A protection device and method for frequency converter and frequency converter

Abstract

The present invention discloses a protection device, method and converter for a frequency converter, the device comprising: a driving board, configured to feed back the fault feedback signal of the power device in the frequency converter to the main control board; a first protection unit, arranged on the main control board and located between the driving board and the driving chip, configured to output a first normal working signal if the level of the fault feedback signal is a first set level when the fault feedback signal is received; and output a first stop working signal if the level of the fault feedback signal is a second set voltage; the driving chip is configured to control the power device to work normally when the first normal working signal is received; and control the power device to stop working when the first stop working signal is received. This scheme can improve the timeliness of the fault protection of the driving board by at least adopting hardware protection when performing fault protection on the driving board of the frequency converter.

Description

Technical Field

[0001] The present invention belongs to the technical field of frequency converters, and specifically relates to a protection device, method and frequency converter for a frequency converter, and more particularly to a fault feedback and fault protection device, method and high-power frequency converter for a high-power frequency converter drive board. Background Art

[0002] IGBT (insulated gate bipolar transistor) is a very common power device in high-power inverters. It is usually used in inverter circuits with a driver board. The inverter's main control board controls the on and off of the IGBT by controlling the output of PWM (pulse width modulation) to achieve the output of U, V, and W three-phase power. As a key component in the inverter, the working state of the IGBT directly affects the normal operation of the inverter. Therefore, timely detection of the working state of the IGBT and timely protection in the event of a fault are very necessary for both the inverter and the IGBT. In the relevant scheme, the fault protection method of the inverter's driver board adopts software protection. Due to the delay in software protection, there is a problem that the fault protection of the driver board is not timely enough.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a protection device, method and inverter for a frequency converter, so as to solve the problem that the fault protection method of the drive board of the frequency converter in the related scheme adopts software protection, and the fault protection of the drive board is not timely enough, so as to achieve the effect of improving the timeliness of the fault protection of the drive board by at least adopting hardware protection when performing fault protection on the drive board of the frequency converter.

[0005] The present invention provides a protection device for a frequency converter, wherein the frequency converter has a drive board and a main control board, and a drive chip is arranged on the main control board; the protection device for the frequency converter comprises: a first protection unit; wherein the drive board is configured to feed back a fault feedback signal of a power device in the frequency converter to the main control board; the first protection unit is arranged on the main control board and is located between the drive board and the drive chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level when the fault feedback signal is received; and output a first stop working signal if the level of the fault feedback signal is a second set voltage; the drive chip is configured to control the power device to work normally when the first normal working signal is received; and control the power device to stop working when the first stop working signal is received.

[0006] In some embodiments, the protection device of the inverter also includes: a second protection unit; the second protection unit is arranged on the main control board and is located between the driver board and the driver chip; the second protection unit includes: a fault feedback module and a control module; wherein the fault feedback module is configured to process the fault feedback signal to obtain a fault detection signal; the control module is configured to determine whether the power device is faulty according to the fault detection signal, and if it is determined that the power device is not faulty, output a second normal working signal; if it is determined that the power device is faulty, output a second stop working signal; the driver chip is also configured to control the power device to work normally when receiving the second normal working signal; and control the power device to stop working when receiving the second stop working signal.

[0007] In some embodiments, the power device forms a three-phase full-bridge module; the fault feedback signal includes: six signals fed back by the six bridge arms of the three-phase full-bridge unit; the number of the fault feedback modules is six; each of the fault feedback modules includes: a first switch tube module and a second switch tube module; each of the fault feedback signals is input to the control end of the first switch tube module in the corresponding fault feedback module; in the fault feedback module, the output end of the first switch tube module is output to the control end of the second switch tube module; the output end of the second switch tube module outputs the fault detection signal corresponding to the fault feedback signal.

[0008] In some embodiments, the first protection unit includes: a level recognition module and a comparison module; the number of the level recognition modules is six; among the six level recognition modules, each level recognition module is configured to recognize the level of the corresponding fault feedback signal, so as to output a signal whose level is the second set level when the level of the corresponding fault feedback signal is the second set level; the comparison module is configured to output the first normal working signal when the levels of the six fault feedback signals are all the first set level; and output the first stop working signal when the level of one of the six fault feedback signals is the second set level.

[0009] In some embodiments, each level identification module includes: a diode module; each fault feedback signal is input to the cathode of the corresponding diode module; the anode of the diode module is output to the same phase input terminal of the comparison module; a set reference signal is input to the inverting input terminal of the comparison module; the output terminal of the comparison module outputs the first normal working signal or the first stop working signal to the enable terminal of the driver chip.

[0010] In some embodiments, the comparison module includes: a comparator, a first voltage divider module, a second voltage divider module, a current limiting module and a pull-down module; wherein, a set DC power supply and an anode of a diode module in each level identification module are input to the same-phase input terminal of the comparator after passing through the first voltage divider module; the set DC power supply is also input to the inverting input terminal of the comparator after passing through the second voltage divider module; the output terminal of the comparator is output to the enable terminal of the driving chip after passing through the current limiting module and the pull-down module.

[0011] Matching the above device, the present invention provides a frequency converter on another aspect, including: the protection device of the frequency converter described above.

[0012] Matching the above-mentioned frequency converter, the present invention provides a frequency converter protection method on another aspect, wherein the frequency converter has a driving board and a main control board, and a driving chip is arranged on the main control board; the frequency converter protection method comprises: through the driving board, feeding back the fault feedback signal of the power device in the frequency converter to the main control board; through the first protection unit, when receiving the fault feedback signal, if the level of the fault feedback signal is a first set level, then outputting a first normal working signal; if the level of the fault feedback signal is a second set voltage, then outputting a first stop working signal; the first protection unit is arranged on the main control board and is located between the driving board and the driving chip; through the driving chip, when receiving the first normal working signal, controlling the power device to work normally; when receiving the first stop working signal, controlling the power device to stop working.

[0013] In some embodiments, the protection method of the inverter also includes: processing the fault feedback signal through a fault feedback module to obtain a fault detection signal; determining whether the power device is faulty based on the fault detection signal through a control module, and if it is determined that the power device is not faulty, outputting a second normal working signal; if it is determined that the power device is faulty, outputting a second stop working signal; through the driving chip, controlling the power device to work normally when the second normal working signal is received; and controlling the power device to stop working when the second stop working signal is received.

[0014] Therefore, the solution of the present invention, by adding a hardware protection circuit between the drive board and the drive chip of the inverter, can utilize the output signal of the drive board for processing, directly control the drive chip, and at least utilize the hardware protection circuit to achieve fault protection for the drive board; thus, by at least adopting hardware protection when performing fault protection on the drive board of the inverter, the timeliness of the fault protection of the drive board can be improved.

[0015] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of a protection device for a frequency converter of the present invention;

[0018] Figure 2 A structural schematic diagram of an embodiment of a fault feedback and fault protection device for a frequency converter drive board;

[0019] Figure 3 It is a structural schematic diagram of an embodiment of a fault protection circuit (such as a drive fault feedback hardware protection circuit) of a frequency converter drive board of the present invention;

[0020] Figure 4 It is a structural schematic diagram of an embodiment of a fault feedback circuit of a frequency converter drive board of the present invention;

[0021] Figure 5 A flow chart of an embodiment of a method for fault feedback and fault protection of a frequency converter drive board;

[0022] Figure 6 A schematic diagram of a flow chart of an embodiment of a frequency converter protection method of the present invention;

[0023] Figure 7The figure is a flow chart of an embodiment of the process of performing software protection on the basis of hardware protection in the method of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In the related scheme, the drive feedback and protection scheme of the inverter is that the driver board outputs a fault feedback signal to the driver fault feedback circuit, and the fault feedback signal is processed by the fault feedback circuit and then outputs a feedback signal to the DSP (digital signal processing) module. The DSP module controls the output of the drive signal according to the feedback signal, and then controls the working state of the driver chip. The fault protection method of the driver board is only software protection, and the protection method is single, and the timeliness and reliability of the protection cannot be guaranteed.

[0026] According to an embodiment of the present invention, a protection device for a frequency converter is provided. Figure 1 The structure diagram of an embodiment of the device of the present invention is shown. The inverter has a drive board and a main control board, and a drive chip is arranged on the main control board. The protection device of the inverter includes: a first protection unit, such as a drive fault hardware protection circuit.

[0027] The driver board is configured to feed back the fault feedback signal of the power device in the inverter to the main control board. The fault feedback signal is such as signals UH_G, UL_G, VH_G, VL_G, WH_G, and WL_G.

[0028] The first protection unit is arranged on the main control board and located between the driver board and the driver chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level when the fault feedback signal is received. If the level of the fault feedback signal is a second set voltage, a first stop working signal is output. The first normal working signal is a signal for controlling or maintaining the operation of the driver chip. The first stop working signal is a signal for controlling the driver chip to stop working.

[0029] The driving chip is configured to control the power device to work normally when receiving the first normal working signal, and to control the power device to stop working when receiving the first stop working signal.

[0030] The solution of the present invention uses a drive fault feedback signal processing circuit to process the drive fault feedback signal, and the output signal can directly control the drive chip to perform drive fault protection in time. By processing the drive fault feedback signal, the hardware can directly control the drive chip to stop working, solve the problem of insufficient fault protection of the inverter drive board, and improve the timeliness of the drive fault protection.

[0031] In some embodiments, the protection device of the frequency converter further includes: a second protection unit. The second protection unit is arranged on the main control board and is located between the driver board and the driver chip. The second protection unit includes: a fault feedback module and a control module. The fault feedback module is such as a driver fault feedback circuit. The control module is such as a DSP module.

[0032] The fault feedback module is configured to process the fault feedback signal to obtain a fault detection signal.

[0033] The control module is configured to determine whether the power device fails according to the fault detection signal, and output a second normal working signal if it is determined that the power device does not fail. If it is determined that the power device fails, a second stop working signal is output. The second normal working signal is a signal for controlling or maintaining the operation of the driver chip. The second stop working signal is a signal for controlling the driver chip to stop working.

[0034] The driver chip is further configured to control the power device to work normally when receiving the second normal working signal, and to control the power device to stop working when receiving the second stop working signal.

[0035] The scheme of the present invention proposes a drive fault feedback and fault protection method for a high-power inverter, which can not only further output control instructions to achieve soft protection according to the feedback signal output by the drive fault feedback circuit, but also perform hardware protection through the output signal of the drive fault hardware protection circuit, thereby achieving dual protection of software and hardware, and improving the timeliness and reliability of fault detection and protection of the inverter drive board.

[0036] The solution of the present invention is applicable to the field of frequency converter control. Figures 2 to 5 The examples shown are used to exemplify the solutions of the present invention.

[0037] Figure 2 FIG. 1 is a schematic diagram of a structure of an embodiment of a fault feedback and fault protection device for a frequency converter drive board. Figure 2As shown, the fault feedback and fault protection device of the inverter drive board includes: a drive board, a drive chip, a drive fault hardware protection circuit, a drive fault feedback circuit and a DSP module. The drive chip, the drive fault hardware protection circuit, the drive fault feedback circuit and the DSP module are arranged on the main control board of the inverter. The first output end of the drive board is output to the input end of the drive fault hardware protection circuit. The output end of the drive fault hardware protection circuit is output to the first protection end of the drive chip. The second output end of the drive board is output to the input end of the drive fault feedback circuit. The output end of the drive fault feedback circuit is output to the input end of the DSP module. The output end of the DSP module is output to the second protection end of the drive chip.

[0038] See also Figure 2 In the example shown, during the operation of the inverter, the driver board will feed back the fault feedback signal (such as signals UH_G, UL_G, VH_G, VL_G, WH_G, WL_G) to the main control board, and the feedback signal drives the fault hardware protection circuit to output the control signal EN to control the working state of the driver chip. At the same time, the feedback signal drives the fault feedback circuit to process the signal, and the output feedback signal (such as signals UH_DSP, UL_DSP, VH_DSP, VL_DSP, WH_DSP, WL_DSP) is processed by DSP to determine whether a fault occurs, and then output the control signal (such as signals UH, UL, VH, VL, WH, WL) to the driver chip to control the output of the PWM drive signal.

[0039] Among them, the driver chip is a chip on the main control board, which is used to process the PWM drive signal output by the main control board. Here, the PWM drive signal is mainly converted to convert the high-level 3.3V into 15V output. The output is then processed by the interlocking circuit and finally outputs 6 drive signals to the driver board.

[0040] The main function of the driver board is to drive the IGBT and feedback the fault signal to the main control board.

[0041] In the related scheme, the driver board outputs a fault feedback signal to the driver fault feedback circuit, and the driver fault circuit processes the fault feedback signal and outputs it to the DSP module. The DSP module then controls the drive signal to control the working state of the driver chip. Based on such a driver fault feedback and fault protection topology, Figure 2 *In terms of structure, a drive fault hardware protection circuit is added. The drive fault hardware protection circuit directly processes the fault feedback signal and directly outputs the control signal EN to control the working state of the drive chip, which belongs to hardware protection. By adding drive fault hardware protection, the problem of single fault protection and untimely protection of the inverter drive board in related solutions is solved.

[0042] In some implementations, the power device forms a three-phase full-bridge module. The fault feedback signal includes: six signals fed back by six bridge arms of the three-phase full-bridge unit.

[0043] The number of the fault feedback modules is six. Each of the fault feedback modules includes: a first switch tube module and a second switch tube module. The first switch tube module is such as a transistor Q1 and its peripheral resistor. The second switch tube module is such as a transistor Q2 and its peripheral resistor.

[0044] Each fault feedback signal is input to the control end of the first switch tube module in the corresponding fault feedback module (such as the base of transistor Q1). In the fault feedback module, the output end of the first switch tube module (such as the collector of transistor Q1) is output to the control end of the second switch tube module (such as the base of transistor Q2). The output end of the second switch tube module (such as the collector of transistor Q2) outputs the fault detection signal corresponding to the fault feedback signal of the path.

[0045] Figure 4 FIG. 1 is a schematic diagram of a structure of an embodiment of a fault feedback circuit of a frequency converter drive board of the present invention. Figure 4 As shown, the fault feedback circuit of the inverter drive board includes: six drive signal processing branches.

[0046] The first driving signal processing branch includes: transistor Q1, transistor Q2, and two current limiting resistors. The fault feedback signal UH_G is input to the base of the transistor Q1, the +3.3V power supply is input to the collector of the transistor Q1 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q2 after passing through a current limiting resistor, the +3.3V power supply is input to the collector of the transistor Q2 after passing through another current limiting resistor, and the collector of the transistor Q2 outputs the fault feedback signal UH_DSP. The emitter of the transistor Q1 and the emitter of the transistor Q2 are both grounded.

[0047] The second driving signal processing branch includes: transistor Q7, transistor Q8, and two current limiting resistors. The fault feedback signal UL_G is input to the base of the transistor Q7, the +3.3V power supply is input to the collector of the transistor Q7 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q8 after passing through a current limiting resistor, the +3.3V power supply is input to the collector of the transistor Q8 after passing through another current limiting resistor, and the collector of the transistor Q8 outputs the fault feedback signal UL_DSP. The emitter of the transistor Q7 and the emitter of the transistor Q8 are both grounded.

[0048] The third driving signal processing branch includes: transistor Q3, transistor Q4, and two current limiting resistors. The fault feedback signal VH_G is input to the base of the transistor Q3, the +3.3V power supply is input to the collector of the transistor Q3 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q4 after passing through a current limiting resistor, the +3.3V power supply is input to the collector of the transistor Q4 after passing through another current limiting resistor, and the collector of the transistor Q4 outputs the fault feedback signal VH_DSP. The emitter of the transistor Q3 and the emitter of the transistor Q4 are both grounded.

[0049] The fourth driving signal processing branch includes: transistor Q9, transistor Q10, and two current limiting resistors. The fault feedback signal VL_G is input to the base of the transistor Q9, the +3.3V power supply is input to the collector of the transistor Q9 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q10 after passing through a current limiting resistor, and the +3.3V power supply is input to the collector of the transistor Q10 after passing through another current limiting resistor, and the collector of the transistor Q10 outputs the fault feedback signal VL_DSP. The emitter of the transistor Q9 and the emitter of the transistor Q10 are both grounded.

[0050] The fifth driving signal processing branch includes: transistor Q5, transistor Q6, and two current limiting resistors. The fault feedback signal WH_G is input to the base of the transistor Q5, the +3.3V power supply is input to the collector of the transistor Q5 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q6 after passing through a current limiting resistor, the +3.3V power supply is input to the collector of the transistor Q6 after passing through another current limiting resistor, and the collector of the transistor Q6 outputs the fault feedback signal WH_DSP. The emitter of the transistor Q5 and the emitter of the transistor Q6 are both grounded.

[0051] The sixth driving signal processing branch includes: a transistor Q11, a transistor Q12, and two current limiting resistors. The fault feedback signal WL_G is input to the base of the transistor Q11, the +3.3V power supply is input to the collector of the transistor Q11 after passing through a current limiting resistor, the +3.3V power supply is also input to the base of the transistor Q12 after passing through a current limiting resistor, the +3.3V power supply is input to the collector of the transistor Q12 after passing through another current limiting resistor, and the collector of the transistor Q12 outputs the fault feedback signal WL_DSP. The emitter of the transistor Q11 and the emitter of the transistor Q12 are both grounded.

[0052] like Figure 4The driving fault feedback circuit shown in the figure processes the six driving signals (i.e., fault feedback signals) and uses the conduction and shutdown of two transistors to process each driving signal to achieve a 3.3V output, so that the driving signal can be input into the DSP module for detection. In other words, the conduction and shutdown of the two transistors are controlled by controlling the base signal of the transistor, and the driving fault feedback signal is converted into 3.3V and output to the DSP module for detection.

[0053] exist Figure 4 In the example shown, transistors Q1 to Q12 are all NPN transistors. When a high level is input to the base, the transistor is turned on. Figure 4 The resistors in are all pull-up resistors. Their purpose is to pull the output DSP signal to 3.3V when the second transistor is not conducting, so that the drive signal can be input into the DSP module for detection. Signals such as UH_DSP are feedback signals of the drive fault feedback signal that are input to the DSP module after being processed by the circuit. When there is a low level in the signal, it indicates that a fault has occurred, and the DSP module stops outputting the PWM drive signal. The six input signals such as signal UH are PWM drive signals output by the DSP. Each of them is connected to a pull-down resistor (i.e., a resistor connected to the corresponding PWM drive signal) to ensure that it will not be triggered by mistake in the initial state.

[0054] Among them, the first transistor, such as the transistor Q1 in the first drive signal processing branch, the transistor Q7 in the second drive signal processing branch, the transistor Q3 in the third drive signal processing branch, the transistor Q9 in the fourth drive signal processing branch, the transistor Q5 in the fifth drive signal processing branch, and the transistor Q11 in the sixth drive signal processing branch.

[0055] The second transistor, such as the transistor Q2 in the first drive signal processing branch, the transistor Q8 in the second drive signal processing branch, the transistor Q4 in the third drive signal processing branch, the transistor Q10 in the fourth drive signal processing branch, the transistor Q6 in the fifth drive signal processing branch, and the transistor Q12 in the sixth drive signal processing branch.

[0056] exist Figure 4 In the example shown, the on-off feedback of two transistors is used to drive the fault feedback signal. On the one hand, the DSP stops the output of the PWM drive signal according to the feedback signal. On the other hand, the processed signal directly pulls down the driver chip enable signal to stop the driver chip from working.

[0057] In some implementations, the first protection unit includes: a level identification module and a comparison module. The number of the level identification modules is six.

[0058] In the six level identification modules, each level identification module is configured to identify the level of the corresponding fault feedback signal, so as to output a signal whose level is the second set level when the level of the corresponding fault feedback signal is the second set level.

[0059] The comparison module is configured to output the first normal working signal when the levels of the six fault feedback signals are all at the first set level. When one of the six level recognition modules outputs a signal with a level of the corresponding fault feedback signal at the second set level, that is, when the level of the six fault feedback signals is at the first set level, the comparison module is configured to output the first normal working signal.

[0060] When the level of one of the fault feedback signals is at the second set level, the first stop working signal is output.

[0061] In the solution of the present invention, a drive fault feedback hardware protection circuit is added on the basis of the related solution, which solves the problem of a single drive fault protection method. Because the hardware protection speed is faster than the software protection speed, it also achieves the effect of more timely drive fault protection.

[0062] The solution of the present invention adopts two circuits to process the drive fault feedback signal respectively, so as to realize the dual protection of hardware and software. The dual protection of hardware and software can be realized by processing the drive fault feedback signal, which solves the problem of single fault protection method of the inverter drive board in the related solution and improves the safety.

[0063] In some implementations, each level identification module includes: a diode module.

[0064] Each fault feedback signal is input to the cathode of the corresponding diode module. The anode of the diode module is output to the non-inverting input terminal of the comparison module. The set reference signal is input to the inverting input terminal of the comparison module. The output terminal of the comparison module outputs the first normal working signal or the first stop working signal to the enable terminal of the driver chip.

[0065] Figure 3 FIG. 1 is a schematic diagram of a structure of an embodiment of a fault protection circuit (such as a drive fault feedback hardware protection circuit) of a frequency converter drive board of the present invention. Figure 3As shown, the drive fault feedback hardware protection circuit includes: diode D1, diode D2, diode D3, diode D4, diode D5, diode D6, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, and comparator U1. The fault feedback signal UH_G is input to the cathode of the diode D1, and the anode of the diode D1 is input to the non-inverting input terminal of the comparator U1 after passing through the resistor R4. The fault feedback signal UL_G is input to the cathode of the diode D2, and the anode of the diode D2 is input to the non-inverting input terminal of the comparator U1 after passing through the resistor R4. The fault feedback signal VH_G is input to the cathode of the diode D3, and the anode of the diode D3 is input to the non-inverting input terminal of the comparator U1 after passing through the resistor R4. The fault feedback signal VL_G is input to the cathode of the diode D4, and the anode of the diode D4 is input to the non-inverting input terminal of the comparator U1 after passing through the resistor R4. The fault feedback signal WH_G is input to the cathode of the diode D5, and the anode of the diode D5 is input to the non-inverting input terminal of the comparator U1 through the resistor R4. The fault feedback signal WL_G is input to the cathode of the diode D6, and the anode of the diode D6 is input to the non-inverting input terminal U+ of the comparator U1 through the resistor R4. The +15V power supply is input to the non-inverting input terminal U+ of the comparator U1 through the resistor R3. The non-inverting input terminal U+ of the comparator U1 is also grounded after passing through the resistor R5. The +15V power supply is input to the inverting input terminal U- of the comparator U1 through the resistor R1. The inverting input terminal U- of the comparator U1 is also grounded after passing through the resistor R2. The output terminal of the comparator U1 outputs the control signal EN to the first input terminal of the driver chip U2 after passing through the resistor R6, such as the enable terminal (such as the EN terminal) of the driver chip U2. The +3.3V power supply is input to the enable terminal (such as the EN terminal) of the driver chip U2 after passing through the resistor R7. The second input terminal of the driving chip U2 is used to input the control signals UH, UL, VH, VL, WH, WL, etc. output by the DSP module.

[0066] like Figure 3 The drive fault feedback hardware protection circuit shown can directly implement fault protection from hardware according to the fault feedback signal. The voltage at the inverting input terminal of the comparator U1 is a fixed value, and the diodes corresponding to the fault feedback signals UH_G, UL_G, VH_G, VL_G, WH_G, and WL_G are connected in parallel to the circuit. When any signal is at a low level, the diode is turned on, the comparator U1 outputs a low level, and the driver chip U2 stops working.

[0067] In some implementations, the comparison module includes: a comparator, a first voltage division module, a second voltage division module, a current limiting module and a pull-down module. The comparator is, for example, comparator U1.

[0068] The set DC power supply and the anode of the diode module in each level recognition module are input to the non-inverting input terminal of the comparator after passing through the first voltage divider module. The set DC power supply is also input to the inverting input terminal of the comparator after passing through the second voltage divider module. The output terminal of the comparator is output to the enable terminal of the driver chip after passing through the current limiting module and the pull-down module.

[0069] exist Figure 3 In the example shown, resistors R1 to R5 are fixed resistance resistors, and the resistance R1 = R2, resistors R3, R4, and R5 are voltage divider resistors, and the resistance R4 < R3 < R5, resistor R6 is a current limiting resistor, and resistor R7 is a pull-up resistor. D1 to D6 are diodes. U1 is a comparator, and its in-phase input voltage is U+, and the reverse input voltage is U- = 7.5V. Chip U2 is a driver chip on the main control board. The main function of this chip is to convert the input signal level when receiving the high-level enable signal output by the DSP. It is a key component in the drive circuit of the inverter. The output terminal of comparator U1 is connected to the enable pin of driver chip U2. The six input signals such as signal UH_G are respectively the upper and lower bridge arm fault feedback signals of the three phases U, V, and W fed back by the driver board. When a fault occurs, the fault feedback signal fed back by the driver board is low level. When the driver board is working normally, the fault feedback signal fed back by the driver board is 15V high level.

[0070] Figure 5 FIG. 1 is a flow chart of an embodiment of a method for fault feedback and fault protection of a frequency converter drive board. Figure 5 As shown, the fault feedback and fault protection method of the inverter drive board includes:

[0071] Step 1: The driver board transmits a fault feedback signal to the main control board, and then executes step 2 and / or step 3. The circuit on the driver board will perform desaturation detection on the upper and lower bridge arms and feed back the detection results to the main control board.

[0072] Step 2: Drive the fault hardware protection circuit to work. For details, please refer to the following exemplary description.

[0073] Step 21, determine whether the fault feedback signal has a low level: if so, execute step 22. Otherwise, execute step 23.

[0074] Step 22, the diode is turned on, the comparator U1 outputs a low level, and the driver chip stops working.

[0075] Step 23: The diode is not conducting, the comparator U1 outputs a high level, and the driver chip works normally.

[0076] Step 3: drive the fault feedback circuit to work, see the following exemplary description for details.

[0077] Step 31, determine whether the fault feedback signal has a low level: if so, execute step 32. Otherwise, execute step 33.

[0078] Step 32: The first transistor is turned off, and the second transistor is turned on. The DSP module receives a low level and stops outputting the PWM drive signal.

[0079] Step 33: The first transistor is turned on, and the second transistor is turned off. The DSP module receives a high level and outputs a PWM drive signal normally.

[0080] When the driver is working normally, the driver board feedback signal UH_G and other six high-level signals are sent to the main control board. Figure 3 In the drive fault feedback hardware protection circuit, the fault feedback signal UH_G is +15V. The cathode potential of all diodes is higher than the anode potential, so they are not conducting. The voltage U+ at the non-inverting input of the comparator U1 is obtained by dividing 15V by R3 and R5. Because R3<R5, the voltage divided by R3 is less than the voltage divided by R5, so The comparator U1 outputs EN at a high level and is pulled up to 3.3V by R7, and the driver chip U2 works normally. Figure 4 In the drive fault feedback circuit, the base of the first transistor is high level, the first transistor is turned on, so the base of the second transistor is grounded at a low level, the second transistor is not turned on, and the output signals such as UH_DSP are high level signals, which are pulled up to 3.3V and input to the DSP module. When the DSP module recognizes that all are high level, it outputs PWM drive signals to the drive chip, and the drive chip works normally.

[0081] When a bridge arm of the IGBT fails, the driver board feeds back the corresponding drive feedback signal as a low level signal to the main control board. Here, UH_G is taken as an example. When the U-phase upper bridge arm IGBT fails, the fault feedback signal UH_G is low level, and the other drive fault feedback signals UL_G are high level. Figure 3 In the drive fault feedback hardware protection circuit, the anode potential of diode D1 is greater than the cathode potential, and diode D1 is turned on. The anode potentials of the other diodes are less than the cathode potentials, and the diodes are not turned on. At this time, resistors R4 and R5 are equivalent to being connected in parallel. The resistance after parallel connection is smaller than R4 and R3, so after the +15V voltage division When the comparator U1 outputs EN at a low level, the enable signal of the driver chip is pulled low, and the driver chip stops working immediately, thus realizing the hardware protection of driver fault feedback. Figure 4In the drive fault feedback circuit, since the fault feedback signal UH_G is at a low level and connected to the base of transistor Q1, transistor Q1 is not conducting, the base of transistor Q2 is connected to the pull-up resistor at a high level, transistor Q2 is conducting, the output signal UH_DSP is grounded as a low level signal and input to DSP, and the other transistors are consistent with the normal working state, and the output signal UL_DSP is 3.3V high level. When DSP recognizes that there is a low level in the input feedback signal, it stops outputting the PWM drive signal to realize software protection of drive fault feedback.

[0082] In the above implementation, the hardware protection + software protection solution is applied to the drive fault feedback and fault protection method, but it is also applicable to other types of fault detection and fault protection circuits (such as overcurrent, overvoltage detection and overcurrent, overvoltage protection circuits).

[0083] The solution of the present invention can control the output of the PWM drive signal after detecting the output signal of the drive fault feedback circuit through the DSP module to achieve software protection. It also uses the unidirectional conduction of the diode to control the voltage of the same-direction input terminal of the comparator, and then controls the output of the comparator to control the working state of the drive chip to achieve hardware protection. Therefore, it can solve the problem of the single fault protection method of the existing inverter drive board and the problem that the fault protection of the inverter drive board is not timely enough, realize the dual protection of software and hardware of the drive fault, and improve the timeliness and reliability of the fault protection of the inverter drive board.

[0084] By adopting the technical solution of the present invention, by adding a hardware protection circuit between the drive board and the drive chip of the frequency converter, the output signal of the drive board can be processed to directly control the drive chip, and at least the hardware protection circuit can be used to implement fault protection of the drive board. Therefore, by at least using hardware protection when performing fault protection on the drive board of the frequency converter, the timeliness of the fault protection of the drive board can be improved.

[0085] According to an embodiment of the present invention, a frequency converter corresponding to the protection device of the frequency converter is also provided. The frequency converter may include: the protection device of the frequency converter described above.

[0086] Since the processing and functions implemented by the frequency converter of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned devices, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0087] By adopting the technical solution of the present invention, a hardware protection circuit is added between the drive board and the drive chip of the inverter, so that the output signal of the drive board can be used for processing and the drive chip can be directly controlled. At least the fault protection of the drive board is realized by using the hardware protection circuit, thereby improving the safety of the fault protection of the drive board.

[0088] According to an embodiment of the present invention, a protection method for a frequency converter corresponding to the frequency converter is also provided. Figure 6 The flowchart of an embodiment of the method of the present invention is shown. The inverter has a driving board and a main control board, and a driving chip is arranged on the main control board. The inverter protection method includes: steps S110 to S130.

[0089] Step S110, feeding back the fault feedback signal of the power device in the inverter to the main control board through the driving board. The fault feedback signal is such as signals UH_G, UL_G, VH_G, VL_G, WH_G, WL_G.

[0090] Step S120, through the first protection unit, such as the driver fault hardware protection circuit, when receiving the fault feedback signal, if the level of the fault feedback signal is the first set level, then output a first normal working signal. If the level of the fault feedback signal is the second set voltage, then output a first stop working signal. The first normal working signal is a signal that controls or maintains the operation of the driver chip. The first stop working signal is a signal that controls the driver chip to stop working. The first protection unit is arranged on the main control board and is located between the driver board and the driver chip.

[0091] Step S130: controlling the power device to work normally when the first normal working signal is received, or to stop working when the first stop working signal is received, by the driving chip.

[0092] The solution of the present invention uses a drive fault feedback signal processing circuit to process the drive fault feedback signal, and the output signal can directly control the drive chip to perform drive fault protection in time. By processing the drive fault feedback signal, the hardware can directly control the drive chip to stop working, solve the problem of insufficient fault protection of the inverter drive board, and improve the timeliness of the drive fault protection.

[0093] In some implementations, the inverter protection method further includes: a process of performing software protection based on hardware protection.

[0094] Protected by a second protection unit. The second protection unit is arranged on the main control board and is located between the driver board and the driver chip. The second protection unit includes: a fault feedback module and a control module. The fault feedback module is such as a driver fault feedback circuit. The control module is such as a DSP module.

[0095] Combine the following Figure 7The flowchart of an embodiment of the process of performing software protection on the basis of hardware protection in the method of the present invention further illustrates the specific process of performing software protection on the basis of hardware protection, including: step S210 to step S230.

[0096] Step S210: Processing the fault feedback signal through a fault feedback module to obtain a fault detection signal.

[0097] Step S220, through the control module, according to the fault detection signal, determine whether the power device fails, if it is determined that the power device does not fail, then output a second normal working signal. If it is determined that the power device fails, then output a second stop working signal. The second normal working signal is a signal for controlling or maintaining the operation of the driver chip. The second stop working signal is a signal for controlling the driver chip to stop working.

[0098] Step S230: Control the power device to work normally by the driver chip when the second normal working signal is received, and control the power device to stop working when the second stop working signal is received.

[0099] The scheme of the present invention proposes a drive fault feedback and fault protection method for a high-power inverter, which can not only further output control instructions to achieve soft protection according to the feedback signal output by the drive fault feedback circuit, but also perform hardware protection through the output signal of the drive fault hardware protection circuit, thereby achieving dual protection of software and hardware, and improving the timeliness and reliability of fault detection and protection of the inverter drive board.

[0100] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned frequency converter, for the details not fully described in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0101] By adopting the technical solution of this embodiment, a hardware protection circuit is added between the drive board and the drive chip of the inverter, so that the output signal of the drive board can be used for processing and the drive chip can be directly controlled. At least the fault protection of the drive board is realized by using the hardware protection circuit, thereby improving the timeliness and reliability of the fault protection of the drive board of the inverter.

[0102] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0103] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A protection device for a frequency converter, characterized in that: The frequency converter comprises a driving board and a main control board, and a driving chip is arranged on the main control board; The protection device of the frequency converter comprises: a first protection unit; wherein, The driving board is configured to feed back a fault feedback signal of a power device in the inverter to the main control board; The first protection unit is arranged on the main control board and located between the driver board and the driver chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level when the fault feedback signal is received; and output a first stop working signal if the level of the fault feedback signal is a second set voltage; The driving chip is configured to control the power device to work normally when receiving the first normal working signal; and control the power device to stop working when receiving the first stop working signal; The first protection unit includes: a level identification module and a comparison module; the number of the level identification modules is six; In the six level recognition modules, each level recognition module is configured to recognize the level of the corresponding fault feedback signal, so as to output a signal whose level of the corresponding fault feedback signal is the second set level when the level of the corresponding fault feedback signal is the second set level; The comparison module is configured to output the first normal working signal when the levels of the six fault feedback signals are all at the first set level; and to output the first stop working signal when the level of one of the six fault feedback signals is at the second set level.

2. The protection device for the frequency converter according to claim 1, characterized in that: The inverter protection device further includes: a second protection unit; the second protection unit is arranged on the main control board and located between the drive board and the drive chip; the second protection unit includes: a fault feedback module and a control module; wherein, The fault feedback module is configured to process the fault feedback signal to obtain a fault detection signal; The control module is configured to determine whether the power device fails according to the fault detection signal, and output a second normal working signal if it is determined that the power device does not fail; and output a second stop working signal if it is determined that the power device fails; The driving chip is further configured to control the power device to work normally when receiving the second normal working signal; and to control the power device to stop working when receiving the second stop working signal.

3. The protection device for the frequency converter according to claim 2, characterized in that: The power devices form a three-phase full-bridge module; The fault feedback signal includes: six signals fed back by six bridge arms of the three-phase full-bridge unit; The number of the fault feedback modules is six; each of the fault feedback modules includes: a first switch tube module and a second switch tube module; Each fault feedback signal is input to the control end of the first switch tube module in the corresponding fault feedback module; in the fault feedback module, the output end of the first switch tube module is output to the control end of the second switch tube module; the output end of the second switch tube module outputs the fault detection signal corresponding to the fault feedback signal of the path.

4. The protection device for the frequency converter according to claim 1, characterized in that: Each level identification module includes: a diode module; Each fault feedback signal is input to the cathode of the corresponding diode module; the anode of the diode module is output to the non-inverting input terminal of the comparison module; the set reference signal is input to the inverting input terminal of the comparison module; the output terminal of the comparison module outputs the first normal working signal or the first stop working signal to the enable terminal of the driver chip.

5. The protection device for the frequency converter according to claim 1, characterized in that: The comparison module includes: a comparator, a first voltage division module, a second voltage division module, a current limiting module and a pull-down module; wherein, The set DC power supply and the anode of the diode module in each level identification module are input to the non-inverting input terminal of the comparator after passing through the first voltage divider module; the set DC power supply is also input to the inverting input terminal of the comparator after passing through the second voltage divider module; the output terminal of the comparator is output to the enable terminal of the driving chip after passing through the current limiting module and the pull-down module.

6. A frequency converter, characterized in that: include: A protection device for a frequency converter as claimed in any one of claims 1 to 5.

7. A method for protecting a frequency converter corresponding to the frequency converter protection device according to any one of claims 1 to 5, characterized in that: The frequency converter comprises a driving board and a main control board, and a driving chip is arranged on the main control board; The inverter protection method comprises: Feedback the fault feedback signal of the power device in the inverter to the main control board through the drive board; Through the first protection unit, when the fault feedback signal is received, if the level of the fault feedback signal is a first set level, a first normal working signal is output; if the level of the fault feedback signal is a second set voltage, a first stop working signal is output; the first protection unit is arranged on the main control board and is located between the driver board and the driver chip; By driving the chip, when the first normal working signal is received, the power device is controlled to work normally; when the first stop working signal is received, the power device is controlled to stop working.

8. The inverter protection method according to claim 7, characterized in that: The protection method of the frequency converter further includes: The fault feedback signal is processed by a fault feedback module to obtain a fault detection signal; By means of a control module, determining whether the power device fails according to the fault detection signal, if it is determined that the power device does not fail, outputting a second normal working signal; if it is determined that the power device fails, outputting a second stop working signal; Through the driving chip, when the second normal working signal is received, the power device is controlled to work normally; when the second stop working signal is received, the power device is controlled to stop working.

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