Pure electric commercial vehicle rotary transformer fault processing method based on LO observer and arc tangent
By using the fault treatment method of LO observer and arctangent in pure electric vehicles, the function of the rotary transformer is taken over, and the power loss caused by rotary failure is solved, and a safe, targeted and economical fault treatment is achieved.
Patent Information
- Application Number
- CN202411986603.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-03-28
AI Technical Summary
When a pure electric vehicle fails in a rotary transformer, it causes power to lose control, the entire vehicle to be under high pressure and cannot drive, causing traffic congestion and safety hazards. The existing technology fault response strategies have problems such as increased costs, high potential risks, and unpredictable braking torque.
The rotational failure treatment method of pure electric commercial vehicles based on LO observer and arctangent is adopted. By monitoring the driving status of the vehicle, switching to the inductive control mode, the LO observer algorithm takes over the function of the rotational transformer, and outputs the control signals required by the MCU to achieve safe handling of rotational failures.
It realizes that when a rotating failure, the vehicle can drive safely, provide a certain distance and time of power, help the vehicle escape from dangerous areas, reduce the risk of failure, and does not increase additional costs.
Smart Images
Figure CN119705079A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a resolver fault processing method for a pure electric commercial vehicle based on an LO observer and an inverse tangent. Background Art
[0002] The resolver (hereinafter referred to as "resolver") is an encoder commonly used in pure electric vehicles. It is designed to provide high-precision angular position feedback, which is essential to ensure the smooth operation of the vehicle. One of the main features of the resolver is that it can generate differential signal output, which gives it excellent anti-interference ability and can work stably in a vehicle environment with a complex electrical environment. In specific operation, the resolver can obtain sine output and cosine output through excitation input and drive motor shaft rotation. Furthermore, the drive system controller decodes the resolver electrical signal to obtain the angular velocity, angle and other control information of the drive motor, and then adjusts the motor torque output according to the vehicle's intention to meet the normal driving needs of the vehicle.
[0003] During the entire life cycle of pure electric vehicles, due to their own assembly reasons, poor performance of the boundary system, and other long-term complex and harsh operating conditions of the whole vehicle, it is easy for the resolver to be damaged, fail, break, and operate poorly. In order to prevent the vehicle from losing control, the resolver failure will generally cause power loss of control. The whole vehicle failure defines the resolver failure as a third-level failure or a power-off failure, which in turn causes the whole vehicle to lose high voltage and the whole vehicle's power system. The vehicle cannot drive on the road, causing traffic jams, or cannot be moved to a safe area on the highway and can only wait for rescue, which makes the user's driving experience somewhat insufficient and leads to some market complaints and other problems.
[0004] In response to current technical problems, there are three main fault response strategies: the first is to add additional back-EMF detection hardware current to facilitate the detection of back-EMF status, but this requires increased device cost, which is not conducive to cost optimization; the second is to directly shield the fault and control driving when a fault occurs, which is not fault-specific and has great potential risks; the third is to determine the FW / ASC braking mode by judging the state of the resolver. In this method, the sensorless algorithm is not clearly defined, and ASC braking under low-speed conditions will produce unexpected braking torque, and the purpose cannot be fully achieved in the ASC mode. At the same time, braking in busy city conditions with complex pedestrian and vehicle conditions and medium and high-speed road conditions is prone to some safety problems. Summary of the invention
[0005] The present invention aims to provide a resolver fault processing method for a pure electric commercial vehicle based on an LO observer and an inverse tangent, which can achieve safe and targeted resolver fault processing without adding additional costs and has good economy.
[0006] The basic solution provided by the present invention is: a method for processing a resolver fault of a pure electric commercial vehicle based on an LO observer and an inverse tangent, comprising the following steps:
[0007] Monitor the driving status of the vehicle, and when the driving status meets the preset conditions, control the vehicle to switch to the sensorless control mode;
[0008] The preset conditions include that the vehicle's MCU detects a fault signal from the rotary transformer, the vehicle's high-voltage system is in a ready state, and the speed switching condition is met;
[0009] A flag bit corresponding to the fault signal is set in the MCU and uploaded to the vehicle's instrument; the vehicle's motor operating parameters just before the fault signal appears are collected as reference parameters, and the function of the rotary transformer is taken over based on the LO observer algorithm, which outputs the control signal required by the MCU based on the reference parameters.
[0010] Furthermore, the control signals required by the MCU include position signals, angle signals, and speed signals.
[0011] Furthermore, the LO observer algorithm takes the voltage and current of the vehicle motor in a stationary coordinate system as input.
[0012] Further, in the LO observer algorithm, the observer model is expressed as:
[0013]
[0014] in, is the state estimate; L is the observer gain matrix to be determined; A is the state matrix coefficient, which is calculated according to the motor speed and the actual inductance and resistance of the motor; B is the input matrix, which is calculated according to the actual inductance of the motor; C is the output matrix coefficient.
[0015] Furthermore, in the observer model:
[0016]
[0017] Where, L S is the actual inductance of the motor; w e is the motor speed; r is the motor resistance.
[0018] Furthermore, in the observer model:
[0019]
[0020] Where L is the observer gain matrix to be determined, and the matrix elements L1 and L2 are obtained by the following steps:
[0021] Setting the state error equation e is the error between the true state and the estimated state;
[0022] The state error equation is converged so that the value of e approaches 0, and L1 and L2 are obtained by solving.
[0023] Furthermore, when the LO observer algorithm outputs the control signal required by the MCU based on the reference parameter, the LO observer first outputs the estimated value of the back electromotive force, and then the estimated value of the back electromotive force outputted by the LO observer is filtered;
[0024] Get the filtered value of the estimated back EMF value e β 、e α ;e β is the β-axis back electromotive force in the stationary coordinate system; e α is the α-axis back electromotive force in the stationary coordinate system;
[0025] Based on e β 、e α , calculate the angle θ of the motor rotor through the inverse tangent T and speed w r , and converted into control signals and input into MCU.
[0026] Furthermore, the LO observer algorithm is debugged and compared with the actual angle output by the resolver to achieve angle following.
[0027] The working principle and advantages of the present invention are:
[0028] The present invention is based on the LO observer and the inverse tangent pure electric commercial vehicle resolver fault processing method. When the vehicle is in a medium or high speed driving scenario, the vehicle loses power and cannot drive due to the third-level fault caused by the resolver fault. The vehicle driving state and the speed signal are judged to switch from the "sensing" state to the "non-sensing" state. Specifically, after the preset conditions are met, the motor controller (MCU) enters the sensorless controller mode (i.e., the sensorless control mode), and sets a flag corresponding to the fault signal inside the motor controller, and uploads it to the vehicle's instrument to remind the driver in time. At the same time, the LO observer algorithm is used to replace the resolver to take over the function through the angle value, speed value, current and voltage signal at the moment before the resolver fault. The voltage and current in the motor's stationary coordinate system are input, and the observer model is used to calculate and output the position signal, angle signal, and speed signal required by the motor controller (MCU). This function benefits from the detailed and accurate performance parameters obtained by the vehicle-grade product test, and can provide a certain distance and a certain time of operation process when the resolver fails, providing the faulty vehicle with emergency driving or driving from a dangerous area to a safe area. The key points are:
[0029] First, this scheme uses the LO observer algorithm and the inverse tangent algorithm. It can use the real system output to perform error feedback correction to construct a closed-loop observer without adding new sensors and other hardware, so that it can ultimately accurately observe the real state of the system without adding additional costs.
[0030] Second, this solution can add the LO observer algorithm without changing the whole vehicle system architecture, improve the stability of the system, and does not increase additional costs. It is easy to operate, has high executability, and has high practical promotion and application value.
[0031] Third, when the resolver fault is triggered, this solution can take over through the observer to leave enough operating time and mileage for the driver to perform corresponding safe operations, which can better adapt to various working conditions and load changes; and can provide power for the faulty vehicle to drive urgently or leave the dangerous area to a safe area, which helps to reduce the risk of failure. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 It is a schematic diagram of a method flow of an embodiment of a method for processing resolver faults of a pure electric commercial vehicle based on LO observer and inverse tangent of the present invention;
[0033] Figure 2 It is a schematic diagram of the observer structure of an embodiment of a method for handling resolver faults of a pure electric commercial vehicle based on an LO observer and an inverse tangent of the present invention;
[0034] Figure 3 It is a schematic diagram of the input and output model of the observer of the embodiment of the method for handling resolver faults of pure electric commercial vehicles based on the LO observer and the inverse tangent of the present invention;
[0035] Figure 4 It is a schematic diagram of the observer model debugging of an embodiment of the method for handling resolver faults of a pure electric commercial vehicle based on LO observer and inverse tangent of the present invention. DETAILED DESCRIPTION
[0036] The following is a further detailed description through specific implementation methods:
[0037] The embodiment is basically as shown in the attached Figure 1 and Figure 2 As shown: A pure electric commercial vehicle resolver fault processing method based on LO observer and inverse tangent includes the following steps:
[0038] Monitor the driving status of the vehicle, and when the driving status meets the preset conditions, control the vehicle to switch to the sensorless control mode.
[0039] The preset conditions include that the vehicle's MCU detects a fault signal from the rotary transformer, the vehicle's high-voltage system is in a ready state, and the speed switching conditions are met.
[0040] A flag corresponding to the fault signal is set in the MCU and uploaded to the vehicle's instrument. The vehicle's motor operating parameters just before the fault signal appears are collected as reference parameters, and the function of the rotary transformer is taken over based on the LO observer algorithm. The LO observer algorithm outputs the control signal required by the MCU based on the reference parameters.
[0041] The control signals required by the MCU include position signals, angle signals, and speed signals. The motor operation parameters include angle values, speed values, current and voltage signals, etc.
[0042] The LO observer algorithm takes the voltage and current of the vehicle motor in a stationary coordinate system as input.
[0043] Specifically, according to the voltage equation of the motor in the stationary coordinate system (α-β coordinate system), it can be obtained:
[0044] u α is the α-axis voltage in the stationary coordinate system; u β is the β-axis voltage in the stationary coordinate system; R is the winding resistance; i β β-axis current in the stationary coordinate system; i α α-axis current in the stationary coordinate system; L s is the winding inductance (surface mount type); if it is an embedded motor, the inductance in the stationary coordinate system is L β , L α ;e β β-axis back electromotive force in the stationary coordinate system; e α The α-axis back electromotive force in the stationary coordinate system.
[0045] In the LO observer algorithm, the observer model is expressed as:
[0046]
[0047] in, is the state estimator, and the motor control system state satisfies the space equation——
[0048] L is the observer gain matrix to be determined; A is the state matrix coefficient, which is calculated based on the motor speed and the actual inductance and resistance of the motor; B is the input matrix, which is calculated based on the actual inductance of the motor; C is the output matrix coefficient.
[0049] Furthermore, if Figure 3 As shown, establish α 、u β is the real input, i β 、i αThe output model is input to the observer of the true output to obtain the back EMF estimate.
[0050] Specifically, in the observer model:
[0051]
[0052] Where, L S is the actual inductance of the motor; w e is the motor speed; r is the motor resistance.
[0053]
[0054] Where L is the observer gain matrix to be determined, and the matrix elements L1 and L2 are obtained by the following steps:
[0055] Setting the state error equation e is the error between the true state and the estimated state;
[0056] The state error equation is converged so that the value of e approaches 0, and L1 and L2 are obtained by solving.
[0057] When the LO observer algorithm outputs the control signal required by the MCU based on the reference parameters, the LO observer first outputs the estimated value of the back electromotive force; then the estimated value of the back electromotive force outputted by the LO observer is filtered;
[0058] Get the filtered value of the estimated back EMF value e β 、e α ;e β is the β-axis back electromotive force in the stationary coordinate system; e α is the α-axis back electromotive force in the stationary coordinate system;
[0059] Based on e β 、e α , calculate the angle θ of the motor rotor through the inverse tangent r and speed ω r , and converted into control signals and input into MCU.
[0060] Debug the LO observer algorithm and compare it with the actual angle output by the resolver to achieve angle following, such as Figure 4 shown.
[0061] Specifically, when debugging the LO observer algorithm, first set the initial value of L in the observer model, run the observer model, compare the angle output by the observer model with the actual angle output by the resolver, and analyze the error size and its changing trend between the two; based on the above analysis results, gradually adjust the elements in L, or modify other related parameters until a satisfactory angle following effect is obtained. Once a suitable set of L parameters is found, this observer model can be applied to the actual system to achieve higher control accuracy.
[0062] The present embodiment provides a resolver fault processing method for a pure electric commercial vehicle based on an LO observer and an inverse tangent, which can achieve safe and targeted resolver fault processing without increasing additional costs and has good economic efficiency.
[0063] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. A pure electric commercial vehicle resolver fault processing method based on LO observer and inverse tangent, characterized in that: The following steps are involved: Monitor the driving status of the vehicle, and when the driving status meets the preset conditions, control the vehicle to switch to the sensorless control mode; The preset conditions include that the vehicle's MCU detects a fault signal from the rotary transformer, the vehicle's high-voltage system is in a ready state, and the speed switching condition is met; A flag bit corresponding to the fault signal is set in the MCU and uploaded to the vehicle's instrument; the vehicle's motor operating parameters just before the fault signal appears are collected as reference parameters, and the function of the rotary transformer is taken over based on the LO observer algorithm, which outputs the control signal required by the MCU based on the reference parameters.
2. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 1, characterized in that: The control signals required by the MCU include position signals, angle signals, and speed signals.
3. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 1, characterized in that: The LO observer algorithm takes the voltage and current of the vehicle motor in a stationary coordinate system as input.
4. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 1, characterized in that: In the LO observer algorithm, the observer model is expressed as: in, is the state estimate; L is the observer gain matrix to be determined; A is the state matrix coefficient, which is calculated according to the motor speed and the actual inductance and resistance of the motor; B is the input matrix, which is calculated according to the actual inductance of the motor; C is the output matrix coefficient.
5. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 4, characterized in that: In the observer model: Where, L S is the actual inductance of the motor; w e is the motor speed; r is the motor resistance.
6. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 4, characterized in that: In the observer model: Where L is the observer gain matrix to be determined, and the matrix elements L1 and L2 are obtained by the following steps: Setting the state error equation e is the error between the true state and the estimated state; The state error equation is converged so that the value of e approaches 0, and L1 and L2 are obtained by solving.
7. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 3, characterized in that: When the LO observer algorithm outputs the control signal required by the MCU based on the reference parameters, the LO observer first outputs the estimated value of the back electromotive force, and then the estimated value of the back electromotive force outputted by the LO observer is filtered; Get the filtered value of the estimated back EMF value e β 、e α ;e β is the β-axis back electromotive force in the stationary coordinate system; e α is the α-axis back electromotive force in the stationary coordinate system; Based on e β 、e α , calculate the angle θ of the motor rotor through the inverse tangent r and speed w r , and converted into control signals and input into MCU.
8. The method for handling resolver faults of pure electric commercial vehicles based on LO observer and inverse tangent according to claim 1, characterized in that: The LO observer algorithm is debugged and compared with the actual angle output by the resolver to achieve angle following.