Power supply circuit and driver

Abstract

The utility model provides a power supply circuit and a driver, and relates to the technical field of drivers, and the power supply circuit comprises a conversion circuit which converts an AC voltage into a DC bus voltage; the braking circuit is connected with the output end of the conversion circuit, and when the braking circuit is connected to the output end of the conversion circuit, back electromotive force is released; the first detection circuit is connected with the output end of the conversion circuit and correspondingly outputs a first voltage detection signal; the second detection circuit is electrically connected with the braking circuit and correspondingly outputs a second voltage detection signal; the control circuit controls the brake circuit to start when the voltage value corresponding to the first voltage detection signal is larger than a first preset voltage value, and controls the conversion circuit to reduce the output power when the voltage value corresponding to the second voltage detection signal is larger than a second preset voltage value. The brake circuit can still operate safely when the brake resistor in the brake circuit is not correctly connected or the brake resistor is damaged due to frequent braking.

Description

Technical Field

[0001] This application relates to the technical field of servo drivers, and particularly to a power supply circuit and a driver. Background Art

[0002] In a driver, a motor load usually generates a large back electromotive force during the braking process. To maintain the safety of the motor load and the driver, the current technology generally uses a braking circuit to dissipate these back electromotive forces. However, if the braking resistor in the braking circuit is not correctly connected, or the braking resistor is damaged due to frequent braking, the back electromotive force generated by the motor load cannot be properly processed, which may cause damage to the motor and its driver. Summary of the Utility Model

[0003] The main purpose of the present utility model is to provide a power supply circuit, aiming to improve the reliability of the power supply circuit and ensure the safe operation of the motor load when the braking resistor is not connected or blown.

[0004] To achieve the above object, the present utility model provides a power supply circuit, and the power supply circuit includes:

[0005] A conversion circuit for converting an AC voltage into a DC bus voltage;

[0006] A braking circuit connected to the output end of the conversion circuit for discharging the back electromotive force of the motor load when connected to the output end of the conversion circuit;

[0007] A first detection circuit connected to the output end of the conversion circuit for detecting the DC bus voltage and correspondingly outputting a first voltage detection signal;

[0008] A second detection circuit electrically connected to the braking circuit, and the second detection circuit is used for detecting the voltage of the braking circuit and correspondingly outputting a second voltage detection signal;

[0009] A control circuit electrically connected to the braking circuit, the first detection circuit, and the second detection circuit respectively. The control circuit is used for controlling the start of the braking circuit when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and is also used for controlling the conversion circuit to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value.

[0010] Optionally, the second detection circuit includes:

[0011] A first optocoupler, with at least one or more capacitors connected in parallel between the positive and negative poles of the first optocoupler, and at least one or more resistors connected in parallel between the positive and negative poles of the first optocoupler. A first resistor is connected in series between the collector of the first optocoupler and the output terminal of the control circuit, and at least one or more capacitors are connected in parallel between the first end of the first resistor and the ground;

[0012] A second diode, with a first diode connected in series between the positive pole of the second diode and the negative pole of the first optocoupler, and a third diode connected in series between the negative pole of the second diode and the braking circuit.

[0013] Optionally, the braking circuit includes:

[0014] A load circuit for discharging the back electromotive force of the motor load;

[0015] A reverse protection circuit arranged in parallel with the load circuit;

[0016] A switch circuit, with the first conduction end of the switch circuit connected to the second end of the load circuit, and the second conduction end of the switch circuit grounded.

[0017] Optionally, the reverse protection circuit includes:

[0018] A fourth diode, with the negative pole of the fourth diode connected to the first end of the load circuit and the positive pole of the fourth diode connected to the second end of the load circuit.

[0019] Optionally, the control circuit includes:

[0020] A switch driving circuit, with the output terminal of the switch driving circuit connected to the controlled terminal of the switch circuit. The switch driving circuit is used to output a corresponding driving signal to drive the switch circuit to conduct the path between the load circuit and the ground, so as to consume the back electromotive force of the motor load;

[0021] A main controller, with the output terminal of the main controller connected to the input terminal of the switch driving circuit. The main controller is used to control the switch driving circuit to output a corresponding driving signal when the voltage value corresponding to the first voltage detection signal is greater than the first preset voltage value.

[0022] Optionally, the switch circuit includes:

[0023] A switch tube, with the controlled terminal of the switch tube connected to the output terminal of the switch driving circuit, the first conduction end of the switch tube connected to the second end of the load circuit, and the second conduction end of the switch tube grounded.

[0024] Optionally, the power supply circuit further includes:

[0025] Overcurrent detection circuit, the input end of the overcurrent detection circuit is connected to the output end of the conversion circuit, the output end of the overcurrent detection circuit is connected to the input end of the control circuit, and the overcurrent detection circuit is used to output a corresponding overcurrent signal to the control circuit when the bus current exceeds a preset threshold.

[0026] Optionally, the overcurrent detection circuit includes:

[0027] A current sensing component, the current sensing component is serially arranged between the output end of the conversion circuit and the braking circuit, the current sensing component is connected to the control circuit, and the current sensing component is used to output a corresponding bus current signal to the control circuit;

[0028] The control circuit is used to turn off the motor load when the bus current exceeds a preset threshold.

[0029] Optionally, the conversion circuit includes:

[0030] A rectifier circuit, the input end of the rectifier circuit is used to connect to a three-phase power supply, and the output end of the rectifier circuit is used to output a DC bus voltage;

[0031] A common ground circuit, the first end of the common ground circuit is connected to the negative output end of the rectifier circuit;

[0032] A filter circuit, the first end of the filter circuit is connected to the positive output end of the rectifier circuit, the second end of the filter circuit is connected to the second end of the common ground circuit, and the filter circuit is used to filter the DC bus voltage.

[0033] In addition, to achieve the above object, the present invention also provides a driver, including the power supply circuit as described above.

[0034] In the embodiment of the present invention, an AC voltage is converted into a DC bus voltage by providing a conversion circuit, and a braking circuit is connected to the output end of the conversion circuit to discharge the back electromotive force of the motor load when accessing the output end of the conversion circuit. In order to be able to detect the state of the braking circuit, a first detection circuit is provided and connected to the output end of the conversion circuit to detect the DC bus voltage and correspondingly output a first voltage detection signal. Then, a second detection circuit is provided and electrically connected to the braking circuit to detect the voltage of the braking circuit and correspondingly output a second voltage detection signal. Finally, a control circuit controls the braking circuit to start when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and controls the conversion circuit to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value, so that it can still operate safely when the braking resistor in the braking circuit fails to be correctly connected or is damaged due to frequent braking, improving the reliability of the power supply circuit. Brief Description of the Drawings

[0035] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0036] 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 be obtained based on these drawings.

[0037] Figure 1 is a circuit block diagram of a power supply circuit according to an embodiment of the present utility model;

[0038] Figure 2 is a circuit block diagram of a power supply circuit according to another embodiment of the present utility model;

[0039] Figure 3 is a circuit block diagram of a power supply circuit according to another embodiment of the present utility model;

[0040] Figure 4 is a circuit block diagram of a power supply circuit according to another embodiment of the present utility model;

[0041] Figure 5 is a circuit block diagram of a power supply circuit according to still another embodiment of the present utility model;

[0042] Figure 6 is a schematic diagram of the principle of the power supply circuit of the present utility model.

[0043] Explanation of the Reference Numerals in the Drawings:

[0044] Label Name Label Name 10 Conversion circuit 33 Switching circuit 11 Rectifier circuit 40 First detection circuit 12 Common ground circuit 50 Second detection circuit 13 Filter circuit 60 Control circuit 30 Braking circuit 61 Switch drive circuit 31 Load circuit 62 Main controller 32 Reverse protection circuit 70 Overcurrent detection circuit

[0045] The realization of the object, functional features and advantages of the present utility model will be further described with reference to the embodiments and the drawings. Detailed Embodiments

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with 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 the embodiments. Well-known modules, units, and their connections, links, communications, or operations are not shown or not described in detail. Moreover, the described features, architectures, or functions can be combined in any way in one or more embodiments. Those skilled in the art should understand that the following various embodiments are only for illustration, rather than for limiting the protection scope of the present utility model. It can also be easily understood that the modules, units, or processing methods in the embodiments described herein and shown in the accompanying drawings can be combined and designed in various different configurations. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present utility model.

[0047] For the definitions of various nouns or methods referred to in the following embodiments, except in cases where it is logically impossible to hold, the nouns or methods generally refer to the broad concepts that can be implemented on the premise of the content disclosed in the embodiments. Under such an understanding, all specific subordinate specific definitions of the nouns or methods should be regarded as the content of the present utility model of the present utility model, and should not be narrowly understood or prejudicially interpreted on the grounds that the specific definition is not disclosed in the specification. Similarly, on the premise that it can be logically realized, the order of each step in the method is flexible and changeable, and all specific subordinate specific definitions in the broad concepts of various nouns or methods belong to the protection scope of the present utility model.

[0048] The main solution of the embodiments of the present application is: an alternating voltage is converted into a DC bus voltage by providing a conversion circuit, and a braking circuit is connected to the output end of the conversion circuit to discharge the back electromotive force of the motor load when accessing the output end of the conversion circuit. In order to be able to detect the state of the braking circuit, a first detection circuit is connected to the output end of the conversion circuit to detect the DC bus voltage and correspondingly output a first voltage detection signal. Then, a second detection circuit is electrically connected to the braking circuit to detect the voltage of the braking circuit and correspondingly output a second voltage detection signal. Finally, a control circuit controls the braking circuit to start when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and controls the conversion circuit to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value.

[0049] Since the prior art generally uses a braking circuit to dissipate these back electromotive forces. However, if the braking resistor in the braking circuit fails to be correctly connected, or the braking resistor is damaged due to frequent braking, the back electromotive force generated by the motor load will not be properly processed, which may cause damage to the motor and its driver.

[0050] The present application provides a solution, so that when the braking resistor in the braking circuit fails to be correctly connected, or the braking resistor is damaged due to frequent braking, the system can still operate safely, improving the reliability of the power supply circuit.

[0051] Refer to Figure 1 , in an embodiment of the present invention, the power supply circuit includes a conversion circuit 10, a braking circuit 30, a first detection circuit 40, a second detection circuit 50, and a control circuit 60, where:

[0052] The conversion circuit 10 is used to convert an AC voltage into a DC bus voltage; the braking circuit 30 is connected to the output end of the conversion circuit 10, and is used to discharge the back electromotive force of the motor load when connected to the output end of the conversion circuit 10; the first detection circuit 40 is connected to the output end of the conversion circuit 10, and is used to detect the DC bus voltage and correspondingly output a first voltage detection signal; the second detection circuit 50 is electrically connected to the braking circuit 30, and the second detection circuit 50 is used to detect the voltage of the braking circuit 30 and correspondingly output a second voltage detection signal; the control circuit 60 is electrically connected to the braking circuit 30, the first detection circuit 40, and the second detection circuit 50 respectively. The control circuit 60 is used to control the start of the braking circuit 30 when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and is also used to control the conversion circuit 10 to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value.

[0053] In this embodiment, the conversion circuit 10 may be a rectifier module to convert the input AC voltage into a DC voltage. The rectifier module may adopt a diode bridge rectifier or a thyristor rectifier to achieve a high-efficiency rectification process. The output end of the conversion circuit 10 may be connected to an inverter, and the inverter may adopt IGBT (Insulated Gate Bipolar Transistor) or MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as a switching element to achieve the inversion of the DC bus voltage. When the conversion circuit 10 reduces the output power, the output of the inverter will also decrease to reduce the speed of the motor load.

[0054] Among them, the braking circuit 30 may be a resistive braking circuit 30 or a regenerative braking circuit 30. The resistive braking circuit 30 discharges by converting the back electromotive force generated by the motor load into heat energy, while the regenerative braking circuit 30 converts the back electromotive force into electrical energy and feeds it back to the power supply system. Among them, the braking circuit 30 may include one or more braking resistors, and corresponding switching elements, such as relays or transistors, for controlling the connection and disconnection of the braking resistors.

[0055] The first detection circuit 40 and the second detection circuit 50 can be implemented by a voltage sensor or a voltage dividing circuit. These detection circuits can monitor the DC bus voltage and the voltage of the braking circuit 30 in real time, and convert the detected voltage values into corresponding voltage detection signals for use by the control circuit 60.

[0056] The control circuit 60 can be implemented by a main controller 62, such as an MCU (Micro controller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), an SOC (System On Chip), etc. The control circuit 60 controls the start of the braking circuit 30 and the output power of the conversion circuit 10 according to the values of the first voltage detection signal and the second voltage detection signal through a preset voltage threshold, so as to ensure the stable operation of the power supply circuit under various working conditions, not only improving the operation efficiency of the motor, but also enhancing the reliability and safety of the power supply circuit.

[0057] In this embodiment, a conversion circuit 10 is provided to convert the AC voltage into a DC bus voltage, and a braking circuit 30 is connected to the output end of the conversion circuit 10 to discharge the back electromotive force of the motor load when accessing the output end of the conversion circuit 10. In order to be able to detect the state of the braking circuit 30, a first detection circuit 40 is connected to the output end of the conversion circuit 10 to detect the DC bus voltage and correspondingly output a first voltage detection signal. Then, a second detection circuit 50 is electrically connected to the braking circuit 30 to detect the voltage of the braking circuit 30 and correspondingly output a second voltage detection signal. Finally, a control circuit 60 is provided to control the start of the braking circuit 30 when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and to control the conversion circuit 10 to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value. Thus, when the braking resistor in the braking circuit 30 fails to be correctly connected or is damaged due to frequent braking, it can still operate safely, improving the reliability of the power supply circuit.

[0058] Optionally, referring to Figure 6 In another embodiment of the present invention, a power supply circuit is provided based on the above Figure 1 shown embodiment. The second detection circuit 50 includes a first optocoupler U1 and a second diode D2, where:

[0059] There are at least one or more capacitors connected in parallel between the positive and negative poles of the first optocoupler U1, and at least one or more resistors are also connected in parallel between the positive and negative poles of the first optocoupler U1. A first resistor R5 is connected in series between the collector of the first optocoupler U1 and the output terminal of the control circuit 60, and at least one or more capacitors are connected in parallel between the first end of the first resistor R5 and the ground; A first diode D1 is connected in series between the positive pole of the second diode D2 and the negative pole of the first optocoupler U1, and a third diode D3 is connected in series between the negative pole of the second diode D2 and the braking circuit 30.

[0060] In this embodiment, the first optocoupler U1 is used to isolate the electrical connection between the detection circuit and the control circuit 60 to ensure the safe operation of the control circuit 60. By connecting capacitors and resistors in parallel, the input terminal of the first optocoupler U1 can be filtered to eliminate possible interference signals and improve the accuracy of detection. The first resistor R5 is connected in series with the collector of the first optocoupler U1 to limit the current flowing through the first optocoupler U1 and protect the optocoupler from overcurrent damage. At the same time, the capacitor connected in parallel between the first resistor R5 and the ground can further filter out high-frequency noise to ensure stable signal transmission.

[0061] Among them, the first diode D1 connected in series between the second diode D2 and the negative pole of the first optocoupler U1 is used to prevent reverse current from flowing through the first optocoupler U1 and protect the normal operation of the optocoupler. The third diode D3 connected in series between the negative pole of the second diode D2 and the braking circuit 30 is used to ensure the unidirectional flow of current and prevent the back electromotive force in the braking circuit 30 from damaging the detection circuit.

[0062] By providing the design of the first optocoupler U1, the first diode D1, the second diode D2 and the third diode D3, the second detection circuit 50 can accurately detect the voltage state of the braking circuit 30 and transmit the detection result to the control circuit 60 in the form of a second voltage detection signal. The control circuit 60 judges whether the braking circuit 30 is working normally according to the value of the second voltage detection signal. If the detected voltage value is greater than the second preset voltage value, the control circuit 60 will control the conversion circuit 10 to reduce the output power, thereby reducing the speed of the motor load at the rear stage to avoid overvoltage problems caused by damage to the braking resistor.

[0063] In addition, the second detection circuit 50 in this embodiment can ensure the stability and reliability of the circuit under different working conditions by reasonably selecting the parameters of capacitors, resistors and diodes, which not only improves the performance of the power supply circuit.

[0064] Optionally, referring to Figure 2 , another embodiment of the present invention provides a power supply circuit. Based on the above Figure 1 shown embodiment, the braking circuit 30 includes a load circuit 31, a reverse protection circuit 32 and a switching circuit 33, wherein:

[0065] The load circuit 31 is used to discharge the back electromotive force of the motor load; the reverse protection circuit 32 is arranged in parallel with the load circuit 31; the first conduction end of the switch circuit 33 is connected to the second end of the load circuit 31, and the second conduction end of the switch circuit 33 is grounded.

[0066] In this embodiment, the load circuit 31 is mainly composed of a braking resistor, whose function is to convert the back electromotive force generated by the motor load into heat energy, thereby achieving braking. The reverse protection circuit 32 is used to prevent the back electromotive force from generating a reverse current on the braking resistor, ensuring the normal operation of the braking circuit 30. The switch circuit 33 is composed of switch elements such as relays or transistors, and is used to control the connection and disconnection of the braking resistor.

[0067] Optionally, referring to Figure 6 In another embodiment of the present invention, a power supply circuit is provided. Based on the above Figure 2 shown embodiment, the reverse protection circuit 32 includes a fourth diode D4, where:

[0068] The negative electrode of the fourth diode D4 is connected to the first end of the load circuit 31, and the positive electrode of the fourth diode D4 is connected to the second end of the load circuit 31.

[0069] In this embodiment, the fourth diode D4 is used to ensure that the current flows unidirectionally in the load circuit 31, preventing the reverse current of the generated back electromotive force from damaging the load circuit 31 when the switching transistor Q1 is turned off. Due to the unidirectional conductivity of the diode, it allows the current to flow from the first end of the load circuit 31 to the second end, but blocks the reverse current. In this way, even when the motor load generates a back electromotive force, the reverse current will not pass through the braking resistor, thus protecting the normal operation of the braking circuit 30.

[0070] In addition, the use of the fourth diode D4 can also reduce the energy loss in the braking circuit 30, because the generation of the reverse current will cause additional energy consumption. By effectively preventing the generation of the reverse current, the fourth diode D4 helps to improve the efficiency of the braking process and ensure that the braking resistor works in the best state.

[0071] In practical applications, the selection of the fourth diode D4 needs to consider its rated current and reverse voltage withstand ability to ensure that it can work normally under the back electromotive force generated by the motor load. At the same time, in order to ensure the reliability and safety of the braking circuit 30, the parameters of the fourth diode D4 should be matched with the specifications of the braking resistor.

[0072] Optionally, referring to Figure 6 In still another embodiment of the present invention, a power supply circuit is provided. Based on the above Figure 2In the illustrated embodiment, the control circuit 60 includes a switch driving circuit 61 and a main controller 62, where:

[0073] The output end of the switch driving circuit 61 is connected to the controlled end of the switch circuit 33. The switch driving circuit 61 is used to output corresponding driving signals to drive the switch circuit 33 to conduct the path between the load circuit 31 and the ground, so as to consume the back electromotive force of the motor load. The output end of the main controller 62 is connected to the input end of the switch driving circuit 61. The main controller 62 is used to control the switch driving circuit 61 to output corresponding driving signals when the voltage value corresponding to the first voltage detection signal is greater than the first preset voltage value.

[0074] In this embodiment, the switch driving circuit 61 serves as a bridge between the main controller 62 and the switch circuit 33, and is responsible for converting the control signal of the main controller 62 into a driving signal suitable for driving the switching element. The main controller 62 determines whether the back electromotive force of the motor load is within a safe range according to the voltage value of the first voltage detection signal. If the detected voltage value exceeds the first preset voltage value, the main controller 62 will send an instruction to the switch driving circuit 61 to make it output a corresponding driving signal, thereby controlling the switch circuit 33 to conduct the path between the load circuit 31 and the ground to discharge the back electromotive force.

[0075] The switch driving circuit 61 generally includes a driving chip and necessary peripheral components such as resistors and capacitors to ensure the stability and reliability of the driving signals. The selection of the driving chip needs to consider its driving ability, response speed, and compatibility with the switching element. To improve the anti-interference ability of the system, the switch driving circuit 61 can also add isolation components such as optocouplers to achieve electrical isolation between the control circuit 60 and the switch circuit 33.

[0076] The main controller 62 is the brain of the entire power supply circuit, responsible for processing various detection signals and making decisions according to the preset control strategy. The main controller 62 is usually composed of intelligent control units such as a microcontroller (MCU) or a digital signal processor (DSP), and has high computing power and flexibility. Through program algorithms, the main controller 62 can realize real-time monitoring and dynamic adjustment of the motor load state to ensure that the motor can operate stably under various working conditions.

[0077] Optionally, referring to Figure 3 and Figure 6 , another embodiment of the present invention provides a power supply circuit. Based on the above Figure 2 illustrated embodiment, the switch circuit 33 includes a switching transistor Q1, where:

[0078] The controlled end of the switching transistor Q1 is connected to the output end of the switch driving circuit 61. The first conducting end of the switching transistor Q1 is connected to the second end of the load circuit 31. The second conducting end of the switching transistor Q1 is grounded.

[0079] In this embodiment, the switching transistor Q1 uses a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) as the main component, which has a low on-resistance and fast switching characteristics, and can effectively control the access and disconnection of the load circuit 31. The switch drive circuit 61 is responsible for providing an appropriate drive signal to the switching transistor Q1 to ensure its reliable operation.

[0080] The controlled terminal of the switching transistor Q1 receives a control signal through the drive circuit. When the control signal is on, the switching transistor Q1 conducts, and the load circuit 31 is connected to the motor load, thereby discharging the back electromotive force. When the control signal is off, the switching transistor Q1 is cut off, the load circuit 31 is disconnected, and the motor load no longer discharges the back electromotive force to ensure the stable operation of the motor under various working conditions.

[0081] Optionally, referring to Figure 4 , another embodiment of the present invention provides a power supply circuit. Based on any of the above Figures 1 to 3 and Figure 6 shown embodiments, the power supply circuit further includes an overcurrent detection circuit 70, wherein:

[0082] The input end of the overcurrent detection circuit 70 is connected to the output end of the conversion circuit 10, and the output end of the overcurrent detection circuit 70 is connected to the input end of the control circuit 60. The overcurrent detection circuit 70 is used to output a corresponding overcurrent signal to the control circuit 60 when the bus current exceeds a preset threshold.

[0083] In this embodiment, the overcurrent detection circuit 70 is responsible for real-time monitoring of the current value at the output end of the conversion circuit 10. When the current exceeds the preset threshold, the overcurrent detection circuit 70 can quickly detect this abnormal situation and send an overcurrent signal to the control circuit 60. After receiving the overcurrent signal, the control circuit 60 will immediately take corresponding protection measures, such as adjusting the state of the switch circuit 33 to reduce or cut off the current, thereby avoiding damage to the motor load or safety accidents caused by overcurrent.

[0084] Among them, the overcurrent detection circuit 70 generally includes a current sensor and a comparator. The current sensor is used to detect the current at the output end of the conversion circuit 10 and convert it into a voltage signal. The comparator then compares the voltage signal with a preset threshold voltage. Once an overcurrent situation is detected, a high-level signal is generated at the output end of the comparator, and this signal is then transmitted to the control circuit 60.

[0085] To ensure the accuracy and reliability of the overcurrent detection circuit 70, a Hall effect sensor or a current transformer is usually adopted, which has good linearity and high precision and can accurately detect the current value within a wide current range. In addition, to improve the response speed of the system, the comparator should have a fast response time and a low input bias current.

[0086] In practical applications, the design of the overcurrent detection circuit 70 also needs to consider the working environment of the power supply circuit and the load characteristics. For example, in a motor drive system, since the current fluctuates greatly during the starting and braking processes of the motor, the overcurrent detection circuit 70 should have a certain anti-interference ability to avoid misoperation.

[0087] Optionally, referring to Figure 6 , another embodiment of the present utility model provides a power supply circuit. Based on the above Figure 4 shown embodiment, the overcurrent detection circuit 70 includes a current sensing element, wherein:

[0088] The current sensing element is serially arranged between the output end of the conversion circuit 10 and the braking circuit 30. The current sensing element is connected to the control circuit 60, and the current sensing element is used to output a corresponding bus current signal to the control circuit 60; the control circuit 60 is used to control the motor load to turn off when the bus current exceeds a preset threshold.

[0089] In this embodiment, the current sensing element is a key part of the overcurrent detection circuit 70, and its performance directly affects the protection effect of the entire power supply circuit. The current sensing element usually adopts a high-precision current sensor, such as a Hall effect sensor or a shunt resistor, which can provide accurate current measurement values. Among them, there can be two current sensing elements, which can include a first current sensing element R1 and a second current sensing element R8. By serially connecting the current sensing element between the output end of the conversion circuit 10 and the braking circuit 30, the magnitude of the current flowing through the load can be monitored in real time.

[0090] When the bus current detected by the current sensing element exceeds the preset threshold, it will send an overcurrent signal to the control circuit 60. After receiving this signal, the control circuit 60 will output a corresponding control signal to turn off the motor load to ensure the safety of the motor load. In some cases, the control circuit 60 may adjust the state of the switch circuit 33, for example, by changing the duty cycle of the PWM (pulse width modulation) signal, to reduce the current of the motor load, thereby avoiding the occurrence of overcurrent phenomenon.

[0091] Optionally, referring to Figure 5 , the present utility model also provides a power supply circuit in another embodiment. Based on any of the above Figures 1 to 3 and Figure 6 shown embodiments, the conversion circuit 10 includes a rectification circuit 11, a common ground circuit 12, and a filtering circuit 13, wherein:

[0092] The input terminal of the rectifier circuit 11 is used to connect to a three-phase power supply, and the output terminal of the rectifier circuit 11 is used to output a DC bus voltage; the first end of the common ground circuit 12 is connected to the negative output terminal of the rectifier circuit 11; the first end of the filter circuit 13 is connected to the positive output terminal of the rectifier circuit 11, and the second end of the filter circuit 13 is connected to the second end of the common ground circuit 12. The filter circuit 13 is used to filter the DC bus voltage.

[0093] In this embodiment, the rectifier circuit 11 is responsible for converting three-phase alternating current into direct current and providing a stable DC bus voltage for the subsequent circuits. To ensure the efficient operation of the rectifier circuit 11, a three-phase full-bridge rectifier is usually adopted, which consists of six diodes and can achieve a lossless rectification process.

[0094] The design of the common ground circuit 12 is to ensure the stability and safety of the power supply circuit. By connecting the first end of the common ground circuit 12 to the negative output terminal of the rectifier circuit 11, electromagnetic interference can be effectively suppressed and the anti-interference ability of the system can be improved. Among them, the common ground circuit 12 can use components such as resistors, magnetoresistors or inductors to achieve its function.

[0095] The filter circuit 13 filters out the ripple components in the DC bus voltage and provides a smoother DC voltage. The filter circuit 13 usually includes capacitors and inductors. Capacitors are used to absorb voltage spikes and high-frequency noise, while inductors are used to suppress low-frequency ripples. By reasonably designing the parameters of the filter circuit 13, the stability and purity of the output voltage can be ensured, thereby providing a high-quality DC power supply for the motor load.

[0096] In practical applications, the design of the conversion circuit 10 also needs to consider the power level and load characteristics of the power supply circuit. For example, in high-power application scenarios, the rectifier circuit 11 may need to use diodes with good heat dissipation performance to cope with the heat problem caused by large currents. The design of the filter circuit 13 also needs to be optimized according to the actual ripple requirements to ensure the stable operation of the motor load.

[0097] The present utility model also proposes a driver, and the driver includes the power supply circuit as described in the above embodiment.

[0098] It should be noted that since the driver of the present utility model is based on the above power supply circuit, therefore, the embodiments of the driver of the present utility model include all the technical solutions of all the embodiments of the above power supply circuit, and the achieved technical effects are also exactly the same, and will not be elaborated here.

[0099] It should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or system including such element.

[0100] The serial numbers of the above embodiments of the present utility model are only for description and do not represent the superiority or inferiority of the embodiments.

[0101] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present utility model, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium as described above (such as ROM / RAM, magnetic disk, optical disc), and includes several instructions to enable a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present utility model.

[0102] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present utility model.

Claims

1. A power supply circuit, characterized in that, The power supply circuit includes: A conversion circuit for converting an AC voltage into a DC bus voltage; A braking circuit connected to the output terminal of the conversion circuit for discharging the back electromotive force of the motor load when connected to the output terminal of the conversion circuit; A first detection circuit connected to the output terminal of the conversion circuit for detecting the DC bus voltage and correspondingly outputting a first voltage detection signal; A second detection circuit electrically connected to the braking circuit for detecting the voltage of the braking circuit and correspondingly outputting a second voltage detection signal; A control circuit electrically connected to the braking circuit, the first detection circuit, and the second detection circuit respectively. The control circuit is configured to control the braking circuit to start when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value, and is further configured to control the conversion circuit to reduce the output power when the voltage value corresponding to the second voltage detection signal is greater than a second preset voltage value.

2. The power supply circuit according to claim 1, wherein The second detection circuit includes: A first optocoupler. At least one or more capacitors are connected in parallel between the positive and negative electrodes of the first optocoupler, and at least one or more resistors are connected in parallel between the positive and negative electrodes of the first optocoupler. A first resistor is connected in series between the collector of the first optocoupler and the output terminal of the control circuit. At least one or more capacitors are connected in parallel between the first end of the first resistor and the ground; A second diode. A first diode is connected in series between the positive electrode of the second diode and the negative electrode of the first optocoupler, and a third diode is connected in series between the negative electrode of the second diode and the braking circuit.

3. The power supply circuit according to claim 1, wherein, The braking circuit includes: A load circuit for discharging the back electromotive force of the motor load; A reverse protection circuit arranged in parallel with the load circuit; A switch circuit. The first conduction end of the switch circuit is connected to the second end of the load circuit, and the second conduction end of the switch circuit is grounded.

4. The power supply circuit according to claim 3, characterized in that, The reverse protection circuit includes: A fourth diode. The negative electrode of the fourth diode is connected to the first end of the load circuit, and the positive electrode of the fourth diode is connected to the second end of the load circuit.

5. The power supply circuit according to claim 3, wherein The control circuit includes: A switch driving circuit. The output terminal of the switch driving circuit is connected to the controlled terminal of the switch circuit. The switch driving circuit is configured to output a corresponding driving signal to drive the switch circuit to conduct the path between the load circuit and the ground to consume the back electromotive force of the motor load; A main controller. The output terminal of the main controller is connected to the input terminal of the switch driving circuit. The main controller is configured to control the switch driving circuit to output a corresponding driving signal when the voltage value corresponding to the first voltage detection signal is greater than a first preset voltage value.

6. The power supply circuit according to claim 5, wherein The switch circuit includes: A switching tube. The controlled terminal of the switching tube is connected to the output terminal of the switch driving circuit. The first conduction end of the switching tube is connected to the second end of the load circuit, and the second conduction end of the switching tube is grounded.

7. The power supply circuit according to any one of claims 1 to 6, characterized in that, The power supply circuit further includes: Overcurrent detection circuit, the input end of the overcurrent detection circuit is connected to the output end of the conversion circuit, the output end of the overcurrent detection circuit is connected to the input end of the control circuit, and the overcurrent detection circuit is used to output a corresponding overcurrent signal to the control circuit when the bus current exceeds a preset threshold.

8. The power supply circuit according to claim 7, characterized in that, The overcurrent detection circuit includes: A current sensing element, the current sensing element is serially arranged between the output end of the conversion circuit and the braking circuit, the current sensing element is connected to the control circuit, and the current sensing element is used to output a corresponding bus current signal to the control circuit; The control circuit is used to turn off the motor load when the bus current exceeds a preset threshold.

9. The power supply circuit according to any one of claims 1 to 6, characterized in that, The conversion circuit includes: A rectification circuit, the input end of the rectification circuit is used to connect to a three-phase power supply, and the output end of the rectification circuit is used to output a DC bus voltage; A common ground circuit, the first end of the common ground circuit is connected to the negative output end of the rectification circuit; A filtering circuit, the first end of the filtering circuit is connected to the positive output end of the rectification circuit, the second end of the filtering circuit is connected to the second end of the common ground circuit, and the filtering circuit is used to filter the DC bus voltage.

10. A driver, characterized in that, The driver includes the power supply circuit according to any one of claims 1 to 9.

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