according to another embodiment of the present utility model.

[0030] Explanation of the reference numerals in the attached drawings:

[0031] Label Name Label Name 10 First current detection circuit 70 First clamping circuit 20 First switching circuit 80 Second clamping circuit 30 Comparison circuit 90 First filter circuit 40 Reference source circuit 100 Second filter circuit 50 Master control circuit 110 Second current detection circuit 60 Power follower circuit 111 Isolation amplifier circuit 112 Equal ratio amplifier circuit 120 Phase detection circuit 121 Comparator circuit

[0032] The realization of the object, functional characteristics and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0034] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0035] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions appears to be contradictory or unable to be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0036] The existing starting method of motors is generally direct starting. However, direct starting of motors usually generates large current and large torque. Due to the armature electromotive force and the inductance of the stator coil, the starting current may reach dozens of times the rated current. Such an excessive starting current will not only cause the grid voltage to drop, affecting the normal power consumption of other users on the grid, but also may seriously deteriorate the commutation of the motor, or even burn out the motor. Moreover, the effect of direct starting is relatively rough, and the equipment is prone to mechanical vibration and noise. The mechanical vibration will affect the stability and accuracy of the equipment, and may even cause damage and failure of the equipment, thus shortening its service life.

[0037] To this end, the present utility model provides a soft start circuit, aiming to solve the problem that the existing direct start method for motors is likely to cause impact and damage to the motors.

[0038] Reference Figure 1 , in an embodiment of the present utility model, a soft start circuit is applied to a motor. The motor includes a power supply terminal, and the soft start circuit includes:

[0039] A first current detection circuit 10, the detection end of the first current detection circuit 10 is electrically connected to the power supply, and the first current detection circuit 10 is used to detect the current of the power supply and output a corresponding first current detection signal;

[0040] A first switch circuit 20, the input end of the first switch circuit 20 is electrically connected to the power supply, and the output end of the first switch circuit 20 is electrically connected to the power supply terminal;

[0041] A comparison circuit 30 and a reference source circuit 40, the first input end of the comparison circuit 30 is electrically connected to the output end of the first current detection circuit 10, the second input end of the comparison circuit 30 is electrically connected to the reference source circuit 40, the reference source circuit 40 is used to output a reference voltage signal, and the comparison circuit 30 is used to compare the first current detection signal with the reference voltage and output a corresponding first control signal;

[0042] A main control circuit 50, the main control circuit 50 is electrically connected to the output end of the comparison circuit 30, and the main control circuit 50 is also electrically connected to the controlled end of the first switch circuit 20. The main control circuit 50 is used to adjust the conduction degree of the first switch circuit 20 according to the first control signal.

[0043] In this embodiment, the comparison circuit 30, the main control circuit 50, and the reference source circuit 40 can all be implemented by a main controller, such as an MCU (Microcontroller Unit, micro control unit), a DSP (Digital Signal Process, digital signal processing chip), an FPGA (Field Programmable Gate Array, programmable logic gate array chip), an SOC (System On Chip, system-level chip), etc.

[0044] In this embodiment, the first switch circuit 20 can be implemented by at least one switching tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc., and / or by at least one switching device, such as a contactor, a circuit breaker, and a relay.

[0045] In this embodiment, the first current detection circuit 10 includes a current sensor. The input end of the current sensor is electrically connected to the power supply, and the output end of the current sensor is electrically connected to the first input end of the comparison circuit 30. The first current detection circuit 10 can also adopt one of a Hall sensor or a current transformer, which is not limited herein.

[0046] In this embodiment, the comparison circuit 30 is implemented by at least one comparator. The inverting end of the comparator is electrically connected to the output end of the first current detection circuit 10, and the non-inverting end of the comparator is electrically connected to the reference source circuit 40. When the first current detection signal is greater than the reference voltage signal, the comparator outputs a high level to the main control circuit 50, and the main control circuit 50 outputs a corresponding first control signal according to the received high level; or, the non-inverting end of the comparator is electrically connected to the output end of the first current detection circuit 10, and the inverting end of the comparator is electrically connected to the reference source circuit 40. When the first current detection signal is greater than the reference voltage signal, the comparator outputs a low level to the main control circuit 50, and the main control circuit 50 outputs a corresponding first control signal according to the received low level.

[0047] Specifically, the technical solution of the present utility model includes a first current detection circuit 10, a first switch circuit 20, a comparison circuit 30, a reference source circuit 40, and a main control circuit 50. The first current detection circuit 10 is used to detect the current of the power supply and output a corresponding first current detection signal. The reference source circuit 40 is used to provide a reference voltage signal. The comparison circuit 30 is used to compare the first current detection signal and the reference voltage signal and output a corresponding first control signal to the controlled end of the first switch circuit 20, such as a PWM control signal. The duty cycle of the PWM control signal is proportional to the conduction degree of the first switch circuit 20, so as to control the magnitude of the current output from the power supply to the power supply terminal. For example, when the current output from the power supply is too large, the main control circuit 50 outputs a PWM control signal with a relatively low duty cycle to the controlled end of the first switch circuit 20 within the first preset time, that is, at the moment when the motor starts, so that the conduction degree of the first switch circuit 20 becomes lower, avoiding damage to the motor due to excessive starting current at the moment of starting. After the first preset time, the duty cycle of the PWM control signal controlled by the main control circuit 50 gradually increases, so that the conduction degree of the first switch circuit 20 gradually increases, and the power supply normally supplies power to the motor. With such a setting, when the motor starts, the soft start circuit of the present utility model can limit the magnitude of the current output from the power supply to the power supply terminal of the motor, thereby avoiding the impact and damage caused by excessive current to the motor during direct starting and shortening its service life. In practical applications, users can adjust the reference source circuit 40 according to actual needs to output a corresponding reference voltage signal, thereby adjusting the magnitude of the current that limits the power supply output to the motor at the moment of motor startup. That is, the soft start circuit of the present utility model can be customized according to the characteristics of the motor, the load situation, and system requirements, ensuring both the smooth startup of the motor and the flexibility of the actual application of the soft start circuit of the present utility model.

[0048] In an embodiment of the present utility model, the reference source circuit 40 includes:

[0049] A trimming circuit, the input end of the trimming circuit is used to access a first current, and the output end of the trimming circuit is electrically connected to the second input end of the comparison circuit 30.

[0050] In this embodiment, the trimming circuit can adopt devices with adjustable resistors such as potentiometers, variable resistors, sliding rheostats, resistance boxes, and trimming resistors.

[0051] In this embodiment, the equivalent resistance value of the trimming circuit can be trimmed. Since the magnitude of the reference voltage signal is equal to the product of the first current and the equivalent resistance value of the trimming circuit, the magnitude of the reference voltage signal can be controlled by adjusting the equivalent resistance value of the trimming circuit, thereby controlling the magnitude of the current output from the power supply to the motor power supply terminal when the motor starts instantaneously. With such a setting, in practical applications, the equivalent resistance value of the trimming circuit can be adjusted according to different requirements, enabling the user to optimize the magnitude of the starting current based on the characteristics of the motor, the load condition, and the application scenario. This flexibility provides the user with more operation options and facilitates personalized settings according to the actual situation.

[0052] Reference Figure 2 , in an embodiment of the present invention, the soft start circuit further includes:

[0053] A voltage follower circuit 60, a first clamping circuit 70, a second clamping circuit 80, a first filtering circuit 90, and a second filtering circuit 100. The input end of the voltage follower circuit 60 is electrically connected to the first ends of the first clamping circuit 70 and the first filtering circuit 90 respectively. The output end of the voltage follower circuit 60 is electrically connected to the first ends of the second clamping circuit 80, the second filtering circuit 100, and the first input end of the comparison circuit 30 respectively. The input end of the voltage follower circuit 60 is further electrically connected to the output end of the first current detection circuit 10. The second ends of the first filtering circuit 90 and the second filtering circuit 100 are both grounded;

[0054] A second voltage follower, a third clamping circuit, a fourth clamping circuit, a third filtering circuit, and a fourth filtering circuit. The input end of the second voltage follower is electrically connected to the first ends of the third clamping circuit and the third filtering circuit respectively. The output end of the second voltage follower is electrically connected to the first ends of the third clamping circuit, the third filtering circuit, and the second input end of the comparison circuit 30 respectively. The input end of the second voltage follower is further electrically connected to the output end of the reference source circuit 40. The second ends of the second filtering circuit 100 and the third filtering circuit are both grounded.

[0055] In this embodiment, both the first filtering circuit 90 and the second filtering circuit 100 can be composed of at least one resistor and capacitor. The filtering circuit is used to filter out the high-frequency noise of the first current detection signal to improve the accuracy of the first current detection signal.

[0056] In this embodiment, both the first clamping circuit 70 and the second clamping circuit 80 can be composed of two diodes. For example Figure 2In the first clamping circuit 70, it is composed of a first diode D1 and a second diode. The second clamping circuit 80 is composed of a third diode D3 and a fourth diode D4. The clamping circuit is used to limit the voltage magnitude at the electrically connected position of the clamping circuit, avoiding damage to the subsequent circuit due to excessive voltage in the previous circuit. For example, the clamping value of the first clamping circuit 70 is 15V, that is, the voltage range at the input end of the voltage follower circuit 60 is clamped to 0 - 15V. The clamping value of the second clamping circuit 80 is 5V, that is, the voltage at the first input end of the comparison circuit 30 is clamped to 0 - 5V. The first current detection signal is generally an analog input signal of 0 - 10V. The clamping value of the first clamping circuit 70 is set to 0 - 15V, that is, the voltage value of the first current detection signal is clamped to 0 - 15V, avoiding damage to the voltage follower due to the first current detection signal being too large or too small under special circumstances. Since the operating voltage of the main control circuit 50 is about 5V, the clamping value of the second clamping circuit 80 needs to be set to 0 - 5V. The user can set the voltage of the first current detection signal output by the first current detection circuit 10 when the detected current exceeds the preset value to be exactly 5V, so that the main control circuit 50 can timely control the conduction degree of the first switch circuit 20 to become lower when receiving a 5V signal, so that the current received by the motor at the moment of directly starting is smaller.

[0057] In this embodiment, the soft start circuit further includes a first current limiting resistor R1 and a second current limiting resistor R2, which are used to limit the magnitude of the current, avoiding damage to the voltage follower circuit 60 or the main control circuit 50 due to excessive received current.

[0058] In this embodiment, the voltage follower circuit 60 is used to isolate the power supply and the main control circuit 50, so that the power supply and the main control circuit 50 do not affect each other.

[0059] In this embodiment, the effects of the second voltage follower, the third clamping circuit, the fourth clamping circuit, the third filtering circuit, and the fourth filtering circuit are the same as those of the voltage follower circuit 60, the first clamping circuit 70, the second clamping circuit 80, the first filtering circuit 90, and the second filtering circuit 100, and will not be elaborated here one by one.

[0060] In an embodiment of the present utility model, the soft start circuit further includes:

[0061] A second current detection circuit 110, the detection end of the second current detection circuit 110 is electrically connected to the power supply, the output end of the second current detection circuit 110 is electrically connected to the main control circuit 50, the second current detection circuit 110 outputs a corresponding second current detection signal according to the current of the power supply, and the main control circuit 50 controls the first switch circuit 20 to conduct or disconnect according to the second current detection signal.

[0062] In this embodiment, the second current detection circuit 110 is configured to output a corresponding second current detection signal according to the current output by the power supply. The main control circuit 50 determines whether the current output by the power supply exceeds a preset current value based on the second current detection signal. If it exceeds, the main control circuit 50 controls the first switch circuit 20 to disconnect, thereby preventing excessive current from being output to the motor and causing damage to the motor. If it does not exceed, the main control circuit 50 controls or maintains the first switch circuit 20 to be conductive, so that the power supply can normally supply power to the motor.

[0063] Reference Figure 3 , in this embodiment, the second current detection circuit 110 includes an isolation amplifier circuit 111 and a proportional amplifier circuit 112. The input end of the isolation amplifier circuit 111 is electrically connected to the power supply, the output end of the isolation amplifier circuit 111 is electrically connected to the input end of the proportional amplifier circuit 112, and the output end of the proportional amplifier circuit 112 is electrically connected to the main control circuit 50.

[0064] In this implementation, the isolation amplifier circuit 111 uses at least one isolation amplifier, and the proportional amplifier circuit 112 uses at least one proportional amplifier circuit 112.

[0065] In this embodiment, the input end of the isolation amplifier circuit 111 is used to collect the current of the power supply and output a corresponding current signal to the proportional amplification circuit. The isolation amplifier can achieve isolation of direct current and voltage between the input and output to prevent short circuits or interference between circuits. The function of the proportional amplifier circuit 112 is to achieve proportional amplification of the input signal. The proportional amplifier circuit 112 can amplify the current signal according to a preset ratio, so that the output signal can better match the input requirements of the main control circuit 50. With such a setting, in practical applications, users can flexibly adapt to different current acquisition requirements by adjusting the amplification ratio, and improve the flexibility and adaptability of the overall circuit.

[0066] In an embodiment of the present invention, the soft start circuit further includes:

[0067] a temperature detection circuit. The temperature detection circuit is electrically connected to the main control circuit 50. The temperature detection circuit is used to detect the temperature of the motor and output a corresponding temperature detection signal. The main control circuit 50 controls the first switch circuit 20 to be conductive or disconnected according to the temperature detection circuit.

[0068] In this embodiment, the temperature detection circuit includes at least one thermistor or platinum resistor. The thermistor or platinum resistor is closely attached to or disposed inside the motor. The resistance value of the thermistor or platinum resistor decreases as the temperature rises. When the main control circuit 50 obtains that the voltage of the thermistor or platinum resistor is lower than a preset value, the main control circuit 50 controls the first switch circuit 20 to disconnect.

[0069] In this embodiment, when the temperature of the motor exceeds the preset value, the main control circuit 50 controls the first switch circuit 20 to disconnect according to the temperature detection signal, so that the motor stops working. With such a setting, in practical applications, when the motor operates in an environment with high temperature, high humidity or poor ventilation, its heat dissipation effect will be affected, resulting in an increase in the motor temperature; or when the motor drags the mechanical belt too tightly or the rotating shaft runs inflexibly, it may cause the motor to operate under long-term overload, resulting in an increase in temperature. The soft start circuit of the present utility model can timely disconnect the power supply path between the power supply and the motor, so that the motor stops working, and avoid damage to the motor in the case of overheating.

[0070] In an embodiment of the present utility model, the soft start circuit further includes:

[0071] A phase detection circuit 120. The power supply includes a rectifier bridge circuit. The detection end of the phase detection circuit 120 is electrically connected to the rectifier bridge circuit, and the output end of the phase detection circuit 120 is electrically connected to the main control circuit 50. When the power supply, the phase detection circuit 120 outputs a corresponding second control signal to the main control circuit 50 according to the current of the rectifier bridge circuit, and the main control circuit 50 controls the first switch circuit 20 to conduct or disconnect according to the second control signal.

[0072] In this embodiment, the power supply is connected to alternating current, and the alternating current is rectified by the rectifier bridge circuit to output corresponding direct current. The phase detection circuit 120 is electrically connected to the rectifier bridge circuit to detect whether the rectifier bridge circuit is missing a phase. If one of the rectifier diodes in the rectifier bridge circuit is damaged and one phase is disconnected, the phase detection circuit 120 detects that the current output by one phase of the rectifier bridge circuit is 0, and outputs a corresponding second control signal to the main control circuit 50. The main control circuit 50 controls the first switch circuit 20 to disconnect according to the second control signal, so as to disconnect the power supply path between the power supply and the motor, and avoid serious consequences such as the motor being unable to work properly, or even damage to the motor and fire caused by a missing or abnormal phase of the rectifier bridge circuit.

[0073] Reference Figure 4 In this embodiment, the phase detection circuit 120 includes:

[0074] An opto-coupler U1, a comparator circuit 121, and a second switching circuit Q1. The opto-coupler U1 includes a photodiode and a phototransistor. The input end of the photodiode is electrically connected to the input end of the rectifier bridge circuit of the power supply. The output end of the photodiode is electrically connected to the output end of the rectifier bridge circuit of the power supply. The first input end of the comparator circuit 121 is used to access a reference voltage. The input end of the phototransistor is electrically connected to the second input end of the comparator circuit 121. The output end of the comparator circuit 121 is electrically connected to the controlled end of the second switching circuit Q1. The input end of the second switching circuit Q1 is electrically connected to the main control circuit 50. The output end of the second switching circuit Q1 is grounded.

[0075] In this embodiment, the second switching circuit Q1 uses a triode. The rectifier bridge circuit includes a fifth diode D5, a sixth diode D6, a seventh diode D7, and an eighth diode D8. When the fifth diode D5 or the sixth diode D6 is damaged, no current passes through the photodiode during the positive half cycle of the alternating current, causing the phototransistor to cut off. The voltage at the second input end of the comparator circuit 121 decreases and is lower than the reference voltage. At this time, the comparator circuit 121 outputs a high-level signal to the second switching circuit Q1, and the second switching circuit Q1 conducts. Since the main control circuit 50 is electrically connected to the input end of the second switching circuit Q1 and the output end of the second switching circuit Q1 is grounded, the voltage of the port of the main control circuit 50 used to connect the second switching circuit Q1 is pulled low. The main control circuit 50 outputs a corresponding control signal according to the low voltage of the port to control the first switching circuit 20 to disconnect, so that the power supply cannot supply power to the motor, avoiding abnormal operation of the motor. When the seventh diode D7 or the eighth diode D8 is damaged, the main control circuit 50 controls the first switching circuit 20 to disconnect in time, avoiding abnormal operation of the motor. The working principle is the same as that when the fifth diode D5 or the sixth diode D6 is damaged, and will not be elaborated here one by one.

[0076] The present invention also proposes a motor, including a power supply end and the soft start circuit as described above.

[0077] It should be noted that since the motor of the present invention is based on the above soft start circuit, therefore, the embodiments of the motor of the present invention include all the technical solutions of all the embodiments of the above soft start circuit, and the achieved technical effects are also exactly the same, and will not be elaborated here.

[0078] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A soft start circuit, applied to a motor, the motor comprising a power supply end, characterized in that: The soft start circuit comprises: a first current detection circuit, wherein a detection end of the first current detection circuit is electrically connected to a power supply, and the first current detection circuit is used to detect a current of the power supply and output a corresponding first current detection signal; A first switch circuit, wherein an input end of the first switch circuit is electrically connected to a power supply, and an output end of the first switch circuit is electrically connected to the power supply end; A comparison circuit and a reference source circuit, wherein a first input terminal of the comparison circuit is electrically connected to an output terminal of the first current detection circuit, a second input terminal of the comparison circuit is electrically connected to the reference source circuit, the reference source circuit is used to output a reference voltage signal, and the comparison circuit is used to compare the first current detection signal with the reference voltage and output a corresponding first control signal; A main control circuit, wherein the main control circuit is electrically connected to the output end of the comparison circuit, and the main control circuit is also electrically connected to the controlled end of the first switch circuit, and the main control circuit is used to adjust the conduction degree of the first switch circuit according to the first control signal.

2. The soft start circuit according to claim 1, characterized in that: The first current detection circuit comprises: A current sensor, wherein an input end of the current sensor is electrically connected to a power supply, and an output end of the current sensor is electrically connected to a first input end of the comparison circuit.

3. The soft start circuit according to claim 1, characterized in that: The reference source circuit comprises: A trimming circuit, wherein an input end of the trimming circuit is used to receive a first current, and an output end of the trimming circuit is electrically connected to a second input end of the comparison circuit.

4. The soft start circuit according to claim 1, characterized in that: The soft start circuit also includes: A voltage follower circuit, a first voltage clamp circuit, a second voltage clamp circuit, a first filter circuit, and a second filter circuit, wherein the input end of the voltage follower circuit is electrically connected to the first end of the first voltage clamp circuit and the first filter circuit respectively, the output end of the voltage follower circuit is electrically connected to the first end of the second voltage clamp circuit, the second filter circuit, and the first input end of the comparison circuit respectively, the input end of the voltage follower circuit is also electrically connected to the output end of the first current detection circuit, and the second end of the first filter circuit and the second end of the second filter circuit are both grounded; A second voltage follower, a third voltage clamp circuit, a fourth voltage clamp circuit, a third filter circuit and a fourth filter circuit, the input end of the second voltage follower is electrically connected to the first end of the third voltage clamp circuit and the third filter circuit respectively, the output end of the second voltage follower is electrically connected to the first end of the third voltage clamp circuit, the third filter circuit and the second input end of the comparison circuit respectively, the input end of the second voltage follower is also electrically connected to the output end of the reference source circuit, and the second end of the second filter circuit and the second end of the third filter circuit are both grounded.

5. The soft start circuit according to claim 1, characterized in that: The soft start circuit also includes: A second current detection circuit, wherein the detection end of the second current detection circuit is electrically connected to the power supply, the output end of the second current detection circuit is electrically connected to the main control circuit, the second current detection circuit outputs a corresponding second current detection signal according to the current of the power supply, and the main control circuit controls the first switch circuit to be turned on or off according to the second current detection signal.

6. The soft start circuit according to claim 5, characterized in that: The second current detection circuit includes an isolation amplifier circuit and a proportional amplifier circuit, the input end of the isolation amplifier circuit is electrically connected to the power supply, the output end of the isolation amplifier circuit is electrically connected to the input end of the proportional amplifier circuit, and the output end of the proportional amplifier circuit is electrically connected to the main control circuit.

7. The soft start circuit according to claim 1, characterized in that: The soft start circuit also includes: A phase detection circuit, wherein the power supply includes a rectifier bridge circuit, a detection end of the phase detection circuit is electrically connected to the rectifier bridge circuit, an output end of the phase detection circuit is electrically connected to the main control circuit, and the phase detection circuit outputs a corresponding second control signal to the main control circuit according to the current of the rectifier bridge circuit, and the main control circuit controls the first switch circuit to be turned on or off according to the second control signal.

8. The soft start circuit according to claim 7, characterized in that: The phase detection circuit comprises: A photoelectric coupler, a comparator circuit and a second switch circuit, wherein the photoelectric coupler includes a photodiode and a phototransistor, the input end of the photodiode is electrically connected to the input end of the rectifier bridge circuit of the power supply, the output end of the photodiode is electrically connected to the output end of the rectifier bridge circuit of the power supply, the first input end of the comparator circuit is used to access a reference voltage, the input end of the phototransistor is electrically connected to the second input end of the comparator circuit, the output end of the comparator circuit is electrically connected to the controlled end of the second switch circuit, the input end of the second switch circuit is electrically connected to the main control circuit, and the output end of the second switch circuit is grounded.

9. A motor, characterized in that: It comprises a power supply end and a soft start circuit as described in any one of claims 1 to 8.

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