A measuring method of a low-loss proportional amplification fluxgate current sensor

Abstract

The application discloses a kind of low-loss proportional amplification fluxgate current sensor measurement methods, it is related to current measurement technical field, including, obtaining the observation set of synchronous demodulation by phase-locked;Based on the scheduling optimization function of prediction set construction, apply soft opening constraint, amplitude stability constraint, phase consistency constraint and saturation depth constraint, output corresponding control variable;According to control variable setting excitation signal parameter and executing excitation drive and compensation injection, extract the harmonic amplitude-phase response of current cycle in demodulation window position;Harmonic amplitude-phase response is converted into linear measurement output of current cycle, while updating observation set.The application implements proportional closed-loop conversion in I / Q rectangular coordinates, combines amplitude error and phase error into compensation current update amount, and combines calibration proportionality coefficient and output amplitude limiting, so that closed-loop converges amplitude-phase deviation in linear interval quickly, improves compensation current stability and response speed and reduces energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current measurement, in particular to a measurement method of a low-loss proportional amplification fluxgate current sensor. BACKGROUND

[0002] The fluxgate current sensor has formed a technical path of high-frequency rectangular excitation and synchronous demodulation in the field of current measurement, combined with digital phase-locked processing, I / Q amplitude and phase estimation, energy recovery type switch control and material parameter calibration, to gradually realize the coordinated design of low power consumption, wide dynamic range and traceable linear output.

[0003] The existing related method still faces key contradictions in the proportional amplification scene, that is, it is difficult to maintain amplitude and phase stability and linear consistency for a long time without triggering saturation and excessive loss, and temperature drift and hysteresis model mismatch will amplify the commutation transient and error accumulation, resulting in difficulty in considering low loss and high consistency for compensation current update and excitation parameter. SUMMARY

[0004] In view of the above existing problems, the present application is proposed.

[0005] Therefore, the present application provides a measurement method of a low-loss proportional amplification fluxgate current sensor to solve the problem of maintaining amplitude and phase stability and linear consistency of proportional amplification output under low loss condition.

[0006] To solve the above technical problems, the present application provides the following technical scheme:

[0007] The present application provides a measurement method of a low-loss proportional amplification fluxgate current sensor, which comprises: obtaining a set of observation quantities after phase-locked synchronous demodulation; inputting the set of observation quantities into a magnetic core hysteresis model, performing model parameter update and generating a set of predicted quantities; constructing a scheduling optimization function based on the set of predicted quantities, applying soft opening constraint, amplitude stability constraint, phase consistency constraint and saturation depth constraint, and outputting corresponding control variables; setting excitation signal parameters according to the control variables and performing excitation driving and compensation injection, extracting the harmonic amplitude and phase response of the current period in the demodulation window position; converting the harmonic amplitude and phase response into the linear measurement output of the current period, and updating the set of observation quantities.

[0008] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, the set of observation quantities comprises second harmonic complex amplitude, excitation frequency, duty cycle, excitation amplitude, demodulation window position, compensation current and temperature information.

[0009] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: the execution model parameter updating and the generation of the prediction set includes taking the difference between the observation and the output of the magnetic core hysteresis model as the updating basis, and performing parameter correction at each excitation cycle boundary.

[0010] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: the soft turn-on constraint is defined as satisfying the zero-voltage and zero-current turn-on condition through energy recovery before excitation commutation; the amplitude stability constraint is defined as the harmonic amplitude and phase response extracted in adjacent cycles being within the amplitude target range and having a deviation from the reference amplitude and phase not greater than the amplitude and phase deviation threshold; the phase consistency constraint is defined as the demodulation window position and the excitation reference phase maintaining a predetermined phase difference; and the saturation depth constraint is defined as the magnetization peak value calculated by the magnetic core hysteresis model not exceeding the saturation upper threshold.

[0011] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: the corresponding control variables of the output include the following specific steps,

[0012] receiving the prediction set and merging to generate a control variable candidate set; evaluating the control variable candidate set according to the scheduling optimization function to form an evaluation sequence;

[0013] eliminating items that do not meet the soft turn-on constraint, the amplitude stability constraint, the phase consistency constraint, and the saturation depth constraint to form a feasible set; and selecting the optimal control variable in the feasible set to form a cooperative scheduling result;

[0014] dividing the cooperative scheduling result into corresponding control variables, including the excitation signal parameters, the compensation current update amount, and the demodulation window position.

[0015] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: event alignment control is adopted in the setting of the excitation signal parameters, the optimal control variable is written into the execution sequence, and the excitation frequency, the duty cycle, and the excitation amplitude are set in sequence, the demodulation window position is set, and the energy recovery timing is arranged according to the soft turn-on constraint.

[0016] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: the excitation driving and compensation injection refer to outputting an excitation waveform and applying a compensation current according to the excitation signal parameters, and performing excitation commutation according to the soft turn-on constraint.

[0017] As a preferred scheme of the measurement method of the low-loss proportional amplification fluxgate current sensor, wherein: the extraction of the harmonic amplitude and phase response of the current cycle in the demodulation window position includes the following specific steps,

[0018] According to the sampling interval positioned by the demodulation window position, phase-locked synchronous demodulation is performed on the output of the fluxgate current sensor in the sampling interval, and non-target components are suppressed.

[0019] The amplitude and phase of the demodulation signal are estimated to obtain a harmonic amplitude and phase response, and the harmonic amplitude and phase response is submitted to a conversion process as an input of a linear measurement output.

[0020] As a preferred solution of the measurement method of the low-loss proportional amplification fluxgate current sensor, in the conversion process, proportional closed-loop mapping is used to convert the harmonic amplitude and phase response into a compensation current update amount, combine the compensation current update amount with the compensation current of the previous period to form a compensation current output of the current period, record the compensation current output, and write the compensation current output into an observation set as a parameter update of the next period.

[0021] As a preferred solution of the measurement method of the low-loss proportional amplification fluxgate current sensor, the update of the observation set includes writing the harmonic amplitude and phase response of the current period, the excitation signal parameter, the demodulation window position, the compensation current output, and the temperature information into the observation set.

[0022] The present application has the following beneficial effects: in the conversion process, proportional closed-loop mapping is used to map the amplitude error and the phase error into in-phase correction and quadrature correction, respectively, and vector synthesis is completed in I / Q rectangular coordinates to generate a compensation current update amount, combined with the proportional coefficient obtained by calibration and output amplitude limiting, so that the closed loop operates in a linear interval with sufficient phase margin, thereby synchronously converging the amplitude and phase deviations, suppressing commutation transient and noise coupling, improving the stability and response speed of the compensation current, reducing energy consumption, and maintaining the continuity of the linear measurement output. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Fig. 1 Flowchart of the measurement method of the low-loss proportional amplification fluxgate current sensor.

[0025] Fig. 2 Flowchart of I / Q rectangular coordinate proportional closed-loop conversion.

[0026] Fig. 3 Flowchart of parameter update driven by numerical Jacobian.

[0027] Fig. 4Flow chart for low-loss scaled-up output. DETAILED DESCRIPTION

[0028] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details given herein. In other instances, well-known methods have not been described in detail in order to avoid unnecessarily obscuring the present application. Accordingly, it will be appreciated that the present application can be practiced with modification and alteration, and that the present application is not limited to the above specific embodiments.

[0030] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. The "in one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent of or mutually exclusive with other embodiments.

[0031] Reference Figs. 1-4 For one embodiment of the present application, the embodiment provides a measurement method of a low-loss scaled-up fluxgate current sensor, comprising the following steps:

[0032] S1: obtaining a set of observed quantities after phase-locked synchronous demodulation, the set of observed quantities including a second harmonic complex amplitude, an excitation frequency, a duty cycle, an excitation amplitude, a demodulation window position, a compensation current and temperature information.

[0033] S1.1: reading the excitation signal parameter setting values to obtain the excitation frequency, the duty cycle and the excitation amplitude, and generating a reference phase consistent with the excitation frequency.

[0034] Specifically, before the start of each excitation cycle, the values named excitation frequency, duty cycle and excitation amplitude in the parameter setting table are read; wherein the parameter setting table refers to a preset table formed by registering after selecting the excitation frequency, the duty cycle and the excitation amplitude as the criteria for real-time driving of the fluxgate current sensor using frequency step scanning, duty cycle step scanning and amplitude step scanning, and as the preferred conditions for linear error and total power consumption not exceeding the specification limit.

[0035] The stable clock is used for converting the excitation frequency into a period and a time reference source for counting the period, ensuring the accuracy and consistency of the measurement results.

[0036] A reference signal consistent with the excitation frequency is monitored in each period; after detecting the rising edge time of the reference signal, the phase accumulator of the reference phase is cleared and the timestamp of the rising edge time is recorded; the recorded timestamp is in one-to-one correspondence with the zero phase of the reference phase.

[0037] It should be noted that the reference phase linearly increases between the adjacent two rising edges according to the counting of the stable clock, and the increment corresponds to the excitation frequency, so that the reference phase completes a whole cycle change in one excitation period and returns to zero at the next rising edge.

[0038] S1.2: According to the demodulation window position, the sampling interval is positioned in each excitation period, and the voltage output of the fluxgate current sensor is sampled in the sampling interval according to a uniform sampling interval. The start and end phases of the sampling interval maintain a predetermined phase difference with the reference phase.

[0039] The predetermined phase difference is obtained by moving the demodulation window position in each excitation period according to a fixed step based on the reference phase, calculating the amplitude of the second harmonic complex amplitude at each position, and selecting the difference between the reference phase and the start and end phases of the sampling interval when the amplitude of the second harmonic complex amplitude reaches the maximum as the predetermined phase difference.

[0040] Further, phase-locked synchronous demodulation is performed in the sampling interval, and the sampling sequence is phase-sensitive detected by the in-phase reference signal and the quadrature reference signal of the second harmonic, and the in-phase component and the quadrature component of the second harmonic are obtained by interval averaging in the sampling interval. The quadrature reference signal refers to a signal with a phase difference of 90 degrees from the in-phase reference signal, which is used to distinguish the in-phase component in the signal demodulation process to extract the quadrature component of the signal.

[0041] S1.3: The second harmonic in-phase component and the quadrature component are combined into a second harmonic complex amplitude, and the second harmonic complex amplitude is in correspondence with the reference phase corresponding to the sampling interval.

[0042] The compensation current output record of the current excitation period is read to obtain the compensation current; the temperature measurement result is read from the temperature sensor to obtain the temperature information.

[0043] Read the demodulation window position used in the current excitation period, write the observation set in the order of the fixed fields of the second harmonic complex amplitude, excitation frequency, duty cycle, excitation amplitude, demodulation window position, compensation current and temperature information, complete the observation set acquisition of the current period.

[0044] S2: input the observation set into the magnetic core hysteresis model, perform model parameter update and generate the prediction set.

[0045] S2.1: read the observation set and establish the excitation period sequence number.

[0046] Specifically, read the second harmonic complex amplitude, excitation frequency, duty cycle, excitation amplitude, demodulation window position, compensation current and temperature information. Establish the current excitation period sequence number , used for recording and updating.

[0047] The establishment of the current excitation period sequence number is determined according to the excitation frequency in the observation set and the obtained reference phase, specifically, the reference phase is normalized to , the rising crossing event of the selected phase zero point is taken as the period boundary, from , the is updated at each rising crossing event. The rising crossing event refers to the instant when the signal rises from zero level and passes through the set reference level (for example, the middle value of the signal).

[0048] S2.2: performing model parameter update and generating the prediction set includes taking the difference between the observation and the output of the magnetic core hysteresis model as the basis for updating, and correcting the parameters at each excitation period boundary.

[0049] Specifically, generate the rectangular excitation current sequence according to the excitation frequency, duty cycle and excitation amplitude, and generate the slowly varying current sequence according to the compensation current;

[0050] Among them, the uniform time reference locked with the reference phase is adopted in the process of generating the rectangular excitation current sequence and the slowly varying current sequence, and a discrete sampling time sequence is established at equal intervals for each excitation period;

[0051] Two steps are performed for each discrete sampling time, including A1 step and A2 step;

[0052] A1 step: determine whether the sampling phase falls into the duty cycle interval according to the duty cycle and excitation amplitude, set the value of the rectangular excitation current to the positive excitation amplitude if it falls into the duty cycle interval, and set it to the negative excitation amplitude if it does not fall into the duty cycle interval; A2 step: set the value of the slowly varying current to the constant value of the compensation current of the current period; output the rectangular excitation current sequence and the slowly varying current sequence in the order of the sampling time.

[0053] In steps A1 and A2, the observations are obtained by measuring signals such as excitation current, compensation current, and phase information at each discrete sampling time to acquire the real-time state of each excitation cycle. The observation set consists of the observations at all discrete sampling times within each excitation cycle, and is used for subsequent updating and prediction of the core hysteresis model parameters.

[0054] Using calibration coefficients, the rectangular excitation current sequence and the slowly varying current sequence are converted into magnetizing fields, respectively, to obtain the magnetizing field input, expressed as:

[0055] ;

[0056] In the formula, The magnetizing field input indicates the corresponding excitation period. In time The instantaneous value, It is a time variable, and its value is located within the excitation cycle. Within the corresponding time interval, This represents the calibration coefficient from the excitation current to the magnetizing field. This represents the calibration coefficient for the compensation current to the magnetizing field;

[0057] It needs to be explained that, and The values ​​are obtained from the geometric parameters and the number of turns of the winding, and are taken as constants.

[0058] The example value range is ; The example value range is ;at the same time The numerical value may differ from ; The unit representing the proportionality coefficient for converting electric current into magnetic field strength, i.e., ampere per meter (ampere per meter), is dimensionlessly equivalent to... .

[0059] Furthermore, perform temperature correction:

[0060] Saturation magnetization parameters of the core hysteresis model based on temperature information Shape-related parameters Coercivity-related parameters Perform a linear correction to form the effective parameters for this period.

[0061] Among them, the saturation magnetization parameter is inversely proportional to the temperature information; the shape-related parameters are directly proportional to the coercivity-related parameters and the temperature information, with the proportionality coefficient given during the calibration stage; the saturation magnetization parameter... Characterizing magnetization saturation value, shape-related parameters Controlling the steepness and scale of the anhysteretic magnetization curve, and the coercivity related parameters Characterizing the effective field strength required for irreversible magnetization;

[0062] It should be noted that the magnetic core hysteresis model adopts the Jiles-Atherton magnetic core hysteresis model structure.

[0063] The Jiles-Atherton magnetic core hysteresis model structure includes an anhysteretic magnetization term, an average field coupling term, and irreversible / reversible component decomposition, and the parameter vector is In a fixed time step within one excitation cycle, the magnetization differential equation is numerically integrated to obtain the magnetization sequence. The initial magnetization is taken as the value at the end of the last excitation cycle to ensure continuity. The " / " represents parallel decomposition, and the purpose is to divide the total magnetization into "reversible component" and "irreversible component" for modeling.

[0064] Wherein, the average field coupling coefficient And the reversible magnetization proportion coefficient Through the measured main loop and several loop data, the least squares fitting is obtained under the Jiles-Atherton magnetic core hysteresis model, and the global optimization can also be done by particle swarm or genetic algorithm, and then refined by local fitting.

[0065] Example value range: Usually a small amount (about to order of magnitude, dimensionless), Located in the open interval 0 to 1 (commonly about 0.1 to 0.9); the average field coupling coefficient , used for linear coupling between instantaneous magnetization and equivalent magnetic field; the reversible magnetization proportion coefficient , used to allocate weights between "reversible component / irreversible component";

[0066] In the specific implementation process, at each discrete sampling time, the coupling relationship between the equivalent magnetic field and the magnetization is determined by , and then is used to split the instantaneous magnetization increment into reversible component increment and irreversible component increment, and the sum of the two is the total increment, which is advanced by time step to form the magnetization sequence; the first value of the magnetization sequence is taken as the value at the end of the last cycle to ensure continuity.

[0067] The adjacent samples in the magnetization sequence are forward-differentiated according to a uniform time step, the magnetization sequence change rate is calculated, and the voltage output prediction sequence is generated according to the magnetization sequence change rate. The phase-locked synchronous demodulation is performed according to the demodulation window position, the second harmonic in-phase and quadrature integrals are completed, and the second harmonic complex amplitude prediction value is obtained. The demodulation reference phase is consistent with the reference phase in the content of step S1.

[0068] S2.3: Calculate the complex difference between the second harmonic complex amplitude value in the observation set and the predicted value of the second harmonic complex amplitude value, as the basis for parameter updates. The difference is recorded in the excitation cycle. At the end of the cycle.

[0069] For parameter vectors By applying small perturbations one by one and recalculating the predicted value of the second harmonic complex amplitude under the same excitation and demodulation conditions (a temporary recalculation for calculating the numerical Jacobian, not written into the parameters), a numerical Jacobian vector of the predicted value of the second harmonic complex amplitude is formed. Used to convert complex differences Projecting onto the parameter-sensitive direction to generate a normalized update, thereby obtaining ;

[0070] It should be noted that the same excitation and demodulation conditions include the same excitation frequency, duty cycle, excitation amplitude, compensation current, demodulation window position and reference phase, the same temperature information and the other parameters after temperature correction remain unchanged; small perturbation refers to applying a fixed relative step additive offset to each parameter in the parameter vector (for example, taking a fixed percentage of the calibration value as the step, and doing it once in the positive direction and once in the negative direction, while other parameters remain unchanged in between).

[0071] At the end of each excitation cycle, a normalized gradient method is used, based on the numerical Jacobian vector. with complex difference Calculate parameter increments and at period boundaries. Perform an update on the parameter vector, expressed as:

[0072] ;

[0073] In the formula, Indicating during the incentive cycle The parameter vector, Indicates the excitation cycle Update the parameter vector for the next excitation cycle. The scalar step size is used to control the magnitude of a single update. Represents a numerical Jacobian vector, a complex five-dimensional vector. for The conjugate transpose of is used in complex vector inner product operations. The complex difference value is defined as the deviation of the second harmonic complex amplitude value in the observation set from the predicted value of the second harmonic complex amplitude value. Let be the complex inner product, representing the complex scalar gain obtained by projecting the complex difference onto the Jacobian direction. It is a real, non-negative scalar, equal to the energy of the Jacobian vector, used to normalize the update quantity. A positive stability term is used to avoid numerical instability caused by too small denominator;

[0074] It should be noted that the scalar step is selected by grid search on a set of representative observations in the device calibration stage, so that the mean square error of the second harmonic complex amplitude is monotonically decreasing in a continuous number of excitation periods, and the minimum value is updated without oscillation. The positive stability term is multiplied by the median of the same calibration data to provide a fixed proportion factor to provide a lower bound for the denominator. The updated parameter vector is used

[0075] The second harmonic complex amplitude prediction value is calculated (one formal forward calculation is performed with the new parameters) in the excitation period The second harmonic complex amplitude prediction value is written into the prediction set in a fixed field order. The prediction set only contains the second harmonic complex amplitude prediction value; the fixed field order means that the real part of the second harmonic complex amplitude prediction value and the imaginary part of the second harmonic complex amplitude prediction value are recorded in this order, with the real part first and the imaginary part last.

[0076] Preferably, at the end of each excitation period, the complex difference between the observed second harmonic complex amplitude and the model prediction value is used to implement normalized gradient update combined with the numerical Jacobian obtained by perturbing the parameters one by one, which can project the error in the direction of the most sensitive parameter and suppress the numerical instability caused by the step size, so that the parameters monotonically converge in the direction of reducing the mean square error without changing the excitation and demodulation conditions, ensuring the continuity and convergence stability across periods. Compared with the conventional method of using fixed parameters or only using real error for scalar proportional correction, the present application uses complex domain Jacobian to handle amplitude and phase information simultaneously, reduces the overall deviation caused by model mismatch, and provides more accurate prediction basis for subsequent scheduling and amplitude limiting.

[0077] S3: Construct a scheduling optimization function based on the prediction set, apply soft turn-on constraints, amplitude stability constraints, phase consistency constraints, and saturation depth constraints, and output the corresponding control variables.

[0078] It should be noted that the soft turn-on constraint is defined as satisfying the zero-voltage zero-current turn-on condition through energy recovery before excitation commutation; the excitation commutation refers to the time when the rectangular current waveform controlled by the excitation signal parameters is switched from positive excitation amplitude to negative excitation amplitude or from negative excitation amplitude to positive excitation amplitude; the zero-voltage zero-current turn-on condition refers to the condition that the switch port current prediction value is equal to zero and the energy recovery path is turned on, resulting in the switch port voltage prediction value being equal to zero at the next conduction instant.

[0079] ​The amplitude stability constraint is defined as the deviation of the amplitude and phase of the extracted harmonic response of the adjacent period from the reference amplitude and phase being within the amplitude target range and the amplitude and phase deviation threshold, respectively. The reference amplitude is derived from the center value of the amplitude target set in the calibration process, and the amplitude and phase deviation threshold is determined according to the calibration parameters to ensure the accuracy of the amplitude and phase.

[0080] The phase consistency constraint is defined as the deviation of the demodulation window position from the reference phase being within the predetermined phase deviation threshold. The saturation depth constraint is defined as the peak value of the magnetization calculated by the magnetic core hysteresis model being less than the saturation upper limit threshold. The peak value of the magnetization is the maximum absolute value of the magnetization sequence in the excitation period. The saturation upper limit threshold is derived from the upper limit threshold of the magnetization given by the magnetic material characteristics, which is derived from the material calibration. For example, the saturation upper limit threshold can be about 80% of the nominal saturation magnetization of the material, and the specific value is determined by the material calibration. The unit is only for illustration and does not constitute a limitation.

[0081] S3.1: receiving a set of prediction quantities, merging to generate a candidate set of control variables; evaluating the candidate set of control variables according to the scheduling optimization function to form an evaluation sequence.

[0082] Specifically, the second harmonic complex amplitude prediction value in the received prediction quantity set is read, and the magnetization sequence and the magnetization derivative sequence are read. The reference phase and the demodulation window position are read. The current excitation frequency, duty cycle, excitation amplitude and compensation current are read.

[0083] Four evaluation quantities are set and weighted to form a single target value according to the calibration weight. The four evaluation quantities are: the amplitude stability evaluation quantity takes the deviation between the amplitude of the second harmonic complex amplitude prediction value and the reference amplitude; the phase stability evaluation quantity takes the deviation between the phase of the second harmonic complex amplitude prediction value and the reference phase; the saturation penalty evaluation quantity takes the amount of exceeding the saturation upper limit threshold of the peak value of the magnetization, and takes zero when it does not exceed; the soft turn-on penalty evaluation quantity takes the sum of the sizes of the non-zero quantities in the soft turn-on condition near the excitation commutation time, and takes zero when it fully satisfies the zero voltage and zero current turn-on condition.

[0084] According to the magnetization field input and the magnetization sequence, the excitation commutation time of each excitation period is determined. An energy recovery window is set before the excitation commutation. The energy recovery window is adjacent to the excitation commutation time. The energy recovery path is conducted in the energy recovery window to make the switch port voltage prediction value zero. At the same time, the switch port current prediction value is calculated, and it is checked whether the switch port current prediction value at the end of the energy recovery window is zero.

[0085] Around the current excitation frequency, duty cycle and excitation amplitude, several combinations are generated in a limited neighborhood with fixed calibration steps. Around the current compensation current, a compensation current update is generated with fixed calibration steps. The demodulation window position is set to the sum of the reference phase and the predetermined phase difference, and a limited number of candidate points are given near the reference position of the demodulation window position for robustness evaluation. The excitation frequency candidate, duty cycle candidate, excitation amplitude candidate, compensation current update candidate and demodulation window position candidate are combined to form a control variable candidate set. The sum of the predetermined phase difference is calculated by calculating the difference between the reference phase and the target phase, and according to the difference and the fixed value set according to the actual application requirement, as the offset of the demodulation window position.

[0086] For each control variable candidate, the formal forward calculation process in S2 step content is called to obtain the second harmonic complex amplitude prediction value and the magnetization sequence; four evaluation quantities are calculated according to the second harmonic complex amplitude prediction value and the magnetization sequence and are combined into a single target value according to the calibration weight;

[0087] After the single target value, the soft opening calculable quantity, the magnetization peak value, the amplitude-phase deviation, the energy recovery window residual quantity and the saturation depth margin are dimensionless, the single target value is sorted in ascending order first, and when there are ties, the soft opening calculable quantity, the magnetization peak value, the amplitude-phase deviation, the energy recovery window residual quantity are taken as small optimization, and the saturation depth margin is taken as large optimization for lexicographic comparison to form an evaluation sequence.

[0088] It should be noted that the soft opening calculable quantity refers to the sum of the absolute value of the switch port current prediction value at the end of the energy recovery window and the maximum value of the absolute value of the switch port voltage prediction value within the energy recovery window; both quantities are generated by the formal forward calculation process, and the energy recovery window position is determined by the excitation frequency, duty cycle and excitation commutation time. The two quantities include the absolute value of the switch port current prediction value at the end of the energy recovery window; the maximum value of the absolute value of the switch port voltage prediction value within the energy recovery window.

[0089] S3.2: According to the soft opening constraint, the amplitude stability constraint, the phase consistency constraint and the saturation depth constraint, the non-satisfactory items are removed to form a feasible set; the optimal control variable is selected in the feasible set to form the collaborative scheduling result. The optimal control variable refers to the control variable that makes the scheduling optimization function take the minimum value in the feasible set.

[0090] Specifically, the item of which the switch port current prediction value at the end of the energy recovery window is not zero is removed, and the item of which the switch port voltage prediction value in the energy recovery window is not zero is removed; the item of which the amplitude of the second harmonic complex amplitude prediction value is not in the amplitude target range is removed, and the item of which the amplitude-phase deviation of the second harmonic complex amplitude prediction value and the reference amplitude phase is greater than the amplitude-phase deviation threshold is removed; the demodulation window position is fixed as the sum of the reference phase and the predetermined phase difference; the candidate item of which the demodulation window position is not equal to the sum of the reference phase and the predetermined phase difference is removed; and the candidate item of which the magnetization peak value exceeds the saturation upper limit threshold is removed.

[0091] In the remaining feasible set, the single target value is sorted from small to large, and the item with the smallest target value is selected as the optimal control variable. If the feasible set has only one item, the item is the optimal control variable.

[0092] S3.3: The cooperative scheduling result is divided into corresponding control variables, including excitation signal parameters, compensation current update amount and demodulation window position.

[0093] The excitation frequency, duty ratio and excitation amplitude are read from the optimal control variable and written into the excitation signal parameter. The duty ratio determines the position relationship between the energy recovery window and the excitation commutation time. The compensation current update amount is read from the optimal control variable and superimposed on the current compensation current to form a new compensation current in the next excitation period.

[0094] The sum of the reference phase and the predetermined phase difference is written into the demodulation window position field. The excitation signal parameters, compensation current update amount and demodulation window position are written into the cooperative scheduling result in the order of fixed fields.

[0095] S4: The excitation signal parameters are set according to the control variables, and the excitation drive and compensation injection are performed, and the harmonic amplitude-phase response of the current period is extracted in the demodulation window position.

[0096] S4.1: In the process of setting the excitation signal parameters, event alignment control is adopted, the optimal control variable is written into the execution sequence, and the excitation frequency, duty ratio and excitation amplitude are set in turn, the demodulation window position is set, and the energy recovery timing is arranged according to the soft turn-on constraint. The excitation drive and compensation injection refer to outputting the excitation waveform according to the excitation signal parameters and applying the compensation current, and the excitation commutation is performed according to the soft turn-on constraint.

[0097] Specifically, the excitation frequency, duty ratio, excitation amplitude, compensation current update amount and demodulation window position in the cooperative scheduling result are read. The reference phase is taken as the time reference to establish the execution sequence of the current excitation period, and the execution sequence includes the order relationship of the energy recovery window, the excitation commutation time and the demodulation window position.

[0098] Write the excitation frequency, duty cycle and excitation amplitude into the excitation signal parameters in the execution sequence; update the current compensation current by the compensation current update amount to form a new compensation current for the current period compensation injection;

[0099] Set an energy recovery window before the excitation commutation, and the energy recovery window is immediately before the excitation commutation time; the energy recovery window starts to open the energy recovery path and lasts until the energy recovery window ends; monitor the switch port current and switch port voltage within the energy recovery window; confirm that the switch port current at the end of the energy recovery window is equal to zero and that the switch port voltage is equal to zero when the energy recovery path is turned on;

[0100] Confirm that the opening is completed at the excitation commutation time, and the zero-voltage and zero-current opening conditions are met;

[0101] Output a rectangular wave current as the excitation drive according to the excitation signal parameters, and output a new compensation current as the compensation injection; at the excitation commutation time, perform opening based on the zero-voltage and zero-current conditions confirmed at the end of the energy recovery window. Record the reference phase, energy recovery window start and end time, and excitation commutation time of the current period for positioning the sampling interval.

[0102] S4.2: Position the sampling interval according to the demodulation window position, and perform phase-locked synchronous demodulation on the fluxgate current sensor output within the sampling interval to suppress non-target components.

[0103] Specifically, taking the reference phase as the reference, set the demodulation window position to the sum of the reference phase and the predetermined phase difference; start sampling at the set position, and the sampling interval covers the length of a continuous demodulation window;

[0104] Within the sampling interval, multiply the voltage output of the fluxgate current sensor by the in-phase reference signal and the quadrature reference signal of the same frequency as the second harmonic, and perform interval averaging within the sampling interval to obtain the in-phase component and the quadrature component;

[0105] Perform phase-consistent interval averaging within the sampling interval to average the direct current component and the component of different frequencies of the second harmonic to a quantity close to zero; the in-phase and quadrature components are processed in pairs to distribute the leakage caused by the same frequency but phase deviation of the second harmonic to the two components, avoiding amplitude and phase estimation deviation; the sampling interval and the demodulation window position maintain a fixed phase relationship, reducing the influence of excitation commutation transient on the second harmonic estimation; after interval averaging, perform single smoothing filtering on the in-phase component and the quadrature component respectively to remove high-frequency random noise without changing the amplitude and phase information of the current period.

[0106] S4.3: Perform amplitude and phase estimation on the demodulation signal to obtain the harmonic amplitude and phase response, and submit the harmonic amplitude and phase response to the conversion process as the input of the linear measurement output.

[0107] The in-phase component and the quadrature component are combined into a second harmonic complex amplitude, the amplitude and the phase are extracted, and a harmonic amplitude and phase response is obtained; the harmonic amplitude and phase response is submitted to a conversion process as an input of a linear measurement output, and a reference phase corresponding to the current period, a demodulation window position, an excitation frequency, a duty cycle, an excitation amplitude and a compensation current are recorded, so that a record item corresponding to the harmonic amplitude and phase response is formed.

[0108] S5: converting the harmonic amplitude and phase response into a linear measurement output of the current period, while updating the observation set.

[0109] S5.1: in the conversion process, a proportional closed-loop mapping is used to convert the harmonic amplitude and phase response into a compensation current update, and the compensation current of the last period is integrated to obtain the compensation current output of the current period, while the compensation current output is recorded and written into the observation set as the next period parameter update.

[0110] Specifically, the harmonic amplitude and phase response, the reference amplitude and phase, the compensation current of the last period, the excitation signal parameters and the temperature information are read; the difference between the amplitude of the harmonic amplitude and phase response and the reference amplitude is calculated to obtain an amplitude error; the difference between the phase of the harmonic amplitude and phase response and the reference phase is calculated, and the phase is normalized to obtain a phase error;

[0111] The amplitude proportional coefficient and the phase proportional coefficient are set. Specifically, under constant temperature conditions, a standard current source is used to sweep the amplitude and phase point by point, the linear interval slope between the harmonic amplitude and phase response and the error is recorded, and the proportional coefficient with stable convergence and sufficient phase margin is taken as the calibration result; for example, the amplitude proportional coefficient is taken as , and the phase proportional coefficient is taken as .

[0112] Based on the amplitude proportional coefficient and the phase proportional coefficient, the amplitude error is mapped into an in-phase correction amount, and the phase error is mapped into a quadrature correction amount; in the I / Q rectangular coordinate (I corresponds to the in-phase axis, and Q corresponds to the quadrature axis), the two correction amounts are used as components for vector synthesis, the direction is determined by the components, the synthesis amplitude is the square root of the square sum of the two components, and the synthesis result is taken as the compensation current update. When mapping, the in-phase axis is determined by the phase direction of the reference amplitude and phase, and the quadrature axis is determined by the phase leading direction of ninety degrees; the in-phase correction amount is taken along the in-phase axis, and the quadrature correction amount is taken along the quadrature axis; the in-phase axis and the quadrature axis form a right-handed rectangular coordinate relationship.

[0113] The compensation current update is applied to the compensation current of the last period to obtain the compensation current output; the compensation current output is subjected to amplitude limiting and clipping, and the amplitude limiting upper and lower boundaries are derived from material and power device calibration; the compensation current output is confirmed as the linear measurement output of the current period;

[0114] The scalar value and the sign information of the compensation current output are recorded and written into the observation set. The time stamp and the period sequence number are recorded and correspond one by one to the harmonic amplitude and phase response.

[0115] Preferably, after comparing the harmonic amplitude-phase response with the reference amplitude-phase, the amplitude error is mapped into in-phase correction quantity, the phase error is mapped into quadrature correction quantity, vector synthesis is performed in I / Q rectangular coordinates to obtain the compensation current update quantity, and the proportional coefficient obtained through calibration and the output amplitude clipping are combined to make the closed loop work in the linear interval with sufficient phase margin, so that the amplitude and phase deviations can be corrected at the same time, the phase leakage and steady-state deviation that easily occur only by using scalar error are avoided, the stability and response speed of the compensation current are improved, the power consumption is reduced, and the consistency of linear measurement output is maintained; compared with the conventional scheme of adjusting only according to the proportional amplitude deviation, the I / Q synthesis can reduce the coupling influence of commutation transient and noise on amplitude-phase estimation.

[0116] S5.2: updating the observation set includes writing the harmonic amplitude-phase response of the current period, the excitation signal parameter, the demodulation window position, the compensation current output and the temperature information into the observation set.

[0117] Specifically, the harmonic amplitude-phase response of the current period is written into the record item; the excitation frequency, the duty cycle and the excitation amplitude in the excitation signal parameter are written into the record item; the demodulation window position is written into the record item; the compensation current output is written into the record item; and the temperature information is written into the record item.

[0118] The record items are arranged in the order of the fixed fields: the harmonic amplitude-phase response, the excitation frequency, the duty cycle, the excitation amplitude, the demodulation window position, the compensation current output and the temperature information. The consistency of the time stamp and the period sequence number is checked to confirm the same period source; the record item is appended to the end of the observation set. The period sequence number and the field check information of the writing result are returned as the input basis for the next period parameter update and scheduling optimization.

[0119] In summary, by using proportional closed loop mapping in the conversion link, the amplitude error and the phase error are respectively mapped into in-phase correction quantity and quadrature correction quantity, vector synthesis is completed in I / Q rectangular coordinates to generate the compensation current update quantity, the proportional coefficient obtained through calibration and the output amplitude clipping are combined to make the closed loop run in the linear interval with sufficient phase margin, so that the amplitude and phase deviations are converged synchronously, the commutation transient and noise coupling are suppressed, the stability and response speed of the compensation current are improved, the energy consumption is reduced, and the continuous consistency of the linear measurement output is maintained.

[0120] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application rather than limiting the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A method of measuring a low-loss proportionally amplified fluxgate current sensor, characterized by: include, Obtain the set of observations after phase-locked loop synchronization demodulation; The set of observations includes second harmonic complex amplitude, excitation frequency, duty cycle, excitation amplitude, demodulation window position, compensation current, and temperature information; Phase-locked synchronous demodulation is performed within the sampling interval. The sampling sequence is phase-sensitively detected by the in-phase reference signal and the quadrature reference signal of the second harmonic frequency, respectively. Interval averaging is performed within the sampling interval to obtain the in-phase component and the quadrature component of the second harmonic. The in-phase component and quadrature component of the second harmonic are combined to form the complex amplitude value of the second harmonic, and a correspondence is established between the complex amplitude value of the second harmonic and the reference phase corresponding to the sampling interval. Input the set of observations into the core hysteresis model, perform model parameter updates, and generate a set of predictions. A scheduling optimization function is constructed based on the set of predictions. Soft turn-on constraints, amplitude stability constraints, phase consistency constraints, and saturation depth constraints are applied, and the corresponding control variables are output. The excitation signal parameters are set according to the control variables and the excitation drive and compensation injection are executed. The harmonic amplitude phase response of the current cycle is extracted within the demodulation window position. The harmonic amplitude and phase response is converted into a linear measurement output for the current period, and the observation set is updated simultaneously.

2. The method of claim 1, wherein the low-loss proportionally amplified fluxgate current sensor is characterized by: The process of updating the execution model parameters and generating a set of predictions includes using the difference between the observed values ​​and the output of the core hysteresis model as the basis for updating, and performing parameter correction at the boundary of each excitation cycle.

3. The method of claim 2, wherein the low-loss, proportionally amplified fluxgate current sensor measurement method is characterized by: The soft-turn-on constraint is defined as the switching port satisfying the zero-voltage and zero-current turn-on condition after energy recovery before excitation switching. The amplitude stability constraint is defined as the harmonic amplitude and phase responses extracted from adjacent periods being within the target amplitude range and the deviation from the reference amplitude and phase not exceeding the amplitude and phase deviation threshold; the phase consistency constraint is defined as the demodulation window position maintaining a predetermined phase difference with the excitation reference phase; the saturation depth constraint is defined as the magnetization peak calculated by the core hysteresis model not exceeding the upper limit threshold of saturation.

4. The method of claim 3, wherein the low-loss, proportionally amplified fluxgate current sensor measurement method is characterized by: The control variables corresponding to the output are defined in the following steps. Receive the predicted set and merge it to generate a candidate set of control variables; evaluate the candidate set of control variables according to the scheduling optimization function to form an evaluation sequence; Based on the soft turn-on constraint, amplitude stability constraint, phase consistency constraint and saturation depth constraint, unsatisfactory items are eliminated to form a feasible set; the optimal control variable is selected from the feasible set to form the collaborative scheduling result. The results of the coordinated scheduling are divided into corresponding control variables, including excitation signal parameters, compensation current update amount and demodulation window position.

5. The method of claim 4, wherein: the low-loss, proportionally amplified fluxgate current sensor is a sensor of claim 1. Event-aligned control is used in setting excitation signal parameters. The optimal control variables are written into the execution sequence and the excitation frequency, duty cycle and excitation amplitude are set in sequence. The demodulation window position is set and the energy recovery timing is arranged according to the soft turn-on constraint.

6. The method of claim 5, wherein the low-loss, proportionally amplified fluxgate current sensor measurement method further comprises: The excitation drive and compensation injection refer to outputting an excitation waveform based on the excitation signal parameters and applying a compensation current, with the excitation commutation executed according to soft-start constraints.

7. The method of claim 6, wherein the low-loss, proportionally amplified fluxgate current sensor measurement method is characterized by: The specific steps for extracting the harmonic amplitude and phase response of the current period within the demodulation window are as follows. The sampling interval is located based on the demodulation window position. Within the sampling interval, phase-locked synchronous demodulation is performed on the output of the fluxgate current sensor to suppress non-target components. The demodulated signal is subjected to amplitude and phase estimation to obtain a harmonic amplitude and phase response, which is submitted to a conversion process as an input of a linear measurement output.

8. The method of claim 7, wherein the low-loss, proportionally amplified fluxgate current sensor is characterized by: The conversion process employs a proportional closed loop mapping to convert the harmonic amplitude and phase response into a compensation current update and to combine the compensation current update with a previous period compensation current to form a compensation current output for a current period, while recording the compensation current output and writing it into an observation set as a next period parameter update.

9. The method of claim 8, wherein the low-loss, proportionally amplified fluxgate current sensor measurement method is characterized by: The update observation set includes writing the harmonic amplitude and phase response, the excitation signal parameters, the demodulation window position, the compensation current output and temperature information of the current period into the observation set.

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