Method and device for determining output current of dc-dc converter, and electronic device

Abstract

The application discloses a DC-DC converter output current determination method and device and electronic equipment, and the method comprises the following steps: acquiring actual output currents corresponding to different working conditions of a DC-DC converter; obtaining actual conversion efficiencies corresponding to the different working conditions of the DC-DC converter according to the actual output currents; taking parameters influencing the conversion efficiency of the DC-DC converter under the different working conditions as input variables, taking the actual conversion efficiencies as output variables, fitting a linear relationship function for solving the output variables according to the input variables by using the parameters and the actual conversion efficiencies corresponding to the different working conditions of the DC-DC converter; and obtaining a predicted output current based on the fitted linear relationship function and the parameter values of the DC-DC converter without a secondary side current sensor. The application does not need to increase other hardware facilities, and improves the original secondary side current conversion accuracy along with the change of the working conditions.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a method and apparatus for determining the output current of a DC-DC converter, and an electronic device. Background Technology

[0002] With the increasing demands for efficiency and power density in DC-DC converters, soft-switching circuits are becoming more widely used. The actual output current of a DC-DC converter varies under different operating conditions, referring to variations in input voltage, output voltage, and load conditions. For example, LLC converters can achieve zero-voltage soft-switching of the power transistors under rated conditions, with controllable turn-off losses and high efficiency. However, under a wide range of input voltage, output voltage, and load conditions, the operating efficiency of LLC converters can vary significantly. Especially under high input voltage, low output voltage, and light load conditions, the efficiency of LLC converters is very low. For isolated DC-DC converters without secondary-side current sensors, the actual output current can only be estimated using the power conservation law between the primary and secondary sides. Because the conversion efficiency of DC-DC converters varies under different operating conditions, the estimated actual output current will deviate significantly from the true output current value. Summary of the Invention

[0003] The purpose of this application is to provide a method, apparatus, and electronic device for determining the output current of a DC-DC converter. This addresses the problem that for DC-DC converters without a secondary current sensor, the actual output current can only be estimated using the law of conservation of energy between the primary and secondary sides. However, due to differences in conversion efficiency under various operating conditions, the predicted output current value deviates significantly from the actual output current value.

[0004] In a first aspect, embodiments of this application provide a method for determining the output current of a DC-DC converter, the method comprising:

[0005] Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0006] The actual conversion efficiency is obtained based on the actual output current of the DC-DC converter under different operating conditions.

[0007] The parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions are used as input variables, and the corresponding actual conversion efficiency is used as output variables. Using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter, a linear relationship function of the output variable is fitted based on the input variables.

[0008] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the predicted output current is obtained.

[0009] In some possible embodiments, using the parameters and actual conversion efficiency of the DC-DC converter under different operating conditions, a linear relationship function is fitted based on the input variables to solve for the output variables, including:

[0010] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0011] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitted conversion efficiency is obtained;

[0012] The objective function is to find the minimum sum of squares of the differences between the actual conversion efficiency and the fitted conversion efficiency. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0013] In some possible embodiments, the parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following:

[0014] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0015] In some possible embodiments, the objective function is:

[0016] The linear relationship function is:

[0017]

[0018] Among them, Efficiency i Vpfc represents the actual conversion efficiency of the DC-DC converter for the i-th operating condition. i Vo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let be the duty cycle of the i-th operating condition of the DC-DC converter, e(Vpfc,Vo,fs,Duty) be the fitted conversion efficiency, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0019] In some possible embodiments, the predicted output current is obtained based on the fitted linear relationship function and the parameter values ​​corresponding to the DC-DC converter without a secondary current sensor, including:

[0020] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitted conversion efficiency is obtained.

[0021] Based on the input current, input voltage, and fitted conversion efficiency of the DC-DC converter without a secondary current sensor, the converted power is determined, and the output current is predicted based on the converted power and output voltage.

[0022] Secondly, embodiments of this application provide a method for determining the output current of a DC-DC converter, the method comprising:

[0023] Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0024] Based on the preset conversion efficiency, determine the estimated output current of the DC-DC converter under different operating conditions, and determine the actual error between the actual output current and the estimated output current of the DC-DC converter under different operating conditions.

[0025] The parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions are used as input variables, and the error between the actual output current and the estimated output current is used as output variables. Using the parameters and actual error under different operating conditions of the DC-DC converter, a linear relationship function of the output variable is fitted based on the input variables.

[0026] Based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current, the predicted output current is obtained.

[0027] In some possible embodiments, using the parameters and actual errors corresponding to different operating conditions of the DC-DC converter, a linear relationship function is fitted based on the input variables to solve for the output variables, including:

[0028] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0029] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitting error is obtained;

[0030] The objective function is to minimize the sum of squares of the differences between the actual error and the fitted error. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0031] In some possible embodiments, the parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following:

[0032] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0033] In some possible embodiments, the objective function is:

[0034]

[0035] The linear relationship function is:

[0036]

[0037] Among them, dio i Vpfc represents the actual error of the DC-DC converter corresponding to the i-th operating condition. i Vo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let i be the duty cycle of the i-th operating condition of the DC-DC converter, i(Vpfc, Vo, fs, Duty) be the fitting error, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0038] In some possible embodiments, the predicted output current is obtained based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current, including:

[0039] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitting error is obtained.

[0040] Based on the preset conversion efficiency, the estimated output current is determined according to the input current, input voltage, and output voltage of the DC-DC converter without a secondary current sensor.

[0041] The output current value is predicted based on the estimated output current and the fitting error.

[0042] Thirdly, embodiments of this application provide a device for determining the output current of a DC-DC converter, the device comprising:

[0043] The module for obtaining actual output current is used to obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0044] The module for obtaining actual conversion efficiency is used to obtain the corresponding actual conversion efficiency based on the actual output current of the DC-DC converter under different operating conditions.

[0045] The fitting module is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the corresponding actual conversion efficiency as output variables. It fits a linear relationship function of the output variable based on the input variables using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter.

[0046] The predicted output current module is used to obtain the predicted output current based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor.

[0047] Fourthly, embodiments of this application provide a device for determining the output current of a DC-DC converter, the device comprising:

[0048] The module for obtaining actual output current is used to obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0049] The actual error acquisition module is used to determine the estimated output current of the DC-DC converter under different operating conditions based on the preset conversion efficiency, and to determine the actual error between the actual output current and the estimated output current under different operating conditions of the DC-DC converter.

[0050] The fitting module is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables, and the error between the actual output current and the estimated output current as output variables. Using the parameters and actual error corresponding to the DC-DC converter under different operating conditions, it fits a linear relationship function of the output variable based on the input variables.

[0051] The output current prediction module is used to obtain the predicted output current based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current.

[0052] Fifthly, embodiments of this application provide an electronic device, including at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method for determining the output current of a DC-DC converter provided in the first aspect above, or to perform the method for determining the output current of a DC-DC converter provided in the second aspect above.

[0053] Sixthly, embodiments of this application provide a system for determining the output current of a DC-DC converter, the system comprising:

[0054] DC-DC converter;

[0055] The detection module is used to collect parameters in the circuit of the DC-DC converter that affect the conversion efficiency of the DC-DC converter;

[0056] The calculation module is used to obtain the predicted output current based on the fitted linear relationship function;

[0057] The host computer module is used to display the power information of the DC-DC converter;

[0058] The linear relationship function is obtained by fitting a linear relationship function derived from the input variables and the actual conversion efficiency under different operating conditions of the DC-DC converter, using the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the actual conversion efficiency as output variables; or

[0059] The linear relationship function is obtained by fitting a linear relationship function obtained by solving the output variable based on the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions, using the parameters and actual error corresponding to the DC-DC converter under different operating conditions as input variables and the error between the actual output current and the predicted output current as output variables.

[0060] In this application embodiment, to address the problem that for DC-DC converters without secondary-side current sensors, the actual output current can only be estimated using the law of conservation of energy between the primary and secondary sides, but since the conversion efficiency of DC-DC converters varies under different operating conditions, the predicted output current value will deviate significantly from the actual output current value, this application embodiment proposes a method, apparatus, and electronic equipment for determining the output current of a DC-DC converter. This method does not require additional hardware facilities and improves the accuracy of primary and secondary side current conversion as operating conditions change.

[0061] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0062] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 This is a schematic diagram of the circuit structure of a DC-DC converter according to an embodiment of this application;

[0064] Figure 2 This is a comparison graph of conversion efficiency curves under different input voltages and different output loads according to an embodiment of this application;

[0065] Figure 3 This is a comparison graph of conversion efficiency curves under different output voltages and different output loads according to an embodiment of this application;

[0066] Figure 4 This is a schematic flowchart of a method for determining the output current of a DC-DC converter according to an embodiment of this application;

[0067] Figure 5 This is a schematic flowchart of another method for determining the output current of a DC-DC converter according to an embodiment of this application;

[0068] Figure 6 This is a schematic diagram of a device for determining the output current of a DC-DC converter according to an embodiment of this application.

[0069] Figure 7 This is a schematic diagram of a device for determining the output current of a DC-DC converter according to an embodiment of this application;

[0070] Figure 8 This is a schematic diagram of a system structure for determining the output current of a DC-DC converter according to an embodiment of this application;

[0071] Figure 9 This is a schematic diagram of an electronic device structure according to an embodiment of this application. Detailed Implementation

[0072] The technical solutions in the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0073] In the description of the embodiments of this application, unless otherwise stated, the term "multiple" refers to two or more, and other quantifiers are similarly understood. The preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0074] To further illustrate the technical solutions provided in the embodiments of this application, a detailed description is provided below in conjunction with the accompanying drawings and specific implementation methods. Although the embodiments of this application provide method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on conventional or non-inventive effort. For steps that do not logically have a necessary causal relationship, the execution order of these steps is not limited to the execution order provided in the embodiments of this application. In actual processing or when the control device executes the method, it may be executed sequentially or in parallel according to the method shown in the embodiments or drawings.

[0075] In related technologies, for DC-DC converters without secondary-side current sensors, the actual output current can only be estimated using the law of conservation of energy between the primary and secondary sides. However, due to the varying conversion efficiency of DC-DC converters under different operating conditions, the predicted output current value deviates significantly from the actual output current value. This application proposes a method, apparatus, and electronic equipment for determining the output current of a DC-DC converter, which requires no additional hardware and improves the accuracy of primary and secondary side current conversion as operating conditions change.

[0076] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0077] See Figure 1 This is a schematic diagram of the circuit structure of a DC-DC converter.

[0078] Figure 1In the topology, the left side is the primary side and the right side is the secondary side. Ui represents the input voltage of the circuit connected to the left side of the DC-DC converter (generally a high-voltage power supply). Co1 and Co2 are electrolytic capacitors of the output positive and negative buses. The voltage across Co1 and Co2 connected in series is the output voltage of the DC-DC converter, which is used to provide the corresponding output voltage to the load circuit connected to the secondary side to meet user requirements. Q1, Q2, Q3, and Q4 are high-frequency switching transistors operating at tens to hundreds of kHz. Lr is a resonant inductor, Cr is a resonant capacitor, Tr is a tapped high-frequency transformer, D1, D2, D3, and D4 are secondary-side rectifier diodes, and Rshunt is the current sampling shunt of the primary side of the converter, which can be understood as a resistor. The input current can be sampled through Rshunt.

[0079] The DC-DC converter uses the input voltage provided by the input circuit. First, appropriate hardware such as Lr, Cr, and Tr are selected. Then, by properly controlling Q1, Q2, Q3, and Q4, appropriate output voltage and output current are generated on the secondary side of the transformer to meet the user's requirements.

[0080] To sample the output current of a DC-DC converter, given the high input voltage and low output voltage, the secondary side output current is relatively large according to the law of conservation of energy. If a current sensor is connected in series in the circuit, and only the secondary side current sensor exists, the primary side semiconductor switching devices will not be protected in time and may be damaged. If current sensors exist on both the primary and secondary sides, losses will increase and the efficiency of the DC-DC converter will decrease. Therefore, the commonly used method is to pre-determine the power conversion efficiency of the secondary side, obtain the input power through the input voltage and input current, and then, based on the energy conservation law, obtain the predicted output power and thus the predicted output current by comparing the input power with the estimated conversion efficiency.

[0081] Regarding the impact of input voltage and output voltage on conversion efficiency, this application obtained conversion efficiency curves through extensive prior experiments.

[0082] Curve 1: This application pre-fixes the output voltage value and obtains a comparison curve of conversion efficiency under different input voltages and different output loads through experiments. See [link / reference]. Figure 2 In the graph, the horizontal axis represents the load, and the vertical axis represents different conversion efficiencies. The two curves in the graph represent the conversion efficiencies under different output loads corresponding to two different input voltages, with the same output voltage. Figure 2 It can be known that:

[0083] a) The converter's conversion efficiency ranges from a minimum of 53% to a maximum of 95.89%, showing a significant difference.

[0084] b) When the input voltage of the curve on the upper side of the figure is 418V and the output load is less than 20%, the conversion efficiency of the converter is less than 82%, and the slope of the conversion efficiency curve of the converter with load change is relatively large.

[0085] c) The curve at the upper end of the figure represents an input voltage of 418V. When the output load exceeds 50%, the converter's conversion efficiency is higher than 95.8%, and the slope of the curve showing the change in conversion efficiency with load is relatively small.

[0086] d) At loads below 70%, the conversion efficiencies of the curves with input voltages of 418V on the upper part of the figure are higher than those of the curves with input voltages of 436V on the lower part of the figure.

[0087] Curve 2: This application pre-fixes the input voltage value and obtains a comparison chart of conversion efficiency curves under different output voltages and different output loads through experiments. (See attached chart.) Figure 3 In the graph, the horizontal axis represents the load, and the vertical axis represents different conversion efficiencies. The two curves in the graph represent the conversion efficiencies under different output loads corresponding to two different output voltages, with the same input voltage. Figure 3 It can be known that:

[0088] a) The converter's conversion efficiency ranges from a minimum of 55.8% to a maximum of 95.89%, showing a significant difference.

[0089] b) The lower curve in the figure represents an output voltage of 42V. When the output load is less than 14%, the converter's conversion efficiency is less than 80%, and the curve showing the change in conversion efficiency with load has a large slope.

[0090] c) The lower curve in the figure represents an output voltage of 42V. When the output load exceeds 57%, the converter's conversion efficiency is higher than 95%, and the slope of the curve showing the change in conversion efficiency with load is relatively small.

[0091] d) Below 57% load, the conversion efficiency of the curves with output voltage of 55.2V on the upper side of the figure is higher than that of the curves with output voltage of 42V on the lower side of the figure.

[0092] In summary, if the calculation is based on the estimated conversion efficiency, the predicted output current will deviate significantly from the actual output current. Therefore, complex compensation is required to achieve the necessary sampling accuracy of the output current.

[0093] Figure 4 This application illustrates a flowchart of a method for determining the output current of a DC-DC converter according to an embodiment of the present application, including:

[0094] Step 401: Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0095] Specifically, the DC-DC converter described above in this application can adopt the following... Figure 1 The circuit structure is shown. In this application, the actual output current of the DC-DC converter under different operating conditions is obtained in advance.

[0096] The actual output current is measured using an external current sensor independent of the DC-DC converter.

[0097] As an optional implementation, the parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following:

[0098] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0099] It should be noted that other circuit factors affecting the conversion efficiency of the DC-DC converter can also be included. If a circuit factor has a positive impact on the conversion efficiency, it is directly used as a parameter. If a circuit factor has a negative impact on the conversion efficiency, its reciprocal is used as a parameter. The switching frequency of the circuit is determined as the frequency of Q1, Q2, Q3, and Q4 in the drive circuit. The switching frequencies of Q1, Q2, Q3, and Q4 are consistent. The switching signals of the drive circuit are the switching signals that drive Q1, Q2, Q3, and Q4. The duty cycles of Q1 and Q4 are the same, and the duty cycles of Q2 and Q3 are the same. The two sets of corresponding switching signals are out of phase, and their duty cycles can be the same or different.

[0100] Step 402: Obtain the actual conversion efficiency based on the actual output current of the DC-DC converter under different operating conditions.

[0101] Based on the law of conservation of energy, the actual conversion efficiency is calculated using the actual input voltage, input current, output voltage, and output current.

[0102] Step 403: Using the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the corresponding actual conversion efficiency as output variables, fit a linear relationship function of the output variable based on the input variables using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter.

[0103] The parameters and actual conversion efficiency of the DC-DC converter under different operating conditions obtained in this application are used as sampling points on the curve corresponding to the fitted linear relationship function. The relationship between the input and output variables is fitted based on these sampling points to obtain the linear relationship function.

[0104] As an optional implementation method, by utilizing the parameters and actual conversion efficiency of the DC-DC converter under different operating conditions, a linear relationship function based on the input variables and the output variables is fitted, including:

[0105] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0106] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitted conversion efficiency is obtained;

[0107] The objective function is to find the minimum sum of squares of the differences between the actual conversion efficiency and the fitted conversion efficiency. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0108] Given a defined objective function, the process of solving for the coefficients of the linear relationship function using the least squares method can be described in detail using the mathematical differentiation process of related techniques.

[0109] As an optional implementation, the parameters affecting the conversion efficiency of the DC-DC converter in this embodiment include: the input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency of the drive circuit, and the duty cycle of the switching signal of the drive circuit.

[0110] The linear relationship function in this embodiment is:

[0111]

[0112] In order to solve for the coefficients a, b, c, d and the constant e of each parameter in the linear relationship function.

[0113] The objective function in this embodiment is:

[0114]

[0115] Among them, Efficiency i Vpfc represents the actual conversion efficiency of the DC-DC converter under the i-th operating condition. i Vo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition.i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let be the duty cycle of the i-th operating condition of the DC-DC converter, e(Vpfc,Vo,fs,Duty) be the fitted conversion efficiency, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0116] It should be noted that the duty cycles of the two sets of corresponding switch signals can be the same or different. When the duty cycles of the two sets of corresponding switch signals are different, the duty cycle of each set of corresponding switch signals is taken as a parameter and multiplied by the corresponding coefficient.

[0117] Based on the different sampling points on the conversion efficiency curve in step 402 above, namely the input voltage, output voltage, switching frequency of the drive circuit, and duty cycle of the switching signal of the drive circuit corresponding to different conversion efficiencies, determine a, b, c, d, and e in the linear relationship function. Using the least squares method, when the sum of the squares of the differences between the actual conversion efficiency and the fitted conversion efficiency reaches its minimum value, it proves that the difference between the fitted conversion efficiency and the actual conversion efficiency is the smallest, that is, the fitted conversion efficiency is closer to the actual conversion efficiency, thus determining the fitted linear relationship function.

[0118] Step 404: Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the predicted output current is obtained.

[0119] Once the linear relationship function is determined, the values ​​of the parameters corresponding to the DC-DC converter without a secondary current sensor are substituted into the linear relationship function as input variables, and the predicted output current can be obtained based on the output conversion efficiency.

[0120] As an optional implementation, based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the predicted output current is obtained as follows:

[0121] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitted conversion efficiency is obtained.

[0122] Based on the input current, input voltage, and fitted conversion efficiency of the DC-DC converter without a secondary current sensor, the converted power is determined, and the output current is predicted based on the converted power and output voltage.

[0123] The determination of the output current of the aforementioned DC-DC converter is achieved by fitting the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the corresponding actual conversion efficiency as the output variable.

[0124] Since the accuracy of the predicted output current of a DC-DC converter without a secondary current sensor is closely related to the conversion efficiency of the DC-DC converter, it is possible to fit the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the error between the actual output current and the predicted output current as the output variable.

[0125] This application also provides a method for determining the output current of a DC-DC converter, such as... Figure 5 As shown, the method includes:

[0126] Step 501: Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0127] As an optional implementation, the parameter affecting the conversion efficiency of the DC-DC converter includes at least one of the following:

[0128] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0129] The specific implementation method of this step is explained in the above step 401, and will not be repeated here.

[0130] Step 502: Determine the estimated output current of the DC-DC converter under different operating conditions based on the preset conversion efficiency, and determine the actual error between the actual output current and the estimated output current under different operating conditions of the DC-DC converter.

[0131] According to the law of conservation of energy, a conversion efficiency is first predetermined. Given the input voltage, input current, and output voltage, the estimated output current can be obtained, as shown in the following formula:

[0132] V PFC ×I DCCURR ×η=V O ×I O ;

[0133]

[0134] Among them, V PFC Input voltage; I DCCURR V is the input current; η is the preset conversion efficiency; V O For output voltage; I O This is the estimated output current.

[0135] Step 503: Using the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables, and the error between the actual output current and the estimated output current as output variables, fit a linear relationship function of the output variables based on the input variables using the parameters and actual error under different operating conditions of the DC-DC converter.

[0136] The parameters and actual errors of the DC-DC converter under different operating conditions obtained in this application are used as sampling points on the curve corresponding to the fitted linear relationship function. The relationship between the input and output variables is fitted based on these sampling points to obtain the linear relationship function.

[0137] As an optional implementation method, using the parameters and actual errors of the DC-DC converter under different operating conditions, a linear relationship function is fitted based on the input variables to solve for the output variables, including:

[0138] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0139] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitting error is obtained;

[0140] The objective function is to minimize the sum of squares of the differences between the actual error and the fitted error. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0141] Given a defined objective function, the process of solving for the coefficients of the linear relationship function using the least squares method can be described in detail using the mathematical differentiation process of related techniques.

[0142] As an optional implementation, the parameters affecting the conversion efficiency of the DC-DC converter in this embodiment include: the input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency of the drive circuit, and the duty cycle of the switching signal of the drive circuit.

[0143] The linear relationship function in this embodiment is:

[0144]

[0145] The objective function in this embodiment is:

[0146]

[0147] Among them, dio i Vpfc represents the actual error of the i-th operating condition corresponding to the DC-DC converter. iVo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let i be the duty cycle of the i-th operating condition of the DC-DC converter, i(Vpfc, Vo, fs, Duty) be the fitting error, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0148] It should be noted that the duty cycles of the two sets of corresponding switch signals can be the same or different. When the duty cycles of the two sets of corresponding switch signals are different, the duty cycle of each set of corresponding switch signals is taken as a parameter and multiplied by the corresponding coefficient.

[0149] Specifically, based on the different sampling points on the conversion efficiency curve in step 402 above—that is, the input voltage and output voltage of the DC-DC converter corresponding to different conversion efficiencies, as well as the switching frequency and duty cycle of the switching signal used in the drive circuit—the linear relationship function a, b, c, d, and e are determined under the preset conversion efficiency. Using the least squares method, when the sum of the squares of the differences between the actual error and the fitted error reaches its minimum value, it proves that the difference between the fitted error and the actual error is the smallest, that is, the fitted error is closer to the actual error. Thus, the fitted linear relationship function is determined.

[0150] Step 504: Based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current, the predicted output current is obtained.

[0151] Once the linear relationship function is determined, the values ​​of the parameters corresponding to the DC-DC converter without a secondary current sensor are substituted into the linear relationship function as input variables. Based on the output error and the estimated output current in step 502, the predicted output current can be obtained.

[0152] As an optional implementation, based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current, the predicted output current is obtained, including:

[0153] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitting error is obtained.

[0154] Based on the preset conversion efficiency, the estimated output current is determined according to the input current, input voltage, and output voltage of the DC-DC converter without a secondary current sensor.

[0155] The output current value is predicted based on the estimated output current and the fitting error. The estimated output current is determined by calculation based on the primary and secondary sides. By adding the estimated output current to the fitting error of the output current, the predicted output current value can be accurately restored, thus improving the sampling accuracy of the output current.

[0156] The two methods for determining the output current of the DC-DC converter disclosed in this application are simple to implement, require no additional hardware, and improve the accuracy of secondary current calculation as operating conditions change. It should be noted that the above-mentioned least squares fitting of the DC-DC converter's conversion efficiency or output current error is performed once; as long as the above parameters are used for fitting, regardless of the fitting method (multiple least squares fitting), it is within the protection scope of this application. Furthermore, the fitting of primary current sampling in this application, including shunt current sampling, current transformer (CT) sampling, Hall effect sampling, etc., are all within the protection scope of this application. This application achieves the goals of high efficiency and high reliability. The DC-DC converter retains only the primary current sensor, eliminating the secondary output current sensor. By using the input voltage, the reciprocal of the output voltage, switching frequency, duty cycle, and other state information of the DC-DC converter as input variables, and the conversion efficiency or error of the DC-DC converter as the output variable, least squares fitting is performed to obtain optimal compensation. This significantly improves the sampling accuracy of the output current.

[0157] Example 2

[0158] Based on the same inventive concept, this application also provides a device for determining the output current of a DC-DC converter, such as... Figure 6 As shown, the device includes:

[0159] The actual output current acquisition module 601 is used to acquire the actual output current corresponding to different operating conditions in the DC-DC converter. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0160] The module 602 for obtaining actual conversion efficiency is used to obtain the corresponding actual conversion efficiency based on the actual output current of the DC-DC converter under different operating conditions.

[0161] The fitting module 603 is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables, the corresponding actual conversion efficiency as output variables, and fit a linear relationship function of the output variable based on the input variables using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter.

[0162] The predicted output current module 604 is used to obtain the predicted output current based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor.

[0163] Optionally, the fitting module 603 is specifically used for:

[0164] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0165] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitted conversion efficiency is obtained;

[0166] The objective function is to find the minimum sum of squares of the differences between the actual conversion efficiency and the fitted conversion efficiency. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0167] Optionally, the parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following:

[0168] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0169] Optionally, the objective function is:

[0170]

[0171] The linear relationship function is:

[0172]

[0173] Among them, Efficiency i Vpfc represents the actual conversion efficiency of the DC-DC converter under the i-th operating condition. i Vo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let be the duty cycle of the i-th operating condition of the DC-DC converter, e(Vpfc,Vo,fs,Duty) be the fitted conversion efficiency, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0174] Optionally, the predicted output current module 604 is specifically used for:

[0175] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitted conversion efficiency is obtained.

[0176] Based on the input current, input voltage, and fitted conversion efficiency of the DC-DC converter without a secondary current sensor, the converted power is determined, and the output current is predicted based on the converted power and output voltage.

[0177] Based on the same inventive concept, this application also provides a device for determining the output current of a DC-DC converter, such as... Figure 7 As shown, the device includes:

[0178] The actual output current acquisition module 701 is used to acquire the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same.

[0179] The actual error acquisition module 702 is used to determine the estimated output current of the DC-DC converter under different operating conditions based on the preset conversion efficiency, and to determine the actual error between the actual output current and the estimated output current under different operating conditions of the DC-DC converter.

[0180] The fitting module 703 is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables, and the error between the actual output current and the estimated output current as output variables. Using the parameters and actual error under different operating conditions of the DC-DC converter, it fits a linear relationship function of the output variable based on the input variables.

[0181] The output current prediction module 704 is used to obtain the predicted output current based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current.

[0182] Optionally, the fitting module 703 is specifically used for:

[0183] Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved;

[0184] Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitting error is obtained;

[0185] The objective function is to minimize the sum of squares of the differences between the actual error and the fitted error. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

[0186] Optionally, the parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following:

[0187] The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

[0188] Optionally, the objective function is:

[0189]

[0190] The linear relationship function is:

[0191]

[0192] Among them, dio i Vpfc represents the actual error of the i-th operating condition corresponding to the DC-DC converter. i Vo is the input voltage for the i-th operating condition of the DC-DC converter. i fs is the reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. i Duty is the switching frequency of the DC-DC converter in the i-th operating condition. i Let i be the duty cycle of the i-th operating condition of the DC-DC converter, i(Vpfc, Vo, fs, Duty) be the fitting error, a, b, c, d be the coefficients, and e be a constant; where n is the number of operating conditions of the DC-DC converter.

[0193] Optionally, the output current prediction module 704 is specifically used for:

[0194] Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitting error is obtained.

[0195] Based on the preset conversion efficiency, the estimated output current is determined according to the input current, input voltage, and output voltage of the DC-DC converter without a secondary current sensor.

[0196] The output current value is predicted based on the estimated output current and the fitting error value.

[0197] Example 3

[0198] Based on the same inventive concept, this application also provides a system for determining the output current of a DC-DC converter, such as... Figure 8 As shown, the system includes:

[0199] DC-DC converter 801;

[0200] The detection module 802 is used to collect parameters in the circuit of the DC-DC converter that affect the conversion efficiency of the DC-DC converter;

[0201] The calculation module 803 is used to obtain the predicted output current based on the fitted linear relationship function;

[0202] The host computer module 804 is used to display the power information of the DC-DC converter;

[0203] The linear relationship function is obtained by fitting a linear relationship function derived from the input variables and the actual conversion efficiency under different operating conditions of the DC-DC converter, using the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the actual conversion efficiency as output variables; or

[0204] The linear relationship function is obtained by fitting a linear relationship function obtained by solving the output variable based on the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions, using the parameters and actual error corresponding to the DC-DC converter under different operating conditions as input variables and the error between the actual output current and the predicted output current as output variables.

[0205] The linear relationship function in this application can be pre-fitted, and the fitted relationship can be sent to the calculation module. After the calculation module collects the parameters from the detection module, it can directly calculate based on the fitted relationship curve. Alternatively, the fitting process can be directly executed by the calculation module.

[0206] Specifically, the DC-DC converter includes one or more phase-interleaved full-bridge and half-bridge DC-DC circuits. If it is an N-phase interleaved DC-DC circuit (N is an integer greater than 1), the first phase is called the main phase, and the other phases are sequentially called slave phase 1...slave phase N-1. The DC-DC converter includes a DC-DC primary-side high-frequency power transistor and a DC-DC secondary-side high-frequency power transistor. The DC-DC primary-side high-frequency power transistor used in this application can be a GaN (gallium nitride) MOSFET, a SiC (silicon carbide) MOSFET, or a Si (silicon) MOSFET; the DC-DC secondary-side high-frequency power transistor can be a GaN (gallium nitride) MOSFET, a SiC (silicon carbide) MOSFET, a Si (silicon) MOSFET, or a Si (silicon) or SiC (silicon carbide) diode.

[0207] Having described the method and apparatus for determining the output current of a DC-DC converter according to exemplary embodiments of this application, we will now describe an electronic device according to another exemplary embodiment of this application.

[0208] Those skilled in the art will understand that various aspects of this application can be implemented as a system, method, or program product. Therefore, various aspects of this application can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, collectively referred to herein as a "circuit," "module," or "system."

[0209] In some possible implementations, the electronic device according to this application may include at least one processor and at least one memory. The memory stores program code that, when executed by the processor, causes the processor to perform the steps in the method for determining the output current of a DC-DC converter according to various exemplary embodiments of this application described above.

[0210] The following reference Figure 9 To describe the electronic device 130 according to this embodiment of the present application, namely the device for determining the output current of the DC-DC converter described above. Figure 9 The electronic device 130 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0211] like Figure 9 As shown, the electronic device 130 is presented in the form of a general-purpose electronic device. The components of the electronic device 130 may include, but are not limited to: at least one processor 131, at least one memory 132, and a bus 133 connecting different system components (including memory 132 and processor 131).

[0212] Bus 133 represents one or more of several bus structures, including a memory bus or memory controller, peripheral bus, processor, or local bus using any of the various bus structures.

[0213] The memory 132 may include a readable medium in the form of volatile memory, such as random access memory (RAM) 1321 and / or cache memory 1322, and may further include read-only memory (ROM) 1323.

[0214] The memory 132 may also include a program / utility 1325 having a set (at least one) of program modules 1324, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0215] Electronic device 130 can also communicate with one or more external devices 134 (e.g., keyboard, pointing device, etc.), and with one or more devices that enable a user to interact with electronic device 130, and / or with any device that enables electronic device 130 to communicate with one or more other electronic devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 135. Furthermore, electronic device 130 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 136. As shown, network adapter 136 communicates with other modules used in electronic device 130 via bus 133. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 130, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0216] In some possible implementations, various aspects of the temperature prediction model training and temperature decision method provided in this application can also be implemented in the form of a program product, which includes program code that, when the program product is run on a computer device, causes the computer device to perform the steps of a method for determining the output current of a DC-DC converter according to various exemplary embodiments of this application as described above.

[0217] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0218] The monitoring program product of the embodiments of this application may employ a portable compact disc read-only memory (CD-ROM) and include program code, and may run on an electronic device. However, the program product of this application is not limited thereto. In this document, the readable storage medium may be any tangible medium that contains or stores a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0219] A readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying readable program code. This propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0220] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0221] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's electronic device, partially on the user's device, as a standalone software package, partially on the user's electronic device and partially on a remote electronic device, or entirely on a remote electronic device or server. In cases involving remote electronic devices, the remote electronic device can be connected to the user's electronic device via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external electronic device (e.g., via the Internet using an Internet service provider).

[0222] It should be noted that although several units or sub-units of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units.

[0223] Furthermore, although the operations of the method of this application are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0224] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0225] This application is described with reference to flowchart illustrations and block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block and / or block in the flowchart illustrations and block diagrams, as well as combinations of blocks and processes in the flowchart illustrations and block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0226] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and boxes Figure 1 The function specified in one or more boxes.

[0227] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and boxes Figure 1 The steps of the function specified in one or more boxes.

[0228] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0229] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for determining the output current of a DC-DC converter, characterized in that, The method includes: Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same. The actual conversion efficiency is obtained based on the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions are used as input variables, and the corresponding actual conversion efficiency is used as output variables. Using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter, a linear relationship function of the output variable is fitted based on the input variables. Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the predicted output current is obtained.

2. The method according to claim 1, characterized in that, Using the parameters and actual conversion efficiency of the DC-DC converter under different operating conditions, a linear relationship function is fitted based on the input variables to solve for the output variables, including: Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved; Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitted conversion efficiency is obtained; The objective function is to find the minimum sum of squares of the differences between the actual conversion efficiency and the fitted conversion efficiency. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

3. The method according to claim 2, characterized in that, The parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following: The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

4. The method according to claim 3, characterized in that, The objective function is: Min( ) The linear relationship function is: ； in, This represents the actual conversion efficiency of the DC-DC converter under the i-th operating condition. Let be the input voltage for the i-th operating condition of the DC-DC converter. The reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. Let be the switching frequency of the DC-DC converter in the i-th operating condition. Let be the duty cycle of the i-th operating condition of the DC-DC converter. For the fitted conversion efficiency, a, b, c, and d are the coefficients, and e is a constant; where n is the number of DC-DC converter operating conditions.

5. The method according to claim 1, characterized in that, Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the predicted output current is obtained as follows: Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitted conversion efficiency is obtained. Based on the input current, input voltage, and fitted conversion efficiency of the DC-DC converter without a secondary current sensor, the converted power is determined, and the output current is predicted based on the input power, conversion efficiency, and output voltage.

6. A method for determining the output current of a DC-DC converter, characterized in that, The method includes: Obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same. Based on the preset conversion efficiency, determine the estimated output current of the DC-DC converter under different operating conditions, and determine the actual error between the actual output current and the estimated output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions are used as input variables, and the error between the actual output current and the estimated output current is used as output variables. Using the parameters and actual error under different operating conditions of the DC-DC converter, a linear relationship function of the output variable is fitted based on the input variables. Based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current, the predicted output current is obtained.

7. The method according to claim 6, characterized in that, Using the parameters and actual errors of the DC-DC converter under different operating conditions, a linear relationship function is fitted based on the input variables to solve for the output variables, including: Construct a linear relationship function expression that solves for the output variable based on the input variable, wherein the linear relationship function expression includes the coefficients of each parameter to be solved; Substituting the parameters corresponding to different operating conditions of the DC-DC converter into the above linear relationship function expression, the fitting error is obtained; The objective function is to minimize the sum of squares of the differences between the actual error and the fitted error. The coefficients of the linear relationship function expression are then solved using the least squares method to obtain the linear relationship function.

8. The method according to claim 7, characterized in that, The parameters affecting the conversion efficiency of the DC-DC converter include at least one of the following: The input voltage of the DC-DC converter, the reciprocal of the output voltage, the switching frequency used in the drive circuit, and the duty cycle of the switching signal used in the drive circuit.

9. The method according to claim 8, characterized in that, The objective function is: Min( ); The linear relationship function is: ； in, This represents the actual error for the i-th operating condition corresponding to the DC-DC converter. Let be the input voltage for the i-th operating condition of the DC-DC converter. The reciprocal of the output voltage of the DC-DC converter under the i-th operating condition. Let be the switching frequency of the DC-DC converter in the i-th operating condition. Let be the duty cycle of the i-th operating condition of the DC-DC converter. The fitting error is represented by coefficients a, b, c, and d, and e is a constant; where n is the number of DC-DC converter operating conditions.

10. The method according to claim 6, characterized in that, Based on the fitted linear relationship function, and the parameter values ​​and estimated output current of the DC-DC converter without a secondary current sensor, the predicted output current is obtained, including: Based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor, the fitting error is obtained. Based on the preset conversion efficiency, the estimated output current is determined according to the input current, input voltage, and output voltage of the DC-DC converter without a secondary current sensor. The output current value is predicted based on the estimated output current and the fitting error.

11. A device for determining the output current of a DC-DC converter, characterized in that, The device includes: The module for obtaining actual output current is used to obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same. The module for obtaining actual conversion efficiency is used to obtain the corresponding actual conversion efficiency based on the actual output current of the DC-DC converter under different operating conditions. The fitting module is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the corresponding actual conversion efficiency as output variables. It fits a linear relationship function of the output variable based on the input variables using the parameters and actual conversion efficiency under different operating conditions of the DC-DC converter. The predicted output current module is used to obtain the predicted output current based on the fitted linear relationship function and the parameter values ​​of the DC-DC converter without a secondary current sensor.

12. A device for determining the output current of a DC-DC converter, characterized in that, The device includes: The module for obtaining actual output current is used to obtain the actual output current of the DC-DC converter under different operating conditions. The parameters affecting the conversion efficiency of the DC-DC converter are not entirely the same. The actual error acquisition module is used to determine the estimated output current of the DC-DC converter under different operating conditions based on the preset conversion efficiency, and to determine the actual error between the actual output current and the estimated output current under different operating conditions of the DC-DC converter. The fitting module is used to take the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables, and the error between the actual output current and the estimated output current as output variables. Using the parameters and actual error corresponding to the DC-DC converter under different operating conditions, it fits a linear relationship function of the output variable based on the input variables. The output current prediction module is used to obtain the predicted output current based on the fitted linear relationship function, the parameter values ​​of the DC-DC converter without a secondary current sensor, and the estimated output current.

13. An electronic device, characterized in that, The method includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method as described in any one of claims 1-5, or to perform the method as described in any one of claims 6-10.

14. A system for determining the output current of a DC-DC converter, characterized in that, The system includes: DC-DC converter; The detection module is used to collect parameters in the circuit of the DC-DC converter that affect the conversion efficiency of the DC-DC converter; The calculation module is used to obtain the predicted output current based on the fitted linear relationship function; The host computer module is used to display the power information of the DC-DC converter; The linear relationship function is obtained by fitting a linear relationship function derived from the input variables and the actual conversion efficiency under different operating conditions of the DC-DC converter, using the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions as input variables and the actual conversion efficiency as output variables; or The linear relationship function is obtained by fitting a linear relationship function obtained by solving the output variable based on the parameters affecting the conversion efficiency of the DC-DC converter under different operating conditions, using the parameters and actual error corresponding to the DC-DC converter under different operating conditions as input variables and the error between the actual output current and the predicted output current as output variables.

Images