Brake resistor overload protection method, motor driving system, storage medium and servo driver

Abstract

The invention discloses a brake resistor overload protection method, a motor driving system, a storage medium and a servo driver, relates to the technical field of brake resistors, and discloses the brake resistor overload protection method which is applied to the motor driving system comprising the brake resistor. The overload protection method for the brake resistor comprises the following steps: acquiring a heat dissipation coefficient and a heating coefficient of the brake resistor; determining an overload protection point of the brake resistor based on the heat dissipation coefficient and the heating coefficient; and in the operation process of the motor driving system, the brake resistor is protected based on the overload protection point.

Description

Technical Field

[0001] The present invention relates to the technical field of brake resistors, and in particular to a brake resistor overload protection method, a motor drive system, a storage medium and a servo driver. Background Art

[0002] The traditional method of overload protection of brake resistors is to install a temperature sampling probe on the brake resistor for real-time temperature monitoring, thereby providing direct protection. However, installing a temperature sampling probe will increase the complexity of the circuit, and the temperature sampling probe is easily affected by environmental factors and the self-heating of the brake resistor, resulting in measurement errors. If the temperature sampling probe or the monitoring system fails, it may affect the normal operation of the brake resistor and even cause system failure.

[0003] In summary, the disadvantages of installing a temperature sampling probe on the brake resistor for real-time temperature monitoring include the complexity of installation and maintenance, error and reliability, self-heating, and impact on system performance. Summary of the invention

[0004] The main purpose of the present invention is to provide a braking resistor overload protection method, aiming to solve the technical problem of overload protection of the braking resistor when no temperature sampling probe is installed.

[0005] To achieve the above object, the present invention provides a braking resistor overload protection method, which is applied to a motor drive system including a braking resistor;

[0006] The braking resistor overload protection method comprises:

[0007] Obtaining the heat dissipation coefficient and the heat generation coefficient of the brake resistor;

[0008] Based on the heat dissipation coefficient and the heat generation coefficient, determining an overload protection point of the brake resistor;

[0009] During the operation of the motor drive system, the braking resistor is protected based on the overload protection point.

[0010] In one embodiment, the step of determining the overload protection point of the brake resistor based on the heat dissipation coefficient and the heat generation coefficient specifically includes:

[0011] According to the heat dissipation coefficient and the heat generation coefficient, a total energy value of the braking resistor in the entire working cycle is obtained;

[0012] Determining the temperature change value of the braking resistor according to the total energy value;

[0013] Based on the temperature change value, the overload protection point is obtained.

[0014] In one embodiment, the step of obtaining the overload protection point based on the temperature change value includes:

[0015] Obtaining a maximum temperature change value of the brake resistor;

[0016] When the temperature change value reaches the maximum temperature change value of the brake resistor, the total energy value corresponding to the maximum temperature change value is used as the overload protection point.

[0017] In one embodiment, the step of obtaining the total energy value of the brake resistor in the entire working cycle according to the heat dissipation coefficient and the heat generation coefficient specifically includes:

[0018] Acquire a first voltage threshold and a second voltage threshold;

[0019] When it is detected that the braking resistor is in a working state, obtaining a DC bus voltage;

[0020] Controlling the working state of the braking resistor by comparing the DC bus voltage with the first voltage threshold and the second voltage threshold respectively;

[0021] According to the working state of the braking resistor, the absorbed energy value of the braking resistor and the released energy value of the braking resistor are obtained, and the total energy value is determined.

[0022] In one embodiment, the step of controlling the working state of the braking resistor by comparing the DC bus voltage with the first voltage threshold and the second voltage threshold, respectively, specifically includes:

[0023] When the DC bus voltage reaches the first voltage threshold, controlling the brake resistor to be in a heat absorption state;

[0024] When the DC bus voltage reaches the second voltage threshold, the braking resistor is controlled to be in a heat release state.

[0025] In one embodiment, the step of obtaining the absorbed energy value of the braking resistor and the released energy value of the braking resistor according to the working state of the braking resistor, and determining the total energy value specifically includes:

[0026] Obtaining the resistance value of the brake resistor, the DC bus voltage, and the time the switch tube is used in the on state and the off state;

[0027] The heat dissipation coefficient and the heat generation coefficient are calculated respectively with the resistance value of the brake resistor, the DC bus voltage, and the time used for the switch tube to be turned on and off, to obtain the absorbed energy value and the released energy value;

[0028] The total energy value is obtained according to the difference between the absorbed energy value and the released energy value.

[0029] In addition, to achieve the above object, the present invention further provides a motor drive system, the motor drive system comprising:

[0030] Controller, switch tube, capacitor and brake resistor;

[0031] The first end of the capacitor is connected to the first end of the brake resistor; the gate of the switch tube is connected to the controller, the source of the switch tube is connected to the second end of the capacitor, and the drain of the switch tube is connected to the second end of the brake resistor;

[0032] The controller is used to control the switch tube to be turned on when it is detected that the DC bus voltage is equal to the first voltage threshold, so that the brake resistor is in a heat absorption state;

[0033] The controller is further configured to control the switch tube to be turned off when it is detected that the DC bus voltage is equal to a second voltage threshold, so that the brake resistor is in a heat dissipation state.

[0034] In one embodiment, the motor drive system further comprises:

[0035] rectifiers, diodes and inverters;

[0036] The rectifier is respectively connected to the capacitor, the first end of the brake resistor, the source of the switch tube, the cathode of the diode and the inverter;

[0037] The inverter is respectively connected to the cathode of the diode, the first end of the braking resistor, the source of the switch tube and the capacitor;

[0038] The cathode of the diode is connected to the first end of the braking resistor, and the anode of the diode is connected to the second end of the braking resistor and the drain of the switch tube respectively.

[0039] In addition, to achieve the above-mentioned purpose, the present invention also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the braking resistor overload protection method described above are implemented.

[0040] The present invention also provides a servo driver, which includes the motor drive system.

[0041] One or more technical solutions proposed in the present invention have at least the following technical effects:

[0042] The present invention obtains the heat dissipation coefficient and the heating coefficient of the braking resistor, and then calculates the total energy value generated by the braking resistor in the entire working cycle, and then obtains the maximum temperature change value of the braking resistor through the total energy value, and the total energy value corresponding to the maximum temperature change value is the overload protection point. Since the present invention first obtains the heat dissipation coefficient and the heating coefficient of the braking resistor, and then obtains the resistance value of the braking resistor, the DC bus voltage, and the on-time and off-time of the switch tube according to the actual working state of the braking resistor, and then calculates the total energy value and the maximum temperature change value of the braking resistor in the entire working cycle, thereby determining the overload protection point of the braking resistor, by determining the overload protection point, not only can the braking resistor be protected, but also the maximum use range of the braking resistor can be applied. Compared with the existing method of installing a temperature sampling probe on the braking resistor for real-time temperature monitoring to perform direct protection, the present invention does not need to add additional circuits and equipment, and can directly protect the braking resistor through testing and calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0045] Figure 1 A schematic diagram of a flow chart provided for a first embodiment of a braking resistor overload protection method of the present invention;

[0046] Figure 2 A schematic diagram of a flow chart provided for a second embodiment of a braking resistor overload protection method of the present invention;

[0047] Figure 3 This is a schematic diagram of the DC bus voltage change of the present invention;

[0048] Figure 4 This is a schematic diagram of the DC bus current variation of the present invention;

[0049] Figure 5 This is a schematic diagram of the power change of the brake resistor of the present invention during braking;

[0050] Figure 6 A schematic diagram of energy changes generated by the braking resistor of the present invention during the entire working cycle;

[0051] Figure 7 A schematic diagram of a flow chart provided for a third embodiment of a braking resistor overload protection method of the present invention;

[0052] Figure 8 is a first structural schematic diagram of an embodiment of a motor drive system of the present invention;

[0053] Fig. 9 It is a second structural schematic diagram of an embodiment of the motor drive system of the present invention.

[0054] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0055] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present invention and are not used to limit the present invention.

[0056] In order to better understand the technical solution of the present invention, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0057] The main solution of the embodiment of the present invention is: first obtain the heat dissipation coefficient and the heat generation coefficient of the braking resistor, and then calculate the total energy value and the maximum temperature change value generated by the braking resistor in the entire working cycle, so as to determine the overload protection point. No additional circuits and equipment are required, and the braking resistor can be protected directly through testing and calculation.

[0058] In this embodiment, for the convenience of description, the motor drive system is used as the execution subject for explanation below.

[0059] Since the existing technology requires the installation of a temperature sampling probe on the brake resistor for real-time temperature monitoring, this not only requires the addition of an additional circuit to the original motor drive system, but also generates additional factors to interfere with the actual application of the brake resistor, causing errors and affecting the use of the brake resistor.

[0060] The present invention provides a solution. On the basis of providing overload protection for a brake resistor, the maximum use range of the brake resistor is applied. The heat dissipation coefficient and the heat generation coefficient of the brake resistor are first measured, and the overload protection point of the brake resistor can be obtained by calculation. When a motor drive system reaches the overload protection point during operation, the motor drive system is stopped to protect the brake resistor.

[0061] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or other motor drive devices capable of realizing the above functions, etc. The above motor drive system is taken as an example to illustrate this embodiment and the following embodiments.

[0062] Based on this, the embodiment of the present invention provides a braking resistor overload protection method, referring to Figure 1 , Figure 1 It is a flow chart of the first embodiment of the braking resistor overload protection method of the present invention.

[0063] In this embodiment, the braking resistor overload protection method includes steps S10 to S30:

[0064] Step S10, obtaining the heat dissipation coefficient and the heat generation coefficient of the braking resistor.

[0065] It should be noted that the heat dissipation coefficient is the efficiency of the brake resistor transferring heat to the surrounding medium during the heat dissipation process, and the heat generation coefficient is the efficiency of the brake resistor absorbing voltage and causing its own temperature to rise during operation.

[0066] It is understandable that the above heat dissipation coefficient and heat generation coefficient are different for different brake resistors.

[0067] In a specific implementation, the above heat dissipation coefficient and heat generation coefficient are obtained through experimental equipment and data analysis.

[0068] Step S20: determining an overload protection point of the brake resistor based on the heat dissipation coefficient and the heat generation coefficient.

[0069] It should be noted that the above-mentioned overload protection point may be the maximum temperature critical value of the braking resistor.

[0070] It is understandable that based on different brake resistors, the heat dissipation coefficient and heat generation coefficient obtained are different, and therefore the overload protection points obtained are also different.

[0071] In a specific implementation, before obtaining the above-mentioned overload protection point, it is necessary to calculate the energy absorbed and dissipated by the above-mentioned braking resistor during operation to obtain the total energy value of the above-mentioned braking resistor, and determine the maximum temperature change value of the above-mentioned braking resistor based on the above-mentioned total energy value, thereby determining the above-mentioned overload protection point.

[0072] Step S30: During the operation of the motor drive system, the brake resistor is protected based on the overload protection point.

[0073] In a specific implementation, after the overload protection point of the braking resistor is determined, during the operation of the motor drive system, the temperature of the braking resistor itself continues to rise. When the system detects that the temperature of the braking resistor has reached the overload protection point, the system issues a shutdown command to protect the braking resistor from being damaged due to excessive temperature, and the maximum application range of the braking resistor is applied.

[0074] It should be understood that, for the protection of the above-mentioned braking resistor, data related to the above-mentioned overload protection point can be obtained through the above-mentioned calculation method, and the above-mentioned braking resistor can be protected from overload. Compared with the existing method of installing a temperature sampling probe on the braking resistor for real-time temperature monitoring, there is no need to add additional circuits and equipment in the system, and it can solve the complexity of installation and maintenance, errors and reliability, self-heating phenomenon, and problems affecting system performance.

[0075] This embodiment provides a braking resistor overload protection method, by obtaining the heat dissipation coefficient and the heat generation coefficient of the braking resistor; then determining the overload protection point of the braking resistor according to the heat dissipation coefficient and the heat generation coefficient; in the operation process of the motor drive system, the braking resistor is protected based on the overload protection point. Since the present invention first obtains the heat dissipation coefficient and the heat generation coefficient of the braking resistor, then obtains the resistance value of the braking resistor, the DC bus voltage, and the on-time and off-time of the switch tube according to the actual working state of the braking resistor, and then obtains the total energy value and the maximum temperature change value of the braking resistor in the entire working cycle by calculation, thereby determining the overload protection point of the braking resistor, by determining the overload protection point, not only the braking resistor can be protected, but also the maximum use range of the braking resistor can be applied. Compared with the existing method of installing a temperature sampling probe on the braking resistor for real-time temperature monitoring to perform direct protection, the present invention does not need to add additional circuits and equipment, and can directly protect the braking resistor through testing and calculation.

[0076] Based on the first embodiment of the present invention, in the second embodiment of the present invention, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be described in detail later. Figure 2 , Figure 2 A schematic diagram of a flow chart of a second embodiment of a braking resistor overload protection method according to the present invention.

[0077] In this embodiment, step S20 includes steps S201 to S203.

[0078] Step S201, obtaining the total energy value of the braking resistor in the entire working cycle according to the heat dissipation coefficient and the heat generation coefficient.

[0079] It should be noted that the above-mentioned entire working cycle may be the time taken by the above-mentioned brake resistor from the start of working until its own temperature reaches a critical value.

[0080] It is understandable that different brake resistors have different working cycles.

[0081] In a specific implementation, the time t used by the above-mentioned braking resistor in the heat absorption state of the i-th cycle is detected. on_i and the time t used in the heat release state of the i-th cycle off_iThe sum is the entire working cycle mentioned above. By calculating the absorbed energy Q of the above braking resistor in the i-th cycle + i and the released energy Q of the ith cycle - i The difference is the energy difference Q of the i-th cycle i , and then accumulate the energy difference of each cycle to obtain the above total energy value Q, where P BR is the power of the above braking resistor during braking, V BUS is the voltage passing through the DC bus, R is the resistance of the braking resistor, τ is the heat dissipation coefficient, and the calculation formula for the absorbed energy in the i-th cycle is:

[0082]

[0083] in,

[0084]

[0085] The formula for calculating the released energy of the above i-th cycle is:

[0086]

[0087] The energy difference Q of the above i-th cycle i The calculation formula is:

[0088]

[0089] The energy difference Q of the i-th cycle is obtained i After that, the energy difference of each cycle is accumulated through the accumulation formula to obtain the above energy total value Q. The calculation formula of the above energy total value Q is:

[0090]

[0091] The above DC bus voltage changes refer to Figure 3 , Figure 3 The schematic diagram of the DC bus voltage change of the present invention is shown in FIG. Figure 4 , Figure 4 The schematic diagram of the DC bus current change of the present invention is shown in FIG. 1 . The power change of the above-mentioned braking resistor during braking is shown in FIG. Figure 5 , Figure 5 This is a schematic diagram of the power change of the brake resistor of the present invention during braking.

[0092] Step S211, determining the temperature change value of the brake resistor by the total energy value. It should be noted that the temperature change value is the temperature value of the brake resistor itself caused by continuous absorption and release of energy during operation.

[0093] In the specific implementation, first obtain the above heating coefficient K br , let K br =c*m, where c is the specific heat coefficient of the braking resistor, m is the equivalent mass of the braking resistor, △T is the temperature rise of the braking resistor. According to the thermodynamic equation, the calculation formula of the total energy value Q can also be:

[0094] Q=c*m*ΔT

[0095] Arranging all the above formulas, the temperature rise formula is:

[0096]

[0097] The temperature change value of the above brake resistor can be calculated using the temperature rise formula.

[0098] Step S212: obtaining the overload protection point based on the temperature change value.

[0099] It should be noted that the above-mentioned overload protection point is related to the change of the above-mentioned temperature change value and the above-mentioned total energy value.

[0100] In a specific implementation, by calculating the temperature rise of the braking resistor, the temperature change value of the braking resistor can be found to determine the total energy value Q corresponding to the overload protection point. OP ,refer to Figure 6 , Figure 6 The figure is a schematic diagram of the energy change generated by the braking resistor of the present invention during the entire working cycle.

[0101] Based on the second embodiment of the present invention, in the third embodiment of the present invention, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be described in detail later. Figure 7 , Figure 7 A flow chart of a third embodiment of the braking resistor overload protection method of the present invention is provided.

[0102] In this embodiment, the step S212 further includes steps S2121 to S2122;

[0103] Step S2121, obtaining the maximum temperature change value of the brake resistor.

[0104] It should be noted that the above-mentioned maximum temperature change value is the critical temperature value that the above-mentioned brake resistor can withstand due to the temperature change caused by the continuous absorption and release of energy during operation. When the temperature of the above-mentioned brake resistor exceeds the maximum temperature change value, the above-mentioned brake resistor will be damaged.

[0105] In a specific implementation, the temperature of the braking resistor increases continuously during operation, and when the temperature reaches a maximum temperature change value, the value is recorded.

[0106] Step S2122: When the temperature change value reaches the maximum temperature change value of the braking resistor, the total energy value corresponding to the maximum temperature change value is used as the overload protection point.

[0107] It should be noted that the total energy value is the difference between the energy absorbed and the energy released when the brake resistor reaches the maximum temperature during the entire working cycle, that is, the maximum energy value absorbed by the brake resistor.

[0108] In a specific implementation, when the maximum temperature change value is obtained, the total energy value corresponding to the maximum temperature change value can be obtained by calculation, and the total energy value Q OP As the above-mentioned overload protection point.

[0109] In a feasible implementation manner, step S201 may further include steps S2011' to S2014':

[0110] Step S2011', obtaining a first voltage threshold and a second voltage threshold.

[0111] It should be noted that the voltage levels of the first voltage threshold and the second voltage threshold can be adjusted according to different braking resistors.

[0112] It should be noted that the voltage sizes of the above-mentioned first voltage threshold and the above-mentioned second voltage threshold can be adjusted according to different braking resistors. When the voltage of the DC bus continues to rise until the switch tube is turned on, the voltage measured when it is turned on is used as the above-mentioned first voltage threshold. When the voltage of the DC bus reaches the above-mentioned first voltage threshold, the voltage is reduced until the switch tube is turned off, and the voltage measured when it is turned off is used as the above-mentioned second voltage threshold.

[0113] In a specific implementation, by measuring the voltage change in the DC bus, when the voltage of the above-mentioned motor drive system continues to rise and reaches a certain voltage value, the switch tube is turned on, and the instantaneous voltage value when the switch tube is turned on is used as the above-mentioned first voltage threshold. After the system has worked for a period of time, the switch tube needs to be turned off. At this time, the voltage in the DC bus begins to drop. When the voltage of the above-mentioned motor drive system continues to drop and reaches another voltage value, the switch tube is turned off, and the instantaneous voltage value when the switch tube is turned off is used as the above-mentioned second voltage threshold.

[0114] Step S2012': when it is detected that the braking resistor is in working state, obtaining the DC bus voltage.

[0115] It should be noted that the DC bus voltage will change according to the working cycle of the braking resistor.

[0116] It should be noted that the DC bus voltage can be directly measured and obtained through a multimeter, and the DC bus voltage will change according to the working cycle of the braking resistor.

[0117] In a specific implementation, when it is detected that the braking resistor starts to work, the voltage of the DC bus can be obtained by using a cable clamp to connect the power line and the measuring line of the multimeter to the power input terminal and the DC side connector respectively.

[0118] Step S2013': controlling the working state of the braking resistor by comparing the DC bus voltage with the first voltage threshold and the second voltage threshold respectively.

[0119] It should be noted that the DC bus voltage is constantly changing in the working state, and the system needs to detect the voltage change in real time and compare it with the set first voltage threshold and the second voltage threshold.

[0120] In a specific implementation, when the DC bus voltage passes through the braking resistor, the system will detect the real-time voltage magnitude, and compare the DC bus voltage with the first voltage threshold and the second voltage threshold respectively, and feed back the comparison result to the motor drive system. At this time, the system will control the working state of the braking resistor.

[0121] Step S2014': obtaining the absorbed energy value of the braking resistor and the released energy value of the braking resistor according to the working state of the braking resistor, and determining the total energy value.

[0122] It should be noted that the total energy value is determined by the absorbed energy value and the released energy value, and the total energy value is related to the working time of the braking resistor.

[0123] In a specific implementation, the time taken by the switch tube to be turned on and off is one cycle, the energy value absorbed by the above-mentioned braking resistor during the time when the switch tube is turned on is the energy value absorbed within one cycle, and the energy value released by the above-mentioned braking resistor during the time when the switch tube is turned off is the energy value released within one cycle. The energy values ​​absorbed by the above-mentioned braking resistor in all cycles are accumulated to be the above-mentioned absorbed energy value, and the energy released by the above-mentioned braking resistor in all cycles are accumulated to be the above-mentioned released energy value. Then, the above-mentioned absorbed energy value is subtracted from the above-mentioned released energy value to obtain the above-mentioned total energy value.

[0124] In a feasible implementation manner, step S2013' may further include steps S20131' to S20132':

[0125] Step S20131': when the DC bus voltage reaches the first voltage threshold, control the braking resistor to be in a heat absorption state.

[0126] It should be noted that the above-mentioned heat absorption state may be a state in which the above-mentioned braking resistor is in a state where the energy absorbed by itself is greater than the energy released.

[0127] Step S20132': when the DC bus voltage reaches the second voltage threshold, control the braking resistor to be in a heat release state.

[0128] It should be noted that the heat release state may be a state in which the brake resistor releases more energy than it absorbs.

[0129] In a specific implementation, since the above-mentioned braking resistor absorbs energy and releases heat simultaneously when it is in a working state, when the above-mentioned DC bus voltage reaches the above-mentioned first voltage threshold, the switch tube is turned on, at this time, the energy absorbed by the above-mentioned braking resistor is greater than the heat released and the above-mentioned DC bus voltage drops, so the above-mentioned braking resistor is in a heat absorption state, when the above-mentioned DC bus voltage drops to the above-mentioned second voltage threshold, the switch tube is turned off, at this time, the energy absorbed by the above-mentioned braking resistor is less than the heat released and the above-mentioned DC bus voltage rises, so the above-mentioned braking resistor is in a heat release state.

[0130] In a feasible implementation manner, step S2014' may further include steps S20141' to S20143':

[0131] Step S20141', obtaining the resistance value of the braking resistor, the DC bus voltage, and the time the switch tube is used in the on state and the off state.

[0132] It should be noted that the time that the switch tube is used in the on state and the off state may be the time that the brake resistor is used in the heat absorbing state and the heat releasing state respectively.

[0133] Step S20142', calculating the heat dissipation coefficient and the heat generation coefficient respectively with the resistance of the brake resistor, the DC bus voltage, and the time taken for the switch to be turned on and off, to obtain the absorbed energy value and the released energy value.

[0134] Step S20143', obtaining the total energy value according to the difference between the absorbed energy value and the released energy value.

[0135] In a specific implementation, the resistance value, the DC bus voltage, the time the switch tube is used in the on state and the off state, and the heat dissipation coefficient and the heat generation coefficient are obtained, and the absorbed energy value and the released energy value of the brake resistor in the entire working cycle are obtained by calculation, and then the absorbed energy value and the released energy value are subtracted to obtain the total energy value generated by the brake resistor in the entire working cycle.

[0136] refer to Figure 8 , Figure 8 It is a first structural schematic diagram of an embodiment of a motor drive system of the present invention.

[0137] The present invention further provides a motor drive system, characterized in that the motor drive system comprises:

[0138] Controller, switch tube, capacitor and brake resistor;

[0139] The first end of the capacitor is connected to the first end of the brake resistor; the gate of the switch tube is connected to the controller, the source of the switch tube is connected to the second end of the capacitor, and the drain of the switch tube is connected to the second end of the brake resistor;

[0140] The controller is used to control the switch tube to be turned on when it is detected that the DC bus voltage is equal to the first voltage threshold, so that the brake resistor is in a heat absorption state;

[0141] The controller is further configured to control the switch tube to be turned off when it is detected that the DC bus voltage is equal to a second voltage threshold, so that the brake resistor is in a heat dissipation state.

[0142] In this embodiment, when the controller K1 detects that the DC bus voltage reaches the first voltage threshold, the switch tube Q1 is controlled to be turned on, so that the brake resistor R1 is in a heat absorption state. When the controller K1 detects that the DC bus voltage reaches the second voltage threshold, the switch tube Q1 is controlled to be turned off, so that the brake resistor R1 is in a heat dissipation state. The switch tube is used to control the conduction and disconnection between the brake resistor R1 and the capacitor C1. The capacitor C1 is used for filtering.

[0143] The controller K1 may include L6470HTR and L6470H, etc. The switch tube Q1 may include a PMOS tube, an NMOS tube and a common transistor, etc. The value of the capacitor C1 is set according to different brake resistors, and the brake resistor R1 may include TO126, TO252, TO263, etc.

[0144] refer to Fig. 9 , Fig. 9 It is a second structural schematic diagram of an embodiment of the motor drive system of the present invention.

[0145] In one embodiment, the motor drive system further comprises:

[0146] rectifiers, diodes and inverters;

[0147] The rectifier is respectively connected to the capacitor, the first end of the brake resistor, the source of the switch tube, the cathode of the diode and the inverter;

[0148] The inverter is respectively connected to the cathode of the diode, the first end of the braking resistor, the source of the switch tube and the capacitor;

[0149] The cathode of the diode is connected to the first end of the braking resistor, and the anode of the diode is connected to the second end of the braking resistor and the drain of the switch tube respectively.

[0150] The rectifier Z1 may include KBPC3504, KBPC3510, KBPC2510, KBPC2510W, etc., the diode D1 may include 1N4001, 1N4728, 2AP9, etc., and the inverter Y1 may include a single-phase inverter and a three-phase inverter, etc.

[0151] The present invention provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the braking resistor overload protection method in the above-mentioned embodiment.

[0152] The computer-readable storage medium provided by the present invention may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM: Random Access Memory), a read-only memory (ROM: Read Only Memory), an erasable programmable read-only memory (EPROM: Erasable Programmable Read Only Memory or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM: CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency: Radio Frequency), etc., or any suitable combination thereof.

[0153] The computer-readable storage medium may be included in the braking resistor overload protection device; or may exist independently without being assembled into the braking resistor overload protection device.

[0154] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the braking resistor overload protection device, the braking resistor overload protection device: obtains the heat dissipation coefficient and the heat generation coefficient of the braking resistor; determines the overload protection point of the braking resistor based on the heat dissipation coefficient and the heat generation coefficient; and protects the braking resistor based on the overload protection point during the operation of the motor drive system.

[0155] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0156] The modules involved in the embodiments of the present invention may be implemented by software or hardware, wherein the name of the module does not limit the unit itself in some cases.

[0157] The readable storage medium provided by the present invention is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned braking resistor overload protection method, and can solve the technical problem of braking resistor overload protection. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present invention are the same as the beneficial effects of the braking resistor overload protection method provided by the above-mentioned embodiment, and are not described in detail here.

[0158] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the braking resistor overload protection method as described above are implemented.

[0159] The computer program product provided by the present invention can solve the technical problem of brake resistor overload protection. Compared with the prior art, the beneficial effects of the computer program product provided by the present invention are the same as the beneficial effects of the brake resistor overload protection method provided by the above embodiment, which will not be repeated here.

[0160] The present invention further provides a servo drive, which includes a motor drive system.

[0161] The specific structure of the servo driver refers to the above embodiments. Since the servo driver adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0162] The above descriptions are only some embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A braking resistor overload protection method, characterized in that: The braking resistor overload protection method is applied to a motor drive system including a braking resistor; The braking resistor overload protection method comprises: Obtaining the heat dissipation coefficient and the heat generation coefficient of the brake resistor; Based on the heat dissipation coefficient and the heat generation coefficient, determining an overload protection point of the brake resistor; During the operation of the motor drive system, the braking resistor is protected based on the overload protection point.

2. The braking resistor overload protection method according to claim 1, characterized in that: The step of determining the overload protection point of the brake resistor based on the heat dissipation coefficient and the heat generation coefficient specifically includes: According to the heat dissipation coefficient and the heat generation coefficient, a total energy value of the brake resistor in the entire working cycle is obtained; Determining the temperature change value of the braking resistor according to the total energy value; Based on the temperature change value, the overload protection point is obtained.

3. The braking resistor overload protection method according to claim 2, characterized in that: The step of obtaining the overload protection point based on the temperature change value comprises: Obtaining a maximum temperature change value of the brake resistor; When the temperature change value reaches the maximum temperature change value of the brake resistor, the total energy value corresponding to the maximum temperature change value is used as the overload protection point.

4. The braking resistor overload protection method according to claim 3, characterized in that: The step of obtaining the total energy value of the brake resistor in the entire working cycle according to the heat dissipation coefficient and the heat generation coefficient specifically includes: Acquire a first voltage threshold and a second voltage threshold; When it is detected that the braking resistor is in a working state, obtaining a DC bus voltage; Controlling the working state of the braking resistor by comparing the DC bus voltage with the first voltage threshold and the second voltage threshold respectively; According to the working state of the braking resistor, the absorbed energy value of the braking resistor and the released energy value of the braking resistor are obtained, and the total energy value is determined.

5. The braking resistor overload protection method according to claim 4, characterized in that: The step of controlling the working state of the braking resistor by comparing the DC bus voltage with the first voltage threshold and the second voltage threshold respectively comprises: When the DC bus voltage reaches the first voltage threshold, controlling the brake resistor to be in a heat absorption state; When the DC bus voltage reaches the second voltage threshold, the braking resistor is controlled to be in a heat release state.

6. The braking resistor overload protection method according to claim 5, characterized in that: The step of obtaining the absorbed energy value of the braking resistor and the released energy value of the braking resistor according to the working state of the braking resistor, and determining the total energy value specifically includes: Obtaining the resistance value of the brake resistor, the DC bus voltage, and the time the switch tube is used in the on state and the off state; The heat dissipation coefficient and the heat generation coefficient are calculated respectively with the resistance value of the brake resistor, the DC bus voltage, and the time used for the switch tube to be turned on and off, to obtain the absorbed energy value and the released energy value; The total energy value is obtained according to the difference between the absorbed energy value and the released energy value.

7. A motor drive system, characterized in that: The motor drive system comprises: Controller, switch tube, capacitor and brake resistor; The first end of the capacitor is connected to the first end of the brake resistor; the gate of the switch tube is connected to the controller, the source of the switch tube is connected to the second end of the capacitor, and the drain of the switch tube is connected to the second end of the brake resistor; The controller is used to control the switch tube to be turned on when it is detected that the DC bus voltage is equal to the first voltage threshold, so that the brake resistor is in a heat absorption state; The controller is further configured to control the switch tube to be turned off when it is detected that the DC bus voltage is equal to a second voltage threshold, so that the brake resistor is in a heat dissipation state.

8. The motor drive system according to claim 7, characterized in that: The motor drive system further comprises: rectifiers, diodes and inverters; The rectifier is respectively connected to the capacitor, the first end of the brake resistor, the source of the switch tube, the cathode of the diode and the inverter; The inverter is respectively connected to the cathode of the diode, the first end of the braking resistor, the source of the switch tube and the capacitor; The cathode of the diode is connected to the first end of the braking resistor, and the anode of the diode is connected to the second end of the braking resistor and the drain of the switch tube respectively.

9. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the braking resistor overload protection method according to any one of claims 1 to 6 are implemented.

10. A servo driver, characterized in that: The servo drive comprises the motor drive system according to any one of claims 7 to 8.

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