Disclosure of Invention
The invention provides a motor overvoltage protection circuit and a motor, and aims to solve the problems that the overvoltage protection of the motor cannot be realized by the existing motor control method, and when the motor is connected with a voltage larger than a rated value, the voltage cannot be timely turned off to protect the motor, so that the safety of the whole motor is poor.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention provides a motor overvoltage protection circuit, which comprises a sampling circuit, a rectifying circuit, a control circuit and a controllable switch circuit, wherein the sampling circuit is connected with the rectifying circuit;
the controllable switch circuit is connected with the L line of the motor and is used for controlling the on or off of a power supply path of the motor;
the sampling circuit is used for sampling the power supply voltage of the motor in real time;
the rectifying circuit is connected with the output end of the sampling circuit and is used for converting the alternating current sampling voltage output by the sampling circuit into direct current voltage;
and the control circuit is connected between the output end of the rectifying circuit and the control end of the controllable switch circuit and used for outputting an overvoltage protection level signal when the direct-current voltage output by the rectifying circuit is greater than a preset voltage threshold value so as to cut off a power supply path of the motor by disconnecting the controllable switch circuit.
Optionally, the sampling circuit includes a first resistor R1, and the first resistor R1 is connected between the L line of the motor and the L line of the external ac power source.
Optionally, the rectifier circuit includes a rectifier bridge composed of a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, an ac input end of the rectifier bridge is connected to two ends of the sampling circuit, and a dc output end of the rectifier bridge is connected to an input end of the control circuit.
Optionally, the control circuit includes a first photocoupler U1, an input terminal of the first photocoupler U1 is connected to the dc output terminal of the rectifier bridge, an emitter of the first photocoupler U1 is grounded, and a collector of the first photocoupler U1 is connected to the control terminal of the controllable switching circuit of the motor.
Optionally, the motor overvoltage protection circuit further comprises a first capacitor C1, and the first capacitor C1 is connected in parallel between the dc output ends of the rectifier bridge.
Optionally, the controllable switching circuit comprises a thyristor SC1 and a thyristor SC1 control circuit;
the controllable silicon SC1 is connected with the L line of the motor, the output end of the controllable silicon SC1 control circuit is connected with the control electrode of the controllable silicon SC1, and the input end of the controllable silicon SC1 control circuit is connected with the output end of the control circuit.
Optionally, the thyristor SC1 control circuit includes a second photocoupler U2 and a filter circuit composed of a second resistor R2 and a second capacitor C2, an input end of the filter circuit is connected to an output end of the control circuit, an output end of the filter circuit is connected to an input end of the second photocoupler U2, and an output end of the second photocoupler U2 is connected to a control electrode of the thyristor SC 1.
Optionally, the thyristor SC1 control circuit further includes a third resistor R3, and the third resistor R3 is connected between the output terminal of the second photocoupler U2 and the control electrode of the thyristor SC 1.
Optionally, the motor overvoltage protection circuit further comprises a resistor-capacitor module RC3, and the resistor-capacitor module RC3 is connected between the L line and the N line of the motor.
In addition, the embodiment of the invention also provides a motor, which comprises the motor overvoltage protection circuit.
Compared with the prior art, the technical scheme of the invention has the following main advantages:
according to the motor overvoltage protection circuit and the motor provided by the embodiment of the invention, when the sampling voltage of the sampling resistor is greater than a certain voltage threshold, the controllable switch circuit is disconnected to turn off the L-line power supply circuit of the motor, so that overvoltage protection of the motor is realized, when the motor is connected to the voltage greater than the rated value, the L-line voltage is timely turned off to protect the motor, the safety of the whole machine is improved, and the user experience is improved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Fig. 1 is a schematic structural diagram of a motor overvoltage protection circuit according to an embodiment of the present invention. As shown in fig. 1, the motor overvoltage protection circuit provided by this embodiment includes a sampling circuit 10, a rectifying circuit 20, a control circuit 30, and a controllable switch circuit 40;
the controllable switch circuit 40 is connected to an L line of the motor and is used for controlling the on or off of a power supply path of the motor;
the sampling circuit 10 is used for sampling the power supply voltage of the motor in real time;
the rectifying circuit 20 is connected with the output end of the sampling circuit 10 and is used for converting the alternating current sampling voltage output by the sampling circuit into direct current voltage;
and the control circuit 30 is connected between the output end of the rectifying circuit 20 and the control end of the controllable switch circuit 40, and is used for outputting an overvoltage protection level signal when the direct-current voltage output by the rectifying circuit 20 is greater than a preset voltage threshold value so as to cut off a motor power supply path by disconnecting the controllable switch circuit 40.
According to the motor overvoltage protection circuit provided by the embodiment of the invention, when the sampling voltage of the sampling resistor is greater than a certain voltage threshold, the controllable switch circuit is disconnected to cut off the L-line power supply line of the motor, so that overvoltage protection of the motor is realized, and when the motor receives the voltage greater than the rated value, the L-line voltage is timely cut off to protect the motor, so that the safety of the whole machine is improved, and the user experience is improved.
Fig. 2 is a schematic structural diagram of a motor overvoltage protection circuit according to another embodiment of the present invention. As shown in fig. 2, the sampling circuit 10 in the motor overvoltage protection circuit in the embodiment includes a first resistor R1, and the first resistor R1 is connected between an L line of the motor and an L line of an external ac power supply.
The rectifier circuit 20 comprises a rectifier bridge composed of a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, wherein an alternating current input end of the rectifier bridge is connected to two ends of the first resistor R1, and a direct current output end of the rectifier bridge is connected to an input end of the control circuit. Specifically, a positive input end of the rectifier bridge is connected between the first diode D1 and the second diode D2, and a negative input end of the rectifier bridge is connected between the third diode D3 and the fourth diode D4.
Further, the motor overvoltage protection circuit further comprises a first capacitor C1, and the first capacitor C1 is connected in parallel between the direct current output ends of the rectifier bridge.
The control circuit 30 includes a first photocoupler U1, an input terminal of the first photocoupler U1 is connected to the dc output terminal of the rectifier bridge, specifically, an anode input terminal of the first photocoupler U1 is connected to the positive output terminal of the rectifier bridge, a cathode input terminal of the first photocoupler U1 is connected to the negative output terminal of the rectifier bridge, an emitter of the first photocoupler U1 is grounded, and a collector of the first photocoupler U1 is connected to the control terminal of the controllable switch circuit 40 of the motor.
Further, the motor overvoltage protection circuit further comprises a resistance-capacitance module RC1, and the resistance-capacitance module RC1 is connected between the L line and the N line of the motor. When the load is an inductive load, the interference can be absorbed by the resistance-capacitance module.
The controllable switch circuit 40 comprises a silicon controlled rectifier SC1 and a silicon controlled rectifier SC1 control circuit;
the controllable silicon SC1 is connected with the L line of the motor, the output end of the controllable silicon SC1 control circuit is connected with the control electrode of the controllable silicon SC1, and the input end of the controllable silicon SC1 control circuit is connected with the output end of the control circuit.
The silicon controlled rectifier SC1 control circuit comprises a second photoelectric coupler U2 and a filter circuit composed of a second resistor R2 and a second capacitor C2, the input end of the filter circuit is connected with the output end of the control circuit, the output end of the filter circuit is connected with the input end of the second photoelectric coupler U2, and the output end of the second photoelectric coupler U2 is connected with the control electrode of the silicon controlled rectifier SC 1.
The controlled silicon SC1 control circuit further comprises a third resistor R3, and the third resistor R3 is connected between the output end of the second photoelectric coupler U2 and the control electrode of the controlled silicon SC 1.
In the embodiment of the invention, R1 is a sampling resistor, when an external alternating current power supply enables the voltage connected to the motor to be a rated voltage UM0, the voltage sampled by the sampling resistor R1 is UR0, UR0 is alternating current voltage, the alternating current voltage is converted into direct current voltage VR0 after passing through a rectifier bridge (D1, D2, D3 and D4), the voltage is set to be the conduction voltage of the first photoelectric coupler U1, when the voltage at the input end of the first photoelectric coupler U1 is greater than the voltage, the first photoelectric coupler U1 is conducted, and when the circuit is connected with normal working voltage, the first photoelectric coupler U1 is not conducted.
When an external alternating current power supply enables the voltage connected to the motor to be larger than the rated voltage UM0, the voltage sampled by the sampling resistor R1 is larger than UR0, the converted direct current voltage after passing through the rectifier bridge (D1, D2, D3 and D4) is correspondingly larger than the breakover voltage VR0 of the first photoelectric coupler U1, therefore, the first photoelectric coupler U1 is turned on, the output end of the first photoelectric coupler U1 is pulled to the ground, the second photoelectric coupler U2 is cut off, the control end of the silicon controlled rectifier SC1 is disconnected due to the fact that no control signal exists, the motor is cut off on the circuit, and therefore the motor is protected when overvoltage occurs.
In addition, the embodiment of the invention also provides a motor, which comprises the motor overvoltage protection circuit.
According to the motor overvoltage protection circuit and the motor provided by the embodiment of the invention, when the sampling voltage of the sampling resistor is greater than a certain voltage threshold, the controllable switch circuit is disconnected to turn off the L-line power supply circuit of the motor, so that overvoltage protection of the motor is realized, when the motor is connected to the voltage greater than the rated value, the L-line voltage is timely turned off to protect the motor, the safety of the whole machine is improved, and the user experience is improved.
Those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than others, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.