CN213279145U

CN213279145U - Protection device and motor system of IGBT module in converter

Info

Publication number: CN213279145U
Application number: CN202022267578.7U
Authority: CN
Inventors: 刘玲; 曹巍; 于安波; 刘金芝; 归柒荣; 花峰海
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-10-13
Filing date: 2020-10-13
Publication date: 2021-05-25
Anticipated expiration: 2030-10-13

Abstract

The utility model discloses a protection device and motor system of IGBT module in converter, the device includes: the collecting unit is used for collecting three-phase current of the frequency converter, collecting peak voltage between a collector electrode and an emitter electrode of the IGBT module, and collecting bus voltage of a direct-current power supply; the control unit is used for determining whether the frequency converter works normally or not according to at least one of the collected three-phase current, the collected peak voltage and the collected bus voltage; and under the condition that the frequency converter does not work normally, controlling the IGBT module to keep a closed state, and starting a control signal to control the IGBT spike voltage suppression unit to suppress the spike voltage between the collector and the emitter of the IGBT module. According to the scheme, when the frequency converter is overloaded and the inverter bridge is in short circuit with a bridge arm, the IGBT is turned off, peak voltage of the IGBT module is restrained, and the situation that the IGBT module damages a device when the frequency converter is overloaded or the inverter bridge is in short circuit with the bridge arm is avoided.

Description

Protection device and motor system of IGBT module in converter

Technical Field

The utility model belongs to the technical field of the converter, concretely relates to protection device and motor system of IGBT module in converter especially relates to an IGBT module fault detection device and motor system in converter.

Background

The front end of the frequency converter converts the industrial alternating current into direct current through a rectifier bridge and supplies the direct current to the rear end; the rear end of the frequency converter can realize the inversion of direct current into alternating current by a controllable inversion bridge formed by IGBT modules to supply the alternating current to a motor winding to drive the motor to run. The IGBT module can damage devices when a frequency converter is overloaded or a bridge arm of an inverter bridge is short-circuited.

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

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a protection device and motor system of IGBT module in converter to solve the problem that the IGBT module can damage the device when the converter transships or the contravariant bridge takes place the bridge arm short circuit, reach and avoid the IGBT module to overload at the converter or the contravariant bridge takes place the effect that the bridge arm short circuit damaged the device.

The utility model provides a protection device of IGBT module in converter, include: the IGBT power supply comprises an acquisition unit, an IGBT spike voltage suppression unit and a control unit; the collecting unit is configured to collect three-phase current of the frequency converter, collect peak voltage between a collector and an emitter of the IGBT module and collect bus voltage of a direct-current power supply of the frequency converter under the condition that an inverter bridge works after the frequency converter is powered on; the control unit is configured to determine whether the frequency converter works normally according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module and the bus voltage of the direct-current power supply of the frequency converter; and under the condition that the frequency converter does not work normally, controlling the IGBT module to keep a closed state, and initiating a control signal capable of controlling the IGBT spike voltage suppression unit; the IGBT spike voltage suppression unit is configured to suppress a spike voltage between a collector and an emitter of the IGBT module under the control of the control signal.

In some embodiments, the acquisition unit comprises: the device comprises a current acquisition unit, a voltage acquisition unit and a voltage capture unit; the number of the voltage acquisition units is consistent with that of the IGBT modules in the inverter bridge; each voltage acquisition unit is configured to acquire peak voltage between a collector and an emitter of one corresponding IGBT module under the condition that the inverter bridge works after the frequency converter is powered on; wherein, the collection unit gathers the three-phase current of converter to gather the spike voltage between the collecting electrode of IGBT module and the projecting pole, include: the current acquisition unit is configured to acquire three-phase currents of the frequency converter; the voltage acquisition unit is configured to acquire a spike voltage between a collector and an emitter of the IGBT module; the voltage capture unit is configured to collect bus voltage of a direct current power supply of the frequency converter; correspondingly, the determining, by the control unit, whether the frequency converter is working normally according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module, and the bus voltage of the dc power supply of the frequency converter includes: if the collected three-phase current of the frequency converter shows that the frequency converter has normal three-phase current output, and the amplitude of the three-phase current output by the frequency converter is increased and exceeds the set current amplitude, determining that the frequency converter is overloaded; if the collected peak voltage between the collector and the emitter of the IGBT module exceeds a set voltage threshold, determining that the frequency converter does not work normally, namely determining that the frequency converter is overloaded and does not work normally; or comparing the collected peak voltage between the collector and the emitter of the IGBT module with the set voltage between the collector and the emitter of the IGBT module; comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage; and if the collected peak voltage between the collector and the emitter of the IGBT module is sudden change relative to the set voltage between the collector and the emitter of the IGBT module; and if the bus voltage of the direct-current power supply of the frequency converter is lowered relative to the set bus voltage, determining that the frequency converter does not work normally, namely determining that the bridge arms of the inverter bridge are short-circuited.

In some embodiments, the number of the IGBT spike voltage suppression units is the same as the number of IGBT modules in the inverter bridge of the frequency converter; each IGBT spike voltage suppression unit is specifically arranged between one corresponding IGBT module and a drive plate of the IGBT module; the control unit controls the IGBT module to keep a closed state and initiates a control signal capable of controlling the IGBT spike voltage suppression unit, and the control unit comprises: and under the condition that the frequency converter does not work normally, the IGBT module is closed, and a control signal for controlling the IGBT spike voltage suppression unit corresponding to the other IGBT module on the bridge arm where the IGBT module is located is initiated.

In some embodiments, each of the IGBT spike voltage suppression units includes: the device comprises a resistance suppression module and a voltage source suppression module; the resistance suppression module is arranged between the output end of the drive plate of the IGBT module and the gate pole of the IGBT module; the voltage source suppression module is arranged between the input end of the driving plate of the IGBT module and the emitter of the IGBT module; wherein the IGBT spike voltage suppression unit suppresses a spike voltage between a collector and an emitter of the IGBT module under the control of the control signal, and includes: the resistance suppression module is configured to suppress spike voltage between a collector and an emitter of the IGBT module by utilizing the resistance value of the resistance suppression module; the voltage source suppression module is configured to further suppress spike voltage between a collector and an emitter of the IGBT module by utilizing a negative voltage source provided by the voltage source suppression module under the condition that the voltage source suppression module is connected.

In some embodiments, the control signal comprises: the resistance value adjusting signal can adjust the resistance value of the resistance suppression module, and the voltage source access or cut-out signal can control the access or cut-out of the voltage source suppression module; the method for controlling the IGBT peak voltage suppression unit comprises the following steps that: initiating a resistance value adjusting signal for adjusting the resistance value of the gate pole resistance value suppression module corresponding to the other IGBT module; after the resistance value of the gate pole resistance value suppression module corresponding to the other IGBT module is adjusted based on the resistance value adjustment signal, whether the peak voltage between the collector and the emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold value is determined again; and if the peak voltage between the collector and the emitter of the IGBT module switched off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold, initiating a voltage source access signal capable of controlling the access of the voltage source suppression module corresponding to the other IGBT module.

In some embodiments, further comprising: the control unit is further configured to initiate a prompting message of the overload of the frequency converter to prompt a user to adjust the load of the frequency converter to be within a rated load range if the frequency converter is overloaded under the condition that the frequency converter does not work normally after initiating a control signal capable of controlling the IGBT spike voltage suppression unit; if the situation that the frequency converter does not work normally is that the bridge arms of the inverter bridge are short-circuited, positioning and removing faults of the short-circuited bridge arms of the inverter bridge; and transmitting a short-circuit message of a bridge arm of the inverter bridge to the bearing controller through a communication channel under the condition that the frequency converter outputs the short-circuit message to the bearing controller, so that the bearing controller can start a self-protection mechanism in time under the condition that the inverter bridge has a fault.

In some embodiments, the control unit, for positioning a short-circuit bridge arm of the inverter bridge, includes: comparing the collected peak voltage between the collector and the emitter of the IGBT module with the set voltage between the collector and the emitter of the IGBT module to obtain a first voltage residual error; comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage to obtain a second voltage residual error; and processing the first voltage residual and the second voltage residual to realize the positioning of a short-circuit bridge arm of the inverter bridge.

With the above device phase-match, the utility model discloses another aspect provides a motor system, include: the protection device of the IGBT module in the frequency converter is described above.

Therefore, the utility model discloses a scheme sets up IGBT peak voltage suppression unit through the gate pole at IGBT, when the converter transships and the inverter bridge takes place the bridge arm short circuit, closes IGBT to suppress IGBT module peak voltage through IGBT peak voltage suppression unit, avoid the IGBT module to transship at the converter or the inverter bridge takes place the bridge arm short circuit and damages the device.

Further, the utility model discloses a scheme is after the suppression measure inefficacy, and when spike voltage exceeded the settlement threshold value promptly, detects the trouble of IGBT module rapidly, in time cuts off the trouble, does not let the system lack the looks operation, guarantees the operation of converter system safe and reliable.

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

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

Drawings

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

FIG. 2 is a schematic diagram of an embodiment of a frequency converter;

FIG. 3 is a schematic diagram of an embodiment of a power control system for an electric machine;

FIG. 4 is a schematic diagram of a driving structure of an embodiment of an IGBT;

FIG. 5 is a schematic diagram of an embodiment of an inverter bridge IGBT spike voltage suppression and fault detection system;

FIG. 6 is a schematic diagram of the curves of the Ic current, the PWM driving signal and the Vce voltage when the peak voltage is 820V without peak voltage suppression;

FIG. 7 is a graph illustrating the Ic current, PWM driving signal and Vce voltage at 780V peak voltage with peak voltage suppression;

FIG. 8 is a schematic flow chart diagram of an embodiment of a method for detecting an IGBT fault in a frequency converter;

fig. 9 is a schematic protection flow diagram of an embodiment of the protection device for the IGBT module in the frequency converter according to the present invention;

fig. 10 is a schematic flowchart of an embodiment of a process for determining whether the inverter is overloaded in the protection device for the IGBT module in the inverter according to the present invention;

fig. 11 is a schematic flow chart illustrating an embodiment of a process for determining whether a bridge arm of an inverter bridge is short-circuited in the protection device for an IGBT module in a frequency converter according to the present invention;

fig. 12 is a schematic flow chart of an embodiment of the present invention of a control signal for controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located, which is initiated in the protection device for the IGBT module in the frequency converter;

fig. 13 is a schematic flow diagram of an embodiment of the present invention, which is used for positioning the short-circuit bridge arm of the inverter bridge in the protection device for the IGBT module in the frequency converter.

Detailed Description

To make the purpose, technical solution and advantages of the present invention clearer, the following will combine the embodiments of the present invention and the corresponding drawings to clearly and completely describe the technical solution of the present invention. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

According to the utility model discloses an embodiment provides a protection device of IGBT module in converter. Referring to fig. 1, a schematic structural diagram of an embodiment of the apparatus of the present invention is shown. The protection device of the IGBT module in the frequency converter can comprise: the device comprises an acquisition unit, an IGBT spike voltage suppression unit and a control unit. And the GBT spike voltage suppression unit is arranged between the gate pole of the IGBT module and the drive plate of the IGBT module. An IGBT module comprising: the IGBT comprises an IGBT and a diode connected in parallel between a collector and an emitter of the IGBT.

Specifically, the acquisition unit is configured to acquire a three-phase current of the frequency converter, acquire a peak voltage between a collector and an emitter of the IGBT module, and acquire a bus voltage of a dc power supply of the frequency converter, when the inverter bridge operates after the frequency converter is powered on.

Specifically, the control unit is configured to determine whether the frequency converter normally operates according to at least one of the collected three-phase current of the frequency converter, a peak voltage between a collector and an emitter of the IGBT module, and a bus voltage of a dc power supply of the frequency converter, that is, determine whether the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited; and under the condition that the frequency converter does not work normally, namely whether the frequency converter is overloaded or not or under the condition that a bridge arm of the inverter bridge is short-circuited, controlling the IGBT module to keep a closed state, and initiating a control signal capable of controlling the IGBT peak voltage suppression unit so as to control the IGBT peak voltage suppression unit to start and control the IGBT peak voltage suppression unit to suppress the peak voltage between a collector and an emitter of the IGBT module.

When the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited, the other IGBT module of the bridge arm is controlled to be not conducted (namely, when the upper tube of the bridge arm is overloaded and short-circuited, the lower tube is always closed).

Specifically, the IGBT spike voltage suppression unit is configured to suppress a spike voltage between a collector and an emitter of the IGBT module under control of the control signal.

Therefore, aiming at the problem that the device is damaged when the inverter is overloaded and the inverter bridge is in short circuit of the bridge arm, the IGBT peak voltage suppression unit is arranged at the gate pole of the IGBT, when the inverter is overloaded and the inverter bridge is in short circuit of the bridge arm, the IGBT is closed, the peak voltage of the IGBT module is suppressed through the IGBT peak voltage suppression unit, and the device is prevented from being damaged when the inverter is overloaded or the inverter bridge is in short circuit of the bridge arm.

In some embodiments, the acquisition unit comprises: the device comprises a current acquisition unit, a voltage acquisition unit and a voltage capture unit. The number of the voltage acquisition units is consistent with that of the IGBT modules in the inverter bridge. Each voltage acquisition unit is configured to acquire the peak voltage between the collector and the emitter of the corresponding IGBT module under the condition that the inverter bridge works after the frequency converter is powered on.

The collecting unit collects three-phase current of the frequency converter and collects spike voltage between a collector and an emitter of the IGBT module under the condition that the inverter bridge works after the frequency converter is powered on, and the collecting unit comprises:

the current collection unit, such as a current sensor, is configured to collect three-phase currents of the frequency converter.

The voltage collection unit, such as a voltage sensor, is configured to collect a spike voltage between a collector and an emitter of the IGBT module.

The voltage capture unit, such as a voltage capture circuit, is configured to collect a bus voltage of a direct current power supply of the frequency converter.

Correspondingly, the determining, by the control unit, whether the frequency converter normally operates according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module, and the bus voltage of the dc power supply of the frequency converter, that is, whether the frequency converter is overloaded or the bridge arm of the inverter bridge is short-circuited includes: the process of determining whether the frequency converter is overloaded may specifically include:

the control unit is specifically configured to determine that the frequency converter is overloaded if the collected three-phase current of the frequency converter indicates that the frequency converter has normal three-phase current output, and the amplitude of the three-phase current output by the frequency converter becomes larger and exceeds a set current amplitude. And the number of the first and second groups,

the control unit is specifically configured to determine that the frequency converter does not normally operate, that is, determine that the frequency converter is overloaded and does not normally operate, if the collected peak voltage between the collector and the emitter of the IGBT module exceeds a set voltage threshold, under the condition that the frequency converter is overloaded.

Specifically, the current sensor detects that the frequency converter has normal three-phase current output, and the amplitude value becomes larger and exceeds a set threshold value i_limAnd judging that the frequency converter is in an overload state. When the peak voltage V of the bridge arm IGBT_CEAnd if the set voltage threshold is exceeded, the peak voltage of the IGBT needs to be restrained.

Or, the control unit determines whether the frequency converter normally operates according to at least one of the collected three-phase current of the frequency converter, a peak voltage between a collector and an emitter of the IGBT module, and a bus voltage of a dc power supply of the frequency converter, that is, determines whether the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited, and further includes: the process of determining whether a bridge arm of the inverter bridge is short-circuited may specifically include:

the control unit is specifically further configured to compare the collected peak voltage between the collector and the emitter of the IGBT module with a set voltage between the collector and the emitter of the IGBT module; comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage; and the number of the first and second groups,

the control unit is specifically configured to, if the collected peak voltage between the collector and the emitter of the IGBT module is suddenly changed with respect to a set voltage between the collector and the emitter of the IGBT module; and if the bus voltage of the direct-current power supply of the frequency converter is lowered relative to the set bus voltage, determining that the frequency converter does not work normally, namely determining that the bridge arms of the inverter bridge are short-circuited.

Specifically, when the inverter bridge of the frequency converter is short-circuited, the peak voltage value V between the collector and emitter of the IGBT_CEMutations (u as shown in FIG. 4)_ce4) Bus voltage U_DCInstantaneous pull-down also occurs.

In some embodiments, the number of the IGBT spike voltage suppression units corresponds to the number of IGBT modules in the inverter bridge of the frequency converter. Each IGBT spike voltage suppression unit is specifically arranged between one corresponding IGBT module and the drive plate of the IGBT module. Specifically, three bridge arms of the inverter bridge are provided with an IGBT spike voltage suppression unit and a fault detection processing unit.

The control unit controls the IGBT module to maintain a closed state and to initiate a control signal capable of controlling the IGBT spike voltage suppression unit when the frequency converter does not operate normally, that is, when the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited, and includes: the control unit is specifically configured to turn off the IGBT module and initiate a control signal for controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located, when the frequency converter does not operate normally.

Therefore, when the frequency converter is overloaded and the bridge arm of the inverter bridge is short-circuited, the IGBT is closed, the non-fault IGBT can be ensured not to be influenced and damaged, and the reliability of the frequency converter system is enhanced. When the IGBT module is turned off, that is, when the gate of the faulty IGBT is turned off, a peak voltage exists between the collector and the emitter of the faulty IGBT, and since the current flowing through the branch is large and the peak voltage is also large, the influence of the peak voltage between the collector and the emitter of the faulty IGBT on the non-faulty IGBT needs to be suppressed; therefore, the peak voltage of the IGBT module can be suppressed by the IGBT peak voltage suppressing unit to ensure that the non-faulty IGBT is not damaged when the faulty IGBT is turned off.

In some embodiments, each of the IGBT spike voltage suppression units includes: resistance suppression module (e.g. adjustable resistor R)_G) And a voltage source suppression module (e.g., voltage source V)_neg). The resistance suppression module is arranged between the output end of the driving plate of the IGBT module and the gate pole of the IGBT module. The voltage source suppression module is arranged between the input end of the driving plate of the IGBT module and the emitter of the IGBT module.

Wherein the IGBT spike voltage suppression unit suppresses a spike voltage between a collector and an emitter of the IGBT module under the control of the control signal, and includes:

the resistance suppression module is configured to suppress spike voltage between a collector and an emitter of the IGBT module by utilizing resistance of the resistance suppression module.

In particular, an adjustable resistor R is added at the gate pole of the IGBT_GAdjustable resistance R_GWhich is used to limit the voltage spike when the switching tube (i.e. IGBT) is turned on. For example, adding a first adjustable resistor R at the gate of the first switch tube Q1_G1Adding a fourth adjustable resistor R at the gate of a fourth switching tube Q4_G4And so on.

The voltage source suppression module is configured to further suppress spike voltage between a collector and an emitter of the IGBT module by utilizing a negative voltage source provided by the voltage source suppression module under the condition that the voltage source suppression module is connected.

Specifically, an inverter bridge in the frequency converter consists of 6 IGBTs, and a voltage source V is added between a gate pole of each IGBT and a driving plate_negE.g. first IGBT Q₁Between the gate pole and the driving board thereof is added a first voltage source V_neg1Second IGBT Q₂Between the gate pole and its drive plate, a second voltage source V is added_neg2. Fig. 4 shows only the voltage source of one IGBT and the device for detecting the failure of the main control board, and the voltage spike suppression and failure detection of the other 5 IGBTs are not shown.

Wherein, when the frequency converter is overloaded and when the peak voltage V of the IGBT of the bridge arm is_CEExceeding the set voltage threshold by adjusting the adjustable resistor R_GIt can be controlled at a threshold u_limInsofar, then the gate voltage source of the other IGBT need not be switched into the circuit. At this time, the fault detection module is also not activated. If gate pole adjustable resistance R of IGBT is adjusted_GThe peak voltage cannot be suppressed to the threshold value u_limWithin the range, the voltage source V_negOn, after on, gate voltage V_GEThe IGBT can be lifted, and the spike voltage impact when the IGBT is turned off can be resisted.

Therefore, when the frequency converter is overloaded or the IGBT is short-circuited, the voltage source is connected into the system, and then voltage spikes are restrained, so that the IGBT of the faultless phase is prevented from being damaged.

In some embodiments, the control signal comprises: the resistance value regulating circuit comprises a resistance value regulating signal capable of regulating the resistance value of the resistance suppression module and a voltage source access or cut-out signal capable of controlling access or cut-out of the voltage source suppression module. In particular, the control of the switching in or out of the voltage source suppression module may be controlled by a switching module, such as a relay, arranged in the line in which the voltage source suppression module is located.

The method for controlling the IGBT peak voltage suppression unit comprises the following steps that:

the control unit is specifically configured to, when the peak voltage between the collector and the emitter of one IGBT module acquired by the acquisition unit suddenly changes with respect to the set voltage between the collector and the emitter of the IGBT module, turn off the IGBT module, and initiate a resistance value adjustment signal for adjusting the resistance value of the gate resistance value suppression module corresponding to the other IGBT module, so as to realize suppression of the peak voltage between the collector and the emitter of the other IGBT module by adjusting the resistance value of the gate resistance value suppression module.

Specifically, when the frequency converter is overloaded, the peak voltage V of one tube of the bridge arm is_CEWill exceed the set threshold if adjusted by adjusting the adjustable resistance R_GIt can be controlled within a threshold range and the gate voltage source of another tube does not need to be switched into the circuit. If the adjustable resistance R is adjusted_GIf the voltage of the IGBT is not controlled within the threshold range, the gate voltage source of the other tube is connected into the circuit to increase the limit voltage V of the IGBT gate_GEAnd the other IGBT of the bridge arm is prevented from being triggered to be conducted when the other IGBT is conducted, so that a fault is prevented.

The control unit is specifically configured to determine again whether a peak voltage between a collector and an emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold after the gate resistance suppression module corresponding to the other IGBT module adjusts the resistance based on the resistance adjustment signal.

The control unit is specifically configured to initiate a voltage source access signal capable of controlling access of a voltage source suppression module corresponding to the other IGBT module if the peak voltage between the collector and the emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold, so as to further suppress the peak voltage between the collector and the emitter of the other IGBT module by accessing the voltage source suppression module.

Specifically, when the peak voltage exceeds a set threshold, the detected instantaneous voltage value can be captured by the voltage sensor, and the voltage analyzer is immediately started to perform fault analysis and processing. When the inverter bridge is short-circuited, the adjustable resistor R is adjusted_GThe peak voltage V cannot be controlled_CEThen, the voltage source is connected into the circuit to increase the IGBT gate limiting voltage V_GEPreventing the other IGBT of the bridge arm from being onWhen the switch is switched on, the switch is triggered to be switched on, and a fault occurs. The voltage source is controlled by an inter-board relay KA1, and when the peak voltage is in a threshold range, the voltage source is cut off, so that the reliability can be ensured, and the switching loss can be reduced to the minimum as much as possible. After the gate pole of the IGBT adopts a negative voltage source, the peak voltage generated at the moment of turn-off of the IGBT can be inhibited, and the turn-off reliability is ensured.

Of course, if the peak voltage between the collector and the emitter of one IGBT module turned off on the bridge arm where the other IGBT module is located does not exceed the set threshold, the voltage source suppression module corresponding to the other IGBT module does not need to be connected.

Specifically, when the frequency converter works normally (the frequency converter is not overloaded, and the inverter bridge is not short-circuited), the adjustable resistor R is adjusted_GThe resistance value of the bridge arm enables the peak voltage of the IGBT to be within a reasonable threshold range, and the other IGBT of the bridge arm does not need to connect a voltage source into a circuit, so that the circuit loss can be reduced.

In some embodiments, further comprising: and carrying out fault processing when the inverter bridge has a bridge arm short-circuit fault.

The control unit is further configured to initiate a warning message of the overload of the frequency converter to remind a user to adjust the load of the frequency converter to a rated load range after initiating a control signal capable of controlling the IGBT spike voltage suppression unit, specifically after initiating a control signal controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on a bridge arm where the IGBT module is located, if the frequency converter does not normally operate, the frequency converter is overloaded. Specifically, the overload information can be fed back to the client, so that the client can adjust the load of the unit within a rated range.

Or, the control unit is specifically configured to, after initiating a control signal capable of controlling the IGBT spike voltage suppression unit, specifically after initiating a control signal controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located, if the situation that the frequency converter does not normally operate is that the bridge arm of the inverter bridge is short-circuited, perform positioning and fault removal processing on the short-circuited bridge arm of the inverter bridge, and then enable the frequency converter to be powered up again; and transmitting a short-circuit message of a bridge arm of the inverter bridge to the bearing controller through a communication channel under the condition that the frequency converter outputs the short-circuit message to the bearing controller, so that the bearing controller can start a self-protection mechanism in time under the condition that the inverter bridge has a fault.

Specifically, the main control board is added with a fault detection and fault processing circuit. A voltage capture circuit is added at one side of a bus capacitor C, namely the direct-current output end of the bus voltage, so that the peak voltage between the DC + and the DC-of the direct-current bus can be acquired in real time, and whether the bus voltage is in the working range of the bearing switch power supply or not is judged through a voltage analyzer. When the inverter bridge of the frequency converter is short-circuited, the peak voltage value V between the collector and the emitter of the IGBT_CEWill suddenly change, the bus voltage U_DCA momentary pull-down may also occur, dropping the voltage range of the DC-DC switching power supply supplying the bearing controller. The switching power supply is not input instantly, so that output abnormity can be caused, the bearing controller works abnormally, and further the bearing is suspended abnormally, the precision of the floating shaft of the bearing is poor if the bearing is light, the shaft is still rotated to touch the shaft if the bearing is heavy, and even the shaft is smashed, which are not allowed. Adding V to IGBT gate pole_negRear, V_GEAnd whether the actual value exceeds the set value or not, if the bridge arm is short-circuited, the fault processing is carried out.

On the one hand, the frequency converter detects the voltage value u of the IGBT_ce4If the value exceeds the set value, the detected voltage value is processed by the voltage analyzer and then is compared with data in the inverter bridge topology analyzer, the residual value can represent the deviation rate, the residual error is transmitted to the fault recognizer, the IGBT which has short circuit is positioned, the fault is processed, a fault signal is transmitted to the main control DSP, the main control DSP displays short circuit protection, a loop is cut off, and shutdown inspection is carried out; and after the fault is eliminated, the power is supplied again.

On the other hand, the voltage capture circuit detects that the bus voltage is abnormal, the voltage analyzer judges the fault, the fault generator sends the fault to the fault responder of the bearing controller through CAN communication after judging the fault, the bearing controller receives and responds to the fault and feeds the fault back to the main control MCU, the MCU main program immediately sends an instruction to excite the standby power supply to be started, the power supply of the bearing controller is ensured to be normal, and the shaft is suspended stably before the motor stops rotating. The motor stops rotating, and the shaft normally falls. And waiting for the frequency converter to troubleshoot. And after the fault is eliminated, the power is supplied again.

Therefore, the fault is rapidly detected and the fault source is timely cut off under the condition that the peak voltage suppression measure is invalid, so that the frequency converter system can not run in a phase failure mode, and the safe and reliable running of the frequency converter system is ensured. Therefore, after the IGBT peak voltage suppression unit fails, the frequency converter system performs fault identification and fault diagnosis, and the setting of the frequency converter system is quickly adjusted or a fault source is cut off so as to ensure the reliability of the frequency converter system.

In some embodiments, the control unit, for positioning a short-circuit bridge arm of the inverter bridge, includes:

the control unit is specifically configured to compare the collected peak voltage between the collector and the emitter of the IGBT module with a set voltage between the collector and the emitter of the IGBT module to obtain a first voltage residual error; and comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage to obtain a second voltage residual error. And the number of the first and second groups,

the control unit is specifically configured to process the first voltage residual and the second voltage residual, so as to position a short-circuit bridge arm of the inverter bridge.

Therefore, when the inverter bridge is short-circuited, the voltage of the short-circuit phase is instantly reduced to zero, and the current is rapidly increased. Capturing voltage change by using a voltage sensor, and analyzing the voltage value V of the IGBT at the moment by using a voltage analyzer_CEAnd the bus voltage has a residual error compared with a set normal value, and the residual error is analyzed and processed to realize the identification and positioning of the fault so as to further process the fault.

Through a large amount of experimental verifications, adopt the technical scheme of the utility model, set up protective resistor and protective voltage source through the gate pole at IGBT, when the converter transships and the inverter bridge takes place the bridge arm short circuit, close IGBT to restrain IGBT module peak voltage through protective resistor and protective voltage source, avoid the IGBT module to transship at the converter or the inverter bridge takes place the bridge arm short circuit and damages the device.

According to the utility model discloses an embodiment still provides a motor system corresponding to the protection device of IGBT module in the converter. The motor system may include: the protection device of the IGBT module in the frequency converter is described above.

With the rapid development of the semiconductor industry, the cost of the IGBT module is gradually reduced, and replacing expensive IPM (intelligent power module) with the IGBT module has become the first choice for the frequency converter developer.

Fig. 2 is a schematic structural diagram of an embodiment of a frequency converter. As shown in fig. 2, the frequency converter includes: rectifier bridge, inverter bridge, inductance, electric capacity, resistance and switch. The alternating current power supply is input to the input end of the rectifier bridge, and the first end of the output end of the rectifier bridge is output to the first end of the input end of the inverter bridge after passing through the inductor; and the second end of the output end of the rectifier bridge is output to the second end of the input end of the inverter bridge after passing through the resistor. And the output end of the inverter bridge outputs the output to the motor. The switch is connected in parallel at two ends of the resistor, and the capacitor is connected in parallel between the first end of the input end of the inverter bridge and the second end of the input end of the inverter bridge. The alternating current at the input side of the frequency converter shown in fig. 2 is three-phase 380V alternating current, is direct current after being rectified by the full-bridge rectifier bridge, and is inverted into alternating current by the full-bridge inverter bridge to supply the alternating current to the motor for operation.

In the example shown in fig. 2, in the diode inverter, an uncontrolled rectifier bridge composed of diode modules is generally used to convert the industrial ac power into dc power for supplying to the rear end, and a controllable inverter bridge composed of IGBT modules is used to convert the dc power into ac power for supplying to the motor winding for driving the motor to operate.

In the example shown in fig. 2, when the IPM is replaced with an IGBT module, the IGBT module has a problem of failure such as overload and short circuit.

Specifically, because reliable IGBT protection measures are integrated in the IPM, the IPM can hardly break down under severe conditions such as overload, overcurrent and overvoltage in the operation process of the frequency converter. However, the IGBT modules are different, and when the inverter is overloaded or a bridge arm of the inverter bridge is short-circuited, if the IGBT is to be turned off, the voltage spike generated is very high, and at this time, the IGBT is very easily broken. The branch circuit where the broken IGBT is located is in an open-circuit state, but after an open-circuit fault occurs, the system can still run for a period of time in a phase-lacking manner, if a fault source is not switched off in time, the non-faulty IGBT can be caused to be in overcurrent, generate heat and be damaged in insulation, and even the system can be affected to be broken down, so that huge economic loss is caused.

In addition, commercial variable frequency air conditioning systems are usually used in large-scale places such as buildings, factories and the like, the frequency converter systems are generally arranged in roofs or underground warehouses due to large size, the environment is severe, overload can easily occur to the systems, and when the frequency converter systems run under overload, if the load cannot be adjusted in time, the frequency converter systems can run under overload.

In some embodiments, the present invention provides a fault detection scheme for an IGBT module in a frequency converter, which can solve the problem that a device is damaged when a bridge arm short circuit occurs to a frequency converter overload and an inverter bridge, and close the IGBT and suppress a peak voltage of the IGBT module when the bridge arm short circuit occurs to the frequency converter overload and the inverter bridge; and after the suppression measures are invalid, namely when the peak voltage exceeds a set threshold value, rapidly detecting the fault of the IGBT module, and timely cutting off the fault to prevent the system from operating in a phase-lacking manner, so that the safe and reliable operation of the frequency converter system is ensured.

Specifically, the utility model discloses a scheme, when the converter transships and the contravariant bridge takes place the bridge arm short circuit, closes IGBT, can ensure that non-trouble IGBT is not influenced and damage, has strengthened the reliability of converter system. When the IGBT module is turned off, that is, when the gate of the faulty IGBT is turned off, a peak voltage exists between the collector and the emitter of the faulty IGBT, and since the current flowing through the branch is large and the peak voltage is also large, the influence of the peak voltage between the collector and the emitter of the faulty IGBT on the non-faulty IGBT needs to be suppressed; therefore, the peak voltage of the IGBT module can be suppressed by the IGBT peak voltage suppressing unit to ensure that the non-faulty IGBT is not damaged when the faulty IGBT is turned off.

Specifically, the utility model discloses a scheme under the condition that peak voltage suppression measure became invalid, detects the trouble rapidly, in time cuts off the trouble source, can not let the converter system lack the looks operation, guarantees converter system safe and reliable operation. Therefore, after the IGBT peak voltage suppression unit fails, the frequency converter system performs fault identification and fault diagnosis, and the setting of the frequency converter system is quickly adjusted or a fault source is cut off so as to ensure the reliability of the frequency converter system.

The following describes an exemplary implementation process of the scheme of the present invention with reference to the examples shown in fig. 3 to 8.

Fig. 3 is a schematic structural diagram of an embodiment of a power supply control system of a motor. As shown in fig. 3, the power supply control system of the motor includes: the device comprises a rectifier bridge, a direct current reactor L, a bus capacitor C, a charging resistor R, a contactor K, a first DC-DC power supply, a main control board, a driving board, an inverter bridge, a second DC-DC power supply, a bearing controller and a bearing load.

Wherein, the input of rectifier bridge can input three-phase alternating current. The first end of the output end of the rectifier bridge is output to the first end of the input end of the inverter bridge after passing through the direct current reactor L, and the second end of the output end of the rectifier bridge is output to the second end of the input end of the inverter bridge after passing through the charging resistor R. The contactor K is connected with the charging resistor R in parallel. The first end of the bus capacitor C is connected to one end, far away from the rectifier bridge, of the direct current reactor L, and the second end of the bus capacitor C is connected to one end, far away from the rectifier bridge, of the charging resistor R. And the output end of the bus capacitor C is output to the inverter bridge through the first DC-DC power supply, the main control board and the drive board. And the output end of the bus capacitor C is also output to a bearing load after passing through a second DC-DC power supply and a bearing controller.

In the power supply control system of the motor shown in fig. 3, the inductance between the rectifier bridge and the inverter bridge is a dc reactor L. The rectifier bridge is composed of 6 diodes, is uncontrolled in rectification and does not need a main control board or a drive board; the inverter bridge is composed of 3 bridge arms of a full bridge formed by 6 IGBTs, and the bridge arms are controlled by a main control board and a driving board. When the frequency converter is just electrified, the contactor K is disconnected, and the bus charges the capacitor C through the charging resistor R. When the bus capacitor C is charged, the contactor K is closed, the charging resistor R is bypassed, and the motor runs.

Fig. 4 is a schematic diagram of a driving structure of an embodiment of an IGBT, which can show a gate driving principle of the IGBT. In the example shown in fig. 4, the pulse modulator of the IGBT can perform isolated conversion of the front-end control signal and the back-end drive signal of the drive board in the example shown in fig. 3. The pulse modulator of the IGBT outputs a corresponding level signal by detecting the jumping edge of the control signal, thereby controlling the opening and closing of the gate pole of the IGBT.

Fig. 5 is a schematic structural diagram of an embodiment of an inverter bridge IGBT spike voltage suppression and fault detection system. In the inverter bridge IGBT spike voltage suppression and fault detection system as shown in fig. 5, the inverter bridge in the frequency converter is composed of 6 IGBTs, and a voltage source V is added between the gate of each IGBT and the driving board_negE.g. first IGBT Q₁Between the gate pole and the driving board thereof is added a first voltage source V_neg1Second IGBT Q₂Between the gate pole and its drive plate, a second voltage source V is added_neg2. Fig. 5 shows only the voltage source of one IGBT and the device for detecting the failure of the main control board, and the voltage spike suppression and failure detection of the other 5 IGBTs are not shown. When the frequency converter is overloaded or the IGBT is short-circuited, the voltage source is connected into the system, and then voltage spikes are restrained, so that the IGBT of the faultless phase is prevented from being damaged.

The voltage source is controlled by an inter-board relay KA1, and when the peak voltage is in a threshold range, the voltage source is cut off, so that the reliability can be ensured, and the switching loss can be reduced to the minimum as much as possible. After the gate pole of the IGBT adopts a negative voltage source, the peak voltage generated at the moment of turn-off of the IGBT can be inhibited, and the turn-off reliability is ensured. When the peak voltage exceeds the threshold value, the detected instantaneous voltage value can be captured by the voltage sensor, and the voltage analyzer is immediately started for fault analysis and processing.

In the example shown in fig. 5, an adjustable resistor R is added to the gate of the IGBT_GCan beRegulated resistance R_GWhich is used to limit the voltage spike when the switching tube (i.e. IGBT) is turned on. For example, adding a first adjustable resistor R at the gate of the first switch tube Q1_G1Adding a fourth adjustable resistor R at the gate of a fourth switching tube Q4_G4And so on.

In the example shown in fig. 5, the master control board incorporates fault detection and fault handling circuitry. A voltage capture circuit is added at one side of a bus capacitor C, namely the direct-current output end of the bus voltage, so that the peak voltage between the DC + and the DC-of the direct-current bus can be acquired in real time, and whether the bus voltage is in the working range of the bearing switch power supply or not is judged through a voltage analyzer.

As shown in fig. 4, for the IGBT itself, a high spike voltage is generated between the gate G and the collector C during the turn-off period of the IGBT based on the coupling between the gate G and the collector C. As shown in fig. 5, 6 IGBTs form 3 arms of the inverter bridge, each arm generates a varying dV/dt when the upper tube Q1(Q3/Q5) is turned on, the voltage passes through the lower tube Q4(Q6/Q2), the current causes a voltage difference across the gate resistance of the lower tube, and if the voltage exceeds the gate driving threshold of the IGBT, the lower tube is turned on, which poses a shoot-through risk. Such misconduction may cause the IGBT to be damaged, and thus the system may malfunction.

When gate voltage source V is added_negThen, IGBT gate pole limits voltage V_GEThe lifting is realized:

V_GE＝(R_d+R_G)*I_CG+V_neg。

in the formula, V_GEIs the gate voltage of IGBT, R_dTo drive a resistor, R_GIs a gate resistance, I_CGIs the on-current of IGBT, V_negIs an externally connected voltage source.

Fig. 6 is a schematic graph of the Ic current, the PWM driving signal and the Vce voltage when the IGBT is turned off and the peak voltage is 820V without peak voltage suppression. Fig. 7 is a graph showing Ic current, PWM driving signal and Vce voltage when the IGBT is turned off and the peak voltage is 780V when the peak voltage is suppressed. Fig. 8 is a flowchart of an IGBT fault detection method in a frequency converter.

In fig. 6, when there is no spike voltage suppression, the gate turn-on signal PWM signal of the upper tube IGBT changes from "1" to "0", and the upper tube IGBT turns off, and the Vce voltage spike is 820V. In fig. 7, when the peak voltage is suppressed, the gate turn-on signal PWM signal of the upper tube IGBT changes from "1" to "0", and the upper tube IGBT is turned off, and the Vce voltage peak is 780V at this time.

In some embodiments, as shown in fig. 8, the adjustable resistor R is adjusted when the frequency converter is in normal operation (the frequency converter is not overloaded, and the inverter bridge is not short-circuited)_GThe resistance value of the bridge arm enables the peak voltage of the IGBT to be within a reasonable threshold range, and the other IGBT of the bridge arm does not need to connect a voltage source into a circuit, so that the circuit loss can be reduced.

When the frequency converter works abnormally, the partial frequency converter is overloaded or the inverter bridge is short-circuited, and the specific mode of fault protection processing is exemplarily explained.

The first failure protection processing specific mode:

when the frequency converter is overloaded, the peak voltage V of one tube of the bridge arm_CEWill exceed the set threshold if adjusted by adjusting the adjustable resistance R_GIt can be controlled within a threshold range and the gate voltage source of another tube does not need to be switched into the circuit. If the adjustable resistance R is adjusted_GIf the voltage of the IGBT is not controlled within the threshold range, the gate voltage source of the other tube is connected into the circuit to increase the limit voltage V of the IGBT gate_GEAnd the other IGBT of the bridge arm is prevented from being triggered to be conducted when the other IGBT is conducted, so that a fault is prevented.

The second failure protection processing specific mode: when the inverter bridge is short-circuited, the adjustable resistor R is adjusted_GThe peak voltage V cannot be controlled_CEThen, the voltage source is connected into the circuit to increase the IGBT gate limiting voltage V_GEAnd the other IGBT of the bridge arm is prevented from being triggered to be conducted when the other IGBT is conducted, so that a fault is prevented.

In some embodiments, as shown in fig. 5, when the frequency converter operates abnormally, in which case the abnormality refers to overload of the frequency converter and short-circuit of the bridge arm, the voltage source is connected to the circuit.

The first failure detection mode:

when the frequency converter is overloaded, the current sensor detects that the frequency converter has normal three-phase current output and the amplitude value is increased and exceeds a set threshold value i_limAnd judging that the frequency converter is in an overload state. When the peak voltage V of the bridge arm IGBT_CEExceeding the set voltage threshold by adjusting the adjustable resistor R_GIt can be controlled at a threshold u_limInsofar, then the gate voltage source of the other IGBT need not be switched into the circuit. At this time, the fault detection module is also not activated. If gate pole adjustable resistance R of IGBT is adjusted_GThe peak voltage cannot be suppressed to the threshold value u_limWithin the range, the voltage source V_negOn, after on, gate voltage V_GEThe IGBT can be lifted, and the spike voltage impact when the IGBT is turned off can be resisted. And the overload information can be fed back to the client, so that the client can adjust the load of the unit within a rated range.

The second failure detection mode:

when the inverter bridge is short-circuited, the voltage of the short-circuit phase is instantly reduced to zero, and the current is rapidly increased. Capturing voltage change by using a voltage sensor, and analyzing the voltage value V of the IGBT at the moment by using a voltage analyzer_CEAnd the bus voltage has a residual error compared with a set normal value, and the residual error is analyzed and processed to realize the identification and positioning of the fault so as to further process the fault.

Wherein, analyzing and processing the residual error may include: the voltage analyzer is set with a Vce threshold value, which is a given calibration value. When the captured voltage deviates from the value, there is a residual voltage, the residual voltage is amplified, and a fault is identified according to the residual voltage, thereby starting a fault handling program.

In some embodiments, the frequency converter is used in a magnetic suspension centrifugal machine set. The magnetic suspension centrifuge is different from the common frequency conversion centrifuge in that the motor adopts a magnetic suspension motor, and a shaft of the magnetic suspension motor needs to be suspended when the motor runs, namely the shaft needs to be suspended through a bearing controller.

When the inverter bridge of the frequency converter is short-circuited, the IGBTBetween collector and emitter of (2) a peak voltage value V_CEMutations (u as shown in FIG. 5) occur_ce4) Bus voltage U_DCA momentary pull-down may also occur, dropping the voltage range of the DC-DC switching power supply supplying the bearing controller. The switching power supply is not input instantly, so that output abnormity can be caused, the bearing controller works abnormally, and further the bearing is suspended abnormally, the precision of the floating shaft of the bearing is poor if the bearing is light, the shaft is still rotated to touch the shaft if the bearing is heavy, and even the shaft is smashed, which are not allowed.

Adding V to IGBT gate pole_negRear, V_GEAnd whether the actual value exceeds the set value or not, if the bridge arm is short-circuited, the fault processing is carried out.

In the above embodiment, fig. 5 shows the fault detection device of only one arm (Q1 and Q4), and actually, three arms of the inverter bridge have the IGBT spike voltage suppression means and the fault detection processing means.

In some embodiments, the same function can be achieved by improving the algorithm and adding an external single-pole double-throw switch.

Specifically, 6 IGBTs are controlled by individual switches without causing the gate of the IGBT to be uncontrolled due to a delay in the mutual switching signals or contact failure. If the single-pole double-throw switch has two contacts of one coil, when the coil is out of control, the switch state can not be switched.

Since the processes and functions implemented by the motor system of this embodiment substantially correspond to the embodiments, principles, and examples of the apparatus shown in fig. 1, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

Through a large number of tests, the technical scheme of the utility model is adopted, the IGBT is closed when the frequency converter is overloaded and the inverter bridge is in bridge arm short circuit, so that the damage of the non-fault IGBT without being influenced can be ensured, and the reliability of the frequency converter system is enhanced; through the IGBT peak voltage suppression unit, the peak voltage of the IGBT module is suppressed, so that the non-fault IGBT is not damaged when the fault IGBT is turned off.

According to the embodiment of the present invention, there is also provided a protection method for an IGBT module in a frequency converter corresponding to a motor system, as shown in fig. 9. The protection method of the IGBT module in the frequency converter can comprise the following steps: step S110 to step S130.

In step S110, the acquisition unit acquires the three-phase current of the frequency converter, acquires the peak voltage between the collector and the emitter of the IGBT module, and acquires the bus voltage of the dc power supply of the frequency converter, when the inverter bridge operates after the frequency converter is powered on.

At step S120, determining, by a control unit, whether the frequency converter normally operates according to at least one of the collected three-phase current of the frequency converter, a peak voltage between a collector and an emitter of the IGBT module, and a bus voltage of a dc power supply of the frequency converter, that is, determining whether the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited; and under the condition that the frequency converter does not work normally, namely whether the frequency converter is overloaded or not or under the condition that a bridge arm of the inverter bridge is short-circuited, controlling the IGBT module to keep a closed state, and initiating a control signal capable of controlling the IGBT peak voltage suppression unit so as to control the IGBT peak voltage suppression unit to start and control the IGBT peak voltage suppression unit to suppress the peak voltage between a collector and an emitter of the IGBT module.

At step S130, the IGBT spike voltage suppression unit suppresses the spike voltage between the collector and the emitter of the IGBT module under the control of the control signal.

In step S110, acquiring, by an acquisition unit, a three-phase current of the frequency converter and a peak voltage between a collector and an emitter of the IGBT module under a condition that the inverter bridge operates after the frequency converter is powered on, including:

and collecting the three-phase current of the frequency converter through a current collecting unit, such as a current sensor.

And collecting the peak voltage between the collector and the emitter of the IGBT module through a voltage collecting unit, such as a voltage sensor.

And collecting the bus voltage of the direct current power supply of the frequency converter through a voltage capture unit, such as a voltage capture circuit.

Correspondingly, determining whether the frequency converter normally works or not according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module and the bus voltage of the direct-current power supply of the frequency converter through a control unit, namely determining whether the frequency converter is overloaded or whether a bridge arm of the inverter bridge is short-circuited, includes: and judging whether the frequency converter is overloaded or not.

The following description, with reference to fig. 10, illustrates an embodiment of a process for determining whether the frequency converter is overloaded according to the method of the present invention, which further describes a specific process of determining whether the frequency converter is overloaded, and may include: step S210 and step S220.

Step S210, if the collected three-phase current of the frequency converter shows that the frequency converter has normal three-phase current output, and the amplitude of the three-phase current output by the frequency converter is increased and exceeds a set current amplitude, determining that the frequency converter is overloaded. And the number of the first and second groups,

step S220, under the condition that the frequency converter is overloaded, if the collected peak voltage between the collector and the emitter of the IGBT module exceeds a set voltage threshold, determining that the frequency converter is not operating normally, that is, determining that the frequency converter is overloaded and does not operate normally.

Or, determining, by a control unit, whether the frequency converter normally operates according to at least one of the collected three-phase current of the frequency converter, a peak voltage between a collector and an emitter of the IGBT module, and a bus voltage of a dc power supply of the frequency converter, that is, determining whether the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited, further including: and judging whether the bridge arms of the inverter bridge are short-circuited.

Referring to fig. 11, an embodiment of a process for determining whether the bridge arm of the inverter bridge is short-circuited according to the method of the present invention is schematically illustrated, and a specific process of determining whether the bridge arm of the inverter bridge is short-circuited may include: step S310 and step S320.

Step S310, comparing the collected peak voltage between the collector and the emitter of the IGBT module with the set voltage between the collector and the emitter of the IGBT module; and comparing the bus voltage of the direct current power supply of the frequency converter with a set bus voltage. And the number of the first and second groups,

step S320, if the collected peak voltage between the collector and the emitter of the IGBT module is suddenly changed relative to the set voltage between the collector and the emitter of the IGBT module; and if the bus voltage of the direct-current power supply of the frequency converter is lowered relative to the set bus voltage, determining that the frequency converter does not work normally, namely determining that the bridge arms of the inverter bridge are short-circuited.

In step S120, the controlling unit controls the IGBT module to maintain the off state and to initiate a control signal capable of controlling the IGBT spike voltage suppression unit when the frequency converter does not normally operate, that is, when the frequency converter is overloaded or a bridge arm of the inverter bridge is short-circuited, and the controlling unit includes: and under the condition that the frequency converter does not work normally, the IGBT module is closed, and a control signal for controlling the IGBT spike voltage suppression unit corresponding to the other IGBT module on the bridge arm where the IGBT module is located is initiated.

Therefore, when the frequency converter is overloaded and the bridge arm of the inverter bridge is short-circuited, the IGBT is closed, the non-fault IGBT can be ensured not to be influenced and damaged, and the reliability of the frequency converter system is enhanced. When the IGBT module is turned off, that is, when the gate of the faulty IGBT is turned off, there is a spike voltage between the collector and the emitter of the faulty IGBT, and since the current flowing through the branch is large and the spike voltage is also large, the influence of the spike voltage between the collector and the emitter of the faulty IGBT on the non-faulty IGBT needs to be suppressed. Therefore, the peak voltage of the IGBT module can be suppressed by the IGBT peak voltage suppressing unit to ensure that the non-faulty IGBT is not damaged when the faulty IGBT is turned off.

In step S130, the suppressing, by the IGBT spike voltage suppressing unit, the spike voltage between the collector and the emitter of the IGBT module under the control of the control signal includes:

through the resistance suppression module, the suppression of the peak voltage between the collector and the emitter of the IGBT module is realized by utilizing the resistance value of the resistance suppression module.

Through the voltage source suppression module, under the condition that the voltage source suppression module is connected in, the voltage source provided by the voltage source suppression module is utilized to further suppress the peak voltage between the collector and the emitter of the IGBT module.

Specifically, an inverter bridge in the frequency converter consists of 6 IGBTs, and a voltage source V is added between a gate pole of each IGBT and a driving plate_negE.g. first IGBT Q₁Between the gate pole and the driving board thereof is added a first voltage source V_neg1Second IGBT Q₂Between the gate pole and its drive plate, a second voltage source V is added_neg2. Fig. 4 shows the methods of detecting the voltage source and the main control board fault of only one IGBT, and the voltage spike suppression and fault detection of the other 5 IGBTs are not shown.

A specific process of initiating a control signal for controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located by the control unit may be referred to as the following exemplary description.

The following description, in combination with fig. 12, shows the utility model discloses an embodiment flow diagram of the control signal that the IGBT spike voltage suppression unit controls that initiates another IGBT module on the bridge arm where this IGBT module is located in the method, further describe the specific process of initiating the control signal that the IGBT spike voltage suppression unit controls that another IGBT module on the bridge arm where this IGBT module is located corresponds, can include: step S410 to step S430.

Step S410, when the peak voltage between the collector and the emitter of one IGBT module collected by the collection unit suddenly changes with respect to the set voltage between the collector and the emitter of the IGBT module, the IGBT module is turned off, and a resistance value adjustment signal for adjusting the resistance value of the gate resistance value suppression module corresponding to the other IGBT module is initiated, so as to suppress the peak voltage between the collector and the emitter of the other IGBT module by adjusting the resistance value of the gate resistance value suppression module.

Step S420, after the gate resistance suppression module corresponding to the other IGBT module adjusts the resistance based on the resistance adjustment signal, determining again whether the peak voltage between the collector and the emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold.

Step S430, if the peak voltage between the collector and the emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold, a voltage source access signal capable of controlling access of the voltage source suppression module corresponding to the other IGBT module is initiated, so as to further suppress the peak voltage between the collector and the emitter of the other IGBT module by accessing the voltage source suppression module.

Specifically, when the peak voltage exceeds a set threshold, the detected instantaneous voltage value can be captured by the voltage sensor, and the voltage analyzer is immediately started to perform fault analysis and processing. When the inverter bridge is short-circuited, the adjustable resistor R is adjusted_GThe peak voltage V cannot be controlled_CEThen, the voltage source is connected into the circuit to increase the IGBT gate limiting voltage V_GEAnd the other IGBT of the bridge arm is prevented from being triggered to be conducted when the other IGBT is conducted, so that a fault is prevented. The voltage source is controlled by an inter-board relay KA1, and when the peak voltage is in a threshold range, the voltage source is cut off, so that the reliability can be ensured, and the switching loss can be reduced to the minimum as much as possible. After the gate pole of the IGBT adopts a negative voltage source, the peak voltage generated at the moment of turn-off of the IGBT can be inhibited, and the turn-off reliability is ensured.

In some embodiments, further comprising: the process of performing fault processing when the inverter bridge has a bridge arm short-circuit fault may specifically include:

through the control unit, after a control signal capable of controlling the IGBT spike voltage suppression unit is initiated, specifically, after a control signal controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located is initiated, if the frequency converter is overloaded under the condition that the frequency converter does not work normally, a warning message of the frequency converter overload is initiated to remind a user to adjust the load of the frequency converter to a rated load range. Specifically, the overload information can be fed back to the client, so that the client can adjust the load of the unit within a rated range.

Or, the control unit is specifically configured to, after initiating a control signal capable of controlling the IGBT spike voltage suppression unit, specifically after initiating a control signal controlling the IGBT spike voltage suppression unit corresponding to another IGBT module on the bridge arm where the IGBT module is located, if the situation that the frequency converter does not normally operate is that the bridge arm of the inverter bridge is short-circuited, perform positioning and fault removal processing on the short-circuited bridge arm of the inverter bridge, and then enable the frequency converter to be powered up again. And transmitting a short-circuit message of a bridge arm of the inverter bridge to the bearing controller through a communication channel under the condition that the frequency converter outputs the short-circuit message to the bearing controller, so that the bearing controller can start a self-protection mechanism in time under the condition that the inverter bridge has a fault.

Specifically, the main control board is added with a fault detection and fault processing circuit. A voltage capture circuit is added at one side of a bus capacitor C, namely the direct-current output end of the bus voltage, so that the peak voltage between the DC + and the DC-of the direct-current bus can be acquired in real time, and whether the bus voltage is in the working range of the bearing switch power supply or not is judged through a voltage analyzer. When the inverter bridge of the frequency converter is short-circuited, the peak voltage value V between the collector and the emitter of the IGBT_CEWill suddenly change, the bus voltage U_DCA momentary pull-down may also occur, dropping the voltage range of the DC-DC switching power supply supplying the bearing controller. The switching power supply is not input instantly, so that output abnormity can be caused, the bearing controller works abnormally, and further the bearing is suspended abnormally, the precision of the floating shaft of the bearing is poor if the bearing is light, the shaft is still rotated to touch the shaft if the bearing is heavy, and even the shaft is smashed, which are not allowed. Adding V to IGBT gate pole_negRear, V_GEPractice ofAnd whether the value exceeds a set value or not, if the bridge arm is short-circuited, fault processing is carried out.

In some embodiments, a specific process for positioning the short-circuit bridge arm of the inverter bridge may be referred to in the following exemplary description.

Referring to fig. 13, the following describes a specific process of positioning the short-circuit bridge arm of the inverter bridge according to an embodiment of the method of the present invention, which is schematically illustrated in the flowchart of the method of positioning the short-circuit bridge arm of the inverter bridge, and may include: step S510 and step S520.

Step S510, comparing the collected peak voltage between the collector electrode and the emitter electrode of the IGBT module with the set voltage between the collector electrode and the emitter electrode of the IGBT module to obtain a first voltage residual error; and comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage to obtain a second voltage residual error. And the number of the first and second groups,

and step S520, processing the first voltage residual and the second voltage residual to realize the positioning of a short-circuit bridge arm of the inverter bridge.

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

Through a large number of tests, the technical scheme of the embodiment is adopted, the IGBT is turned off and the peak voltage of the IGBT module is suppressed when the frequency converter is overloaded and the inverter bridge is in bridge arm short circuit; and after the suppression measures are invalid, namely when the peak voltage exceeds a set threshold value, rapidly detecting the fault of the IGBT module, and timely cutting off the fault to prevent the system from operating in a phase-lacking manner, so that the safe and reliable operation of the frequency converter system is ensured.

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 various modifications and changes may be made by those skilled in the art. 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. A protection device of IGBT module in converter, its characterized in that includes: the IGBT power supply comprises an acquisition unit, an IGBT spike voltage suppression unit and a control unit; wherein the content of the first and second substances,

the acquisition unit is configured to acquire a three-phase current of the frequency converter, acquire a peak voltage between a collector and an emitter of the IGBT module, and acquire a bus voltage of a direct-current power supply of the frequency converter under the condition that an inverter bridge works after the frequency converter is powered on;

the control unit is configured to determine whether the frequency converter works normally according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module and the bus voltage of the direct-current power supply of the frequency converter; and under the condition that the frequency converter does not work normally, controlling the IGBT module to keep a closed state, and initiating a control signal capable of controlling the IGBT spike voltage suppression unit;

the IGBT spike voltage suppression unit is configured to suppress a spike voltage between a collector and an emitter of the IGBT module under the control of the control signal.

2. The protection device for the IGBT module in the frequency converter according to claim 1, wherein the collecting unit comprises: the device comprises a current acquisition unit, a voltage acquisition unit and a voltage capture unit; the number of the voltage acquisition units is consistent with that of the IGBT modules in the inverter bridge; each voltage acquisition unit is configured to acquire peak voltage between a collector and an emitter of one corresponding IGBT module under the condition that the inverter bridge works after the frequency converter is powered on;

wherein, the collection unit gathers the three-phase current of converter to gather the spike voltage between the collecting electrode of IGBT module and the projecting pole, include:

the current acquisition unit is configured to acquire three-phase currents of the frequency converter;

the voltage acquisition unit is configured to acquire a spike voltage between a collector and an emitter of the IGBT module;

the voltage capture unit is configured to collect bus voltage of a direct current power supply of the frequency converter;

correspondingly, the determining, by the control unit, whether the frequency converter is working normally according to at least one of the collected three-phase current of the frequency converter, the peak voltage between the collector and the emitter of the IGBT module, and the bus voltage of the dc power supply of the frequency converter includes:

if the collected three-phase current of the frequency converter shows that the frequency converter has normal three-phase current output, and the amplitude of the three-phase current output by the frequency converter is increased and exceeds the set current amplitude, determining that the frequency converter is overloaded; and the number of the first and second groups,

if the collected peak voltage between the collector and the emitter of the IGBT module exceeds a set voltage threshold, determining that the frequency converter does not work normally, namely determining that the frequency converter is overloaded and does not work normally;

alternatively, the first and second electrodes may be,

comparing the collected peak voltage between the collector and the emitter of the IGBT module with the set voltage between the collector and the emitter of the IGBT module; comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage; and the number of the first and second groups,

if the collected peak voltage between the collector and the emitter of the IGBT module is suddenly changed relative to the set voltage between the collector and the emitter of the IGBT module; and if the bus voltage of the direct-current power supply of the frequency converter is lowered relative to the set bus voltage, determining that the frequency converter does not work normally, namely determining that the bridge arms of the inverter bridge are short-circuited.

3. The protection device for the IGBT modules in the frequency converter according to claim 2, wherein the number of the IGBT spike voltage suppression units is the same as the number of the IGBT modules in the inverter bridge of the frequency converter; each IGBT spike voltage suppression unit is specifically arranged between one corresponding IGBT module and a drive plate of the IGBT module;

the control unit controls the IGBT module to keep a closed state and initiates a control signal capable of controlling the IGBT spike voltage suppression unit, and the control unit comprises:

and under the condition that the frequency converter does not work normally, the IGBT module is closed, and a control signal for controlling the IGBT spike voltage suppression unit corresponding to the other IGBT module on the bridge arm where the IGBT module is located is initiated.

4. The protection device for the IGBT module in the frequency converter according to claim 3, wherein each IGBT spike voltage suppression unit comprises: the device comprises a resistance suppression module and a voltage source suppression module; the resistance suppression module is arranged between the output end of the drive plate of the IGBT module and the gate pole of the IGBT module; the voltage source suppression module is arranged between the input end of the driving plate of the IGBT module and the emitter of the IGBT module;

the resistance suppression module is configured to suppress spike voltage between a collector and an emitter of the IGBT module by utilizing the resistance value of the resistance suppression module;

5. The protection device for the IGBT module in the frequency converter according to claim 4, wherein the control signal comprises: the resistance value adjusting signal can adjust the resistance value of the resistance suppression module, and the voltage source access or cut-out signal can control the access or cut-out of the voltage source suppression module;

initiating a resistance value adjusting signal for adjusting the resistance value of the gate pole and gate pole resistance value suppression module corresponding to the other IGBT module;

after the resistance value of the gate pole resistance value suppression module corresponding to the other IGBT module is adjusted based on the resistance value adjustment signal, whether the peak voltage between the collector and the emitter of the IGBT module turned off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold value is determined again;

and if the peak voltage between the collector and the emitter of the IGBT module switched off on the bridge arm where the other IGBT module is located still exceeds the set voltage threshold, initiating a voltage source access signal capable of controlling the access of the voltage source suppression module corresponding to the other IGBT module.

6. The protection device for the IGBT module in the frequency converter according to any one of claims 1 to 5, characterized by further comprising:

the control unit further configured to, after initiating a control signal capable of controlling the IGBT spike voltage suppression unit,

if the frequency converter does not work normally, the frequency converter is overloaded, a reminding message of the frequency converter overload is initiated to remind a user to adjust the load of the frequency converter to be within a rated load range;

if the situation that the frequency converter does not work normally is that the bridge arms of the inverter bridge are short-circuited, positioning and removing faults of the short-circuited bridge arms of the inverter bridge; and transmitting a short-circuit message of a bridge arm of the inverter bridge to the bearing controller through a communication channel under the condition that the frequency converter outputs the short-circuit message to the bearing controller, so that the bearing controller can start a self-protection mechanism in time under the condition that the inverter bridge has a fault.

7. The device according to claim 6, wherein the control unit locates the short-circuit bridge arm of the inverter bridge, and comprises:

comparing the collected peak voltage between the collector and the emitter of the IGBT module with the set voltage between the collector and the emitter of the IGBT module to obtain a first voltage residual error; comparing the bus voltage of the direct-current power supply of the frequency converter with a set bus voltage to obtain a second voltage residual error; and the number of the first and second groups,

and processing the first voltage residual error and the second voltage residual error to realize the positioning of a short-circuit bridge arm of the inverter bridge.

8. An electric machine system, comprising: protection device of an IGBT module in a frequency converter according to any one of claims 1 to 7.