Brake resistor protection circuit and protection method

Abstract

The embodiment of the invention provides a brake resistor protection circuit and a protection method, the brake resistor protection circuit is configured in a motor driving device, the protection circuit comprises a buffer circuit, a second detection unit, a brake resistor and a brake switch, the brake resistor and the brake switch are connected in series, the buffer circuit comprises a buffer switch and a buffer resistor, and the buffer switch and the buffer resistor are connected in parallel. The second detection unit outputs a second signal based on the detected short circuit or conduction condition of the brake switch, the protection circuit is characterized by comprising a first detection unit which outputs a first signal control unit based on the detected voltage between the positive direct current bus end and the negative direct current bus end of the motor driving device, and a second detection unit which outputs a second signal based on the detected voltage between the positive direct current bus end and the negative direct current bus end of the motor driving device; and the controller is used for determining whether the brake switch is abnormal or not according to the first signal and the second signal, and controlling the buffer switch to be switched off when the brake switch is abnormal. Therefore, the abnormal condition of the brake switch can be accurately identified, and the brake resistor can be protected without an external device.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of industrial control. BACKGROUND

[0002] In the existing motor drive device, for example, in the servo driver, when decelerating or braking, the operating mode of the motor will be switched from the "electric mode" (consumes electric energy to output mechanical energy) to the "power generation mode" - at this time the motor is equivalent to a generator, which converts mechanical energy (such as inertial kinetic energy, gravitational potential energy) into electric energy, such electric energy is called "regenerative energy" (regenerative energy). At this time, the regenerative energy generated by the motor will be fed back to the DC bus of the motor drive device, and the bus voltage will quickly rise, which may exceed the voltage withstand limit of the capacitor and other elements. In the prior art, by setting the regenerative transistor to form a loop with the regenerative resistor, the regenerative energy is consumed in the form of heat energy through the resistor, thereby processing the regenerative energy generated by the servo driver when decelerating or braking, preventing the DC bus voltage from being too high to damage the bus capacitor or other modules in the servo driver, and ensuring the safe and stable operation of the servo driver.

[0003] In the existing technology, when the regenerative transistor is short-circuited or abnormally turned on, a fault signal is output by the motor drive device, and when the external device detects the fault signal, the power supply of the system is powered off.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application, and for the convenience of understanding by those skilled in the art, and cannot be considered as the prior art known by those skilled in the art only because these solutions are described in the background section of the present application. SUMMARY

[0005] The present inventors have found that in the existing motor drive device, if the regenerative transistor is short-circuited or abnormally turned on, the motor drive device may not be able to correctly identify and output a fault signal, resulting in the external device being unable to power off the power supply in time or being unable to limit the abnormal current, thereby causing the regenerative resistor in the motor drive device to burn out, and even causing the circuit to catch fire.

[0006] To solve at least one of the above technical problems or at least a similar problem, embodiments of the present application provide a braking resistor protection circuit. The braking resistor protection circuit determines whether a braking switch is abnormal by combining a voltage between a positive DC bus end and a negative DC bus end of a motor drive device and a short circuit or conduction of the braking switch, and limits the braking switch by opening a buffer switch. The braking resistor protection circuit determines whether the braking switch is abnormal by combining the voltage between the positive DC bus end and the negative DC bus end of the motor drive device and the short circuit or conduction of the braking switch, and protects the braking resistor by a buffer circuit inside the motor drive device. Thus, the braking resistor protection circuit can more accurately determine abnormality of the braking switch, and can protect the braking resistor without relying on an external device and without detecting a control signal of a regeneration transistor, thereby avoiding determining abnormality by the control signal when the regeneration transistor is abnormally conducted, and thus avoiding failure of protection of the braking resistor.

[0007] According to an embodiment of the first aspect of the present application, a braking resistor protection circuit is provided. The braking resistor protection circuit is configured in a motor drive device. The braking resistor protection circuit includes a buffer circuit, a second detection unit, and a braking resistor and a braking switch connected in series. The buffer circuit includes a buffer switch and a buffer resistor connected in parallel. The second detection unit outputs a second signal based on detection of a short circuit or conduction of the braking switch. The braking resistor protection circuit further includes:

[0008] a first detection unit that outputs a first signal based on detection of a voltage between a positive DC bus end and a negative DC bus end of the motor drive device;

[0009] a control unit that determines whether the braking switch is abnormal based on the first signal and the second signal, and controls the buffer switch to be opened when the braking switch is abnormal.

[0010] In at least one embodiment, the buffer resistor includes a positive temperature coefficient (PTC) thermistor, the braking switch includes a regeneration transistor, and the buffer circuit is configured to prevent inrush current when the motor drive device is powered on.

[0011] In at least one embodiment, the first signal includes a first result when the voltage detected by the first detection unit is in a first range, and the first signal includes a second result otherwise.

[0012] In at least one embodiment, the second signal includes a third result when the second detection unit determines that the braking switch is short-circuited or conducted based on the detected voltage or current, and the second signal includes a fourth result otherwise.

[0013] In at least one embodiment, the control unit determines that the braking switch is abnormal when the first signal is the first result and the second signal is the third result.

[0014] In at least one embodiment, the second detection unit detects a voltage or a current between a source and a drain, or a collector and an emitter of a freewheeling transistor of the braking switch.

[0015] In at least one embodiment, the first range is related to a system supply voltage interval of the motor drive device, and / or a maximum value of the first range is less than a minimum value of a regenerative energy utilization interval voltage of the motor drive device.

[0016] In at least one embodiment, when the buffer switch is turned off, the current of the braking resistor is guided to the buffer resistor.

[0017] In at least one embodiment, the buffer circuit is connected in series with a source and a drain of the braking switch and the braking resistor.

[0018] According to an embodiment of the second aspect of the present application, a braking resistor protection method is provided, applied to a motor drive device, the motor drive device comprising a buffer circuit, a second detection unit, and a braking resistor and a braking switch connected in series, the buffer circuit comprising a buffer switch and a buffer resistor connected in parallel, the second detection unit detecting a short circuit or conduction of the braking switch, characterized in that the method comprises:

[0019] outputting a first signal based on a detected voltage between a positive DC bus terminal and a negative DC bus terminal of the motor drive device;

[0020] outputting a second signal based on a detected short circuit or conduction of the braking switch;

[0021] determining whether the braking switch is abnormal according to the first signal and the second signal, and controlling the buffer switch to be turned off when the braking switch is abnormal.

[0022] One of the beneficial effects of the embodiment of the present application is that whether the braking switch is abnormal is determined by combining the voltage between the positive DC bus terminal and the negative DC bus terminal of the motor drive device and the short circuit or conduction of the braking switch, and the braking resistor is protected by the buffer circuit inside the motor drive device. Thus, the abnormal condition of the braking switch can be more accurately determined, and the braking resistor can be protected without relying on external devices and without detecting the control signal of the freewheeling transistor, avoiding the failure of protection of the braking resistor caused by judging the abnormality through the control signal when the freewheeling transistor is abnormally turned on.

[0023] The foregoing overview of the application, as generically and broadly described herein, as well as the embodiments of the application described below, can be implemented using one or more computer programs or software. Such programs can be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in a low level assembly or machine language, if desired. Accordingly, the software can be embodied BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0025] Figure 1 is a schematic diagram of a braking resistor protection circuit of an embodiment of the application;

[0026] Figure 2 is a schematic diagram of a voltage threshold interval of a DC bus of an embodiment of the application;

[0027] Figure 3 is a schematic diagram of a braking resistor, a braking switch and a second detection unit of an embodiment of the application;

[0028] Figure 4 is a schematic diagram of a buffer circuit of an embodiment of the application;

[0029] Figure 5 is a schematic diagram of a braking resistor protection method of an embodiment of the application;

[0030] Figure 6 is a schematic diagram of an electronic device of an embodiment of the application. DETAILED DESCRIPTION

[0031] The foregoing and other features of the present application will become apparent to those skilled in the art upon consideration of the following description with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The embodiments of the present application will be described with reference to the following description in conjunction with the drawings in which:

[0032] In the embodiments of the present application, the terms "first", "second" and the like are used to distinguish different elements from each other, but do not indicate the spatial arrangement or time sequence of the elements, and the elements should not be limited by these terms. The term "and / or" includes any one and all combinations of the associated listed terms. The terms "comprise", "include", "have" and the like mean the presence of the stated features, elements, components or assemblies, but do not exclude the presence or addition of one or more other features, elements, components or assemblies.

[0033] In the embodiments of the present application, the singular form "a", "an" and the like includes the plural form, should be broadly understood as "one" or "a kind of", and not limited to the meaning of "one"; in addition, the term "said" should be understood as including both the singular form and the plural form, unless the context clearly indicates otherwise. In addition, the term "according to" should be understood as "at least partially according to", and the term "based on" should be understood as "at least partially based on", unless the context clearly indicates otherwise.

[0034] Features described and / or illustrated with respect to one implementation can be used in one or more other implementations in the same or similar manner, combined with or substituted for features in other implementations, or used in different combinations. The term "comprise / comprising" as used herein indicates the presence of the stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0035] Embodiments of the first aspect

[0036] The embodiments of the present application provide a braking resistance protection circuit.

[0037] Figure 1 is a schematic diagram of the braking resistance protection circuit of the embodiments of the present application, which is configured in a motor drive device. As shown in Figure 1 , the braking resistance protection circuit 100 includes a buffer circuit 101, a second detection unit 105, and a braking resistance 102 and a braking switch 103 connected in series, the buffer circuit 101 includes a buffer switch 1011 (not shown in Figure 1 ) and a buffer resistance 1012 (not shown in Figure 1 ) connected in parallel, the second detection unit 105 outputs a second signal based on detection of short circuit or conduction of the braking switch 103, characterized in that the braking resistance protection circuit 100 further comprises:

[0038] a first detection unit 104, which outputs a first signal based on detection of the voltage between the positive and negative DC bus terminals of the motor drive device;

[0039] A control unit 106 determines whether the brake switch 103 is abnormal based on the first signal and the second signal, and controls the buffer switch 101 to be turned off when the brake switch 103 is abnormal. Figure 1

[0040] It is worth noting that the above-mentioned Figure 1 Only the components or modules related to the present application are described, but the present application is not limited thereto. The above-mentioned device can also include other components or modules, and the specific content of these components or modules can be referred to the related art.

[0041] In some embodiments, the motor driving device can be configured on an automatic processing winding brake device, such as a coating device, a winding device, etc. The motor driving device can receive a control signal from an external control system, convert the control signal into high-power electric energy capable of driving the motor to operate through its internal circuit, and adjust the circuit output in real time according to the feedback signal, thereby achieving precise control of the motor speed, torque, direction or position. Different types of motors need to be matched with different types of drivers for control. Figure 1 For example, the motor driving device 200 can precisely control the speed, torque, direction or position of the motor 300. In the embodiments of the present application, the types of the motor driving device 200 and the motor 300 are not limited, the motor 300 can be an AC servo motor, and the corresponding motor driving device 200 can be a servo driver; or the motor 300 can be a variable frequency motor, and the corresponding motor driving device 200 can be a variable frequency driver. The motor 300 and the motor driving device 200 can also be of other types, and the present application is not limited thereto. In the following embodiments, the motor 300 is taken as an AC servo motor, and the motor driving device is taken as a servo driver for illustration of the present application. In some embodiments, the regeneration transistor is mainly used to control the connection and disconnection of the regeneration resistor in the motor driving device. When the motor decelerates or brakes, the actual speed of the motor will exceed the synchronous speed corresponding to the current output frequency of the motor driving device. The motor will convert mechanical energy back to electric energy, generating a regeneration current to charge the energy storage capacitor. The voltage on the DC bus of the motor driving device rises sharply. At this time, the regeneration transistor is turned on, and the regeneration current flows through the regeneration resistor. In this way, the excess energy generated by the motor is converted into heat energy, thereby reducing the voltage on the DC bus. Figure 1 For example, when the motor 300 decelerates or brakes, the motor 300 will generate a regeneration current, causing the voltage on the DC bus of the motor driving device 200 to rise sharply. At this time, the brake switch 103 (i.e., the regeneration transistor) is turned on, and the regeneration current flows through the brake resistor 102 (i.e., the regeneration resistor). In this way, the excess energy generated by the motor 300 is converted into heat energy.

[0042] Figure 2 ​is a schematic diagram of voltage threshold intervals of a DC bus of an embodiment of the present application.

[0043] In some embodiments, as shown in Figure 1 , the voltage between the P (Positive) pole (positive DC bus end) and the N (Negative) pole (negative DC bus end) of the motor drive device 200 is the voltage on the DC bus of the motor drive device 200, which can be divided into voltage threshold intervals as shown in Figure 2 , as shown in Figure 2 , the motor 300 is in a normal working state, and the voltage of the DC bus is in the system power supply interval, that is, the voltage of the DC bus is less than the threshold value Y. When the motor decelerates or brakes, the voltage on the DC bus rises to be in the regenerative energy utilization interval, that is, the voltage of the DC bus is in the interval (X, Y). When the voltage of the DC bus continues to rise to be greater than the threshold value X, that is, in the regenerative action voltage interval, it indicates that the motor 300 generates too much regenerative current, resulting in too large voltage of the DC bus. At this time, the regenerative transistor is controlled to be turned on to reduce the voltage of the DC bus and protect the circuit. When the voltage of the DC bus is less than the threshold value X through the protection of the regenerative transistor, it indicates that the excess energy generated by the motor 300 has been consumed. At this time, the regenerative transistor is controlled to be turned off.

[0044] In the above embodiments, for example Figure 2 , the voltage thresholds X and Y of the DC bus can be set according to different motor drive devices and motors. For details, refer to the related art, which is not limited in the present application.

[0045] The structure of the braking resistor protection circuit of the embodiment of the present application is described below.

[0046] In some embodiments, as shown in Figure 1 , when the motor 300 is working normally, the motor drive device 200 converts the input AC voltage into a DC voltage through a rectifier circuit. The DC voltage is stored by the energy storage of the capacitor C1 connected in parallel between the P (Positive) pole (positive DC bus end) and the N (Negative) pole (negative DC bus end) of the DC bus, forming a smooth and stable DC voltage (i.e., DC bus voltage). At this time, the motor drive device 200 inverts the DC bus voltage through an inverter bridge circuit to output a three-phase AC voltage with adjustable frequency and voltage, and drives the motor 300 with the three-phase AC voltage. The above is only an example for illustration. The driving process of the motor drive device 200 to the motor 300 can refer to the related art, which is not limited in the present application. In addition, Figure 1 , the connection mode between the motor drive device 200 and the motor 300 is only an example for illustration. How the motor drive device 200 and the motor 300 are connected can refer to the related art, which is not limited in the present application.

[0047] In some embodiments, as shown in FIG. 1, the first detection unit 104 is configured at the P pole and the N pole of the motor driving device 200 to detect the voltage between the P pole and the N pole of the motor driving device and output a first signal according to the detection result. Figure 1 Figure 1 For example, the first detection unit 104 is connected in parallel to the P pole and the N pole of the motor driving device 200, the first input end D1 of the first detection unit 104 is connected to the N pole, and the second input end D2 of the first detection unit 104 is connected to the P pole. However, the first input end D1 can also be connected to the P pole, and the second input end D2 can also be connected to the N pole. In this way, the first detection unit 104 can detect the voltage between the P pole and the N pole.

[0048] In some embodiments, when the voltage detected by the first detection unit 104 is in a first range, the first signal includes a first result, otherwise, the first signal includes a second result, that is, the first signal indicates whether the voltage between the P pole and the N pole of the motor driving device 200 is in the first range. The first signal can represent the first result and the second result by high logic or low logic, for example, using a high logic signal to represent the first result and a low logic signal to represent the second result, or using a high logic signal to represent the second result and a low logic signal to represent the first result, which is not limited in the present application, or other ways can also be used to represent whether the voltage between the P pole and the N pole is in the first range, for example, using "1" to represent the first result and "0" to represent the second result, or using "0" to represent the first result and "1" to represent the second result, which can be referred to related technologies, and is not limited in the present application.

[0049] In some embodiments, the first range is related to the system power supply voltage interval of the motor driving device 200, and / or the maximum value of the first range is less than the minimum value of the regenerative energy utilization interval voltage of the motor driving device 200. That is, in some examples, the first range can be determined according to the allowable power supply voltage of the motor driving device 200, or according to the maximum voltage that each component (for example, a capacitor) in the motor driving device 200 and the motor 300 can withstand, for example, the maximum power supply voltage after rectification is 500V, and the maximum voltage that each component can withstand is 560V. The first range can be set to 0-500V or 0-560V, or the maximum value of the first range is set to a value between 500V and 560V. Alternatively, the first range can also be determined according to the regenerative energy utilization interval voltage of the motor driving device 200, that is, the maximum value of the first range is less than the minimum value of the regenerative energy utilization interval voltage of the motor driving device 200. Figure 2 ​For example, the first range can be directly set to 0 to Y, or the maximum value of the first range can be set to other values ​​less than Y; this application does not impose any restrictions. Therefore, when the voltage detected by the first detection unit 104 is within the first range, if the motor 300 is in a motoring state, the regeneration transistor is in a non-conducting state; if the motor 300 is in a deceleration or braking state, the regeneration transistor is in a conducting state. In this case, the regeneration transistor may be abnormally turned on, or a short circuit may occur.

[0050] Furthermore, in some examples, the first detection unit 104 can output the first signal after continuous detection for a period of time, for example, after the continuous detection time reaches a first time period. This can avoid the voltage change in the motor drive device 200 causing the output result of the first detection unit 104 to be inaccurate. The first time period can be set according to specific needs, and this application does not impose any restrictions.

[0051] According to the above embodiment, the first detection unit 104 is used to detect whether the voltage between the P and N poles of the motor drive device 200 is within a first range. It is possible to use the judgment of whether the DC bus voltage is too low as one of the bases for judging whether the regeneration transistor is in a short circuit or abnormal conduction state.

[0052] Figure 3 This is a schematic diagram of the braking resistor, braking switch, and second detection unit according to an embodiment of this application.

[0053] In some embodiments, such as Figure 3 As shown, the braking resistor 102 in the braking resistor protection circuit 100 is also a regeneration transistor. This regeneration transistor can be an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). The braking resistor 102 is also a regeneration resistor. This regeneration resistor is a high-power, high-heat-resistant, low-resistance ceramic resistor or an aluminum-cased resistor, or it can be other resistors that meet the requirements. This application is not limited to these.

[0054] by Figure 3 For example, the A terminal of the brake switch 103 is connected to the first terminal F1 of the brake resistor 102 so that the brake switch 103 and the brake resistor 102 are connected in series. Alternatively, the A terminal of the brake switch 103 can also be connected to the second terminal F2 of the brake resistor 102. This application does not impose any restrictions.

[0055] In some examples, the brake switch 103 (regenerative transistor) is LGBT, such as... Figure 3As shown, the A end of the brake switch 103 is the emitter (E), and the B end is the collector (C). The collector of the brake switch 103 is connected to the P pole (positive pole) of the motor driving device 200, and the emitter of the brake switch 103 is connected to the first terminal F1 of the brake resistor 102. Thus, when the brake switch 103 is turned on, the current flows from the collector, flows out from the emitter, and then enters the regeneration resistor, so that the brake resistor 102 converts the electrical energy into heat energy and dissipates the heat energy, thereby achieving the purpose of reducing the voltage.

[0056] In other examples, the brake switch 103 (regeneration transistor) is a MOSFET, such as Figure 2 As shown, the A end of the brake switch 103 is the source (Source), and the B end is the drain (Drain). The drain of the brake switch 103 is connected to the P pole (positive pole) of the motor driving device 200, and the source of the brake switch 103 is connected to the first terminal F1 of the brake resistor 102. Thus, when the brake switch 103 is turned on, the current flows from the drain, flows out from the source, and then enters the regeneration resistor, so that the brake resistor 102 converts the electrical energy into heat energy and dissipates the heat energy, thereby achieving the purpose of reducing the voltage. The above describes the brake switch 103 by taking the IGBT and the MOSFET as examples, but the application is not limited thereto. The brake switch 103 can also be other regeneration transistors that meet the requirements. For details, refer to the related technology, which is not limited in the present application.

[0057] In some embodiments, the second detection unit 105 is connected to the A end and the B end of the brake switch 103, respectively, so as to detect the voltage of the brake switch 103 or the current passing through the brake switch 103, and output a second signal. Figure 3 For example, the first input end E1 of the second detection unit 105 is connected to the A end of the brake switch 103, and the second input end E2 of the second detection unit 105 is connected to the B end of the brake switch 103. The application is not limited thereto. The first input end E1 can be connected to the B end of the brake switch, and the second input end E2 can be connected to the A end of the brake switch 103, so as to detect the voltage of the brake switch 103 or the current passing through the brake switch 103.

[0058] In some examples, when the voltage between the collector and the emitter of the brake switch 103 is less than a second threshold value, or when the voltage between the source and the drain of the brake switch 103 is less than a second threshold value, the second signal includes a third result, otherwise, the second signal includes a fourth result. Alternatively, when the current between the collector and the emitter of the brake switch 103 is detected, or when the current between the source and the drain of the brake switch 103 is detected, the second signal includes a third result, otherwise, the second signal includes a fourth result.

[0059] The third and fourth results can be represented by high and low logic signals, respectively. For example, the third result can be a high logic signal and the fourth result a low logic signal, or vice versa. Alternatively, other symbols can be used to represent the third and fourth results, such as using "0" to represent the third result and "1" to represent the fourth result, or using "1" to represent the third result and "0" to represent the fourth result. For specific details, please refer to relevant technologies. This application does not impose any limitations.

[0060] According to the above embodiment, the second detection unit 105 can determine whether the brake switch 103 is abnormal based on the voltage or current of the brake switch 103 combined with the detection result of the first detection unit 104.

[0061] In the above embodiments, the first detection unit and the second detection unit can be implemented by a voltage divider circuit combined with a comparator, but the embodiments of this application are not limited thereto.

[0062] Figure 4 This is a schematic diagram of a buffer circuit according to an embodiment of this application.

[0063] In some embodiments, such as Figure 3 and Figure 4 As shown, the buffer circuit 101 includes a buffer switch 1011 and a buffer resistor 1012 connected in parallel. The buffer circuit 101 is connected in series with the braking switch 103 and the braking resistor 102. Specifically, the buffer circuit 101 is connected in series with the A terminal (emitter or source) and B terminal (collector or drain) of the braking switch 103 and the braking resistor 102, that is, with Figure 4 For example, the third terminal G1 of the buffer circuit 101 is connected to the B terminal of the brake switch 103, or the fourth terminal G2 of the buffer circuit 101 is connected to the B terminal of the brake switch 103. The control unit 106 determines whether the brake switch 103 is abnormal based on the first signal output by the first detection unit 104 and the second signal output by the second detection unit 105.

[0064] In some embodiments, such as Figure 4 As shown, the buffer circuit 101 can be a relay, specifically, it can be a surge relay. When the buffer circuit 101 is a surge relay, when the motor drive device 200 is first powered on, the buffer switch 1011 in the buffer circuit 101 is in the open state. At this time, the current can only pass through the buffer resistor 1012, thereby preventing the surge current when the motor drive device 200 is powered on. After the current in the motor drive device 200 gradually stabilizes, the buffer switch closes.

[0065] That is, in the embodiment of the present application, the snub circuit originally provided in the motor drive device 200 to prevent inrush current can be used to protect the braking resistor 102. The inrush relay is turned off when the motor drive device 200 is powered on to protect the inrush current, and is turned on when the motor 300 is running normally and the voltage reaches a certain value, and the current flows through the inrush relay. After the motor is decelerated or braked, when the abnormality of the brake switch is detected, the inrush relay is turned off to protect the braking resistor 102. Thus, the braking resistor is protected and the circuit structure is simplified, and no external device is needed to power off the power supply, and no other circuit elements need to be provided in the motor drive device 200. In addition, the snub circuit 101 can also be other types of relays, or other types of circuits with parallel snub switches 1011 and snub resistors 1012, which are not limited in the present application.

[0066] The following describes how the control unit 106 of the embodiment of the present application determines whether the brake switch 103 is abnormal.

[0067] In some embodiments, as shown in Figure 1 When the first signal is the first result and the second signal is the third result, the control unit 106 determines that the brake switch 103 is abnormal. That is, when the first detection unit 104 detects that the voltage between the P and N poles of the motor drive device is in the first range, and the second detection unit 105 detects that the current or voltage is less than the second threshold, it is determined that the brake switch 103 is abnormal (short circuit or abnormal conduction).

[0068] For example, when the first result and the third result are represented by high logic signals, and the second result and the fourth result are represented by low logic signals, when the control unit 106 receives high logic signals in both the first signal and the second signal, the control unit 106 determines that the brake switch 103 is abnormal, and when the control unit 106 receives a low logic signal in any of the signals, the control unit 106 determines that the brake switch 103 is not abnormal.

[0069] That is, if the second result is output, it means that the PN voltage is not in the first range, for example, it is detected that the PN voltage is in Figure 2The regenerative energy utilization interval or the regenerative action voltage interval, at this time, no matter the second detection unit outputs the third result or the fourth result, it will not cause damage to the braking resistor, because the braking resistor is still in the period of consuming electric energy, its design parameters allow the regenerative energy to need to be completely dependent on the braking resistor to consume. But if the second result is output, it means that the PN voltage is in the first range, that is, the PN voltage after the consumption of the braking resistor falls back to the system power supply voltage interval, at this time, if the second detection unit outputs the third result, it means that the protection of the braking resistor needs to be started, if it is not protected, the braking resistor may be burned out. But if the second detection unit outputs the fourth result at this time, it means that the braking switch is in the open state, the braking resistor no longer passes through the current, and will not be burned out. Therefore, the control unit 106 can determine whether the braking switch 103 is abnormal by combining the voltage between the P pole and the N pole of the motor driving device 200 and the short circuit or conduction of the braking switch 103 itself, thereby more accurately determining the state of the braking switch 103 and protecting the braking resistor 102. It is not accurate to determine whether the protection of the braking resistor needs to be started according to a single detection result. For example, if the protection of the braking resistor is started only when the third result is detected, if the PN voltage is in the first range at this time, the braking resistor may still be consuming electric energy, which will waste the system design.

[0070] In some examples, during the operation of the motor driving device 200, the first detection unit 104 and the second detection unit 105 send the first signal and the second signal to the control unit 106 every certain period of time, thereby the control unit 106 can continuously monitor whether the braking switch 103 is abnormal and protect the braking resistor 102, which can more timely detect the abnormality of the braking switch 103 compared to the power supply being powered off by the motor driving device outputting a fault signal.

[0071] The following describes how the control unit 106 protects the braking resistor 102 when detecting the abnormality of the braking switch.

[0072] In some embodiments, when it is determined that the braking switch 103 is abnormal, the control unit 106 controls the buffer switch 1011 to be disconnected, thereby guiding the current passing through the braking resistor 102 to the buffer resistor 1012 to protect the braking resistor 102.

[0073] In some embodiments, as Figure 4As shown, the buffer resistor 1012 can be a positive temperature coefficient (PTC) thermistor. The PTC thermistor has a low resistance at room temperature, and when the temperature exceeds a certain temperature (Curie point), the resistance value will increase sharply with the temperature. According to this characteristic, when the buffer switch 1011 is disconnected, the current passing through the braking resistor 102 is guided to the buffer resistor 1012, and the resistance value of the buffer resistor 1012 will increase sharply with the temperature, thereby inhibiting the current passing through the braking resistor 102, and avoiding the braking resistor 102 from being burned due to excessive temperature caused by excessive current. The Curie point of the PTC thermistor can be adjusted according to the material characteristics of the braking resistor 102 and the buffer resistor 1012. For details, refer to related technologies, which are not limited in the present application. In addition, the buffer resistor 1012 can also use other types of resistors, which can inhibit the current passing through the braking resistor 102 by increasing the resistance value, and the present application is not limited thereto.

[0074] The braking resistor protection circuit 100 of the embodiment of the present application is described above. Figure 1 For example, the present application does not limit how the braking resistor protection circuit 100 is connected and configured in the motor drive device 200. For details, refer to related technologies.

[0075] According to the above embodiment, the abnormality of the braking switch is determined by combining the voltage between the positive and negative DC bus terminals of the motor drive device and the short circuit or conduction of the braking switch, and the braking resistor is protected by the buffer circuit. Therefore, the abnormality of the braking switch can be more accurately determined, and the braking resistor can be protected without relying on external devices and detecting the control signal of the regeneration transistor, thereby avoiding the protection of the braking resistor from being invalid due to the determination of the abnormality by the control signal when the regeneration transistor is abnormally conducted.

[0076] It should be noted that the above only describes the components or modules related to the present application, but the present application is not limited thereto. The above device can also include other components or modules, and the specific content of these components or modules can be referred to related technologies.

[0077] For simplicity, Figure 1 , Figure 3 and Figure 4 only show the connection relationship or signal direction between each component or module, but those skilled in the art should understand that various related technologies such as bus connection can be used. The above components or modules can be realized by hardware facilities such as processors, memories, etc.; the embodiments of the present application are not limited thereto.

[0078] The above embodiments are only illustrative of the embodiments of the present application, but the present application is not limited thereto, and can be appropriately modified on the basis of the above embodiments. For example, the above embodiments can be used alone or in combination of one or more of the above embodiments.

[0079] Embodiments of the second aspect

[0080] Embodiments of the second aspect relate to a braking resistance protection method applied to a motor driving device, the motor driving device comprising a buffer circuit, and a braking resistance and a braking switch connected in series, the buffer circuit comprising a buffer switch and a buffer resistance connected in parallel. Since the principle of the method is similar to that of the braking device protection circuit of the embodiments of the first aspect for solving the problem, the specific implementation thereof can refer to the implementation of the braking resistance protection circuit of the embodiments of the first aspect, and the same content will not be described repeatedly.

[0081] Figure 5 is a schematic diagram of the braking resistance protection method of the embodiments of the present application. As shown in Figure 5 , the method comprises:

[0082] 501, outputting a first signal based on the detected voltage between the positive DC bus end and the negative DC bus end of the motor driving device;

[0083] 502, outputting a second signal based on the detection of the short circuit or conduction of the braking switch;

[0084] 503, determining whether the braking switch is abnormal according to the first signal and the second signal, and controlling the buffer switch to be turned off when the braking switch is abnormal.

[0085] For the description of steps 501-503 above, reference can be made to the embodiments of the first aspect, which will not be described repeatedly here.

[0086] In some embodiments, the buffer resistance comprises a positive temperature coefficient (PTC) thermistor, the braking switch comprises a regenerative transistor, and the buffer circuit is used to prevent inrush current when the motor driving device is powered on.

[0087] In some embodiments, when the detected voltage between the positive DC bus end and the negative DC bus end of the motor driving device is in a first range, the first signal comprises a first result, otherwise, the first signal comprises a second result.

[0088] In some embodiments, when it is determined that the brake switch is short-circuited or turned on based on the detected voltage or current, the second signal comprises a third result, otherwise, the second signal comprises a fourth result.

[0089] In some embodiments, when the first signal is the first result and the second signal is the third result, it is determined that the brake switch is abnormal.

[0090] In some embodiments, the voltage or current between the source and the drain, or the collector and the emitter of the regenerative transistor of the brake switch is detected.

[0091] In some embodiments, the first range is related to a system power supply voltage interval of the motor driving device, and / or the maximum value of the first range is less than the minimum value of a regenerative energy utilization interval voltage of the motor driving device.

[0092] In some embodiments, when the buffer switch is turned off, the current of the brake resistance is guided to the buffer resistance.

[0093] In some embodiments, the buffer circuit is connected in series with the source and the drain of the brake switch and the brake resistance.

[0094] The above only describes the steps or processes related to the present application, but the present application is not limited thereto. The method can also include other steps or processes, and the specific content of these steps or processes can be referred to the prior art.

[0095] The above embodiments only exemplarily describe the embodiments of the present application, but the present application is not limited thereto, and appropriate modifications can be made on the basis of the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0096] Embodiments of the third aspect

[0097] The embodiments of the present application provide an electronic device comprising the brake resistance protection circuit 100 as described in the embodiments of the first aspect, the content of which is incorporated herein. The electronic device may, for example, be a computer, a server, a workstation, a laptop computer, a smart phone, etc., but the embodiments of the present application are not limited thereto.

[0098] Figure 6 is a schematic diagram of an electronic device according to an embodiment of the present application. As shown in Figure 6As shown, the electronic device 600 may include a processor (e.g., a central processing unit, CPU) 610 and a memory 620; the memory 620 is coupled to the central processing unit 610. The memory 620 can store various types of data; it also stores an information processing program 621, and executes the program 621 under the control of the processor 610.

[0099] In some embodiments, the function of the braking resistor protection circuit 100 is integrated into the processor 610. The processor 610 is configured to implement the braking resistor protection method as described in the embodiments of the second aspect.

[0100] In some embodiments, the braking resistor protection circuit 100 is configured separately from the processor 610. For example, the braking resistor protection circuit 100 can be configured as a chip connected to the processor 610, and the function of the braking resistor protection circuit 100 can be realized through the control of the processor 610.

[0101] In addition, such as Figure 6 As shown, the electronic device 600 may also include: an input / output (I / O) device 630 and a display 640, etc.; the functions of the above components are similar to those in the prior art, and will not be described in detail here. It is worth noting that the electronic device 600 is not necessarily required to include... Figure 6 All components shown; in addition, the electronic device 600 may also include Figure 6 For components not shown, please refer to relevant technologies.

[0102] This application also provides a computer-readable program, wherein when the program is executed in an electronic device, the program causes the computer in the electronic device to perform the braking resistor protection method as described in the second aspect of the embodiment.

[0103] This application also provides a storage medium storing a computer-readable program, wherein the computer-readable program causes a computer in an electronic device to perform the braking resistor protection method as described in the second aspect of the embodiment.

[0104] This application also provides a computer program product that causes a computer to perform the braking resistor protection method as described in the second aspect of the embodiment in an electronic device.

[0105] The apparatus and methods described above in this application can be implemented in hardware or in combination with software. This application relates to a computer-readable program that, when executed by a logic component, enables the logic component to implement the apparatus or components described above, or to implement the various methods or steps described above. This application also relates to storage media for storing the above programs, such as hard disks, magnetic disks, optical disks, DVDs, flash memory, etc.

[0106] The methods / apparatuses described in connection with the embodiments disclosed herein can be embodied directly in hardware, software executed by a processor, or combination thereof. For example, one or more of the functional blocks depicted in the figures and / or combinations of one or more of the functional blocks can correspond to software modules executed by a processor, or to hardware modules, or to combinations thereof. The software modules can correspond to the individual steps depicted in the figures. The hardware modules can be implemented using, for example, field-programmable gate arrays (FPGAs) to hardwire the software modules.

[0107] The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. The software modules can be stored in a memory of the mobile terminal, or in a memory card that can be inserted into the mobile terminal. For example, if the device (e.g., mobile terminal) uses a MEGA-SIM card or a large capacity flash memory device, the software modules can be stored in the MEGA-SIM card or the large capacity flash memory device.

[0108] One or more of the functional blocks depicted in the figures and / or combinations of one or more of the functional blocks can be implemented as a general purpose processor, a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any appropriate combination thereof, for performing the functions described herein. One or more of the functional blocks depicted in the figures and / or combinations of one or more of the functional blocks can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0109] The present application has been described above with the attachment of particular embodiments, but it is clear to those skilled in the art that these descriptions are exemplary and are not intended to limit the scope of the present application. Those skilled in the art can make various modifications and changes to the present application according to the principles of the present application, and these modifications and changes are also within the scope of the present application.

Claims

1. A braking resistor protection circuit, configured in a motor drive device, the protection circuit comprising a buffer circuit, a second detection unit, and a braking resistor and a braking switch connected in series, the buffer circuit comprising a buffer switch and a buffer resistor connected in parallel, the second detection unit outputting a second signal based on detecting a short circuit or conduction condition of the braking switch, characterized in that, The protection circuit also includes: The first detection unit outputs a first signal based on the detected voltage between the positive DC bus terminal and the negative DC bus terminal of the motor drive device; The control unit determines whether the brake switch is malfunctioning based on the first signal and the second signal, and controls the buffer switch to open when the brake switch is malfunctioning.

2. The braking resistor protection circuit according to claim 1, characterized in that, The buffer resistor includes a positive temperature coefficient (PTC) thermistor, the brake switch includes a regenerative transistor, and the buffer circuit is used to prevent inrush current when the motor drive device is powered on.

3. The braking resistor protection circuit according to claim 1, characterized in that, When the voltage detected by the first detection unit is within a first range, the first signal includes a first result; otherwise, the first signal includes a second result.

4. The braking resistor protection circuit according to claim 1, characterized in that, When the second detection unit determines that the brake switch is short-circuited or on based on the detected voltage or current, the second signal includes a third result; otherwise, the second signal includes a fourth result.

5. The braking resistor protection circuit according to claim 3 or 4, characterized in that, When the first signal is the first result and the second signal is the third result, the control unit determines that the brake switch is abnormal.

6. The braking resistor protection circuit according to claim 4, characterized in that, The second detection unit detects the voltage or current between the source and drain, or between the collector and emitter, of the regenerative transistor that serves as the braking switch.

7. The braking resistor protection circuit according to claim 3, characterized in that, The first range is related to the system power supply voltage range of the motor drive device, and / or the maximum value of the first range is less than the minimum value of the regenerative energy utilization range voltage of the motor drive device.

8. The braking resistor protection circuit according to claim 1, characterized in that, When the buffer switch is open, the current in the braking resistor is directed to the buffer resistor.

9. The braking resistor protection circuit according to claim 1, characterized in that, The buffer circuit is connected in series with the source and drain of the brake switch and the brake resistor.

10. A braking resistor protection method applied to a motor drive device, the motor drive device comprising a buffer circuit, a second detection unit, and a braking resistor and a braking switch connected in series, the buffer circuit comprising a buffer switch and a buffer resistor connected in parallel, the second detection unit detecting the short circuit or conduction status of the braking switch, characterized in that, The method includes: Based on the detected voltage between the positive DC bus terminal and the negative DC bus terminal of the motor drive device, a first signal is output; Based on the detection of a short circuit or conduction condition of the brake switch, a second signal is output; Based on the first signal and the second signal, determine whether the brake switch is abnormal, and when the brake switch is abnormal, control the buffer switch to open.

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