CN216056311U

CN216056311U - Protection device and converter of converter

Info

Publication number: CN216056311U
Application number: CN202122394322.7U
Authority: CN
Inventors: 李思琪; 于安波; 花峰海; 孙庚君
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2022-03-15
Anticipated expiration: 2031-09-30

Abstract

The utility model discloses a protection device of a frequency converter and the frequency converter, the device comprises: the driving 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, is positioned between the driving board and the driving chip and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level under the condition of receiving the fault feedback signal; if the level of the fault feedback signal is a second set voltage, outputting a first working stopping signal; the driving chip is configured to control the power device to normally work under the condition of receiving the first normal working signal; and controlling the power device to stop working under the condition of receiving the first stop working signal. According to the scheme, when the drive plate of the frequency converter is subjected to fault protection, at least hardware protection is adopted, and the timeliness of the fault protection of the drive plate can be improved.

Description

Protection device and converter of converter

Technical Field

The utility model belongs to the technical field of frequency converters, particularly relates to a protection device of a frequency converter and the frequency converter, and particularly relates to a fault feedback and fault protection device and method of a high-power frequency converter driving plate and the high-power frequency converter.

Background

An IGBT (insulated gate bipolar transistor) is a commonly used power device in a high-power frequency converter, and is usually used in an inverter circuit in combination with a driving board. The main control board of the frequency converter controls the on and off of the IGBT by controlling the output of PWM (pulse width modulation), thereby realizing the output of U, V, W three-phase power supply. As a key device in the frequency converter, the working state of the IGBT directly influences whether the frequency converter normally works, so that timely detection of the working state of the IGBT and timely protection when a fault occurs are very necessary for the frequency converter and the IGBT. In a related scheme, a fault protection mode of a drive board of a frequency converter adopts software protection, and the problem that the fault protection of the drive board is not timely enough exists due to the delay of the software protection.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a protection device of a frequency converter and the frequency converter, which solve the problem that the fault protection of a drive plate of the frequency converter in a related scheme is not timely enough due to the fact that software protection is adopted to protect the fault of the drive plate, and achieve the effect of improving the timeliness of the fault protection of the drive plate by at least adopting hardware protection when the drive plate of the frequency converter is subjected to the fault protection.

The utility model provides a protection device of a frequency converter, wherein the frequency converter is provided with a driving plate and a main control plate, and a driving chip is arranged on the main control plate; the protection device of converter includes: a first protection unit; the driving 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, is positioned between the driving board and the driving chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level under the condition that the fault feedback signal is received; if the level of the fault feedback signal is a second set voltage, outputting a first working stopping signal; the driving chip is configured to control the power device to normally operate under the condition of receiving the first normal operation signal; and controlling the power device to stop working under the condition of receiving the first stop working signal.

In some embodiments, the protection device for the frequency converter further includes: a second protection unit; the second protection unit is arranged on the main control board and is positioned between the driving board and the driving chip; the second protection unit includes: the fault feedback module and the control module; 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 the power device is determined not to fail; if the power device is determined to be in fault, outputting a second stop working signal; the driving chip is further configured to control the power device to normally operate under the condition that the second normal operation signal is received; and controlling the power device to stop working under the condition of receiving the second stop working signal.

In some embodiments, the power device, forms a three-phase full bridge module; the fault feedback signal comprises: six paths of 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: the first switch tube module and the second switch tube module; each path of fault feedback signal is input to a control end of a first switch tube module in a corresponding path of 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; and the output end of the second switching tube module outputs a fault detection signal corresponding to the fault feedback signal.

In some embodiments, the first protection unit comprises: the device comprises a level identification module and a comparison module; the number of the level identification modules is six; in the six paths of the level identification modules, each path of the level identification module is configured to identify a level of a corresponding path of the fault feedback signal, so as to output a signal of which the level of the corresponding path of the fault feedback signal is a second set level when the level of the corresponding path of the fault feedback signal is the second set level; the comparison module is configured to output the first normal working signal in the six paths of fault feedback signals under the condition that the levels of the six paths of fault feedback signals are all a first set level; and in the six paths of fault feedback signals, under the condition that the level of one path of fault feedback signals is a second set level, outputting the first stop working signal.

In some embodiments, each of the level identifying modules includes: a diode module; each path of fault feedback signal is input to the cathode of the corresponding path of diode module; the anode of the diode module is output to the non-inverting input end of the comparison module; the set reference signal is input to the inverting input end of the comparison module; and the output end of the comparison module outputs the first normal working signal or the first stop working signal to the enabling end of the driving chip.

In some embodiments, the comparison module comprises: the voltage divider comprises a comparator, a first voltage dividing module, a second voltage dividing module, a current limiting module and a pull-down module; the set direct-current power supply and the anode of each path of diode module are input to the non-inverting input end of the comparator after passing through the first voltage division module; the set direct-current power supply is input to the inverting input end of the comparator after passing through the second voltage division module; and the output end of the comparator is output to the enabling end of the driving chip after passing through the current limiting module and the pull-down module.

In accordance with the above apparatus, another aspect of the present invention provides a frequency converter, including: the protection device of the frequency converter is described above.

Therefore, according to the scheme of the utility model, the hardware protection circuit is added between the drive plate and the drive chip of the frequency converter, the output signal of the drive plate can be utilized for processing, the drive chip is directly controlled, and the fault protection of the drive plate is realized at least by utilizing the hardware protection circuit; therefore, when the drive plate of the frequency converter is subjected to fault protection, at least hardware protection is adopted, and the timeliness of the fault protection of the drive plate can be improved.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a protection device of a frequency converter according to the present invention;

FIG. 2 is a schematic structural diagram of an embodiment of a fault feedback and fault protection device of a frequency converter driving board;

FIG. 3 is a schematic structural diagram of an embodiment of a fault protection circuit (e.g., a drive fault feedback hardware protection circuit) of a frequency converter drive board according to the present invention;

FIG. 4 is a schematic structural diagram of a fault feedback circuit of a frequency converter driving board according to an embodiment of the present invention;

FIG. 5 is a schematic flow chart diagram illustrating one embodiment of a method for fault feedback and fault protection of a frequency converter driver board;

fig. 6 is a schematic flowchart of a protection method for a frequency converter according to an embodiment of the present invention;

fig. 7 is a flowchart illustrating an embodiment of a process of performing software protection based on hardware protection in the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the related scheme, the driving feedback and protection scheme of the frequency converter is that the driving board outputs a fault feedback signal to the driving fault feedback circuit, the fault feedback signal is processed by the fault feedback circuit and then outputs a feedback signal to a DSP (digital signal processing) module, and the DSP module controls the output of the driving signal according to the feedback signal so as to control the working state of the driving chip. The failure protection mode of the drive board is only software protection, the protection mode is single, and the timeliness and the reliability of protection cannot be guaranteed.

According to an embodiment of the present invention, there is provided a protection apparatus for a frequency converter. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The frequency converter is provided with a driving plate and a main control plate, and a driving chip is arranged on the main control plate. The protection device of converter includes: and a first protection unit, such as a drive fault hardware protection circuit.

The driving board is configured to feed back a fault feedback signal of a power device in the frequency converter to the main control board. Fault feedback signals such as signal UH _ G, UL _ G, VH _ G, VL _ G, WH _ G, WL _ G.

The first protection unit is arranged on the main control board, is positioned between the driving board and the driving chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level under the condition that the fault feedback signal is received. And if the level of the fault feedback signal is a second set voltage, outputting a first work stopping signal. The first normal working signal is a signal for controlling or maintaining the working of the driving chip. The first stop signal is a signal for controlling the driving chip to stop working.

The driving chip is configured to control the power device to normally operate when the first normal operation signal is received. And controlling the power device to stop working under the condition of receiving the first stop working signal.

According to the scheme of the utility model, the driving fault feedback signal is processed by using the driving fault feedback signal processing circuit, and the output signal can directly control the driving chip to timely carry out driving fault protection. Through the processing of the drive fault feedback signal, the hardware can directly control the drive chip to stop working, the problem that the fault protection of the frequency converter drive plate is not timely enough is solved, and the timeliness of the drive fault protection is improved.

In some embodiments, the protection device for the frequency converter further includes: and a second protection unit. The second protection unit is arranged on the main control board and is positioned between the driving board and the driving chip. The second protection unit includes: the device comprises a fault feedback module and a control module. And a fault feedback module, such as a driving fault feedback circuit. And a control module, such as a DSP module.

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 operation signal if it is determined that the power device does not fail. And if the power device is determined to be in fault, outputting a second stop working signal. The second normal working signal is a signal for controlling or maintaining the working of the driving chip. The second stop signal is a signal for controlling the driving chip to stop working.

The driving chip is further configured to control the power device to normally operate when the second normal operation signal is received. And controlling the power device to stop working under the condition of receiving the second stop working signal.

The scheme of the utility model provides a driving fault feedback and fault protection method of a high-power frequency converter, which not only can further output a control instruction to realize soft protection according to a feedback signal output by a driving fault feedback circuit, but also can carry out hardware protection through an output signal of a driving fault hardware protection circuit, thereby realizing double protection of software and hardware, and improving timeliness and reliability of fault detection and protection of a driving plate of the frequency converter.

The solution of the utility model, which is applicable in the field of frequency converter control, is exemplified below with reference to the examples shown in fig. 2 to 5 in connection with specific operations.

Fig. 2 is a schematic structural diagram of an embodiment of a fault feedback and fault protection device of a frequency converter driving board. As shown in fig. 2, the fault feedback and fault protection device for the driving board of the frequency converter includes: the device comprises a driving board, a driving chip, a driving fault hardware protection circuit, a driving fault feedback circuit and a DSP module. The driving chip, the driving fault hardware protection circuit, the driving fault feedback circuit and the DSP module are arranged on a main control board of the frequency converter. And the first output end of the driving plate is output to the input end of the driving fault hardware protection circuit. And the output end of the drive fault hardware protection circuit is output to the first protection end of the drive chip. And the second output end of the driving plate is output to the input end of the driving fault feedback circuit. And the output end of the driving fault feedback circuit is output to the input end of the DSP module. And the output end of the DSP module is output to the second protection end of the driving chip.

Referring to the example shown in fig. 2, during the operation of the frequency converter, the driving board feeds back a fault feedback signal (e.g., the signal UH _ G, UL _ G, VH _ G, VL _ G, WH _ G, WL _ G) to the main control board, and the feedback signal outputs a control signal EN through the driving fault hardware protection circuit to control the operating state of the driving chip. Meanwhile, the feedback signal drives the fault feedback circuit to process the signal, the output feedback signal (such as signals UH _ DSP, UL _ DSP, VH _ DSP, VL _ DSP, WH _ DSP and WL _ DSP) is processed by the DSP, whether a fault occurs is judged, and then a control signal (such as signals UH, UL, VH, VL, WH and WL) is output to the drive chip to control the output of the PWM drive signal.

The driving chip is a chip on the main control board and is used for performing signal processing on the PWM driving signal output by the main control board, wherein the level conversion is mainly performed on the PWM driving signal, high-level 3.3V is converted into 15V for output, the output is processed by the interlocking circuit, and finally 6 paths of driving signals are output to the driving board.

The driving board is mainly used for driving the IGBT and feeding back a fault signal to the main control board.

In the related scheme, the driving board outputs a fault feedback signal to the driving fault feedback circuit, the driving fault circuit processes the fault feedback signal and outputs the processed fault feedback signal to the DSP module, and the DSP module further controls the driving signal so as to control the working state of the driving chip. Based on the drive fault feedback and fault protection topology, a drive fault hardware protection circuit is added in the structure of fig. 2, the drive fault hardware protection circuit directly processes a fault feedback signal, directly outputs a control signal EN and controls the working state of a drive chip, and the drive fault hardware protection circuit belongs to hardware protection. Through newly adding drive fault hardware protection, the problems of single fault protection and untimely protection of the drive plate of the frequency converter in the related scheme are solved.

In some embodiments, the power device forms a three-phase full bridge module. The fault feedback signal comprises: and six paths of 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: the switch comprises a first switch tube module and a second switch tube module. And a first switching transistor module, such as transistor Q1 and its peripheral resistor. And a second switching transistor module, such as transistor Q2 and its peripheral resistor.

Each path of the fault feedback signal is input to a control end (such as a base of a transistor Q1) of a first switching tube module in a corresponding path of the fault feedback module. In this way, the output terminal of the first switch tube module (e.g., the collector of the transistor Q1) is output to the control terminal of the second switch tube module (e.g., the base of the transistor Q2). And the output end (such as the collector of the transistor Q2) of the second switching tube module outputs a fault detection signal corresponding to the fault feedback signal.

Fig. 4 is a schematic structural diagram of a fault feedback circuit of a frequency converter driving board according to an embodiment of the present invention. As shown in fig. 4, the fault feedback circuit of the frequency converter driving board includes: and six driving signal processing branches.

The first drive signal processing branch comprises: a transistor Q1, a transistor Q2, and two current limiting resistors. The fault feedback signal UH _ G is input to the base of the triode Q1, the +3.3V power supply is input to the collector of the triode Q1 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q2 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q2 after passing through another current-limiting resistor, and the collector of the triode Q2 outputs the fault feedback signal UH _ DSP. The emitter of transistor Q1 and the emitter of transistor Q2 are both grounded.

The second path of driving signal processing branch circuit comprises: a transistor Q7, a transistor Q8, and two current limiting resistors. The fault feedback signal UL _ G is input to the base of the triode Q7, the +3.3V power supply is input to the collector of the triode Q7 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q8 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q8 after passing through another current-limiting resistor, and the collector of the triode Q8 outputs the fault feedback signal UL _ DSP. The emitter of transistor Q7 and the emitter of transistor Q8 are both grounded.

A third drive signal processing branch comprising: a transistor Q3, a transistor Q4, and two current limiting resistors. The fault feedback signal VH _ G is input to the base of the triode Q3, the +3.3V power supply is input to the collector of the triode Q3 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q4 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q4 after passing through another current-limiting resistor, and the collector of the triode Q4 outputs the fault feedback signal VH _ DSP. The emitter of transistor Q3 and the emitter of transistor Q4 are both grounded.

The fourth drive signal processing branch comprises: a transistor Q9, a transistor Q10, and two current limiting resistors. The fault feedback signal VL _ G is input to the base of the triode Q9, the +3.3V power supply is input to the collector of the triode Q9 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q10 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q10 after passing through another current-limiting resistor, and the collector of the triode Q10 outputs the fault feedback signal VL _ DSP. The emitter of transistor Q9 and the emitter of transistor Q10 are both grounded.

The fifth drive signal processing branch comprises: a transistor Q5, a transistor Q6, and two current limiting resistors. The fault feedback signal WH _ G is input to the base of the triode Q5, the +3.3V power supply is input to the collector of the triode Q5 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q6 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q6 after passing through another current-limiting resistor, and the collector of the triode Q6 outputs the fault feedback signal WH _ DSP. The emitter of transistor Q5 and the emitter of transistor Q6 are both grounded.

The sixth drive signal processing branch comprises: a transistor Q11, a transistor Q12, and two current limiting resistors. The fault feedback signal WL _ G is input to the base of the triode Q11, the +3.3V power supply is input to the collector of the triode Q11 after passing through a current-limiting resistor, the +3.3V power supply is also input to the base of the triode Q12 after passing through a current-limiting resistor, the +3.3V power supply is input to the collector of the triode Q12 after passing through another current-limiting resistor, and the collector of the triode Q12 outputs a fault feedback signal WL _ DSP. The emitter of transistor Q11 and the emitter of transistor Q12 are both grounded.

As shown in fig. 4, the driving fault feedback circuit processes the driving signals of six paths of driving signals (i.e., the fault feedback signals), and processes each path of driving signals by using the on and off states of two triodes to realize the output of 3.3V, so that the driving signals can be input into the DSP module for detection. That is to say, the base signals of the triodes are controlled to control the on and off of the two triodes, and the driving fault feedback signals are converted into 3.3V signals to be output to the DSP module for detection.

In the example shown in fig. 4, the transistors Q1 to Q12 are NPN transistors, and when a high level is input to the base, the transistors are turned on. The resistors in fig. 4 are pull-up resistors, and are used for pulling the output DSP signal to 3.3V when the second transistor is not turned on, so that the driving signal can be input into the DSP module for detection. UH _ DSP and other signals are feedback signals which are input to the DSP module after being processed by the circuit, and when low level exists in the signals, the signals indicate that a fault occurs, and the DSP module stops outputting PWM driving signals. Six input signals such as a signal UH and the like are PWM driving signals output by the DSP, and each input signal is connected with a pull-down resistor (namely a resistor connected with the corresponding PWM driving signal) to ensure that false triggering cannot occur in an initial state.

The first transistor, for example, drives the transistor Q1 in the signal processing branch in the first path, drives the transistor Q7 in the signal processing branch in the second path, drives the transistor Q3 in the signal processing branch in the third path, drives the transistor Q9 in the signal processing branch in the fourth path, drives the transistor Q5 in the signal processing branch in the fifth path, and drives the transistor Q11 in the signal processing branch in the sixth path.

The second triode, for example, the triode Q2 in the first driving signal processing branch, the triode Q8 in the second driving signal processing branch, the triode Q4 in the third driving signal processing branch, the triode Q10 in the fourth driving signal processing branch, the triode Q6 in the fifth driving signal processing branch, and the triode Q12 in the sixth driving signal processing branch.

In the example shown in fig. 4, the fault feedback signal is driven using the on-off feedback of the two transistors. On the one hand, the DSP stops the output of the PWM driving signal according to the feedback signal. On the other hand, the processed signal directly pulls down the enable signal of the driving chip to stop the driving chip.

In some embodiments, the first protection unit comprises: the device comprises a level identification module and a comparison module. The number of the level identification modules is six.

In the sixth level identification module, each level identification module is configured to identify a level of a corresponding one of the fault feedback signals, so as to output a signal that the level of the corresponding one of the fault feedback signals is a second set level when the level of the corresponding one of the fault feedback signals is the second set level.

The comparison module is configured to output the first normal operation signal when the levels of the six fault feedback signals are all a first set level in the six fault feedback signals. In the six level recognition modules, when one level recognition module outputs a corresponding signal with the level of the fault feedback signal being a second set level, that is, in the six fault feedback signals

In the signal, the first stop signal is output under the condition that the level of one path of the fault feedback signal is a second set level.

In the scheme of the utility model, a drive fault feedback hardware protection circuit is added on the basis of the related scheme, so that the problem of single drive fault protection method is solved, the hardware protection speed is higher than the software protection speed, and the effect of more timely drive fault protection is achieved.

According to the scheme of the utility model, two circuits are adopted to respectively process the drive fault feedback signals, so that dual protection of hardware and software can be realized. The double protection of hardware and software can be realized by processing the drive fault feedback signal, the problem of single fault protection method of the frequency converter drive plate in the related scheme is solved, and the safety is improved.

In some embodiments, each of the level identifying modules includes: and a diode module.

And each path of fault feedback signal is input to the cathode of the corresponding path of diode module. The anode of the diode module is output to the non-inverting input end of the comparison module. And the set reference signal is input to the inverting input end of the comparison module. And the output end of the comparison module outputs the first normal working signal or the first stop working signal to the enabling end of the driving chip.

Fig. 3 is a schematic structural diagram of an embodiment of a fault protection circuit (e.g., a drive fault feedback hardware protection circuit) of a frequency converter drive board according to the present invention. As shown in fig. 3, the driving 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 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 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 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 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 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 through a 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 U-of the comparator U1 is also connected to ground through a resistor R2. The output terminal of the comparator U1 outputs the control signal EN to a first input terminal of the driver U2, such as an enable terminal (e.g., EN terminal) of the driver U2, via the resistor R6. The +3.3V power is input to the enable terminal (e.g., EN terminal) of the driver IC U2 through the resistor R7. And a second input end of the driving chip U2 is used for inputting the control signals UH, UL, VH, VL, WH, WL and the like output by the DSP module.

The drive fault feedback hardware protection circuit shown in fig. 3 can implement fault protection directly from hardware according to a fault feedback signal. The voltage of the inverting input terminal of the comparator U1 is a fixed value, the diode corresponding to the fault feedback signal UH _ G, UL _ G, VH _ G, VL _ G, WH _ G, WL _ G is connected in parallel to the circuit, when any one path of signal is low level, the diode is conducted, the comparator U1 outputs low level, and the driving chip U2 stops working.

In some embodiments, the comparison module comprises: the voltage divider comprises a comparator, a first voltage dividing module, a second voltage dividing module, a current limiting module and a pull-down module. Such as comparator U1.

The set direct-current power supply and the anode of each diode module are input to the non-inverting input end of the comparator after passing through the first voltage division module. The set direct current power supply is input to the inverting input end of the comparator after passing through the second voltage division module. And the output end of the comparator is output to the enabling end of the driving chip after passing through the current limiting module and the pull-down module.

In the example shown in fig. 3, the resistors R1 to R5 are fixed-resistance resistors, the resistance R1 is equal to R2, the resistors R3, R4, and R5 are voltage dividing resistors, the resistance R4 < R3 < R5, the resistor R6 is a current limiting resistor, and the resistor R7 is a pull-up resistor. D1-D6 are diodes. U1 is a comparator, and its non-inverting input terminal voltage is U +, and its inverting input terminal voltage U ═ 7.5V. The chip U2 is a driving chip on the main control board, and the chip mainly functions to perform level conversion on an input signal when receiving a high-level enable signal output by the DSP and is a key device in a driving circuit of the frequency converter. The output end of the comparator U1 is connected with an enabling pin of the driving chip U2. Six paths of input signals such as a signal UH _ G and the like are U, V, W three-phase upper and lower bridge arm fault feedback signals fed back by the driving plate respectively, and when a fault occurs, the fault feedback signals fed back by the driving plate are at a low level. When the driving plate works normally, a fault feedback signal fed back by the driving plate is at a high level of 15V.

Fig. 5 is a flowchart illustrating a method for fault feedback and fault protection of a frequency converter driving board according to an embodiment. As shown in fig. 5, the method for fault feedback and fault protection of the frequency converter driving board includes:

and step 1, the driving board transmits a fault feedback signal to the main control board, and then step 2 and/or step 3 are/is executed. And a circuit on the driving board can carry out desaturation detection on the upper and lower bridge arms and feed back the detection result to the main control board.

And step 2, driving the fault hardware protection circuit to work, and specifically referring to the following exemplary description.

Step 21, judging whether the fault feedback signal has a low level: if yes, go to step 22. Otherwise, step 23 is executed.

And step 22, the diode is conducted, the comparator U1 outputs low level, and the driving chip stops working.

And step 23, the diode is not conducted, the comparator U1 outputs high level, and the driving chip works normally.

And 3, driving the fault feedback circuit to work, and specifically referring to the following exemplary description.

Step 31, judging whether the fault feedback signal has a low level: if yes, go to step 32. Otherwise, step 33 is executed.

And step 32, the first triode is not conducted, and the second triode is conducted. And the DSP module stops outputting the PWM driving signal when receiving the low level.

And step 33, conducting the first triode and not conducting the second triode. And the DSP module receives the high level and normally outputs a PWM driving signal.

When the drive is in normal operation, the feedback signals UH _ G and the like of the drive plate are six high-level signals which are sent to the main control plate, in the drive fault feedback hardware protection circuit shown in FIG. 3, the fault feedback signals UH _ G and the like are all +15V, the cathode potential of all diodes is higher than the anode potential, so the diodes are not conducted, the voltage U + of the non-inverting input end of the comparator U1 is obtained by dividing the voltage of 15V by R3 and R5, and the voltage divided by R3 is less than R5, and the voltage divided by R3 is less than the voltage divided by R5, so the voltage divided by R3 and R5 is obtained, so the drive plate is normally driven to work

The output EN of the comparator U1 is high level and is pulled up to 3.3V by R7, and the driver chip U2 works normally. In the driving fault feedback circuit shown in fig. 4, the base electrodes of the first triodes are all at high level, the first triodes are conducted, so that the base electrodes of the second triodes are grounded at low level, the second triodes are not conducted, output signals such as UH _ DSP and the like are high level signals, the signals are pulled up to 3.3V and input to the DSP module, and when the DSP module recognizes that all the signals are at high level, PWM driving signals are output to the driving chip, and the driving chip works normally.

When a certain bridge arm of the IGBT breaks downThe driving board feeds back a corresponding driving 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 breaks down, the fault feedback signal UH _ G is at a low level, and the rest driving fault feedback signals UL _ G and the like are at a high level. In the driving fault feedback hardware protection circuit shown in fig. 3, the anode potential of the diode D1 is greater than the cathode potential, the diode D1 is conductive, the anode potential of the rest of the diodes is less than the cathode potential, and the diodes are non-conductive. At this time, the resistors R4 and R5 are equivalent to parallel connection, and the resistance after parallel connection is smaller than R4 and smaller than R3, so after +15V voltage division, the voltage is obtained

The comparator U1 outputs EN as low level, the enable signal of the driving chip is pulled low, the driving chip stops working immediately, and hardware protection of driving fault feedback is realized. Meanwhile, in the driving fault feedback circuit as shown in fig. 4, since the fault feedback signal UH _ G is at a low level and is connected to the base of the triode Q1, the triode Q1 is not turned on, the base of the triode Q2 is connected to the pull-up resistor at a high level, the triode Q2 is turned on, the output signal UH _ DSP is grounded as a low level signal and is input to the DSP, the other triodes are consistent with a normal working state, the output signals UL _ DSP and the like are at a high level of 3.3V, and when the DSP recognizes that there is a low level in the input feedback signal, the output of the PWM driving signal is stopped, so that software protection of driving fault feedback is realized.

In the above embodiment, the scheme of hardware protection + software protection is applied to the driving fault feedback and fault protection method, but is also applicable to other types of fault detection and fault protection circuits (such as overcurrent and overvoltage detection and overcurrent and overvoltage protection circuits).

According to the scheme of the utility model, the output of the PWM driving signal can be controlled after the output signal of the driving fault feedback circuit is detected by the DSP module, so that software protection is realized. The one-way conduction of the diode is utilized to control the voltage of the equidirectional input end of the comparator, and then the output of the comparator is controlled to control the working state of the driving chip, so that the hardware protection is realized. Therefore, the problem that the existing fault protection method of the frequency converter drive plate is single and the problem that the fault protection of the frequency converter drive plate is not timely enough can be solved, the software and hardware double protection of the drive fault is realized, and the timeliness and the reliability of the fault protection of the frequency converter drive plate are improved.

By adopting the technical scheme of the utility model, the hardware protection circuit is added between the drive plate and the drive chip of the frequency converter, the output signal of the drive plate can be utilized for processing, the drive chip is directly controlled, and the fault protection of the drive plate is realized at least by utilizing the hardware protection circuit. Therefore, when the drive plate of the frequency converter is subjected to fault protection, at least hardware protection is adopted, and the timeliness of the fault protection of the drive plate can be improved.

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

Since the processing and functions implemented by the frequency converter of this embodiment substantially correspond to the embodiments, principles, and examples of the foregoing apparatus, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

By adopting the technical scheme of the utility model, the hardware protection circuit is added between the drive plate and the drive chip of the frequency converter, the output signal of the drive plate can be utilized for processing, the drive chip is directly controlled, the fault protection of the drive plate is realized at least by utilizing the hardware protection circuit, and the safety of the fault protection of the drive plate is improved.

According to an embodiment of the present invention, a method for protecting a frequency converter corresponding to the frequency converter is also provided, as shown in fig. 6, which is a schematic flow chart of an embodiment of the method of the present invention. The frequency converter is provided with a driving plate and a main control plate, and a driving chip is arranged on the main control plate. The protection method of the frequency converter comprises the following steps: step S110 to step S130.

And step S110, feeding back a fault feedback signal of a power device in the frequency converter to the main control board through the driving board. Fault feedback signals such as signal UH _ G, UL _ G, VH _ G, VL _ G, WH _ G, WL _ G.

Step S120, by using a first protection unit, for example, a driving fault hardware protection circuit, in the case of receiving the fault feedback signal, if the level of the fault feedback signal is a first set level, outputting a first normal working signal. And if the level of the fault feedback signal is a second set voltage, outputting a first work stopping signal. The first normal working signal is a signal for controlling or maintaining the working of the driving chip. The first stop signal is a signal for controlling the driving chip to stop working. The first protection unit is arranged on the main control board and is positioned between the driving board and the driving chip.

Step S130, controlling the power device to normally operate through the driving chip under the condition of receiving the first normal operation signal. And controlling the power device to stop working under the condition of receiving the first stop working signal.

In some embodiments, the protection method of the frequency converter further includes: and performing a software protection process on the basis of hardware protection.

Protected by a second protection unit. The second protection unit is arranged on the main control board and is positioned between the driving board and the driving chip. The second protection unit includes: the device comprises a fault feedback module and a control module. And a fault feedback module, such as a driving fault feedback circuit. And a control module, such as a DSP module.

The following further describes, with reference to a flowchart of an embodiment of a process of performing software protection based on hardware protection in the method of the present invention shown in fig. 7, a specific process of performing software protection based on hardware protection, including: step S210 to step S230.

And step S210, processing the fault feedback signal through a fault feedback module to obtain a fault detection signal.

Step S220, determining whether the power device has a fault or not according to the fault detection signal through a control module, and outputting a second normal working signal if the power device has no fault. And if the power device is determined to be in fault, outputting a second stop working signal. The second normal working signal is a signal for controlling or maintaining the working of the driving chip. The second stop signal is a signal for controlling the driving chip to stop working.

Step S230, controlling the power device to normally operate through the driving chip under the condition of receiving the second normal operation signal. And controlling the power device to stop working under the condition of receiving the second stop working signal.

Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the frequency converter, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

By adopting the technical scheme of the embodiment, the hardware protection circuit is additionally arranged between the drive plate and the drive chip of the frequency converter, the output signal of the drive plate can be utilized for processing, the drive chip is directly controlled, the fault protection of the drive plate is realized at least by utilizing the hardware protection circuit, and the timeliness and the reliability of the fault protection of the drive plate of the frequency converter are improved.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The protection device of the frequency converter is characterized in that the frequency converter is provided with a driving plate and a main control plate, and a driving chip is arranged on the main control plate; the protection device of converter includes: a first protection unit; wherein,

the driving 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, is positioned between the driving board and the driving chip, and is configured to output a first normal working signal if the level of the fault feedback signal is a first set level under the condition that the fault feedback signal is received; if the level of the fault feedback signal is a second set voltage, outputting a first working stopping signal;

the driving chip is configured to control the power device to normally operate under the condition of receiving the first normal operation signal; and controlling the power device to stop working under the condition of receiving the first stop working signal.

2. The protection device for frequency converter according to claim 1, further comprising: a second protection unit; the second protection unit is arranged on the main control board and is positioned between the driving board and the driving chip; the second protection unit includes: the fault feedback module and the 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 the power device is determined not to fail; if the power device is determined to be in fault, outputting a second stop working signal;

the driving chip is further configured to control the power device to normally operate under the condition that the second normal operation signal is received; and controlling the power device to stop working under the condition of receiving the second stop working signal.

3. The protection device of the frequency converter according to claim 2, wherein the power device forms a three-phase full-bridge module; the fault feedback signal comprises: six paths of 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: the first switch tube module and the second switch tube module;

each path of fault feedback signal is input to a control end of a first switch tube module in a corresponding path of 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; and the output end of the second switching tube module outputs a fault detection signal corresponding to the fault feedback signal.

4. The protection device of a frequency converter according to any one of claims 1 to 3, wherein the first protection unit comprises: the device comprises a level identification module and a comparison module; the number of the level identification modules is six;

in the six paths of the level identification modules, each path of the level identification module is configured to identify a level of a corresponding path of the fault feedback signal, so as to output a signal of which the level of the corresponding path of the fault feedback signal is a second set level when the level of the corresponding path of the fault feedback signal is the second set level;

the comparison module is configured to output the first normal working signal in the six paths of fault feedback signals under the condition that the levels of the six paths of fault feedback signals are all a first set level; and in the six paths of fault feedback signals, under the condition that the level of one path of fault feedback signals is a second set level, outputting the first stop working signal.

5. The protection device of frequency converter according to claim 4, wherein each of the level identification modules comprises: a diode module;

each path of fault feedback signal is input to the cathode of the corresponding path of diode module; the anode of the diode module is output to the non-inverting input end of the comparison module; the set reference signal is input to the inverting input end of the comparison module; and the output end of the comparison module outputs the first normal working signal or the first stop working signal to the enabling end of the driving chip.

6. The protection device of the frequency converter according to claim 5, wherein the comparison module comprises: the voltage divider comprises a comparator, a first voltage dividing module, a second voltage dividing module, a current limiting module and a pull-down module; wherein,

the set direct-current power supply and the anode of each path of diode module are input to the non-inverting input end of the comparator after passing through the first voltage division module; the set direct-current power supply is input to the inverting input end of the comparator after passing through the second voltage division module; and the output end of the comparator is output to the enabling end of the driving chip after passing through the current limiting module and the pull-down module.

7. A frequency converter, comprising: a protection device of a frequency converter according to any one of claims 1 to 6.