Protection device, motor controller, frequency converter, motor and air conditioner

Abstract

The invention belongs to the technical field of motors, and discloses a protection device, a motor controller, a frequency converter, a motor and an air conditioner, and the device comprises a sampling module which carries out the sampling of a three-phase inversion negative end of an IPM module, and obtains a sampling current; the comparison module is used for comparing the sampling current with a reference threshold value to obtain a comparison result; the comparison result is a first result that the sampling current is not over-current or a second result that the sampling current is over-current; the protection module outputs a first protection signal when the comparison result is a first result, outputs a second protection signal when the comparison result is a second result, and outputs the first protection signal after a set time; and the switch module controls the driving control chip to work when receiving the first protection signal and controls the driving control chip to stop working when receiving the second protection signal. According to the scheme, the overcurrent timing shutdown and self-starting function circuit is arranged between the three-phase inversion negative end of the IPM module and the driving control special chip, so that the IPM module is protected, and the safety is improved.

Description

Technical Field

[0001] The present invention belongs to the field of motor technology, and specifically relates to a protection device, a motor controller, a frequency converter, a motor and an air conditioner, and more particularly to an application device, a motor controller, a frequency converter, a motor and an air conditioner of a circuit with overcurrent timed shutdown and self-start functions on a dedicated chip for motor drive control. Background Art

[0002] In the field of motor drive control (such as brushless DC motors), dedicated drive control chips are often used. These are highly integrated circuits designed specifically for specific motor drive control tasks. These chips are widely used due to their many advantages, including high performance, low power consumption, high reliability, and simple development. However, some motor drive control chips in related solutions lack overcurrent protection and lockout functionality, which can damage power devices in the motor's drive control circuitry and even lead to safety accidents.

[0003] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a protection device, a motor controller, a frequency converter, a motor and an air conditioner to solve the problem in related solutions that the motor drive control dedicated chip does not have an overcurrent protection locking function, which may cause damage to power devices in the motor drive control circuit and even cause safety accidents. By setting a circuit with overcurrent timed shutdown and self-start functions between the three-phase inverter negative terminal of the motor IPM module and the motor drive control dedicated chip that does not have an overcurrent protection locking function, the IPM module is protected and the safety is improved.

[0005] The present invention provides a protection device for use in the drive control of a motor. The protection device is arranged between the three-phase inverter negative terminal of an IPM module of the motor and the enable pin of a drive control chip of the motor. The protection device comprises: a sampling module, a comparison module, a protection module, and a switch module. The sampling module is configured to sample current from the three-phase inverter negative terminal of the IPM module to obtain a sampled current of the IPM module. The comparison module is configured to set a reference threshold and compare the sampled current of the IPM module with the reference threshold to obtain a comparison result. The comparison result is a first result indicating that the sampled current of the IPM module is not overcurrent, or a second result indicating that the sampled current of the IPM module is overcurrent. The protection module is configured to output a first protection signal if the comparison result is the first result; output a second protection signal if the comparison result is the second result; and output the first protection signal again after a set time period after outputting the second protection signal. The switch module is configured to control the drive control chip to operate upon receiving the first protection signal; and control the drive control chip to stop operating upon receiving the second protection signal.

[0006] In some embodiments, the sampling module includes: a first resistance module, a second resistance module and a first capacitor module; wherein the three-phase inverter negative end of the IPM module is grounded after passing through the first resistance module; the three-phase inverter negative end of the IPM module is also grounded after passing through the second resistance module and the first capacitor module; the common end of the second resistance module and the first capacitor module can output the sampling current of the IPM module to the comparison module.

[0007] In some embodiments, the comparison module includes: a third resistor module, a fourth resistor module, a second capacitor module and a first comparison module; wherein, a preset positive DC power supply is grounded after passing through the third resistor module and the fourth resistor module; the common end of the third resistor module and the fourth resistor module is grounded after passing through the second capacitor module; the common end of the third resistor module and the fourth resistor module can output the reference threshold to the non-inverting input end of the first comparison module; the sampling current of the IPM module output by the sampling module can be input to the inverting input end of the first comparison module; the output end of the first comparison module can output the comparison result to the protection module.

[0008] In some embodiments, the protection module includes: a fifth resistor module, a sixth resistor module, a third capacitor module, a fourth capacitor module and a second comparison module; wherein the comparison result output by the comparison module can be input to the inverting input terminal of the second comparison module; a preset positive DC power supply is grounded after passing through the fifth resistor module and the third capacitor module; the common terminal of the fifth resistor module and the third capacitor module is connected to the inverting input terminal of the second comparison module; a preset positive DC power supply is grounded after passing through the sixth resistor module and the fourth capacitor module; the common terminal of the sixth resistor module and the fourth capacitor module is connected to the non-inverting input terminal of the second comparison module; the output terminal of the second comparison module can output the first protection signal or the second protection signal to the control terminal of the switch module.

[0009] In some embodiments, the protection module further includes: at least one of a seventh resistance module and a fifth capacitance module; wherein the seventh resistance module is arranged between the common end of the sixth resistance module and the fourth capacitance module and the ground; and the fifth capacitance module is arranged between the power supply end of the second comparison module and the ground.

[0010] In some embodiments, the switch module includes: an eighth resistor module and a switch tube; wherein the first protection signal or the second protection signal output by the protection module can be input into the control end of the switch tube; a preset positive DC power supply is connected to the control end of the switch tube after passing through the eighth resistor module; the first connection end of the switch tube is connected to the enable pin of the drive control chip of the motor; and the second connection end of the switch tube is grounded.

[0011] Matching the above-mentioned device, the present invention further provides a motor controller, comprising: the protection device described above.

[0012] Matching the above device, the present invention further provides a frequency converter, including: the protection device described above.

[0013] Matching the above-mentioned device, the present invention further provides a motor, comprising: the above-mentioned protection device, or the above-mentioned motor controller, or the above-mentioned frequency converter.

[0014] Matching the above-mentioned device, the present invention further provides an air conditioner, comprising: the protection device mentioned above, or the motor controller mentioned above, or the frequency converter mentioned above, or the motor mentioned above.

[0015] Therefore, the solution of the present invention is to provide a dedicated chip for motor drive control that does not have an overcurrent protection locking function in the motor drive control. An overcurrent timed shutdown and self-start function circuit consisting of a current sampling unit, an overcurrent comparison unit (specifically, an overcurrent comparison unit with an overcurrent comparison function, a shutdown locking function, and a self-start release function), and a switch control unit is provided between the three-phase inverter negative terminal of the motor's IPM module and the dedicated chip. The current sampling unit is used to sample the current at the three-phase inverter negative terminal of the IPM module, and the overcurrent comparison unit is used to determine whether the current is overcurrent. The dedicated chip is controlled by the switch control unit based on the determination result to achieve overcurrent shutdown protection, shutdown locking, and recovery self-start. Thus, by providing a circuit with overcurrent timed shutdown and self-start functions between the three-phase inverter negative terminal of the motor's IPM module and the dedicated chip for motor drive control that does not have an overcurrent protection locking function, protection of the IPM module is achieved and safety is improved.

[0016] Other features and advantages of the present invention 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 present invention.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of an embodiment of a protection device of the present invention; Figure 2 This is a flow chart of the overcurrent shutdown protection process; Figure 3 This is a flow chart of the over-current shutdown lockout / self-start process; Figure 4 This is a structural diagram of the overcurrent timed shutdown and self-start function circuit. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Considering that the motor drive control dedicated chip in the relevant solution does not have an overcurrent protection lock function, it will cause damage to the power devices in the motor drive control circuit, and even cause safety accidents. Specifically, when the motor has an overcurrent, although it can also shut down for protection (for example: overtemperature protection, when an overcurrent occurs, the current increases rapidly, and the current increase causes the power module temperature to rise. When the overtemperature protection point is reached, the motor stops running. The overtemperature process is relatively slow, and the overcurrent is quickly released), but before the overcurrent fault is resolved, oscillation and repeated restarts may occur in a short period of time, thereby disrupting the normal start-stop power-on sequence, causing permanent damage to the relevant power devices, and even causing serious safety accidents.

[0021] Therefore, the solution of the present invention proposes a protection device, specifically an application device of a circuit with overcurrent timing shutdown and self-start functions on a dedicated chip for motor drive control. By providing a circuit with overcurrent timing shutdown and self-start functions, it is possible to monitor the current changes at the negative end of the three-phase inverter of the motor's power module, and make a judgment on whether to shut down based on the changes in current size; when the shutdown is determined, the shutdown is controlled and the shutdown lock is performed to avoid damage caused by oscillation and repeated restarts when the overcurrent is not relieved; after the shutdown lock is performed, the shutdown self-start can be performed to automatically resume normal operation when the fault is relieved, thereby ensuring normal operation and improving reliability.

[0022] According to an embodiment of the present invention, a protection device is provided. Figure 1 The structural diagram of an embodiment of the device of the present invention is shown. The protection device is applied to the drive control of the motor. The protection device is arranged between the three-phase inverter negative terminal of the IPM module of the motor and the enable pin of the drive control chip of the motor; the three-phase inverter negative terminal of the IPM module is the output terminal of the lower bridge of the three-phase inverter bridge in the IPM module, such as the terminal NU or terminal NV or terminal NW of the IPM module, and the drive control chip of the motor does not have an overcurrent protection locking function. In the solution of the present invention, Figure 1 As shown, the protection device includes: a sampling module, a comparison module, a protection module and a switch module. Figure 4 This is a schematic diagram of the structure of the overcurrent timed shutdown and self-start function circuit. The sampling module is as follows: Figure 2 and Figure 4 The current sampling unit shown in the figure and the comparison module are as follows Figure 2 and Figure 4 The overcurrent comparison unit shown in the figure, the protection module is as follows Figure 2 and Figure 4 The shutdown lock function module and the automatic start release function module are shown, and the switch module is as follows Figure 2 and Figure 4 The switch control unit shown.

[0023] The sampling module is provided at the three-phase inverter negative terminal of the IPM module of the motor, and is used to sample current from the three-phase inverter negative terminal of the IPM module to obtain the sampled current of the IPM module.

[0024] The comparison module is arranged at the output end of the sampling module, and is used to set a reference threshold and compare the sampled current of the IPM module with the reference threshold to obtain a comparison result; the comparison result is a first result that the sampled current of the IPM module is not overcurrent, or a second result that the sampled current of the IPM module is overcurrent.

[0025] The protection module is arranged at the output end of the comparison module, and is used to output a first protection signal when the comparison result is the first result; output a second protection signal when the comparison result is the second result; and, when the comparison result is the second result, output the first protection signal after outputting the second protection signal for a set time.

[0026] The switch module is arranged at the output end of the protection module, and is used to control the drive control chip to work when receiving the first protection signal, so that the drive control chip continues to output PWM signals to the power devices in the IPM module; and control the drive control chip to stop working when receiving the second protection signal, so that the drive control chip stops outputting PWM signals to the power devices in the IPM module.

[0027] The present invention aims to provide a safer and more reliable implementation of overcurrent protection. Before the overcurrent problem is resolved, oscillation and repeated restarts may occur within a short period of time. A timed shutdown function can prevent catastrophic damage to power devices caused by oscillation (current fluctuations) within a certain timeframe. Once the overcurrent problem is resolved, the shutdown lockout is terminated, and the motor resumes normal operation, preventing damage to power devices in the motor's drive control circuit, or even safety incidents, thereby improving safety. The power devices in the motor's drive control circuit include, for example, gate-gated bipolar transistors (IGBTs) and insulated-gate field-effect transistors (MOSs).

[0028] In some embodiments, the sampling module includes: a first resistance module, a second resistance module and a first capacitance module, wherein the first resistance module is as follows: Figure 4 The resistors RX1, RX2 and RX3 are connected in parallel, and the second resistor module is as shown. Figure 4 The resistor R3 shown, the first capacitor module is as shown Figure 4 Capacitor C2 is shown.

[0029] The negative terminal of the three-phase inverter of the IPM module is grounded after passing through the first resistor module. The negative terminal of the three-phase inverter of the IPM module is also grounded after passing through the second resistor module and the first capacitor module. The common terminal of the second resistor module and the first capacitor module can output the sampled current of the IPM module to the comparison module.

[0030] exist Figure 4 In the example shown, resistors RX1, RX2, RX3, R3 and C2 constitute Figure 2 The current sampling unit shown in FIG. The current sampling unit is responsible for collecting the three-phase current of the power module, that is, collecting the current of the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module.

[0031] Figure 2 Figure 1 is a flow chart of the overcurrent shutdown protection process. Figure 2 As shown, the negative end of the three-phase inverter of the power module outputs current to the current sampling unit. The overcurrent comparison unit can complete the overcurrent lockout shutdown and restore the self-start function after the overcurrent is released according to the current sampled by the current sampling unit. The switch control unit sends the instruction to the dedicated chip processing unit according to the overcurrent comparison unit, which solves the defect that the motor drive control dedicated chip has no overcurrent protection function, avoids problems such as short circuit, breakdown, and explosion of the power module due to overcurrent, and improves safety.

[0032] In some embodiments, the comparison module includes: a third resistance module, a fourth resistance module, a second capacitance module and a first comparison module, wherein the third resistance module is as follows: Figure 4 The resistor R1 shown, the fourth resistor module is as follows Figure 4 The resistor R2 shown, the second capacitor module is as shown Figure 4 The capacitor C1 shown in FIG. 1 is a first comparison module. Figure 4 Comparator U1-B is shown.

[0033] Among them, a preset positive DC power supply is grounded after passing through the third resistor module and the fourth resistor module; the common end of the third resistor module and the fourth resistor module is grounded after passing through the second capacitor module; the common end of the third resistor module and the fourth resistor module can output the reference threshold to the non-inverting input end of the first comparison module; the sampling current of the IPM module output by the sampling module can be input to the inverting input end of the first comparison module; the output end of the first comparison module can output the comparison result to the protection module.

[0034] exist Figure 4 In the example shown, the comparator U1-B, resistor R1, resistor R2, and capacitor C1 form Figure 2The overcurrent comparison unit shown. The overcurrent comparison unit is responsible for determining the current size of the running motor, specifically the current size of the collected three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module. When the current at the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module is determined to be overcurrent, the output of the comparator U1-B flips to output a low level, and the motor stops running.

[0035] Figure 3 The figure is a flow chart of the over-current shutdown lock / self-start process. Figure 3 As shown, using Figure 2 The current sampling unit, overcurrent comparison unit, switch control unit and dedicated chip processing unit shown in the figure execute the shutdown locking function when overcurrent occurs, and resume automatic start operation when the overcurrent is relieved, thereby avoiding problems such as power module short circuit, breakdown, explosion, etc. caused by overcurrent, thereby improving safety.

[0036] In some embodiments, the protection module includes: a fifth resistance module, a sixth resistance module, a third capacitance module, a fourth capacitance module and a second comparison module, wherein the fifth resistance module is as follows: Figure 4 The resistor R4 shown, the sixth resistor module is as shown Figure 4 The resistor R5 shown, the third capacitor module is as shown Figure 4 The capacitor C3 shown, the fourth capacitor module is as shown Figure 4 The capacitor C4 shown in FIG. Figure 4 Comparator U1-A is shown.

[0037] Among them, the comparison result output by the comparison module can be input to the inverting input terminal of the second comparison module; the preset positive DC power supply is grounded after passing through the fifth resistor module and the third capacitor module; the common end of the fifth resistor module and the third capacitor module is connected to the inverting input terminal of the second comparison module.

[0038] A preset positive DC power supply is grounded after passing through the sixth resistor module and the fourth capacitor module; the common end of the sixth resistor module and the fourth capacitor module is connected to the non-inverting input end of the second comparison module; the output end of the second comparison module can output the first protection signal or the second protection signal to the control end of the switch module.

[0039] The overcurrent timed shutdown and self-start function circuit provided by the solution of the present invention controls the timed start of the MOS tube U2 by setting the charge and discharge time composed of a comparator and a resistor and capacitor, thereby detecting and adjusting the output current value of the power module in real time, making a judgment on whether to shut down according to the change in current magnitude, and controlling the shutdown and performing shutdown lock when shutdown is determined. After the shutdown lock is achieved, the shutdown self-start can be performed, thereby effectively controlling and protecting the power module from overcurrent, ensuring normal operation and safety, and improving reliability.

[0040] In some embodiments, the protection module further includes: at least one of a seventh resistance module and a fifth capacitance module, wherein the seventh resistance module is as follows: Figure 4 The resistor R6 shown, the fifth capacitor module is as shown Figure 4 Capacitor C5 is shown.

[0041] The seventh resistor module is provided between the common end of the sixth resistor module and the fourth capacitor module and the ground; and the fifth capacitor module is provided between the power supply end of the second comparison module and the ground.

[0042] Figure 4 The illustrated overcurrent timed shutdown and self-start circuit is located between the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW) and the enable terminal EN of a dedicated motor drive control chip that lacks an overcurrent protection lockout function. This circuit can compensate for the lack of overcurrent protection lockout in the dedicated motor drive control chip in related solutions. For example, the ROHM BD62011FS brushless DC motor drive control chip lacks an overcurrent protection lockout function. This brushless DC motor drive control chip lacks an overcurrent protection lockout function. When the six PWM signals are turned off, only the three signals in the upper bridge arm are turned off, leaving the three signals in the lower bridge arm unturned. If an overcurrent condition occurs and the lockout is not delayed, the IPM module could burn out at the moment the upper bridge arm is turned off.

[0043] The three-phase inverter negative end of the motor's power module, such as the output end of the lower tube of the three bridge arms in the three-phase inverter bridge, that is, the grounding end of the lower tube of the three bridge arms, such as the output end NU of the lower tube of the U-phase bridge arm or the output end VU of the lower tube of the V-phase bridge arm or the output end WU of the lower tube of the W-phase bridge arm, the terminal NU, the terminal NV, and the terminal NW are respectively connected to the ground through corresponding sampling resistors such as resistor RX1, resistor RX2, and resistor RX3.

[0044] exist Figure 4 In the example shown, resistor R4, capacitor C3, resistor R5, resistor R6, and capacitor C4 constitute Figure 2The shutdown lockout function module in the system. Based on the principle of capacitor charging and discharging, when the motor stops, resistor R4 charges capacitor C3, causing the voltage of capacitor C3 to slowly increase. The time it takes for the voltage of capacitor C3 to slowly rise to the voltage of capacitor C4 is the shutdown lockout time. This prevents problems such as power module short circuits, breakdowns, and explosions caused by repeated short-term motor starts.

[0045] exist Figure 4 In the example shown, resistor R4, capacitor C3, resistor R5, resistor R6, and capacitor C4 also constitute Figure 2 The recovery self-start function module in the recovery self-start function module. When the overcurrent problem of the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module is resolved, the shutdown lock is ended and the motor resumes normal operation.

[0046] Figure 4 The overcurrent timed shutdown and self-start function circuit shown can detect the current change at the negative terminal of the three-phase inverter of the IPM module, and make a judgment on whether to shut down the module based on the current size of the three-phase inverter negative terminal of the IPM module. If the current at the negative terminal of the three-phase inverter of the IPM module is overcurrent and the overcurrent is not relieved, the module can be shut down and locked for a certain period of time to prevent the fault from expanding and causing a major accident, thereby improving safety. When the overcurrent problem at the negative terminal of the three-phase inverter of the IPM module is relieved, the shutdown lock is ended, and the motor resumes normal operation to ensure normal operation.

[0047] The solution of the present invention proposes a controller with an overcurrent timed shutdown and self-start function circuit, which can monitor the current changes at the negative end of the three-phase inverter of the motor's power module, and make a judgment on whether to shut down according to the current changes at the negative end of the three-phase inverter of the motor's power module to ensure reliable protection; it can control the shutdown when it is determined to shut down, and perform shutdown locking to avoid damage caused by oscillation and repeated restarting when the overcurrent is not relieved, thereby improving safety; it can perform shutdown self-start after shutdown locking to automatically resume normal operation when the fault is relieved, thereby ensuring normal operation and improving reliability.

[0048] In some embodiments, the switch module includes: an eighth resistor module and a switch tube, the eighth resistor module is as follows Figure 4 The resistor R7 shown in the figure, the switch tube is as follows Figure 4 The MOS tube U2 is shown.

[0049] The first protection signal or the second protection signal output by the protection module can be input to the control terminal of the switch tube; a preset positive DC power supply is connected to the control terminal of the switch tube after passing through the eighth resistor module; the first connection terminal of the switch tube is connected to the enable pin of the drive control chip of the motor; and the second connection terminal of the switch tube is grounded. The switch tube is, for example, a MOS tube U2, the control terminal of the switch tube is the gate G1 of the MOS tube U2, the first connection terminal of the switch tube is, for example, the drain D of the MOS tube U2, and the second connection terminal of the switch tube is, for example, the source S of the MOS tube U2.

[0050] like Figure 4 As shown, the overcurrent timing shutdown and self-start function circuit includes: resistor RX1, resistor RX2, resistor RX3, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, comparator U1-A, comparator U1-B, MOS tube U2. Figure 4 In the example shown, the comparator U1-A, capacitor C5, resistor R7, and MOS tube U2 form Figure 2 The switch control unit shown in FIG. The switch control unit controls the opening or closing of the MOS tube U2 according to whether there is overcurrent and sends a command to the EN pin of the dedicated chip.

[0051] The negative terminal of the three-phase inverter of the IPM module (such as terminal NU, terminal NV, or terminal NW) is connected to ground via parallel resistors RX1, RX2, and RX3. The negative terminal of the three-phase inverter of the IPM module (such as terminal NU, terminal NV, or terminal NW) is also connected to the inverting input of comparator U1-B via resistor R3. The inverting input of comparator U1-B is also connected to ground via capacitor C2. A +5V power supply is connected to the first terminal of resistor R1; the second terminal of resistor R1 is connected to the non-inverting input of comparator U1-B. The second terminal of resistor R1 is also connected to ground via resistor R2. The common terminal of resistors R1 and R2 is denoted as point E. The second terminal of resistor R1 is also connected to ground via capacitor C1, which is connected to the non-inverting input of comparator U1-B. The +5V power supply is connected to ground via resistor R4 and capacitor C3; the output of comparator U1-B is connected to the common terminal of resistor R4 and capacitor C3. The output of comparator U1-B is also connected to the inverting input of comparator U1-A. The +5V power supply is connected to ground via resistors R5 and R6. The common terminal of resistors R5 and R6 is marked as point F. The common terminal of resistors R5 and R6 is connected to ground via capacitor C4. The common terminal of resistors R5 and R6 is also connected to the non-inverting input of comparator U1-A. The +5V power supply is also connected to the power supply of comparator U1-A. The ground terminal GND of comparator U1-A is also connected to ground. The power supply of comparator U1-A is also connected to ground via capacitor C5. The +5V power supply is connected to the output of comparator U1-A via resistor R7. The output of comparator U1-A is connected to the gate G1 of MOS transistor U2. The drain D of MOS transistor U2 is connected to the enable terminal EN of the dedicated motor drive control chip without overcurrent protection lockout function. The enable terminal EN of the dedicated motor drive control chip without overcurrent protection lockout function is active low. The source S of the MOS tube U2 is grounded.

[0052] See also Figure 4In the example shown, under normal conditions, in comparator U1-B, point E (the common terminal of resistors R1 and R2) is a fixed reference voltage (approximately 0.6V). The voltage V+ at the non-inverting input of comparator U1-B exceeds the voltage V- at its inverting input, resulting in a high output voltage at the output of comparator U1-B. The +5V power supply charges capacitor C3 through resistor R4. In comparator U1-A, the +5V power supply charges capacitor C4 through resistor R5. After charging, the voltage at point F (the common terminal of resistors R5 and R6) is approximately 4.6V. Because the charge and discharge time τ1 of capacitor C3 (τ1 = R4 × C3) is faster than the charge and discharge time τ2 of capacitor C4 (τ2 = R5 × C4), τ1 < τ2. The voltage V at the inverting input of comparator U1-A -> the voltage V+ at the non-inverting input of comparator U1-A. Comparator U1-A outputs a low level, MOSFET U2 is cut off, and the EN pin of the dedicated chip is set to a high level (EN pin active low), allowing the motor to operate normally. Therefore, as long as there is no overcurrent at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the normal operation of the motor is unaffected.

[0053] When an overcurrent occurs at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the voltage V at the inverting input of comparator U1-B changes from V to V+, causing the output of comparator U1-B to flip, outputting a low level and discharging capacitor C3. In comparator U1-A, the voltage V- at the inverting input of comparator U1-A decreases from V+ to V+, causing the output of comparator U1-A to output a high level. MOS transistor U2 is saturated, the EN pin of the dedicated chip is set low, and the motor stops. This indicates that when an overcurrent occurs at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the overcurrent timed shutdown and auto-start circuits quickly respond, shutting off the dedicated chip's drive output signal and stopping the motor. This prevents power module short circuits, breakdown, or rupture caused by overcurrent.

[0054] See also Figure 4In the example shown, with a shutdown lockout, when the motor stops running, the voltage V- at the inverting input of comparator U1-B approaches 0V, while the voltage V+ at the non-inverting input of comparator U1-B exceeds the voltage V- at the inverting input of comparator U1-B. The +5V power supply charges capacitor C3 through resistor R4, and the voltage on capacitor C3 slowly increases. The time it takes for the voltage on capacitor C3 to reach the voltage on capacitor C4 is the shutdown lockout period, which is approximately equal to 3τ1 (τ1 = R4 × C3). This lockout delays startup until the overcurrent at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW) is resolved. This prevents the overcurrent from escalating, potentially leading to power module short circuits, breakdown, or rupture.

[0055] During the shutdown lockout phase, when the voltage of capacitor C3 slowly increases until it exceeds the voltage of capacitor C4, comparator U1-A begins to return to a low output level, MOSFET U2 is cut off, the EN pin of the dedicated chip is high, and the motor automatically restarts and resumes normal operation. This means that once the overcurrent condition at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW) is resolved, the shutdown lockout phase ends and the motor resumes normal operation.

[0056] The overcurrent protection provided by the present invention primarily consists of a comparator, a resistor and capacitor, and a MOS transistor. By utilizing the difference in charge and discharge time between the resistor and capacitor to control the timing of the MOS transistor's activation, the output current of the power module can be detected in real time, effectively protecting the power module from overcurrent. The power module, for example, includes the power devices in a three-phase inverter bridge or an intelligent power module (IPM) for a motor. The overcurrent protection provided by the present invention features locking and self-starting functions, a simple and reliable circuit design, and low cost, making it easy to implement and scale.

[0057] By adopting the technical solution of the present invention, a dedicated chip for motor drive control that does not have an overcurrent protection locking function is provided between the three-phase inverter negative terminal of the IPM module of the motor and the dedicated chip. The circuit is composed of an overcurrent timed shutdown and self-start function circuit, a current sampling unit, an overcurrent comparison unit (specifically, an overcurrent comparison unit with an overcurrent comparison function, a shutdown locking function, and a self-start release function), and a switch control unit. The current sampling unit is used to sample the current at the three-phase inverter negative terminal of the IPM module, the overcurrent comparison unit is used to determine whether the current is overcurrent, and the dedicated chip is controlled by the switch control unit according to the determination result to achieve overcurrent shutdown protection, shutdown locking, and recovery self-start. Thus, by providing a circuit with overcurrent timed shutdown and self-start functions between the three-phase inverter negative terminal of the motor IPM module and the dedicated chip for motor drive control that does not have an overcurrent protection locking function, protection of the IPM module is achieved and safety is improved.

[0058] According to an embodiment of the present invention, a motor controller corresponding to the protection device is also provided. The motor controller may include: the protection device described above.

[0059] Since the processing and functions implemented by the motor controller of this embodiment basically correspond to the embodiments, principles and examples of the device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0060] According to an embodiment of the present invention, a frequency converter corresponding to the protection device is also provided. The frequency converter may include: the protection device described above.

[0061] Since the processing and functions implemented by the frequency converter of this embodiment basically correspond to the embodiments, principles and examples of the device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0062] According to an embodiment of the present invention, a motor corresponding to the protection device is further provided, which may include: the protection device described above, or the motor controller described above, or the frequency converter described above.

[0063] The protection device includes: a sampling module, a comparison module, a protection module and a switch module. The sampling module is as follows: Figure 2 and Figure 4 The current sampling unit shown in the figure and the comparison module are as follows Figure 2 and Figure 4 The overcurrent comparison unit shown in the figure, the protection module is as follows Figure 2 and Figure 4 The shutdown lock function module and the automatic start release function module are shown, and the switch module is as follows Figure 2 and Figure 4The switch control unit shown.

[0064] The sampling module is provided at the three-phase inverter negative terminal of the IPM module of the motor, and is used to sample current from the three-phase inverter negative terminal of the IPM module to obtain the sampled current of the IPM module.

[0065] The comparison module is arranged at the output end of the sampling module, and is used to set a reference threshold and compare the sampled current of the IPM module with the reference threshold to obtain a comparison result; the comparison result is a first result that the sampled current of the IPM module is not overcurrent, or a second result that the sampled current of the IPM module is overcurrent.

[0066] The protection module is arranged at the output end of the comparison module, and is used to output a first protection signal when the comparison result is the first result; output a second protection signal when the comparison result is the second result; and, when the comparison result is the second result, output the first protection signal after outputting the second protection signal for a set time.

[0067] The switch module is arranged at the output end of the protection module, and is used to control the drive control chip to work when receiving the first protection signal, so that the drive control chip continues to output PWM signals to the power devices in the IPM module; and control the drive control chip to stop working when receiving the second protection signal, so that the drive control chip stops outputting PWM signals to the power devices in the IPM module.

[0068] In the solution of the present invention, before the overcurrent problem is resolved, oscillation and repeated restarts may occur within a short period of time. Timed shutdown can prevent catastrophic damage to power devices caused by oscillation (current fluctuation) within a certain time frame. When the overcurrent problem is resolved, the shutdown lock ends and the motor resumes normal operation, avoiding damage to power devices in the motor's drive control circuit or even causing safety accidents, thereby improving safety. The power devices in the motor's drive control circuit include gate bipolar transistors (IGBTs) and insulated gate field effect transistors (MOSs).

[0069] In some embodiments, the sampling module includes: a first resistance module, a second resistance module and a first capacitance module, wherein the first resistance module is as follows: Figure 4 The resistors RX1, RX2 and RX3 are connected in parallel, and the second resistor module is as shown. Figure 4 The resistor R3 shown, the first capacitor module is as shown Figure 4 Capacitor C2 is shown.

[0070] The negative terminal of the three-phase inverter of the IPM module is grounded after passing through the first resistor module. The negative terminal of the three-phase inverter of the IPM module is also grounded after passing through the second resistor module and the first capacitor module. The common terminal of the second resistor module and the first capacitor module can output the sampled current of the IPM module to the comparison module.

[0071] exist Figure 4 In the example shown, resistors RX1, RX2, RX3, R3 and C2 constitute Figure 2 The current sampling unit shown in FIG. The current sampling unit is responsible for collecting the three-phase current of the power module, that is, collecting the current of the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module.

[0072] like Figure 2 As shown, the negative end of the three-phase inverter of the power module outputs current to the current sampling unit. The overcurrent comparison unit can complete the overcurrent lockout shutdown and restore the self-start function after the overcurrent is released according to the current sampled by the current sampling unit. The switch control unit sends the instruction to the dedicated chip processing unit according to the overcurrent comparison unit, which solves the defect that the motor drive control dedicated chip has no overcurrent protection function, avoids problems such as short circuit, breakdown, and explosion of the power module due to overcurrent, and improves safety.

[0073] In some embodiments, the comparison module includes: a third resistance module, a fourth resistance module, a second capacitance module and a first comparison module, wherein the third resistance module is as follows: Figure 4 The resistor R1 shown, the fourth resistor module is as follows Figure 4 The resistor R2 shown, the second capacitor module is as shown Figure 4 The capacitor C1 shown in FIG. 1 is a first comparison module. Figure 4 Comparator U1-B is shown.

[0074] Among them, a preset positive DC power supply is grounded after passing through the third resistor module and the fourth resistor module; the common end of the third resistor module and the fourth resistor module is grounded after passing through the second capacitor module; the common end of the third resistor module and the fourth resistor module can output the reference threshold to the non-inverting input end of the first comparison module; the sampling current of the IPM module output by the sampling module can be input to the inverting input end of the first comparison module; the output end of the first comparison module can output the comparison result to the protection module.

[0075] exist Figure 4 In the example shown, the comparator U1-B, resistor R1, resistor R2, and capacitor C1 form Figure 2The overcurrent comparison unit shown. The overcurrent comparison unit is responsible for determining the current size of the running motor, specifically the current size of the collected three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module. When the current at the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module is determined to be overcurrent, the output of the comparator U1-B flips to output a low level, and the motor stops running.

[0076] like Figure 3 As shown, using Figure 2 The current sampling unit, overcurrent comparison unit, switch control unit and dedicated chip processing unit shown in the figure execute the shutdown locking function when overcurrent occurs, and resume automatic start operation when the overcurrent is relieved, thereby avoiding problems such as power module short circuit, breakdown, explosion, etc. caused by overcurrent, thereby improving safety.

[0077] In some embodiments, the protection module includes: a fifth resistance module, a sixth resistance module, a third capacitance module, a fourth capacitance module and a second comparison module, wherein the fifth resistance module is as follows: Figure 4 The resistor R4 shown, the sixth resistor module is as shown Figure 4 The resistor R5 shown, the third capacitor module is as shown Figure 4 The capacitor C3 shown, the fourth capacitor module is as shown Figure 4 The capacitor C4 shown in FIG. Figure 4 Comparator U1-A is shown.

[0078] Among them, the comparison result output by the comparison module can be input to the inverting input terminal of the second comparison module; the preset positive DC power supply is grounded after passing through the fifth resistor module and the third capacitor module; the common end of the fifth resistor module and the third capacitor module is connected to the inverting input terminal of the second comparison module.

[0079] A preset positive DC power supply is grounded after passing through the sixth resistor module and the fourth capacitor module; the common end of the sixth resistor module and the fourth capacitor module is connected to the non-inverting input end of the second comparison module; the output end of the second comparison module can output the first protection signal or the second protection signal to the control end of the switch module.

[0080] In the solution of the present invention, the timing of the start-up of the MOS tube U2 is controlled by setting the charge and discharge time of the comparator and the resistor and capacitor, so as to detect and adjust the output current value of the power module in real time, and make a judgment on whether to shut down according to the change of the current. When the shutdown is determined, the shutdown is controlled and the shutdown lock is performed. After the shutdown lock is performed, the shutdown can be automatically restarted, and the power module is effectively protected from overcurrent control, thereby ensuring normal operation and safety, and improving reliability.

[0081] In some embodiments, the protection module further includes: at least one of a seventh resistance module and a fifth capacitance module, wherein the seventh resistance module is as follows: Figure 4 The resistor R6 shown, the fifth capacitor module is as shown Figure 4 Capacitor C5 is shown.

[0082] The seventh resistor module is provided between the common end of the sixth resistor module and the fourth capacitor module and the ground; and the fifth capacitor module is provided between the power supply end of the second comparison module and the ground.

[0083] Figure 4 The illustrated overcurrent timed shutdown and self-start circuit is located between the negative terminal of the three-phase inverter of the IPM module (e.g., terminal NU, terminal NV, or terminal NW) and the enable terminal EN of the dedicated motor drive control chip that lacks an overcurrent protection lockout function. This can compensate for the lack of overcurrent protection lockout in the dedicated motor drive control chip in related solutions. The negative terminal of the three-phase inverter of the motor power module, such as the output terminal of the lower transistors of the three bridge arms in a three-phase inverter bridge, that is, the ground terminal of the lower transistors of the three bridge arms, such as the output terminal NU of the lower transistor of the U-phase bridge arm, the output terminal VU of the lower transistor of the V-phase bridge arm, or the output terminal WU of the lower transistor of the W-phase bridge arm, is connected to ground via corresponding sampling resistors such as resistors RX1, RX2, and RX3.

[0084] exist Figure 4 In the example shown, resistor R4, capacitor C3, resistor R5, resistor R6, and capacitor C4 constitute Figure 2 The shutdown lockout function module in the system. Based on the principle of capacitor charging and discharging, when the motor stops, resistor R4 charges capacitor C3, causing the voltage of capacitor C3 to slowly increase. The time it takes for the voltage of capacitor C3 to slowly rise to the voltage of capacitor C4 is the shutdown lockout time. This prevents problems such as power module short circuits, breakdowns, and explosions caused by repeated short-term motor starts.

[0085] exist Figure 4 In the example shown, resistor R4, capacitor C3, resistor R5, resistor R6, and capacitor C4 also constitute Figure 2 The recovery self-start function module in the recovery self-start function module. When the overcurrent problem of the three-phase inverter negative terminal (such as terminal NU, terminal NV, or terminal NW) of the IPM module is resolved, the shutdown lock is ended and the motor resumes normal operation.

[0086] Figure 4The overcurrent timed shutdown and self-start function circuit shown can detect the current change at the negative terminal of the three-phase inverter of the IPM module, and make a judgment on whether to shut down the module based on the current size of the three-phase inverter negative terminal of the IPM module. If the current at the negative terminal of the three-phase inverter of the IPM module is overcurrent and the overcurrent is not relieved, the module can be shut down and locked for a certain period of time to prevent the fault from expanding and causing a major accident, thereby improving safety. When the overcurrent problem at the negative terminal of the three-phase inverter of the IPM module is relieved, the shutdown lock is ended, and the motor resumes normal operation to ensure normal operation.

[0087] In the solution of the present invention, it is possible to monitor the current changes at the negative end of the three-phase inverter of the motor's power module, and make a judgment on whether to shut down the machine based on the current changes at the negative end of the three-phase inverter of the motor's power module to provide reliable protection; it is possible to control the shutdown when it is determined to shut down, and perform shutdown locking to avoid damage caused by oscillation and repeated restarts when the overcurrent is not relieved, thereby improving safety; it is possible to perform shutdown self-restart after shutdown locking to automatically resume normal operation when the fault is relieved, thereby ensuring normal operation and improving reliability.

[0088] In some embodiments, the switch module includes: an eighth resistor module and a switch tube, the eighth resistor module is as follows Figure 4 The resistor R7 shown in the figure, the switch tube is as follows Figure 4 The MOS tube U2 is shown.

[0089] The first protection signal or the second protection signal output by the protection module can be input to the control terminal of the switch tube; a preset positive DC power supply is connected to the control terminal of the switch tube after passing through the eighth resistor module; the first connection terminal of the switch tube is connected to the enable pin of the drive control chip of the motor; and the second connection terminal of the switch tube is grounded. The switch tube is, for example, a MOS tube U2, the control terminal of the switch tube is the gate G1 of the MOS tube U2, the first connection terminal of the switch tube is, for example, the drain D of the MOS tube U2, and the second connection terminal of the switch tube is, for example, the source S of the MOS tube U2.

[0090] like Figure 4 As shown, the overcurrent timing shutdown and self-start function circuit includes: resistor RX1, resistor RX2, resistor RX3, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, comparator U1-A, comparator U1-B, MOS tube U2. Figure 4 In the example shown, the comparator U1-A, capacitor C5, resistor R7, and MOS tube U2 form Figure 2 The switch control unit shown in FIG. The switch control unit controls the opening or closing of the MOS tube U2 according to whether there is overcurrent and sends a command to the EN pin of the dedicated chip.

[0091] The negative terminal of the three-phase inverter of the IPM module (such as terminal NU, terminal NV, or terminal NW) is connected to ground via parallel resistors RX1, RX2, and RX3. The negative terminal of the three-phase inverter of the IPM module (such as terminal NU, terminal NV, or terminal NW) is also connected to the inverting input of comparator U1-B via resistor R3. The inverting input of comparator U1-B is also connected to ground via capacitor C2. A +5V power supply is connected to the first terminal of resistor R1; the second terminal of resistor R1 is connected to the non-inverting input of comparator U1-B. The second terminal of resistor R1 is also connected to ground via resistor R2. The common terminal of resistors R1 and R2 is denoted as point E. The second terminal of resistor R1 is also connected to ground via capacitor C1, which is connected to the non-inverting input of comparator U1-B. The +5V power supply is connected to ground via resistor R4 and capacitor C3; the output of comparator U1-B is connected to the common terminal of resistor R4 and capacitor C3. The output of comparator U1-B is also connected to the inverting input of comparator U1-A. The +5V power supply is connected to ground via resistors R5 and R6. The common terminal of resistors R5 and R6 is marked as point F. The common terminal of resistors R5 and R6 is connected to ground via capacitor C4. The common terminal of resistors R5 and R6 is also connected to the non-inverting input of comparator U1-A. The +5V power supply is also connected to the power supply of comparator U1-A. The ground terminal GND of comparator U1-A is also connected to ground. The power supply of comparator U1-A is also connected to ground via capacitor C5. The +5V power supply is connected to the output of comparator U1-A via resistor R7. The output of comparator U1-A is connected to the gate G1 of MOS transistor U2. The drain D of MOS transistor U2 is connected to the enable terminal EN of the dedicated motor drive control chip without overcurrent protection lockout function. The enable terminal EN of the dedicated motor drive control chip without overcurrent protection lockout function is active low. The source S of the MOS tube U2 is grounded.

[0092] See also Figure 4In the example shown, under normal conditions, in comparator U1-B, point E (the common terminal of resistors R1 and R2) is a fixed reference voltage (approximately 0.6V). The voltage V+ at the non-inverting input of comparator U1-B exceeds the voltage V- at its inverting input, resulting in a high output voltage at the output of comparator U1-B. The +5V power supply charges capacitor C3 through resistor R4. In comparator U1-A, the +5V power supply charges capacitor C4 through resistor R5. After charging, the voltage at point F (the common terminal of resistors R5 and R6) is approximately 4.6V. Because the charge and discharge time τ1 of capacitor C3 (τ1 = R4 × C3) is faster than the charge and discharge time τ2 of capacitor C4 (τ2 = R5 × C4), τ1 < τ2. The voltage V at the inverting input of comparator U1-A -> the voltage V+ at the non-inverting input of comparator U1-A. Comparator U1-A outputs a low level, MOSFET U2 is cut off, and the EN pin of the dedicated chip is set to a high level (EN pin active low), allowing the motor to operate normally. Therefore, as long as there is no overcurrent at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the normal operation of the motor is unaffected.

[0093] When an overcurrent occurs at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the voltage V at the inverting input of comparator U1-B changes from V to V+, causing the output of comparator U1-B to flip, outputting a low level and discharging capacitor C3. In comparator U1-A, the voltage V- at the inverting input of comparator U1-A decreases from V+ to V+, causing the output of comparator U1-A to output a high level. MOS transistor U2 is saturated, the EN pin of the dedicated chip is set low, and the motor stops. This indicates that when an overcurrent occurs at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW), the overcurrent timed shutdown and auto-start circuits quickly respond, shutting off the dedicated chip's drive output signal and stopping the motor. This prevents power module short circuits, breakdown, or rupture caused by overcurrent.

[0094] See also Figure 4In the example shown, with a shutdown lockout, when the motor stops running, the voltage V- at the inverting input of comparator U1-B approaches 0V, while the voltage V+ at the non-inverting input of comparator U1-B exceeds the voltage V- at the inverting input of comparator U1-B. The +5V power supply charges capacitor C3 through resistor R4, and the voltage on capacitor C3 slowly increases. The time it takes for the voltage on capacitor C3 to reach the voltage on capacitor C4 is the shutdown lockout period, which is approximately equal to 3τ1 (τ1 = R4 × C3). This lockout delays startup until the overcurrent at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW) is resolved. This prevents the overcurrent from escalating, potentially leading to power module short circuits, breakdown, or rupture.

[0095] During the shutdown lockout phase, when the voltage of capacitor C3 slowly increases until it exceeds the voltage of capacitor C4, comparator U1-A begins to return to a low output level, MOSFET U2 is cut off, the EN pin of the dedicated chip is high, and the motor automatically restarts and resumes normal operation. This means that once the overcurrent condition at the negative terminal of the IPM module's three-phase inverter (e.g., terminal NU, terminal NV, or terminal NW) is resolved, the shutdown lockout phase ends and the motor resumes normal operation.

[0096] The present invention's solution primarily consists of a comparator, a resistor, a capacitor, and a MOS transistor. By utilizing the difference in charge and discharge times between the resistor and capacitor to control the timing of the MOS transistor's activation, the system can detect the output current of the power module in real time, effectively protecting the power module from overcurrent. The power module can be, for example, a power device in a three-phase inverter bridge or an intelligent power module (IPM) for a motor. The overcurrent protection provided by the present invention features locking and self-starting functions, a simple and reliable circuit design, low cost, and ease of implementation and deployment.

[0097] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0098] According to an embodiment of the present invention, an air conditioner corresponding to the protection device is also provided, which may include: the protection device described above, or the motor controller described above, or the frequency converter described above, or the motor described above.

[0099] Since the processing and functions implemented by the air conditioner of this embodiment basically correspond to the embodiments, principles and examples of the device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0100] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0101] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims.

Claims

1. A protective device, characterized in that: Applied to the drive control of the motor, the protection device is arranged between the three-phase inverter negative terminal of the IPM module of the motor and the enable pin of the drive control chip of the motor; the protection device includes: a sampling module, a comparison module, a protection module and a switch module; wherein, The sampling module is used to sample the current from the negative terminal of the three-phase inverter of the IPM module to obtain the sampled current of the IPM module; The comparison module is configured to set a reference threshold and compare the sampled current of the IPM module with the reference threshold to obtain a comparison result; the comparison result is a first result indicating that the sampled current of the IPM module is not overcurrent, or a second result indicating that the sampled current of the IPM module is overcurrent; The protection module is configured to output a first protection signal if the comparison result is the first result; output a second protection signal if the comparison result is the second result; and output the first protection signal after outputting the second protection signal for a set time. The switch module is configured to control the drive control chip to operate upon receiving the first protection signal; and to control the drive control chip to stop operating upon receiving the second protection signal.

2. The protection device according to claim 1, characterized in that The sampling module includes: a first resistance module, a second resistance module and a first capacitance module; wherein, The three-phase inverter negative terminal of the IPM module is grounded after passing through the first resistor module; The three-phase inverter negative terminal of the IPM module is also grounded after passing through the second resistor module and the first capacitor module; the common terminal of the second resistor module and the first capacitor module can output the sampling current of the IPM module to the comparison module.

3. The protection device according to claim 1, characterized in that: The comparison module includes: a third resistance module, a fourth resistance module, a second capacitance module and a first comparison module; wherein, A preset positive DC power supply is grounded after passing through the third resistor module and the fourth resistor module; a common end of the third resistor module and the fourth resistor module is grounded after passing through the second capacitor module; The common end of the third resistance module and the fourth resistance module can output the reference threshold to the non-inverting input end of the first comparison module; the sampling current of the IPM module output by the sampling module can be input to the inverting input end of the first comparison module; the output end of the first comparison module can output the comparison result to the protection module.

4. The protection device according to claim 1, characterized in that The protection module includes: a fifth resistance module, a sixth resistance module, a third capacitance module, a fourth capacitance module and a second comparison module; wherein, The comparison result output by the comparison module can be input to the inverting input terminal of the second comparison module; a preset positive DC power supply is grounded after passing through the fifth resistor module and the third capacitor module; the common terminal of the fifth resistor module and the third capacitor module is connected to the inverting input terminal of the second comparison module; A preset positive DC power supply is grounded after passing through the sixth resistor module and the fourth capacitor module; the common end of the sixth resistor module and the fourth capacitor module is connected to the non-inverting input end of the second comparison module; the output end of the second comparison module can output the first protection signal or the second protection signal to the control end of the switch module.

5. The protection device according to claim 4, characterized in that: The protection module further includes: at least one of a seventh resistance module and a fifth capacitance module; wherein, The seventh resistor module is provided between a common terminal of the sixth resistor module and the fourth capacitor module and the ground; The fifth capacitor module is arranged between the power supply terminal of the second comparison module and the ground.

6. The protection device according to claim 1, characterized in that The switch module includes: an eighth resistor module and a switch tube; wherein, The first protection signal or the second protection signal output by the protection module can be input to the control terminal of the switch tube; the preset positive DC power supply is connected to the control terminal of the switch tube after passing through the eighth resistor module; The first connection end of the switch tube is connected to the enable pin of the drive control chip of the motor; the second connection end of the switch tube is grounded.

7. A motor controller, characterized in that: include: A protective device as claimed in any one of claims 1 to 6.

8. A frequency converter, characterized in that: include: A protective device as claimed in any one of claims 1 to 6.

9. A motor, characterized in that: include: The protection device according to any one of claims 1 to 6, or the motor controller according to claim 7, or the frequency converter according to claim 8.

10. An air conditioner, characterized in that: include: The protection device according to any one of claims 1 to 6, or the motor controller according to claim 7, or the frequency converter according to claim 8, or the motor according to claim 9.

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