Current value calibration method, motor controller and system

Abstract

The embodiment of the invention relates to the technical field of motor control, and discloses a current value calibration method, a motor controller and a system. The method comprises the following steps: acquiring a current detection current value of a current sensor and emitter voltage and junction temperature of a motor driving unit; determining an actual collector current value associated with the emitter voltage and the junction temperature; and when the current value calibration condition is satisfied, the current detection current value is calibrated based on the current detection current value and the actual collector current value. According to the technical scheme, the deviation between the detected current value of the current sensor and the actual current value can be reduced, and the motor control precision is improved.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a current value calibration method, a motor controller, and a system. Background Technology

[0002] With the booming development of industries such as new energy vehicles, the performance requirements for motor control systems are becoming increasingly stringent. Precise motor control is not only crucial to the reliability of vehicle operation but also directly affects the energy efficiency of the entire system. Against this backdrop, the FOC (Field Oriented Control) vector control algorithm has stood out due to its superior control performance and has become the mainstream control algorithm in the industry.

[0003] The current mainstream FOC vector control algorithm uses the current value detected by the current sensor as the input control parameter to ensure that the algorithm can accurately adjust the control strategy according to the real-time detected current condition, thereby achieving precise control of the motor.

[0004] Because current sensors can be affected by interference, the detected current value may drift dynamically, resulting in a large difference between the detected current value and the actual current value, which in turn affects the control accuracy of the motor. Summary of the Invention

[0005] In view of the above problems, embodiments of the present invention provide a current value calibration method, a motor controller and a system to solve the problem that the detected current value of the current sensor deviates from the actual current value in the prior art, resulting in reduced motor control accuracy.

[0006] According to one aspect of the present invention, a method for calibrating a current value is provided, the method comprising: Acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; Determine the actual collector current value associated with the emitter voltage and junction temperature; If the calibration conditions for the current value are met, the current detected current value is calibrated based on the current detected current value and the actual collector current value.

[0007] According to another aspect of the present invention, a motor controller is provided, including: a motor drive unit, a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus, and the motor drive unit is electrically connected to the processor; The memory is used to store at least one executable instruction that causes the processor to perform the current value calibration method described above.

[0008] According to another aspect of the present invention, a motor control system is provided, the system comprising: The aforementioned motor controller; The motor is connected to the motor drive unit in the motor controller; And a current sensor, which is placed between the motor controller and the motor to detect the current value.

[0009] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein at least one executable instruction is stored therein, the executable instruction causing a motor controller to perform the following operations: Acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; Determine the actual collector current value associated with the emitter voltage and junction temperature; If the calibration conditions for the current value are met, the current detected current value is calibrated based on the current detected current value and the actual collector current value.

[0010] This invention, based on the relationship between collector current, emitter voltage, and junction temperature, calibrates the current detected current value based on the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed using the inherent physical characteristics of the motor drive unit. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the subsequent control accuracy of the motor.

[0011] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0012] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A flowchart illustrating a first embodiment of the current value calibration method provided by the present invention is shown. Figure 2 A schematic diagram of the overall process of the current value calibration method provided by the present invention is shown; Figure 3 A schematic diagram of the module structure of the current value calibration device provided by the present invention is shown; Figure 4A schematic diagram of the structure of a first embodiment of the motor controller provided by the present invention is shown; Figure 5 A schematic diagram of the motor control system provided by the present invention is shown. Detailed Implementation

[0013] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0014] Figure 1 A flowchart of a first embodiment of the current value calibration method of the present invention is shown, which is executed by a motor controller. Figure 1 As shown, the method includes the following steps: Step 110: Obtain the current detection current value of the current sensor, the emitter voltage of the motor drive unit, and the junction temperature.

[0015] In this system, current sensors, such as Hall effect sensors, and shunt resistors are connected in series between the output of the motor drive unit and the motor stator windings. In the FOC vector control algorithm, the current value detected by the current sensor is essentially the phase current detected by the motor stator windings, representing the current flowing through the stator windings in real time. This is the core input data for the algorithm to achieve field-oriented and torque / speed closed-loop control. Due to interference from factors such as temperature, magnetic fields, and aging, the current sensor's detected current value dynamically drifts, potentially causing a significant deviation between the detected and actual current values. Correction is required to reduce this current deviation.

[0016] The motor drive unit can be an insulated-gate bipolar transistor, which will be referred to as IGBT below. Alternatively, it can be a metal-oxide-semiconductor field-effect transistor. The motor drive unit is located within the motor controller and is controlled by the controller's processor.

[0017] To obtain the current value detected by the current sensor, a Hall effect current sensor can be used. Based on the Hall effect principle, when current passes through a conductor, a Hall voltage is generated in the direction perpendicular to the current and the magnetic field. By measuring the Hall voltage and processing it through circuits such as amplification and conversion, a voltage signal proportional to the actual current is obtained. Then, it is converted into a digital quantity by an analog-to-digital converter, thereby obtaining the current detected current value.

[0018] To obtain the emitter voltage of the motor drive unit, a high-precision voltage measurement circuit can be used, such as a voltage follower circuit composed of operational amplifiers. The emitter voltage signal is introduced into the circuit for buffering and isolation, and then converted into a digital quantity by an ADC for subsequent processing. Alternatively, it can be obtained by differential sampling using resistors.

[0019] For the junction temperature of the motor drive unit, a thermistor can be used, which is closely attached near the junction of the transistor. The resistance of the thermistor changes with temperature. By constructing a voltage divider circuit consisting of a thermistor and a fixed resistor, the temperature change is converted into a voltage change, which is then converted into a digital value by an ADC. The junction temperature can be calculated based on the resistance-temperature characteristic curve of the thermistor.

[0020] Step 120: Determine the actual collector current value associated with the emitter voltage and junction temperature.

[0021] The actual collector current value refers to the magnitude of the current actually flowing through the collector of the transistor in the motor drive unit. It reflects the transistor's true current carrying capacity under a given emitter voltage and junction temperature, and is a key current parameter in the actual operation of the motor drive unit, significantly affecting the motor's performance and control accuracy.

[0022] Optionally, for bipolar junction transistors (BJTs), a mathematical model is established based on their physical characteristics, comprising the collector current IC, emitter voltage, gate drive voltage VBE, and junction temperature Tj. The actual collector current value is calculated by substituting the emitter voltage and junction temperature measurements into the model in real time. Alternatively, through extensive experiments, the actual collector current values ​​under different emitter voltage and junction temperature conditions are measured and stored. The data is then fitted to obtain a functional relationship between the emitter voltage, junction temperature, and the actual collector current value. In practical applications, the real-time measured emitter voltage and junction temperature values ​​are substituted into this functional relationship to calculate the actual collector current value. Alternatively, a predictive model of the emitter voltage, junction temperature, and actual collector current value can be established using machine learning algorithms. A large amount of experimental data is used as a training set to train and optimize the model, enabling it to accurately predict the actual collector current value. During actual operation, the real-time acquired emitter voltage and junction temperature values ​​are input into the trained model, and an estimated value of the actual collector current is output.

[0023] Step 130: If the calibration conditions for the current value are met, calibrate the current current value based on the current detected current value and the actual collector current value.

[0024] The calibration conditions are a set of pre-defined rules or parameter ranges used to determine whether the current detected current value needs to be calibrated. These conditions are usually related to the operating state of the motor drive unit, environmental factors, etc. When these conditions are met, it is considered that the current detected current value may have a large deviation, and calibration is required to improve measurement accuracy.

[0025] Optionally, when the calibration conditions are met, the difference between the current detected current value and the actual collector current value is calculated, and then the current detected current value is compensated according to a certain ratio. The ratio k can be adjusted according to the actual situation, for example, by determining a suitable value through experiments to make the calibrated current value closer to the actual collector current value. Alternatively, the current range can be divided into multiple intervals, with different compensation coefficients set for each interval. When the calibration conditions are met, the interval in which the current detected current value falls is first determined, and then the current detected current value is linearly compensated according to the compensation coefficient corresponding to that interval. For example, the current range can be divided into three intervals: low, medium, and high, with different compensation coefficients k1, k2, and k3 set for each interval. The appropriate compensation coefficient is selected based on the interval in which the current detected current value falls. Alternatively, a neural network model can be constructed, using the current detected current value and the actual collector current value as model inputs, outputting a target compensation value, and then calibrating the current detected current value. An appropriate calibration method can be selected to calibrate the current detected current value according to the actual situation.

[0026] In this embodiment, based on the relationship between collector current, emitter voltage, and junction temperature, the current detected current value is calibrated according to the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed by utilizing the inherent physical characteristics of the motor drive unit itself. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the control accuracy of the subsequent motor.

[0027] In other embodiments, after calibrating the current detected current value, the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit are reacquired; the actual collector current value associated with the emitter voltage and junction temperature is determined; if the calibration conditions for the current value are not met, the calibration of the current value is stopped. Otherwise, the calibration of the current sensor's detected current value continues to be performed to improve the accuracy of the current value.

[0028] In an alternative approach, step 130 includes: Step 131: Determine the target compensation value for the current detection current value based on the current detection current value and the actual collector current value.

[0029] The target compensation value is a calculated value used to correct the current detection value, making it closer to the actual collector current value. Due to errors and interference in current sensor measurements, the current detection value may deviate from the actual collector current value. The target compensation value is used to eliminate or reduce this deviation, thereby improving the accuracy of current measurement and providing a reliable basis for the precise control of systems such as motor drives.

[0030] Optionally, the difference between the current detected current value and the actual collector current value can be calculated first, and then the target compensation value can be determined based on the proportional relationship between this difference and the current detected current value. This method takes into account the magnitude of the deviation relative to the current detected value, and can adjust the compensation amount more reasonably. Specifically, in the processor of the motor controller, the digital values ​​of the current detected current value and the actual collector current value are read by programming. The current difference between the current detected current value and the actual collector current value is calculated, and then the current difference is multiplied by a preset proportional coefficient to obtain the target compensation value.

[0031] Optionally, a table relating the current detected current value, the actual collector current value, and the target compensation value can be established beforehand through experiments or theoretical analysis. In practical applications, similar data points are found in the table based on the current detected current value and the actual collector current value, and a more accurate target compensation value is calculated using an interpolation algorithm, which is applicable to situations with complex nonlinear relationships.

[0032] Step 132: The current detected current value is calibrated using the target compensation value.

[0033] Alternatively, the target compensation value can be directly added to the current detected current value to obtain the calibrated current value. This method is simple and direct, and suitable for scenarios where the target compensation value is positive or negative and the calibration accuracy requirement is not particularly high. Specifically, in the processor of the motor controller, the digital value of the current detected current value is added to the digital value of the calculated target compensation value to obtain the digital value of the calibrated current value.

[0034] Optionally, the PID control algorithm is a commonly used control algorithm. It performs proportional, integral, and derivative operations on the difference between the current detected current value and the actual collector current value to obtain a control quantity. This control quantity is used as the target compensation value to dynamically calibrate the current detected current value. Since the PID algorithm can dynamically adjust the compensation quantity according to the magnitude and trend of the error, the calibration process is more stable and accurate.

[0035] In this embodiment, a target compensation value for the current detected current value is determined by comparing the current detected current value with the actual collector current value. This target compensation value is then used to calibrate the current detected current value. Since the actual collector current value is derived from the inherent physical characteristics of the motor drive unit and has strong anti-interference capabilities, the compensation value determined based on this benchmark can effectively offset random fluctuations caused by noise, making the calibrated current value closer to the steady-state characteristics of the real current and improving the consistency and reliability of the measurement data.

[0036] Furthermore, in an alternative approach, step 131 includes: Step 1311: Determine the current error value based on the current detected current value and the actual collector current value.

[0037] The current error value refers to the difference between the detected current value and the actual collector current value at the current moment. It reflects the degree of deviation between the current sensor measurement result and the true value, and is an important basis for subsequent compensation calculations, used to measure the magnitude and direction of the measurement error. The current error value can be obtained by subtracting the current detected current value from the actual collector current value.

[0038] Step 1312: Based on the compensation parameters of the current error value and the historical current values ​​detected by the current sensor, obtain the first compensation value.

[0039] The compensation parameters for historical current values ​​are obtained by analyzing and processing multiple current values ​​detected by the current sensor and the corresponding actual collector current values ​​over a period of time. These parameters reflect the measurement error characteristics of the current sensor under different operating conditions, such as the trend of error change over time and its relationship with the current magnitude, and are used to more accurately compensate for the current being detected.

[0040] The first compensation value is a compensation amount calculated based on compensation parameters derived from the current current error value and historical detected current values. It combines current error information and historical error characteristics, aiming to adaptively correct the current detected current in light of both current and historical operating conditions to improve measurement accuracy.

[0041] Optionally, a table relating the current current error value, historical measured current values, compensation parameters, and the first compensation value can be pre-established through experiments or data analysis. In practical applications, similar data points are found in the table based on the current current error value and compensation parameters, and a more accurate first compensation value is calculated using an interpolation algorithm. Specifically, a multidimensional array is defined in the motor controller's processor program to store the lookup data. Each element of the array contains the current current error value, compensation parameters, and the corresponding first compensation value. By writing code for the lookup and interpolation algorithms, the first compensation value is calculated based on the real-time measured current error value and compensation parameters.

[0042] Optionally, the powerful nonlinear mapping capability of neural networks can be utilized. The current current error value and compensation parameters can be used as input, and after training and learning, the neural network can output a first compensation value. The neural network can automatically learn complex relationships in historical data, thereby more accurately predicting the first compensation value.

[0043] Step 1313: Determine the second compensation value based on the current current error value.

[0044] The second compensation value can be calculated using a specific algorithm or rule based solely on the current current error value. As a real-time compensation value, it is mainly used to quickly respond to and adjust the error situation at the current moment, complementing the first compensation value to jointly determine the final target compensation value.

[0045] Optionally, a mapping relationship between current error value and compensation value can be established based on historical data. The mapping relationship can be found through the current current error value to obtain the second compensation value, thereby improving the efficiency of obtaining the second compensation value.

[0046] Step 1314: Determine the target compensation value for the current detection current value based on the first compensation value and the second compensation value.

[0047] The target compensation value is the final compensation amount used to correct the current detection value, determined by comprehensively considering the first compensation value and the second compensation value. By applying the target compensation value to the current detection current value, the corrected current value can be made closer to the actual collector current value, thus improving the accuracy of current measurement.

[0048] Optionally, a weighting coefficient can be assigned to the first compensation value and the second compensation value according to their relative importance, and then the target compensation value can be calculated by weighted average. This method can comprehensively consider the contributions of the two compensation values, making the target compensation value more reasonable.

[0049] Optionally, the target compensation value for the current detected current value can be obtained based on the average of the first compensation value and the second compensation value. By comprehensively considering the first compensation value and the second compensation value to determine the target compensation value, the compensation accuracy of the current detected current value is improved.

[0050] In this embodiment, by combining the characteristics of the current current error value and the historical current error value, and considering the influence of the current operating conditions and the historical operating conditions, an adaptive compensation value is determined; a real-time compensation value is determined by the current current error value; and finally, a target compensation value is determined by combining these two compensation values, thereby improving the compensation accuracy of the current detected current value.

[0051] Furthermore, in an alternative embodiment, step 1312 includes: Step 13121: Obtain the weighting coefficient of the current current error value, the weighting coefficient of the historical current error value, and the weighting coefficient of the historical average correction value.

[0052] In weighted summation and other operations, the weighting coefficient is a coefficient used to measure the degree of influence of each variable involved in the calculation on the final result. Different weighting coefficients reflect the relative importance of different variables in the overall calculation; the larger the weight, the greater the influence of that variable on the result. The weighting coefficients corresponding to the current error value, historical current error value, and historical average correction value are different, and the sum of the weighting coefficients of the current current error value, historical current error value, and historical average correction value equals 1. The weighting coefficients of the above parameters can be determined experimentally.

[0053] Step 13122: Perform a weighted summation based on the current current error value, historical current error value, historical average correction value, and corresponding weighting coefficients to obtain the gain coefficient; The historical current error value represents the difference between the current value detected by the current sensor and the actual collector current value over a past period. This historical data records the measurement error of the current sensor under different times and operating conditions, which helps to analyze the trend and pattern of error changes.

[0054] The historical average correction value represents the average of multiple correction values ​​obtained over a past period. It comprehensively reflects the overall effect of correcting current measurement errors over a historical period and can serve as a reference for current correction calculations.

[0055] The gain coefficient is a coefficient obtained through weighted summation and other operations. It integrates information such as the current current error, historical current error, and historical average correction value. It is used to adjust relevant parameters of the current sensor, such as the material coefficient, to achieve more accurate compensation for the current detection current.

[0056] Optionally, the current current error value can be multiplied by the weighting coefficient of the current current error value to obtain a first result; the historical current error value can be multiplied by the weighting coefficient of the historical current error value to obtain a second result; the historical average correction value can be multiplied by the weighting coefficient of the historical average correction value to obtain a third result; and the gain coefficient can be obtained by summing the first result, the second result and the third result.

[0057] Step 13123: Correct the material coefficient of the current sensor using the gain coefficient to obtain the first compensation value.

[0058] The material coefficient of a current sensor refers to parameters related to the materials used in the sensor. These parameters affect the sensor's measurement characteristics, such as sensitivity and linearity. The accuracy of the material coefficient directly affects the measurement precision of the current sensor; correcting it can improve the sensor's performance.

[0059] Optionally, the gain coefficient can be multiplied by the material coefficient of the current sensor to obtain the first compensation value. Specifically, when the material coefficient of the current sensor is the sensitivity, the gain coefficient can be multiplied by the sensitivity of the current sensor to obtain the first compensation value.

[0060] By using the above methods, when the operating conditions are stable, such as when the motor is running at a constant speed and the temperature is constant, the weight of the historical current error value and the historical average correction value can be increased, while the weight of the current current error value can be reduced, thus avoiding frequent fluctuations in gain caused by instantaneous noise. When the operating conditions change abruptly, such as when the motor starts or the load changes abruptly, the weight of the current current error value can be increased, while the weight of the historical dimension can be reduced, thus quickly responding to error changes under new operating conditions and ensuring timely correction.

[0061] In this embodiment, the current current error value reflects the real-time detection deviation, the historical current error value reflects the time accumulation characteristics of the deviation, and the historical average correction value reflects the effectiveness of past calibrations. These are the three core dimensions characterizing the current detection error. By assigning weight coefficients to the three dimensions and summing them in a weighted manner, the gain coefficient is obtained. This allows the gain coefficient to comprehensively characterize the real-time nature and regularity of the error, avoiding over-correction or under-correction caused by a single information source, and significantly improving the accuracy of the first compensation value.

[0062] Furthermore, in an alternative embodiment, step 1313 includes: Step 13131: Correct the material coefficient of the current sensor using the current error value to obtain the second compensation value.

[0063] Optionally, the current current error value can be multiplied by the material coefficient of the current sensor to obtain a second compensation value. Specifically, when the material coefficient of the current sensor is the sensitivity, the current current error value can be multiplied by the sensitivity of the current sensor to obtain the second compensation value.

[0064] In this embodiment, the current current error value is the direct deviation between the detected value and the actual value under the current operating condition, reflecting the degree of mismatch in the material coefficient of the current sensor at the current moment. Using this error value to directly correct the material coefficient avoids correction lag caused by sudden changes in operating conditions, compared to correction schemes that rely on historical data.

[0065] Furthermore, in an optional manner, step 132 includes: performing zero-point offset calibration on the voltage value obtained by converting the current detection current value; compensating the voltage value obtained by zero-point offset calibration with a target compensation value; and determining the calibrated current value based on the compensated voltage value.

[0066] Specifically, the compensated voltage value can be determined using the following formula: Vout(k)=Voffset+Sen*Ih(k)+f[ε(k)].

[0067] Where Vout(k) represents the compensated voltage value, Voffset is the fixed value of the zero-point drift calibration voltage device characteristic, Ih(k) represents the current detected current value, and f[ε(k)] represents the target compensation value.

[0068] After obtaining the compensated voltage value, the calibrated current value can be deduced by using the conversion relationship between the voltage and current values.

[0069] In this embodiment, the current signal is converted into a voltage signal that is easy to process through linear conversion between current and voltage; zero-point offset calibration eliminates zero-point error in the circuit, making the measurement starting point more accurate; the target compensation value further corrects the voltage value, compensating for the error caused by various factors during the measurement process of the current sensor; finally, the compensated voltage value is converted back to the current value to obtain the calibrated current value, which significantly improves the accuracy of current measurement overall.

[0070] Furthermore, step 120 includes: Step 121: Determine the actual collector current value based on the mapping relationship between the emitter voltage, junction temperature, preset gate drive voltage, preset emitter voltage, preset temperature, and preset collector current value.

[0071] Before performing step 121, the above mapping relationship needs to be established. Specifically, under each set gate drive voltage of the motor drive unit, for each set temperature, the emitter voltage of the motor drive unit is collected at preset voltage intervals; based on the set gate drive voltage, set temperature, and emitter voltage, multiple sets of measurement points are formed, wherein each set of measurement points has a corresponding set gate drive voltage, emitter voltage, and set temperature; the collector current of the motor drive unit is collected at different measurement points; and a mapping relationship between the measurement points and the collector current is established.

[0072] In this embodiment, the actual collector current value is obtained by searching a pre-built mapping relationship based on the emitter voltage and junction temperature, thereby improving the efficiency of finding the actual collector current value.

[0073] In an alternative approach, prior to step 130, the method may further include: Step 310: Determine the relative error between the current detected current value and the actual collector current value.

[0074] The relative error refers to the ratio of the absolute error caused by the measurement to the true value of the measured value, multiplied by 100%, and expressed as a percentage. It reflects the accuracy of the measurement result and can more intuitively show the degree of deviation between the measured value and the true value. In this embodiment, it is the ratio of the absolute value of the difference between the current detected current value and the actual collector current value to the actual collector current value.

[0075] Step 320: If the relative error is greater than or equal to the preset error, the calibration conditions are met; or, if the number of continuous detection cycles in which the relative error is greater than or equal to the preset error is greater than the preset number, the calibration conditions are met.

[0076] The preset error is a pre-defined upper limit for the allowable error range. When the relative error exceeds this preset value, the deviation between the measurement result and the true value is considered to be outside the acceptable range, which may require calibration of the relevant equipment or measurement system. For example, the preset error can be set to 3%.

[0077] In the process of continuous current monitoring, each complete current detection process is called a detection cycle. The number of continuous detection cycles refers to the number of cycles in which detection is performed continuously within a certain period of time.

[0078] The preset quantity is a pre-defined threshold number of continuous detection cycles used to determine whether calibration conditions are met. When the number of continuous detection cycles with a relative error greater than or equal to the preset error reaches this preset quantity, the calibration conditions are considered met. For example, the preset quantity can be set to 3.

[0079] In this embodiment, the relative error between the current detected current value and the actual collector current value is calculated, and the error in a single cycle and the continuous error over multiple cycles are considered to determine whether the calibration conditions are met, thus avoiding misjudgments caused by accidental factors. Calibration is only performed when the relative error continuously exceeds the allowable range, improving the accuracy and reliability of calibration decisions.

[0080] In other embodiments, the relative error between the current detected current value and the actual collector current value is determined; if the relative error is less than a preset error, it is determined that the calibration condition is not met; or, if the number of continuous detection cycles in which the relative error is greater than or equal to the preset error is less than a preset number, it is determined that the calibration condition is not met. In this case, no correction is made to the current value.

[0081] To better illustrate the calibration method for the current value in this application, Figure 2 Taking this as an example, the calibration method for the current value in this application will be introduced in general: It should be noted that the main concept of this application is to calibrate the current Ih collected by the current sensor based on the relationship between the collector-emitter voltage (Vce) and collector current (Ic) of the IGBT itself without increasing any hardware costs. The core principle is to utilize the characteristic of the IGBT operating in the saturation region. In the saturation region, for a specific collector current Ic, there will be a specific Vce(sat); the larger Ic is, the larger Vce(sat) is, and there is a positive correlation between them. A precise mathematical model of Ic = f(Vce(sat), Tj) is constructed to form a lookup table mapping relationship; and an adaptive gain compensation function f{e(k)} is set to continuously and dynamically optimize the calibration results. When the error ratio of |Ic(k)-Ih(k)| / Ic(k) exceeds a certain range, the calibration process is initiated.

[0082] Specifically, it includes the following steps: S1: Constructing an exact mathematical model of the relationship between Ic = f(Vce(sat), Tj): S1.1 Temperature values ​​are taken based on temperature interval N1 at a specified gate drive voltage Vge to obtain each temperature point; at each temperature point, Vce(sat) is taken based on voltage interval U1 to obtain each voltage point. The IGBT junction temperature Tj and saturation voltage drop Vce(sat) constitute a series of measurement points.

[0083] S1.2 The collector current value of the IGBT at each measuring point is detected by a test bench and is called the collector current measurement value Ic.

[0084] S1.3 Repeat steps S1.1 and S1.2 above, and take the value of Vge according to the voltage interval U2 to form a measurement lookup table under different gate drive voltages Vge.

[0085] S2: Perform deviation calibration procedure: S2.1 Set up dynamic detection of deviation for multiple (k) consecutive switching cycles of IGBT, and determine whether the error ratio λ(k) = |Ic(k)-Ih(k)| / Ic(k) = |Δ(k)| / Ic(k) is within 3% (according to technical requirements). If it exceeds this range, the calibration process is started; otherwise, it is not started. Wherein, Ic(k) represents the actual collector current value, Ih(k) represents the current detected current value, and Δ(k) represents the current current error value.

[0086] S2.2 Based on the error value Δ(k) = Ic(k) - Ih(k), an adaptive compensation function f[φ(k)] is set for the neural network, and the compensation value is adaptively calculated by combining the historical compensation accuracy. A real-time compensation function f[θ(k)] is set to complement and coordinate with f[φ(k)] to eliminate random errors and smooth instantaneous disturbances. Among them, the compensation value calculated by the adaptive compensation function f[φ(k)] is the first compensation value, and the compensation value calculated by the real-time compensation function f[θ(k)] is the second compensation value.

[0087] S2.2.1 Neural network adaptive compensation function f[φ(k)]=α*Sen, where the gain coefficient α=w1*Δ(k)+w2*Δ(k-1)+w3*Δ(his)+b.

[0088] The weighting coefficients are as follows: the weighting coefficient of the current error value w1 = w1 + η * Δβ * Δ(k); the weighting coefficient of the historical current error value w2 = w2 + η * Δβ * Δ(k-1); the weighting coefficient of the historical average correction value w3 = w3 + η * Δβ * Δ(his); the system bias b = b + η * Δβ, the error Δβ = Δ(k) - α; the historical average correction value Δ(his) = [Δ(his) * n + Δ(k)] / (n + 1), and the number of calibrations n = n + 1.

[0089] Initialize the values ​​as follows: w1=1.0, w2=0.1, w3=0.5, b=0, Δ(his)=0, n=0, learning rate η=0.01 to control learning accuracy; these initial values ​​can be set according to actual conditions. As the number of IGBT switching operations increases, the compensation value approaches the true value through the above calculations.

[0090] S2.2.2 Real-time compensation value calculation, f[θ(k)]=Sen*Δ(k), where Sen is the material parameter of the Hall sensor.

[0091] S2.3 The target compensation value is obtained by averaging the compensation value calculated by the neural network and the real-time compensation value using f[ε(k)]={f[φ(k)]+f[θ(k)]} / 2.

[0092] S2.4 is the calibrated Hall sensor Hall Vout(k) = Voffset + Sen*Ih(k) + f[ε(k)]; Voffset is the zero-point drift calibration voltage, a fixed value of the device characteristics.

[0093] S2.5 Determine again whether the error ratio of λ(k+1) meets the range requirements.

[0094] The current value can be calibrated using the methods described above.

[0095] Figure 3 A schematic diagram of an embodiment of the current value calibration device of the present invention is shown. Figure 3 As shown, the device 300 includes: an acquisition module 310, a determination module 320, and a calibration module 330.

[0096] In one alternative approach, the acquisition module 310 is used to acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; the determination module 320 is used to determine the actual collector current value associated with the emitter voltage and junction temperature; and the calibration module 330 is used to calibrate the current detected current value based on the current detected current value and the actual collector current value, provided that the calibration conditions of the current value are met.

[0097] In one alternative approach, the calibration module 330 is used to determine a target compensation value for the current sensed current value based on the current sensed current value and the actual collector current value; and to calibrate the current sensed current value using the target compensation value.

[0098] In one alternative approach, the calibration module 330 is configured to determine a current error value based on the current detected current value and the actual collector current value; obtain a first compensation value based on the current current error value and compensation parameters of the historical detected current values ​​of the current sensor; determine a second compensation value based on the current current error value; and determine a target compensation value for the current detected current value based on the first compensation value and the second compensation value.

[0099] In one alternative approach, the calibration module 330 is used to obtain the weighting coefficient of the current current error value, the weighting coefficient of the historical current error value, and the weighting coefficient of the historical average correction value; to obtain the gain coefficient by weighted summation based on the current current error value, the historical current error value, the historical average correction value, and the corresponding weighting coefficients; and to correct the material coefficient of the current sensor using the gain coefficient to obtain the first compensation value.

[0100] In one alternative approach, calibration module 330 is used to correct the material coefficient of the current sensor using the current error value to obtain a second compensation value.

[0101] In one alternative approach, the calibration module 330 performs zero-point offset calibration on the voltage value converted from the current detection current value; compensates the voltage value obtained from the zero-point offset calibration with a target compensation value; and determines the calibrated current value based on the compensated voltage value.

[0102] In one alternative approach, the determining module 320 is used to determine the actual collector current value based on the emitter voltage, junction temperature, and the mapping relationship between the preset gate drive voltage, preset emitter voltage, preset temperature, and preset collector current value.

[0103] In one alternative, the determining module 320 is further configured to determine the relative error between the current detected current value and the actual collector current value; if the relative error is greater than or equal to a preset error, it is determined that the calibration conditions are met; or, if the number of continuous detection cycles in which the relative error is greater than or equal to the preset error is greater than a preset number, it is determined that the calibration conditions are met.

[0104] This invention, based on the relationship between collector current, emitter voltage, and junction temperature, calibrates the current detected current value based on the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed using the inherent physical characteristics of the motor drive unit. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the subsequent control accuracy of the motor.

[0105] Figure 4 The diagram shows a structural schematic of an embodiment of the motor controller of the present invention. The specific embodiments of the present invention do not limit the specific implementation of the motor controller.

[0106] like Figure 4 As shown, the motor controller may include: a motor drive unit (not shown in the figure), a processor 402, a communication interface 404, a memory 406, and a communication bus 408.

[0107] The processor 402, communication interface 404, and memory 406 communicate with each other via communication bus 408. Communication interface 404 is used to communicate with other network elements, such as clients or other servers. The processor 402 executes program 410, specifically performing the relevant steps described in the embodiment of the current value calibration method.

[0108] Specifically, program 410 may include program code, which includes computer-executable instructions.

[0109] Processor 402 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The motor controller includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0110] Memory 406 is used to store program 410. Memory 406 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0111] Specifically, program 410 can be called by processor 402 to cause the motor controller to perform the following operations: Acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; Determine the actual collector current value associated with the emitter voltage and junction temperature; If the calibration conditions for the current value are met, the current detected current value is calibrated based on the current detected current value and the actual collector current value.

[0112] This invention, based on the relationship between collector current, emitter voltage, and junction temperature, calibrates the current detected current value based on the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed using the inherent physical characteristics of the motor drive unit. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the subsequent control accuracy of the motor.

[0113] Figure 5 A schematic diagram of an embodiment of the motor control system of the present invention is shown. Figure 5As shown, the motor control system includes: a motor controller; a motor connected to a motor drive unit in the motor controller; and a current sensor disposed between the motor controller and the motor for detecting current values. The motor controller executes the aforementioned method program.

[0114] This invention, based on the relationship between collector current, emitter voltage, and junction temperature, calibrates the current detected current value based on the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed using the inherent physical characteristics of the motor drive unit. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the subsequent control accuracy of the motor.

[0115] This invention provides a computer-readable storage medium storing at least one executable instruction that, when executed on a motor controller, causes the motor controller to perform the current value calibration method in any of the above method embodiments.

[0116] Specifically, the executable instructions can be used to cause the motor controller to perform the following operations: Acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; Determine the actual collector current value associated with the emitter voltage and junction temperature; If the calibration conditions for the current value are met, the current detected current value is calibrated based on the current detected current value and the actual collector current value.

[0117] This invention, based on the relationship between collector current, emitter voltage, and junction temperature, calibrates the current detected current value based on the current detected current value and the actual collector current value when the calibration conditions for the current value are met. Since different emitter voltages and junction temperatures correspond to different operating conditions, and the actual collector current value represents the true current situation of the motor drive unit under the current operating conditions, current calibration is performed using the inherent physical characteristics of the motor drive unit. This reduces the deviation between the calibrated current value and the actual current value, thereby improving the subsequent control accuracy of the motor.

[0118] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Furthermore, the embodiments of this invention are not directed to any particular programming language.

[0119] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. Similarly, for the sake of brevity and to aid in understanding one or more aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the embodiments are sometimes grouped together in a single embodiment, figure, or description thereof. The claims, which follow the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0120] Those skilled in the art will understand that the modules in the device of the embodiment can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiment can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components, except that at least some of such features and / or processes or units are mutually exclusive.

[0121] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for calibrating current values, characterized in that, The method includes: Acquire the current detected current value of the current sensor, the emitter voltage and junction temperature of the motor drive unit; Determine the actual collector current value associated with the emitter voltage and the junction temperature; If the calibration conditions for the current value are met, the current detected current value is calibrated based on the current detected current value and the actual collector current value.

2. The method as described in claim 1, characterized in that, The calibration of the current detected current value based on the current detected current value and the actual collector current value includes: Based on the current detected current value and the actual collector current value, determine the target compensation value for the current detected current value; The current detected current value is calibrated using the target compensation value.

3. The method as described in claim 2, characterized in that, The step of determining the target compensation value for the current detected current value based on the current detected current value and the actual collector current value includes: Determine the current error value based on the current detected current value and the actual collector current value; Based on the compensation parameters of the current error value and the historical current values ​​detected by the current sensor, a first compensation value is obtained; Based on the current current error value, determine the second compensation value; Based on the first compensation value and the second compensation value, the target compensation value for the current detected current value is determined.

4. The method as described in claim 3, characterized in that, The compensation parameters include historical current error values ​​and historical average correction values. The first compensation value, obtained based on the compensation parameters of the current error value and the historical detected current values ​​of the current sensor, includes: Obtain the weighting coefficient of the current current error value, the weighting coefficient of the historical current error value, and the weighting coefficient of the historical average correction value; The gain coefficient is obtained by weighted summation based on the current current error value, the historical current error value, the historical average correction value, and the corresponding weighting coefficients. The material coefficient of the current sensor is corrected using the gain coefficient to obtain the first compensation value.

5. The method as described in claim 3, characterized in that, Determining the second compensation value based on the current current error value includes: The material coefficient of the current sensor is corrected using the current error value to obtain the second compensation value.

6. The method as described in claim 2, characterized in that, The calibration of the current detected current value using the target compensation value includes: Zero-point offset calibration is performed on the voltage value obtained by converting the current detection current value; The target compensation value is used to compensate the voltage value obtained from zero-point offset calibration. Based on the voltage value obtained from the compensation, determine the calibrated current value.

7. The method as described in claim 1, characterized in that, Determining the actual collector current value associated with the emitter voltage and the junction temperature includes: The actual collector current value is determined based on the emitter voltage, the junction temperature, and the mapping relationship between the preset gate drive voltage, the preset emitter voltage, the preset temperature, and the preset collector current value.

8. The method according to any one of claims 1 to 7, characterized in that, The method further includes: Determine the relative error between the current detected current value and the actual collector current value; If the relative error is greater than or equal to the preset error, the calibration condition is determined to be met; or... If the number of continuous detection cycles in which the relative error is greater than or equal to the preset error is greater than a preset number, then the calibration condition is determined to be met.

9. A motor controller, characterized in that, include: The system includes a motor drive unit, a processor, a memory, a communication interface, and a communication bus. The processor, the memory, and the communication interface communicate with each other through the communication bus. The motor drive unit is electrically connected to the processor. The memory is used to store at least one executable instruction that causes the processor to perform the operation of the current value calibration method as described in any one of claims 1-8.

10. A motor control system, characterized in that, The system includes: The motor controller as described in claim 9; The motor is connected to the motor drive unit in the motor controller; And a current sensor, which is disposed between the motor controller and the motor, for detecting the current value.

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