Hybrid vehicle boost / lower module overcurrent protection method, system, vehicle and storage medium

Abstract

This invention discloses an overcurrent protection method, system, vehicle, and storage medium for a hybrid vehicle's boost / buck converter module. The method includes: when only the GM motor is operating, if the boost / buck converter module's discharge current exceeds a boundary, limiting the GM motor's electric power; if the boost / buck converter module's charging current exceeds a boundary, limiting the GM motor's charging power; when both the GM and TM motors are operating simultaneously, if the boost / buck converter module's discharge current exceeds a boundary, prioritizing the limiting of the motor power in the electric state; if both the GM and TM motors are in the electric state, prioritizing the limiting of the TM motor's electric power; if the boost / buck converter module's charging current exceeds a boundary, prioritizing the limiting of the motor power in the generator state; if both the GM and TM motors are in the generator state, prioritizing the limiting of the GM motor's generator power; when only the TM motor is operating, if the boost / buck converter module's discharge current exceeds a boundary, limiting the TM motor's electric power; if the boost / buck converter module's charging current exceeds a boundary, limiting the TM motor's charging power. This invention protects the boost / buck converter module's charging and discharging currents from exceeding the fault current threshold.

Description

Technical Field

[0001] The present invention belongs to the technical field of hybrid vehicle, and in particular relates to an overcurrent protection method, system, vehicle and storage medium for a boost / boost module of a hybrid vehicle. Background Art

[0002] For P13 hybrid vehicles with integrated high-voltage buck-boost modules, the buck-boost module is limited by the maximum operating current. When controlling the GM motor and TM motor, the GM motor is directly connected to the engine and has a different response speed from the TM motor. This can easily lead to overcurrent failures in the buck-boost module during high-throttle acceleration and rapid deceleration. If the power of the GM motor or TM motor is blindly limited, it may cause shock, vibration or loss of control of the power system. In mild cases, it may cause shock and vibration of the entire vehicle. In severe cases, it may cause hardware failures and safety accidents. Therefore, a buck-boost module overcurrent protection method is needed to ensure the stable operation of the power system while solving the problem of overcurrent failures reported by the buck-boost module during high-throttle acceleration and deceleration conditions.

[0003] For example, Nissan Motor's "Boost Converter Control Method and Control Device" and Toyota Motor's "Boost Converter Device and Boost Converter Device Control Method" both protect boost converter devices and control methods thereof. There is no patent literature related to current protection methods for boost-boost modules when used in hybrid vehicles.

[0004] Therefore, it is necessary to develop an overcurrent protection method, system, vehicle and storage medium for a hybrid vehicle buck-boost module. Summary of the invention

[0005] The object of the present invention is to provide a hybrid vehicle buck-boost module overcurrent protection method, system, vehicle and storage medium to protect the buck-boost module charging and discharging current from exceeding the fault current threshold.

[0006] In a first aspect, a hybrid vehicle boost / lower voltage module overcurrent protection method according to the present invention comprises the following steps:

[0007] Check whether the GM motor and TM motor are in working condition;

[0008] When only the GM motor is working, if the discharge current of the buck-boost module exceeds the limit, the GM motor electric power is limited; if the charging current of the buck-boost module exceeds the limit, the GM motor charging power is limited;

[0009] When the GM motor and TM motor are working at the same time, if the discharge current of the buck-boost module exceeds the limit, the power of the motor in the electric state will be limited first. If both the GM motor and the TM motor are in the electric state, the electric power of the TM motor will be limited first. If the charging current of the buck-boost module exceeds the limit, the power of the motor in the power generation state will be limited first. If both the GM motor and the TM motor are in the power generation state, the power generation power of the GM motor will be limited first.

[0010] When only the TM motor is working, if the discharge current of the buck-boost module exceeds the limit, the electric power of the TM motor is limited; if the charging current of the buck-boost module exceeds the limit, the charging power of the TM motor is limited.

[0011] Optionally, after determining the motor with priority restriction, identify whether the restricted motor is in the motoring or generating state, calculate the difference between the working current of the buck-boost module under the current working condition and the set current boundary, and revise the charging or discharging torque according to the difference lookup table. At this time, the restricted motor does not respond to the PCU request, and the motor controls itself and executes the corrected torque.

[0012] Optionally, in order to suppress power system oscillation, a torque recovery hysteresis link needs to be set after the torque is limited.

[0013] Optionally, the method specifically comprises the following steps:

[0014] Step S101, determining the working status of the GM motor and the TM motor;

[0015] Step S102: If the GM motor and the TM motor work at the same time, proceed to step S103;

[0016] If only the GM motor is working, then go to step S110;

[0017] If only the TM motor is working, go to step S113;

[0018] If both the GM motor and the TM motor are not working, the process ends;

[0019] Step S103, determining whether the working current Idc of the battery side of the buck-boost module is greater than 0;

[0020] If Idc>0, the buck-boost module is in a discharging state, and the process goes to step S104;

[0021] If Idc≤0, the buck-boost module is in a charging state, and the process goes to step S107;

[0022] Step S104, it is determined whether Idc is greater than the step-up / down voltage module discharge current limit value Idc max, if not, returns to step S101; if so, proceeds to step S105;

[0023] Step S105, determining whether the GM motor DC side current Idc GM is greater than 0;

[0024] If Idc GM≤0, proceed to step S106;

[0025] If Idc GM>0, determine whether the TM motor DC side current Idc TM is greater than 0. If Idc TM>0, both the GM motor and the TM motor are in the motoring state, the TM motor motoring power is limited, and the process goes to step S117; if Idc TM≤0, the GM motor is in the motoring state and the TM motor is in the power generation state, the GM motor motoring power is limited, and the process goes to step S118;

[0026] Step S106, determining whether the TM motor DC side current Idc TM is greater than 0;

[0027] If Idc TM>0, it means that the GM motor is in the generating state and the TM motor is in the motoring state, and the motoring power of the TM motor is limited, and the process goes to step S117;

[0028] If Idc TM≤0, it means that both the GM motor and the TM motor are in the power generation state, and the process returns to step S101;

[0029] Step S107, determining whether Idc is less than the charging current limit value Idc min of the buck-boost module;

[0030] If Idc≥Idc min, return to step S101;

[0031] If Idc<Idc min, determine whether the GM motor DC side current IdcGM is greater than 0. If Idc GM>0, proceed to step 108;

[0032] If Idc GM≤0, proceed to step 109;

[0033] Step 108, judging whether the TM motor DC side current Idc TM is greater than 0, if Idc TM>0, the GM motor and the TM motor are both in the electric state, and returning to step S101;

[0034] If Idc TM≤0, the GM motor is in the electric state, the TM motor is in the generating state, limiting the TM motor electric power, and proceeds to step S117;

[0035] Step S109, determine whether the TM motor DC side current Idc TM is greater than 0, if Idc TM>0, the GM motor is in a generating state, the TM motor is in a discharging state, and the generating power of the GM motor is limited; proceed to step S118;

[0036] If Idc TM≤0, both the GM motor and the TM motor are in the power generation state, the power generation of the GM motor is limited, and the process goes to step S118;

[0037] Step S110, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S111; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S112;

[0038] Step S111, determine whether Idc is greater than the discharge current limit value Idc max of the buck-boost module. If so, the GM motor is in an electric state, the electric power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101;

[0039] Step S112, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the GM motor is in a power generation state, the power generation power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101;

[0040] Step S113, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S114; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S115;

[0041] Step S114, determine whether Idc is greater than the step-up / step-down module discharge current limit value Idc max. If so, the TM motor is in the electric state, the electric power of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101;

[0042] Step S115, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the TM motor is in a power generation state, the power generation of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101;

[0043] S117, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the TM motor torque limit value ΔT3 according to the TM motor speed and ΔPdc; the TM motor executes the torque instruction T=T3-ΔT3; limit the TM motor torque boundary and boundary recovery speed; return to step S101; T is the actual torque executed after the limited motor torque is corrected, and T3 is the actual torque of the TM motor;

[0044] S118, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the GM motor torque limit value ΔT1 according to the GM motor speed and ΔPdc; the GM motor executes the torque instruction T=T1-ΔT1; limit the GM motor torque boundary and boundary recovery rate; return to step S101, T1 is the actual torque of the GM motor.

[0045] Optionally, the calculation method of ΔPdc is: ΔPdc=Udc*ΔIdc, wherein Udc is the voltage on the battery side of the buck-boost module, and ΔIdc is the difference between the actual current Idc and Idc max or Idc min when the current exceeds the limit.

[0046] In a second aspect, a hybrid vehicle buck-boost module overcurrent protection system described in the present invention includes a memory and a controller, wherein the memory stores a computer-readable program, and when the computer-readable program is called by the controller, it can execute the steps of the hybrid vehicle buck-boost module overcurrent protection method described in the present invention.

[0047] In a third aspect, a vehicle described in the present invention adopts the hybrid vehicle boost / lower module overcurrent protection system described in the present invention.

[0048] In a fourth aspect, a storage medium according to the present invention stores a computer-readable program therein, and when the computer-readable program is called by a controller, the steps of the hybrid vehicle boost / boost module overcurrent protection method according to the present invention can be executed.

[0049] The present invention has the following advantages:

[0050] (1) The present invention provides a current protection method for a buck-boost module of a P13 configuration hybrid vehicle, which solves the overcurrent problem of the buck-boost module caused by system power fluctuations under extreme conditions such as rapid acceleration and deceleration of the vehicle, thereby not only protecting the power system components, but also ensuring driving safety.

[0051] (2) The present invention formulates priority restriction principles and paths for the GM motor and the TM motor according to their working conditions, reasonably limits the power of the power system, ensures the stability of the power system and smooth driving, and avoids problems such as vehicle impact and runaway.

[0052] (3) In the power limitation link, the present invention obtains the torque correction value according to the actual vehicle calibration and sets the torque hysteresis, which not only ensures that the boost / boost module is effectively protected without affecting the power performance of the whole vehicle, but also avoids the vibration of the whole vehicle caused by the oscillation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram for describing the power system of a P13 integrated buck-boost module series-configured extended-range hybrid vehicle;

[0054] Figure 2 It is a schematic diagram for describing the configuration of a hybrid vehicle power system of a P13 integrated buck-boost module in series-parallel configuration;

[0055] Figure 3 is a flow chart of the method;

[0056] Figure 4 This is the GM motor torque limit MAP diagram;

[0057] Figure 5 This is the TM motor torque limit MAP diagram;

[0058] Figure 6 is a detailed flow chart of this method. DETAILED DESCRIPTION

[0059] The present invention will be described in detail below with reference to the accompanying drawings.

[0060] like Figure 1 As shown, the method is applicable to a P13 series range-extended hybrid vehicle integrated with a buck-boost module, which includes an engine S1, a GM motor S4 connected to the engine S1, a power battery S2, a buck-boost module S3 connected to the power battery S2, and a TM motor S5 for driving a wheel S6 and connected to the buck-boost module S3. The buck-boost module S3 is located between the battery S2 and the GM motor S4 and the TM motor S5, so that the voltages of the battery S2 and the GM motor S4 and the TM motor S5 are decoupled.

[0061] like Figure 2 As shown, the present invention is applicable to a P13 series-parallel hybrid vehicle integrated with a buck-boost module, which includes an engine S1, a GM motor S4 connected to the engine S2, a power battery S2, and a high-voltage buck-boost module S3 connected to the power battery S2. When the clutch S7 is disconnected, only the TM motor S5 drives the wheel S6 to travel. When the clutch S7 is engaged, the TM motor S5 and the engine S1 drive the wheel S6 in parallel. The buck-boost module S3 is located between the power battery S2 and the GM motor S4 and TM motor S5, so that the voltages of the battery S2 and the GM motor S4 and TM motor S5 are decoupled.

[0062] like Figure 3 As shown, a hybrid vehicle boost / lower voltage module overcurrent protection method comprises the following steps:

[0063] Check whether the GM motor and TM motor are in working condition;

[0064] When only the GM motor is working, if the discharge current of the buck-boost module exceeds the limit, the electric power of the GM motor will be limited; if the charging current of the buck-boost module exceeds the limit, the charging power of the GM motor will be limited.

[0065] When the GM motor and TM motor are working at the same time, if the discharge current of the buck-boost module exceeds the limit, the power of the motor in the electric state will be limited first. If both the GM motor and the TM motor are in the electric state, the electric power of the TM motor will be limited first.

[0066] If the charging current of the buck-boost module exceeds the limit, the power of the motor in the power generation state will be limited first. If both the GM motor and the TM motor are in the power generation state, the power generation power of the GM motor will be limited first.

[0067] When only the TM motor is working, if the discharge current of the buck-boost module exceeds the limit, the electric power of the TM motor is limited; if the charging current of the buck-boost module exceeds the limit, the charging power of the TM motor is limited.

[0068] In this embodiment, according to the current threshold Idc_limit of the buck-boost module charging and discharging fault, the buck-boost module current protection values ​​Idc_max and Idc_min are set according to a certain safety factor as the allowable current boundary of the buck-boost module. When the charging or discharging current is greater than the allowable current boundary, the charging and discharging current of the buck-boost module can be protected from exceeding the fault current threshold by reasonably limiting the operating power of the GM motor or TM motor, while not affecting vehicle safety and driving stability. In addition to being set according to a certain safety factor, the allowable current boundary can also be obtained through actual vehicle calibration.

[0069] In this embodiment, after the GM motor and the TM motor determine the motor with priority restriction, it is identified that the restricted motor is in the motoring or generating state, and the difference between the working current of the buck-boost module in the current working condition and the set current boundary is calculated. The charging or discharging torque is revised according to the difference (torque correction Map is shown in the table). Figure 4 and Figure 5 ), at this time, the limited motor does not respond to the PCU request, and the motor controls itself and executes the corrected torque. In order to suppress the oscillation of the power system, a torque recovery hysteresis link needs to be set after the torque is limited. The torque correction map and torque hysteresis slope are obtained through real vehicle calibration.

[0070] like Figure 6 As shown, a hybrid vehicle boost / lower voltage module overcurrent protection method specifically includes the following steps:

[0071] Step S101, determining the working status of the GM motor and the TM motor;

[0072] Step S102: If the GM motor and the TM motor work at the same time, proceed to step S103;

[0073] If only the GM motor is working, then go to step S110;

[0074] If only the TM motor is working, go to step S113;

[0075] If both the GM motor and the TM motor are not working, the process ends;

[0076] Step S103, determining whether the working current Idc of the battery side of the buck-boost module is greater than 0;

[0077] If Idc>0, the buck-boost module is in a discharging state, and the process goes to step S104;

[0078] If Idc≤0, the buck-boost module is in a charging state, and the process goes to step S107;

[0079] Step S104, it is determined whether Idc is greater than the step-up / down voltage module discharge current limit value Idc max, if not, returns to step S101; if so, proceeds to step S105;

[0080] Step S105, determining whether the GM motor DC side current Idc GM is greater than 0;

[0081] If Idc GM≤0, proceed to step S106;

[0082] If Idc GM>0, determine whether the TM motor DC side current Idc TM is greater than 0. If Idc TM>0, both the GM motor and the TM motor are in the motoring state, the TM motor motoring power is limited, and the process goes to step S117; if Idc TM≤0, the GM motor is in the motoring state and the TM motor is in the power generation state, the GM motor motoring power is limited, and the process goes to step S118;

[0083] Step S106, determining whether the TM motor DC side current Idc TM is greater than 0;

[0084] If Idc TM>0, it means that the GM motor is in the generating state and the TM motor is in the motoring state, and the motoring power of the TM motor is limited, and the process goes to step S117;

[0085] If Idc TM≤0, it means that both the GM motor and the TM motor are in the power generation state, and the process returns to step S101;

[0086] Step S107, determining whether Idc is less than the charging current limit value Idc min of the buck-boost module;

[0087] If Idc≥Idc min, return to step S101;

[0088] If Idc<Idc min, determine whether the GM motor DC side current IdcGM is greater than 0. If Idc GM>0, proceed to step 108;

[0089] If Idc GM≤0, proceed to step 109;

[0090] Step 108, judging whether the TM motor DC side current Idc TM motor is greater than 0, if Idc TM>0, the GM motor and the TM motor are both in the electric state, and returning to step S101;

[0091] If Idc TM≤0, the GM motor is in the electric state, the TM motor is in the generating state, limiting the TM motor electric power, and proceeds to step S117;

[0092] Step S109, determine whether the TM motor DC side current Idc TM is greater than 0, if Idc TM>0, the GM motor is in a generating state, the TM motor is in a discharging state, and the generating power of the GM motor is limited; proceed to step S118;

[0093] If Idc TM≤0, both the GM motor and the TM motor are in the power generation state, the power generation of the GM motor is limited, and the process goes to step S118;

[0094] Step S110, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S111; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S112;

[0095] Step S111, determine whether Idc is greater than the discharge current limit value Idc max of the buck-boost module. If so, the GM motor is in an electric state, the electric power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101;

[0096] Step S112, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the GM motor is in a power generation state, the power generation power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101;

[0097] Step S113, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S114; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S115;

[0098] Step S114, determine whether Idc is greater than the step-up / step-down module discharge current limit value Idc max. If so, the TM motor is in the electric state, the electric power of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101;

[0099] Step S115, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the TM motor is in a power generation state, the power generation of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101;

[0100] S117, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the TM motor torque limit value ΔT3 according to the TM motor speed and ΔPdc; the TM motor executes the torque instruction T=T3-ΔT3, which can protect the buck-boost module current from exceeding the limit. At this time, the restricted motor does not respond to the request instruction; limit the TM motor torque boundary and boundary recovery speed; return to step S101; T is the actual torque executed after the limited motor torque is corrected, and T3 is the actual torque of the TM motor;

[0101] S118, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the GM motor torque limit value ΔT1 according to the GM motor speed and ΔPdc; the GM motor executes the torque instruction T=T1-ΔT1, which can protect the buck-boost module current from exceeding the limit. At this time, the restricted motor does not respond to the request instruction; limit the GM motor torque boundary and boundary recovery rate; return to step S101; T1 is the actual torque of the GM motor.

[0102] In this embodiment, a hybrid vehicle buck-boost module overcurrent protection system includes a memory and a controller. The memory stores a computer-readable program. When the computer-readable program is called by the controller, it can execute the steps of the hybrid vehicle buck-boost module overcurrent protection method as described in this embodiment.

[0103] In this embodiment, a vehicle adopts the hybrid vehicle boost / lower voltage module overcurrent protection system as described in this embodiment.

[0104] In the present embodiment, a storage medium stores a computer-readable program, and when the computer-readable program is called by a controller, the steps of the hybrid vehicle buck-boost module overcurrent protection method as described in the present embodiment are executed.

[0105] In this embodiment, the symbols are defined as follows:

[0106] GM motor: A generator directly connected to the engine, mainly used for power generation, but can also be used for electric power.

[0107] TM motor: drive motor, mainly used to drive the vehicle and can also generate electricity.

[0108] Idc: Working current of the battery side of the buck-boost module.

[0109] Udc: Buck-boost module battery side voltage.

[0110] Idc GM: GM motor DC side current.

[0111] Idc TM: TM motor DC side current.

[0112] Idc_limit: The threshold for the discharge current on the battery side of the buck-boost module to report a fault.

[0113] Idc_max: Buck-boost module discharge current limit value.

[0114] Idc_min: Buck-boost module charging current limit value.

[0115] ΔIdc: The difference between the actual current Idc and Idc max or Idc min when the current exceeds the limit.

[0116] T1: GM motor actual torque.

[0117] T3: TM motor actual torque.

[0118] ΔT1: GM motor torque limit value.

[0119] ΔT3: TM motor torque limit value.

[0120] T: Actual torque executed after limited motor torque correction.

[0121] ΔPdc: The power that needs to be limited when the buck-boost module exceeds the limit, ΔPdc=Udc*ΔIdc.

[0122] It should be noted that the above-mentioned implementation mode is not used to limit the present invention, and any modification, equivalent substitution, improvement, etc. made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hybrid vehicle boost / lower module overcurrent protection method, characterized in that: The following steps are involved: Check whether the GM motor and TM motor are in working condition; When only the GM motor is working, if the discharge current of the buck-boost module exceeds the limit, the GM motor electric power is limited; if the charging current of the buck-boost module exceeds the limit, the GM motor charging power is limited; When the GM motor and TM motor are working at the same time, if the discharge current of the buck-boost module exceeds the limit, the power of the motor in the electric state will be limited first. If both the GM motor and the TM motor are in the electric state, the electric power of the TM motor will be limited first. If the charging current of the buck-boost module exceeds the limit, the power of the motor in the power generation state will be limited first. If both the GM motor and the TM motor are in the power generation state, the power generation power of the GM motor will be limited first. When only the TM motor is working, if the discharge current of the buck-boost module exceeds the limit, the electric power of the TM motor is limited; if the charging current of the buck-boost module exceeds the limit, the charging power of the TM motor is limited.

2. The overcurrent protection method for the boost / boost module of a hybrid vehicle according to claim 1, characterized in that: After determining the motor with priority restriction, identify whether the restricted motor is in the motoring or generating state, calculate the difference between the working current of the buck-boost module under the current working condition and the set current boundary, and revise the charging or discharging torque based on the difference lookup table. At this time, the restricted motor does not respond to the PCU request, and the motor controls itself and executes the corrected torque.

3. The overcurrent protection method for the boost / boost module of a hybrid vehicle according to claim 2, characterized in that: In order to suppress the oscillation of the power system, a torque recovery hysteresis link needs to be set after the torque is limited.

4. The overcurrent protection method for a boost / step-down module of a hybrid vehicle according to any one of claims 1 to 3, characterized in that: The method specifically comprises the following steps: Step S101, determining the working status of the GM motor and the TM motor; Step S102: If the GM motor and the TM motor work at the same time, proceed to step S103; If only the GM motor is working, then go to step S110; If only the TM motor is working, go to step S113; If both the GM motor and the TM motor are not working, the process ends; Step S103, determining whether the working current Idc of the battery side of the buck-boost module is greater than 0; If Idc>0, the buck-boost module is in a discharging state, and the process goes to step S104; If Idc≤0, the buck-boost module is in a charging state, and the process goes to step S107; Step S104, it is determined whether Idc is greater than the step-up / down voltage module discharge current limit value Idc max, if not, returns to step S101; if so, proceeds to step S105; Step S105, determining whether the GM motor DC side current Idc GM is greater than 0; If Idc GM≤0, proceed to step S106; If Idc GM>0, determine whether the TM motor DC side current Idc TM is greater than 0. If Idc TM>0, both the GM motor and the TM motor are in the motoring state, the TM motor motoring power is limited, and the process goes to step S117; if Idc TM≤0, the GM motor is in the motoring state and the TM motor is in the power generation state, the GM motor motoring power is limited, and the process goes to step S118; Step S106, determining whether the TM motor DC side current Idc TM is greater than 0; If Idc TM>0, it means that the GM motor is in the generating state and the TM motor is in the motoring state, and the motoring power of the TM motor is limited, and the process goes to step S117; If Idc TM≤0, it means that both the GM motor and the TM motor are in the power generation state, and the process returns to step S101; Step S107, determining whether Idc is less than the charging current limit value Idc min of the buck-boost module; If Idc≥Idc min, return to step S101; If Idc<Idc min, determine whether the GM motor DC side current Idc GM is greater than 0. If Idc GM>0, proceed to step 108; If Idc GM≤0, proceed to step 109; Step 108, judging whether the TM motor DC side current Idc TM is greater than 0, if Idc TM>0, the GM motor and the TM motor are both in the electric state, and returning to step S101; If Idc TM≤0, the GM motor is in the electric state, the TM motor is in the generating state, limiting the TM motor electric power, and proceeds to step S117; Step S109, determine whether the TM motor DC side current Idc TM is greater than 0, if Idc TM>0, the GM motor is in a generating state, the TM motor is in a discharging state, and the generating power of the GM motor is limited; proceed to step S118; If Idc TM≤0, both the GM motor and the TM motor are in the power generation state, the power generation of the GM motor is limited, and the process goes to step S118; Step S110, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S111; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S112; Step S111, determine whether Idc is greater than the discharge current limit value Idc max of the buck-boost module. If so, the GM motor is in an electric state, the electric power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101; Step S112, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the GM motor is in a power generation state, the power generation power of the GM motor is limited, and the process proceeds to step S118; if not, return to step S101; Step S113, judging whether the working current Idc of the battery side of the buck-boost module is greater than 0, if Idc>0, judging that the buck-boost module is in a discharging state, then proceeding to step S114; otherwise, judging that the buck-boost module is in a charging state, then proceeding to step S115; Step S114, determine whether Idc is greater than the step-up / step-down module discharge current limit value Idc max. If so, the TM motor is in the electric state, the electric power of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101; Step S115, determine whether Idc is less than the charging current limit value Idc min of the buck-boost module. If so, the TM motor is in a power generation state, the power generation of the TM motor is limited, and the process proceeds to step S117; if not, return to step S101; S117, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the TM motor torque limit value ΔT3 according to the TM motor speed and ΔPdc; the TM motor executes the torque instruction T=T3-ΔT3; limit the TM motor torque boundary and boundary recovery speed; return to step S101; T is the actual torque executed after the limited motor torque is corrected, and T3 is the actual torque of the TM motor; S118, calculate the power ΔPdc that needs to be limited when the buck-boost module exceeds the limit, and obtain the GM motor torque limit value ΔT1 according to the GM motor speed and ΔPdc; the GM motor executes the torque instruction T=T1-ΔT1; limit the GM motor torque boundary and boundary recovery rate; return to step S101; T1 is the actual torque of the GM motor.

5. The overcurrent protection method for the boost / boost module of a hybrid vehicle according to claim 4, characterized in that: The calculation method of ΔPdc is: ΔPdc=Udc*ΔIdc, wherein Udc is the voltage on the battery side of the buck-boost module, and ΔIdc is the difference between the actual current Idc and Idc max or Idc min when the current exceeds the limit.

6. A hybrid vehicle boost / lower module overcurrent protection system, characterized in that: It comprises a memory and a controller, wherein the memory stores a computer-readable program, and when the computer-readable program is called by the controller, it can execute the steps of the hybrid vehicle boost / boost module overcurrent protection method as claimed in any one of claims 1 to 5.

7. A vehicle, characterized in that: The hybrid vehicle boost / lower module overcurrent protection system as claimed in claim 6 is adopted.

8. A storage medium, characterized in that: A computer-readable program is stored therein, and when the computer-readable program is called by the controller, the steps of the hybrid vehicle buck-boost module overcurrent protection method as claimed in any one of claims 1 to 5 can be executed.

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