CN110901392B - Protection method and device for judging vehicle running state according to motor loss and vehicle - Google Patents

Abstract

The invention relates to a protection method and a device for judging the running state of a vehicle according to motor loss and the vehicle, wherein the method comprises the steps of firstly collecting the actual rotating speed of a driving motor, and calculating the normal range of the rotating speed of the driving motor according to the input power of the driving motor and the motor loss in the current running state; and then comparing the actual rotating speed of the driving motor with a normal rotating speed range in the current operating state, if the actual rotating speed of the driving motor is in the normal rotating speed range, the driving motor normally operates, and if the actual rotating speed of the driving motor is not in the normal rotating speed range, the driving motor is judged to be in a fault state, the driving motor is controlled to stop outputting, and corresponding protection is carried out. Therefore, the method can judge the running state of the vehicle according to the rotating speed of the motor, and intervene in control in time when the rotating speed of the motor is excessively deviated from a normal running range, namely a desired value, so that the safe running of the vehicle is ensured, and the safety factor of the running of the vehicle is improved.

Description

Protection method and device for judging vehicle running state according to motor loss and vehicle

Technical Field

The invention relates to a protection method and device for judging a vehicle running state according to motor loss and a vehicle.

Background

At present, torque control is mostly adopted for pure electric vehicles, namely, according to specific vehicle working condition requirements such as a current gear, a rotating speed, an accelerator pedal opening degree and a brake pedal opening degree, a Vehicle Control Unit (VCU) gives an instant torque requirement value according to required power, the torque requirement value is sent to a Motor Controller (MCU), and the motor controller realizes that a driving motor outputs a corresponding torque value and power by controlling the output value of alternating-current side current so as to meet the operation requirements of the vehicle. The control mode adopting the torque control is relatively simple and stable, and is used on most vehicles at present.

The torque control method described above is technically mature regardless of control accuracy or response speed. However, when the electric angle is deviated in the operation process of the driving motor, if the torque is normally output, the deviation between the rotation speed of the motor and the expected value is too large, and unexpected acceleration or braking is caused, so that not only the driving experience is influenced, but also the safe operation of the vehicle is greatly influenced. Therefore, a corresponding protection strategy needs to be established for the situation so as to improve the running safety of the vehicle.

Disclosure of Invention

The invention aims to provide a protection method and a protection device for judging the running state of a vehicle according to motor loss and the vehicle, which are used for solving the problem that the safe running of the vehicle is greatly influenced when the deviation between the rotating speed of a driving motor and an expected value is overlarge.

In order to achieve the above object, the present invention includes the following technical solutions.

The invention provides a protection method for judging the running state of a vehicle according to the loss of a motor, which comprises the following steps:

(1) collecting the actual rotating speed of a driving motor;

(2) comparing the actual rotating speed of the driving motor with a normal rotating speed range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the normal rotating speed range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

And calculating to obtain a normal rotating speed range of the driving motor in a corresponding operating state according to the input power of the driving motor and the motor loss, wherein in the operating process, if the actual rotating speed of the driving motor is in the corresponding normal range, the driving motor normally operates, and if the actual rotating speed of the driving motor is not in the normal range, the driving motor is judged to be in a fault state, and the driving motor is controlled to stop outputting. Therefore, the running state of the vehicle is judged according to the rotating speed of the motor, and when the rotating speed of the motor and the normal running range, namely the deviation of the expected value is overlarge, the control can be timely intervened, the safe running of the vehicle is ensured, and the safety factor of the running of the vehicle is improved.

Further, the input power of the drive motor is calculated from the voltage and current output from the ac side of the motor controller. Since the driving motor is generally an ac motor, the input power of the driving motor can be calculated from the voltage and current output from the ac side of the motor controller.

Further, the motor loss has the following two calculation modes:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

The motor loss of the drive motor can be calculated in either of these two ways.

The invention also provides a protection device for judging the running state of a vehicle according to the loss of the motor, which comprises the following components:

the rotating speed acquisition module is used for acquiring the actual rotating speed of the driving motor;

the control module is used for comparing the actual rotating speed of the driving motor with a rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}For motor losses, aAnd E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening degree of an accelerator pedal.

And calculating to obtain a normal rotating speed range of the driving motor in a corresponding operating state according to the input power of the driving motor and the motor loss, wherein in the operating process, if the actual rotating speed of the driving motor is in the corresponding normal range, the driving motor normally operates, and if the actual rotating speed of the driving motor is not in the normal range, the driving motor is judged to be in a fault state, and the driving motor is controlled to stop outputting. Therefore, the running state of the vehicle is judged according to the rotating speed of the motor, and when the rotating speed of the motor and the normal running range, namely the deviation of the expected value is overlarge, the control can be timely intervened, the safe running of the vehicle is ensured, and the safety factor of the running of the vehicle is improved.

Further, the input power of the drive motor is calculated from the voltage and current output from the ac side of the motor controller. Since the driving motor is generally an ac motor, the input power of the driving motor can be calculated from the voltage and current output from the ac side of the motor controller.

Further, the motor loss has the following two calculation modes:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

The motor loss of the drive motor can be calculated in either of these two ways.

The present invention also provides a vehicle including a vehicle body and a protection device for judging a running state of the vehicle according to a loss of a motor, the protection device including:

the rotating speed acquisition module is used for acquiring the actual rotating speed of the driving motor;

the control module is used for comparing the actual rotating speed of the driving motor with a rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

And calculating to obtain a normal rotating speed range of the driving motor in a corresponding operating state according to the input power of the driving motor and the motor loss, wherein in the operating process, if the actual rotating speed of the driving motor is in the corresponding normal range, the driving motor normally operates, and if the actual rotating speed of the driving motor is not in the normal range, the driving motor is judged to be in a fault state, and the driving motor is controlled to stop outputting. Therefore, the running state of the vehicle is judged according to the rotating speed of the motor, and when the rotating speed of the motor and the normal running range, namely the deviation of the expected value is overlarge, the control can be timely intervened, the safe running of the vehicle is ensured, and the safety factor of the running of the vehicle is improved.

Further, the input power of the drive motor is calculated from the voltage and current output from the ac side of the motor controller. Since the driving motor is generally an ac motor, the input power of the driving motor can be calculated from the voltage and current output from the ac side of the motor controller.

Further, the motor loss has the following two calculation modes:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

The motor loss of the drive motor can be calculated in either of these two ways.

Drawings

Fig. 1 is a flowchart illustrating a protection method for determining a vehicle running state according to a motor loss.

Detailed Description

Protection method embodiment for judging vehicle running state according to motor loss

A protection method for judging the running state of a vehicle according to the loss of a motor comprises the following steps:

(1) collecting the actual rotating speed of a driving motor;

(2) and comparing the actual rotating speed of the driving motor with the rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range.

The calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

In this embodiment, a vehicle to which the method is applied takes a new energy vehicle as an example. The following describes the protection method for determining the vehicle operating state according to the motor loss according to the present invention in further detail with reference to the accompanying drawings.

In the normal running process of the vehicle, the VCU monitors the running state of the vehicle in real time, including working modes (driving, generating, sliding and the like), an accelerator signal, a brake signal and the like, generates corresponding required torque according to the running state, and outputs the current required torque to the MCU. The MCU obtains electricity from the power battery, inverts the direct current output by the power battery into corresponding alternating voltage and alternating current according to the torque requirement value of the whole vehicle, outputs the alternating voltage and the alternating current to the driving motor for doing work, and outputs torque and power by the driving motor.

The vehicle is in the operation in-process, gathers driving motor's actual rotational speed in real time through rotational speed collection module, and wherein, rotational speed collection module can be conventional rotational speed check out test set.

In this embodiment, the related safety control according to the actual rotation speed is realized by the MCU, and then the rotation speed acquisition module outputs the actual rotation speed signal to the MCU. The MCU compares the received actual rotating speed of the driving motor with the rotating speed normal range in the current running state, and makes the following judgments: as shown in fig. 1, when the actual rotating speed is within the normal rotating speed range, the rotating speed is reasonable, the rotating speed is judged to be in a normal state, the MCU continues to output normally, and the vehicle continues to operate normally; when the actual rotating speed is not in the normal rotating speed range, the rotating speed is unreasonable, the fault state is judged, the MCU controls the driving motor to stop outputting, and protective measures such as alarming or zero-torque switch protection are executed, so that the running safety of the vehicle is enhanced.

Here, the MCU calculates the normal range of the rotation speed in the current operation state according to parameters such as the input power of the motor and the loss of the motor, and the following are specific:

according to the AC voltage U output by the MCU AC side_{Side of alternating current}And an alternating current I_{Side of alternating current}Calculating the input power P of the driving motor in the current state_{Input device}The calculation formula is as follows:

P_{input device}＝1.732*U_{Side of alternating current}*I_{Side of alternating current}Power factor

Calculating the loss P of the motor by combining the calibration data during the design of the motor_{Loss of power}. The motor calibration data is test data of output power, efficiency and the like of each rotating speed point of the motor under different torques through the dynamometer when the motor is developed. Electric powerMechanical loss P_{Loss of power}There are two calculation modes, and the motor loss P can be obtained by adopting any one of the two calculation modes_{Loss of power}：

Mode 1:

P_{loss of power}＝P_{Input device}-P_{Input device}*η

Wherein η is the motor efficiency, specifically the motor efficiency calibration data, which is a known value.

Mode 2:

P_{loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}

Wherein, P_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor. P_{Copper loss}By an alternating current I_{Side of alternating current}And motor phase resistance R_{Phase (C)}And calculating to obtain the following three-phase permanent magnet synchronous motor:

P_{copper loss}＝I_{Side of alternating current} ²*R_{Phase (C)}*3

P_{Iron loss}And P_{Mechanical wear}P can be obtained by testing loss values under various currents and rotating speeds through a false rotor test_{Iron loss}And P_{Mechanical wear}And writing the test data into the MCU program.

Of course, the output power P of the drive motor can also be calculated_{Output of}The calculation formula is as follows:

P_{output of}Rotational speed/torque 9.55

Therefore, considering the error margin a (0 < a < 1, e.g., a is 10%), if the output power P is P_{Output of}Satisfies the following conditions:

(P_{input device}-P_{Loss of power})*(1-a)≤P_{Output of}≤(P_{Input device}-P_{Loss of power})*(1+a)

Determining as normal state if the output power P_{Output of}If the output is not within the range, the state is judged as a fault state, and the output is interrupted.

The output power P is measured_{Output of}The inequalities satisfied are converted to obtain the following ranges of the rotating speed n under normal conditions:

k*(P_{input device}-P_{Loss of power})*(1-a)/E≤n≤k*(P_{Input device}-P_{Loss of power})*(1+a)/E

Wherein k is a coefficient, and 9.55 is taken. And E is the torque of the driving motor in the current state.

For the torque E in the current state of the drive motor: the driving motor has different torques at different vehicle speeds and different accelerator pedal openings. Therefore, the torque of the drive motor can be obtained from the vehicle motor output characteristic and the vehicle acceleration performance, that is, from the current vehicle speed and the opening degree of the accelerator pedal. The VCU of the vehicle control unit can calculate a corresponding torque calibration value through simulation by combining the current vehicle speed and the opening degree of an accelerator pedal, and the driving motor has different torque calibration values under different vehicle speeds and different opening degrees of the accelerator pedal. Therefore, when the vehicle actually runs, the corresponding torque calibration value can be obtained according to different vehicle speeds and the opening degree of the accelerator pedal, and specific torque is output according to the obtained torque calibration value. Therefore, the torque of the driving motor in the current state can be obtained according to the above process, and the torque value is a calibration value and is not a calculated value.

The normal range for the speed n is therefore:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

The specific embodiments are given above, but the present invention is not limited to the described embodiments. The basic idea of the present invention lies in the above basic scheme, and it is obvious to those skilled in the art that no creative effort is needed to design various modified models, formulas and parameters according to the teaching of the present invention. Variations, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the invention, and still fall within the scope of the invention.

Protection device embodiment for judging vehicle running state according to motor loss

The embodiment provides a protection device for judging vehicle running state according to motor loss, which comprises two modules, wherein the two modules are respectively as follows:

the rotating speed acquisition module is used for acquiring the actual rotating speed of the driving motor;

and the control module is used for comparing the actual rotating speed of the driving motor with the rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range.

The calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power in the current state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

Therefore, the protection device for judging the vehicle running state according to the motor loss is essentially a protection method for judging the vehicle running state according to the motor loss. Since the protection method has been described in detail in the above-described embodiment of the protection method for determining the vehicle running state based on the motor loss, it will not be described in detail here.

Vehicle embodiment

The embodiment provides a vehicle, which comprises a vehicle body, and in addition, a protection device for judging the running state of the vehicle according to the loss of a motor is further arranged in the vehicle, so that the safe running control of the vehicle is realized. Since the protection device has been described in detail in the above embodiment of the protection method for determining the vehicle running state based on the motor loss, it will not be described in detail here.

Claims (9)

1. A protection method for judging a vehicle running state according to motor loss is characterized by comprising the following steps:

(1) collecting the actual rotating speed of a driving motor;

(2) comparing the actual rotating speed of the driving motor with a normal rotating speed range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the normal rotating speed range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

2. The protection method for determining the running state of a vehicle according to the motor loss of claim 1, wherein the input power of the driving motor is calculated based on the voltage and current output from the ac side of the motor controller.

3. The protection method for judging the running state of a vehicle according to the motor loss as claimed in claim 1, wherein the motor loss is calculated in two ways:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

4. A protection device for determining a running state of a vehicle based on a loss of a motor, comprising:

the rotating speed acquisition module is used for acquiring the actual rotating speed of the driving motor;

the control module is used for comparing the actual rotating speed of the driving motor with a rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

5. The apparatus for protecting an operating state of a vehicle from a loss of a motor according to claim 4, wherein the input power of the driving motor is calculated based on a voltage and a current output from an ac side of the motor controller.

6. The protection device for determining the running state of the vehicle according to the motor loss as claimed in claim 4, wherein the motor loss is calculated in two ways:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

7. A vehicle, including the vehicle body, its characterized in that still includes a protection device who judges vehicle running state according to the motor loss, protection device includes:

the rotating speed acquisition module is used for acquiring the actual rotating speed of the driving motor;

the control module is used for comparing the actual rotating speed of the driving motor with a rotating speed normal range in the current running state, and controlling the driving motor to stop outputting when the actual rotating speed is not in the rotating speed normal range;

the calculation process of the normal range of the rotating speed in the current running state comprises the following steps:

1) calculating the input power and the motor loss of the driving motor in the current running state;

2) calculating a normal range of the rotating speed as follows:

[k*(P_{input device}-P_{Loss of power})*(1-a)/E，k*(P_{Input device}-P_{Loss of power})*(1+a)/E]

Wherein k is a coefficient, P_{Input device}Is the input power of the driving motor in the present state, P_{Loss of power}And a is the motor loss, a is an error allowance, a is more than 0 and less than 1, and E is the torque of the driving motor in the current state and is determined by the current vehicle speed and the opening of an accelerator pedal.

8. The vehicle of claim 7, wherein the input power to drive the motor is calculated based on the voltage and current output from the ac side of the motor controller.

9. The vehicle of claim 7, wherein the motor loss is calculated in two ways:

mode 1: p_{Loss of power}＝P_{Input device}-P_{Input device}Eta, wherein eta is the motor efficiency;

mode 2: p_{Loss of power}＝P_{Copper loss}+P_{Iron loss}+P_{Mechanical wear}Wherein P is_{Copper loss}For the motor copper loss, P_{Iron loss}For iron loss of the motor, P_{Mechanical wear}Is a mechanical loss of the motor.

Images