Converter inductance correction method and converter

Abstract

The invention discloses a converter inductance correction method and a converter, and belongs to the technical field of electric power. The converter inductance correction method comprises the following steps: controlling the secondary side bridge arm circuit and the secondary side of the transformer to form a loop; controlling the primary bridge arm circuit to provide an excitation power supply for the transformer; under the condition of transformer excitation, obtaining an actually measured peak current of the inductor to be measured; and correcting an expected inductance value of the inductor to be measured according to the actually measured peak current and the expected peak current to obtain an actual inductance value. A loop is constructed for an impedance unit by controlling the on-off combination of a secondary-side bridge arm circuit of the converter, then a primary-side bridge arm circuit is controlled in an open-loop manner, an excitation power supply is provided for the impedance unit, an inductive current peak value of an inductive current under a steady-state condition is detected, correction is completed by combining a theoretical design value, and therefore, on the premise that no additional circuit is added, the design of the converter is simplified, and the cost is reduced. The inductance value correction is realized, the device can be conveniently integrated into the existing function test of a production line, the mass production quality of the converter is improved, and the production efficiency is not reduced.

Description

Technical Field

[0001] The present application belongs to the field of electric power technology, and in particular relates to a converter inductance correction method and a converter. Background Art

[0002] The control effect of the power converter is more dependent on the size of the inductor. Generally, the transformer leakage inductance is used as the equivalent series inductor, or as a discrete inductor. In mass production, the size of the inductor is discrete. The deviation of the actual inductance may cause the converter to lose soft switching, or the effective value of the inductor current increases, which reduces the reliability of the mass-produced power converter or makes the conversion efficiency unguaranteed. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a converter inductance correction method and a converter, which can realize inductance correction without adding additional circuits, facilitate integration into the existing functional test of the production line, improve the quality of converter mass production, and do not reduce production efficiency.

[0004] In a first aspect, the present application provides a converter inductance correction method, wherein the converter includes a transformer, a primary bridge arm circuit connected to the primary side of the transformer, and a secondary bridge arm circuit connected to the secondary side of the transformer, and the primary side or the secondary side of the transformer is provided with an inductance to be measured; the converter inductance correction method includes:

[0005] Control the secondary side bridge arm circuit to form a loop with the secondary side of the transformer;

[0006] Control the primary bridge arm circuit to provide excitation power to the transformer;

[0007] Under transformer excitation, obtain the measured peak current of the inductor to be measured;

[0008] The expected inductance value of the inductor to be measured is corrected according to the measured peak current and the expected peak current to obtain the actual inductance value.

[0009] According to an embodiment of the present application, the measured peak current is collected using an inductor current peak detection circuit, and the switching frequency of the primary bridge arm circuit when providing an excitation power supply is higher than the cutoff frequency of the inductor current peak detection circuit.

[0010] According to an embodiment of the present application, the inductor to be measured is also connected in series with a resonant capacitor, and the switching frequency of the primary bridge arm circuit when providing an excitation power supply is greater than the resonant frequency of the inductor to be measured and the resonant capacitor.

[0011] According to one embodiment of the present application, the loop includes an output capacitor on the output side of the secondary bridge arm circuit, and the switching frequency of the primary bridge arm circuit when providing excitation power is greater than the resonant frequency of the inductor to be measured and the output capacitor.

[0012] According to one embodiment of the present application, the expected peak current is determined based on the secondary-to-primary turns ratio of the transformer, the input side voltage of the primary bridge arm circuit, the positive or negative level duty cycle of the excitation power supply, the switching frequency of the primary bridge arm circuit when providing the excitation power supply, and the expected inductance.

[0013] According to one embodiment of the present application, the duty cycle of the positive or negative level of the excitation power supply is 1.

[0014] According to an embodiment of the present application, the loop includes a short-circuit loop formed on the secondary side of the transformer, or the loop includes a loop in which the secondary side of the transformer is connected to an output capacitor on the output side of the secondary side bridge arm circuit.

[0015] According to one embodiment of the present application, the secondary bridge arm circuit includes a half-bridge cycloidal conversion circuit or a full-bridge cycloidal conversion circuit, and the converter is a resonant type or a non-resonant type.

[0016] According to an embodiment of the present application, the inductor to be measured is a discrete inductor element, or the inductor to be measured is a leakage inductance of a transformer.

[0017] In a second aspect, the present application provides a converter, including a controller, a transformer, a primary bridge arm circuit connected to the primary side of the transformer, and a secondary bridge arm circuit connected to the secondary side of the transformer, the controller is connected to the primary bridge arm circuit and the secondary bridge arm circuit, and is configured to implement the converter inductance correction method described above.

[0018] According to the converter inductance correction method and converter of the present application, a loop is constructed for the impedance unit by controlling the on-off combination of the secondary bridge arm circuit of the converter, and then the primary bridge arm circuit is open-loop controlled to provide an excitation power supply for the impedance unit, and the peak value of the inductor current is detected in a steady state. The correction is completed in combination with the theoretical design value. Inductance correction can be achieved without adding additional circuits, which is convenient for integration into the existing functional tests of the production line, thereby improving the quality of mass production of converters without reducing production efficiency.

[0019] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 is one of the circuit topology diagrams of the converter provided in the embodiment of the present application;

[0022] Figure 2It is a flow chart of a converter inductance correction method provided in an embodiment of the present application;

[0023] Figure 3-Figure 6 is an equivalent circuit of the converter provided in the embodiment of the present application during calibration;

[0024] Figure 7 is a waveform diagram of the converter provided in an embodiment of the present application under a three-level excitation power supply;

[0025] Figure 8 is a waveform diagram of the converter provided in the embodiment of the present application under a two-level excitation power supply;

[0026] Fig. 9 This is the second circuit topology diagram of the converter provided in the embodiment of the present application;

[0027] Figure 10-Figure 19 Circuit topology diagram of the transformer and the primary-secondary bridge arm provided in the embodiment of the present application.

[0028] Reference numerals:

[0029] Primary bridge arm circuit 100, secondary bridge arm circuit 200, overcurrent protection circuit 300, transformer T, inductor to be measured L cal , resonant capacitor Cr, DC blocking capacitor Cb, output capacitor C0, sensor CT. DETAILED DESCRIPTION

[0030] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0031] In the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "coupled to" or "connected to" another element or an element / circuit is said to be "coupled to" or "connected to" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0032] In the description, the terms "first", "second", etc. are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the numerical descriptors used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0033] In addition, descriptions with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0034] The converter mentioned in this application can be applied to scenarios such as new energy photovoltaic, energy storage or charging. In the converter, inductance or inductance plus capacitance is the key main power parameter, through a phase-shifted non-resonant design based on inductor volt-second balance, or a phase-shifted frequency modulation resonant design based on inductance plus capacitance. Reasonable parameter design can realize the soft switching design of the switch tube and the optimization of the effective value of the inductor current, ensuring the power factor of the grid-connected current while meeting the high conversion efficiency of the converter.

[0035] The control effect of the power converter is more dependent on the size of the inductor, which can be equivalent to the transformer leakage inductance or a discrete inductor. The size of the inductance will affect the slope of the inductor current during the switching cycle, and then affect the size of the switch tube turn-off current, the size of the freewheeling current in the dead zone of the switch tube, the size of the effective value of the inductor current, and the instantaneous value of the grid-connected current, which plays a key role in the converter reliability, conversion efficiency, grid-connected current harmonic components and other performance requirements.

[0036] In mass production, the magnitude of the inductance is somewhat discrete, and is generally normally distributed, and its tolerance range needs to be considered, such as + / -5%, + / -10%. Although a sufficiently large design margin can be left to ensure that all converters can achieve soft switching within the tolerance range of the inductance to ensure its reliability, for converters with appropriate inductance (i.e., not far from the nominal value of the inductance), an excessively large soft switching design margin makes the effective value of the inductor current too large, increases the conduction loss, and sacrifices a certain conversion efficiency. Therefore, the deviation of the actual inductance may cause the converter to lose soft switching, or the effective value of the inductor current increases, which reduces the reliability of mass-produced power converters or makes the conversion efficiency impossible to guarantee.

[0037] To this end, the present application proposes a converter inductance correction method and a converter, which constructs a loop for an impedance unit by controlling the on-off combination of the secondary bridge arm circuit of the converter, and then open-loop controls the primary bridge arm circuit to provide an excitation power supply for the impedance unit, detects the peak value of the inductor current in a steady state, and completes the correction in combination with the theoretical design value. Inductance correction can be achieved without adding additional circuits, which is convenient for integration into the existing functional tests of the production line, thereby improving the quality of mass production of converters without reducing production efficiency.

[0038] Reference Figure 1 , Figure 1 The circuit topology of a converter is shown. The converter includes a transformer T, a primary bridge arm circuit 100 connected to the primary side of the transformer T, and a secondary bridge arm circuit 200 connected to the secondary side of the transformer T. The primary side or the secondary side of the transformer T is provided with an inductor L to be measured. cal The inductor to be measured is L cal It can be equivalent to the leakage inductance of the transformer T, or a discrete inductor component.

[0039] The converter can be resonant or non-resonant. In a resonant converter, the inductor to be measured L cal There is a resonant capacitor Cr in series; in a non-resonant converter, there is no resonant capacitor Cr, but the inductor to be measured L cal A DC blocking capacitor Cb is connected in series. Among them, the capacitance of the resonant capacitor Cr is often small, and the capacitance of the DC blocking capacitor Cb is often large.

[0040] Usually, a sensor CT is provided on the secondary side of the transformer T. The sensor CT is connected to a detection circuit at the rear stage to monitor the converter. For example, the converter includes an overcurrent protection circuit 300, and the output end of the sensor CT is connected to the overcurrent protection circuit 300 through a rear stage processing circuit. The detection value of the sensor CT can obtain a current peak value after being processed by the rear stage circuit, and the overcurrent protection circuit 300 implements overcurrent protection according to the current peak value. The converter can also be configured with other functional circuits to utilize the detection value of the sensor CT, which is not limited in this embodiment.

[0041] Reference Figure 2 , Figure 2 The flow chart of a converter inductance correction method is shown in FIG. 1 . An embodiment of the present application proposes a converter inductance correction method. In this embodiment, Figure 1 Taking the converter shown in FIG. 1 as an example, the converter inductance correction method includes step 10, step 20, step 30 and step 40.

[0042] Step 10, controlling the secondary side bridge arm circuit and the secondary side of the transformer to form a loop;

[0043] Step 20, controlling the primary bridge arm circuit to provide excitation power to the transformer;

[0044] Step 30, when the transformer is excited, obtaining the measured peak current of the inductor to be measured;

[0045] Step 40: Correct the expected inductance value of the inductor to be measured according to the measured peak current and the expected peak current to obtain the actual inductance value.

[0046] exist Figure 1 In the circuit topology shown, the converter may further include a controller (not shown in the figure), which is connected to the primary bridge arm circuit 100 and the secondary bridge arm circuit 200 to control the switch tube actions in the primary bridge arm circuit 100 and the secondary bridge arm circuit 200. The controller may also be connected to the overcurrent protection circuit 300 to obtain the current peak value obtained after the detection value of the sensor CT is processed by the subsequent circuit. The execution subject of the converter inductance correction method mentioned in this embodiment may be the controller.

[0047] When implementing the converter inductance correction method, the input side of the primary bridge arm circuit 100 can be connected to a power supply (such as a DC source), and the controller controls the switch tube in the primary bridge arm circuit 100 to switch on and off at a certain frequency to form an excitation power supply. During the correction process, the frequency of the excitation power supply is fixed to keep the current stable. The excitation power supply can be a two-level voltage source or a three-level voltage source. The secondary side of the transformer T generates current under the action of the excitation power supply. Since the secondary side bridge arm circuit 200 forms a loop with the secondary side of the transformer T, the current flows from the secondary winding of the transformer T to the secondary side bridge arm circuit 200, and then flows back to the secondary winding.

[0048] Reference Figure 3-Figure 6 , Figure 3 and Figure 4 The equivalent circuit of the non-resonant converter is shown; Figure 5 and Figure 6 The equivalent circuit of the resonant converter is shown; Figure 3 and Figure 5 The equivalent circuit without output capacitor C0 is shown; Figure 4 and Figure 6 When implementing the converter inductance correction method, the converter can be formed as follows: Figure 3-Figure 6 Any equivalent circuit in .

[0049] The output capacitor C0 is usually arranged at the output side of the secondary bridge arm circuit 200, and the input side of the secondary bridge arm circuit 200 is connected to the secondary side of the transformer T. The output capacitor C0 is used to maintain the output stability of the secondary bridge arm circuit 200 when the converter works normally.

[0050] In some embodiments, the secondary bridge arm circuit 200 includes a half-bridge cyclic conversion circuit or a full-bridge cyclic conversion circuit. In an equivalent circuit without output capacitor C0, the switch tube in the secondary bridge arm circuit 200 is turned on, so that the two ends of the secondary winding of the transformer T are short-circuited. In an equivalent circuit with output capacitor C0, the switch tube in the secondary bridge arm circuit 200 is turned off, so that the two ends of the secondary winding of the transformer T are connected through the output capacitor C0.

[0051] The measured peak current of the inductor to be tested can use this overcurrent detection circuit, so that the output signal of the conditioning circuit reflects the peak value of the inductor current. Figure 1 For example, the output current of the sensor CT is rectified by diodes D11 to D14, forming a voltage signal on the resistor R11, which is filtered by the resistor R12 and the capacitor C11, amplified by the operational amplifier Amp11 and R13, R14, and finally outputs a DC signal to the overcurrent protection circuit 300. The controller can obtain the DC signal to measure the inductance L cal The measured peak current.

[0052] During the production process of the converter, the inductor L to be tested cal Usually there is a corresponding inductance design value. The expected peak current refers to the inductance L to be measured under the same excitation power supply in the above equivalent circuit. cal The expected measured peak current of the inductor to be measured with the designed inductance value. The controller can store the expected measured peak current, and then combine it with the actual measured peak current obtained by acquiring the DC signal to obtain the deviation value of the measured peak current. Then, the designed inductance value is corrected based on the deviation value to obtain the actual inductance value. The converter can substitute the obtained actual inductance value and correct the control parameters, so that each converter can obtain a suitable soft switching margin, and the converters produced in batches can take into account both reliability and conversion efficiency.

[0053] In some embodiments, the expected peak current is determined based on the secondary-to-primary turns ratio of the transformer T, the input side voltage of the primary bridge arm circuit 100, the positive or negative level duty cycle of the excitation power supply, the switching frequency of the primary bridge arm circuit 100 when providing the excitation power supply, and the expected inductance.

[0054] In the non-resonant converter, the impedance unit is the inductor L to be corrected. cal (or inductance L cal And the DC blocking capacitor Cb, Cb has a large capacitance, and Cb and L cal The oscillation effect of the sensor CT can be ignored). The output current peak value of the sensor CT can be calculated according to the following formula:

[0055] I CT_output_pk =n T *U in *D*n CT / (4f sw L cal )

[0056] Among them, n T is the turns ratio of the secondary side to the primary side of the transformer T, U in is the DC input voltage of the converter, D is the duty cycle of the positive or negative level of the excitation voltage source formed by the primary wave (related to the phase shift angle between the primary bridge arms, when D = 1, the excitation voltage source changes from three levels to two levels), n CT is the turns ratio of the sensor CT, f sw is the primary side switching frequency, L cal is the inductance to be measured.

[0057] by Figure 1 Taking the circuit topology shown in the figure as an example, the DC signal output by the operational amplifier Amp11 is proportional to the peak value of the CT output current and inversely proportional to the inductance Lcal. T 、n CT It is a fixed value designed for hardware, input voltage Uin , duty cycle D and primary wave switching frequency f sw It is a fixed value controlled during calibration. Therefore, the ratio of the actual inductance of the inductor Lcal to the designed median inductance can be obtained by calculating the ratio of the ADC value obtained by the output of the operational amplifier Amp11 to the expected ADC value. The formula is as follows:

[0058] Lcal=L designed *ADC expected / ADC measured

[0059] Among them, Lcal is the actual sense value, L designed is the design value of inductance, ADC expected is the expected peak current, ADC measured is the measured peak current.

[0060] In some embodiments, the duty cycle of the positive or negative level of the excitation power supply is 1.

[0061] When the positive or negative level duty cycle D of the excitation power supply is equal to 1, the excitation power supply is a two-level power supply; when the positive or negative level duty cycle D of the excitation power supply is not equal to 1, the excitation power supply is a three-level power supply.

[0062] Reference Figure 7 and Figure 8 , Figure 7 shows a waveform corresponding to a three-level excitation power supply, Figure 8 1 shows a waveform diagram corresponding to a two-level excitation power supply. In the figure, the horizontal axis t represents time, the vertical axis S1-S8 represents the drive signal of each switch tube in the full bridge circuit as the primary bridge arm circuit 100, Uin represents the input side voltage of the primary bridge arm circuit 100, and i Lcal represents the inductor current, and Amp_output to ADC represents the output voltage of the operational amplifier. As can be seen from the figure, when the excitation power supply is two-level, the waveform of the inductor current is simpler and the absolute value of its slope is the same. Therefore, when the excitation power supply adopts two levels, the detection of the inductor current is simpler, which is conducive to improving the detection accuracy.

[0063] In some embodiments, the measured peak current is collected using an inductor current peak detection circuit, and the switching frequency of the primary bridge arm circuit 100 when providing an excitation power supply is higher than the cutoff frequency of the inductor current peak detection circuit.

[0064] The inductor current peak detection circuit can be the sensor CT and the subsequent circuit as mentioned above. The inductor current peak detection circuit is usually used to realize converter detection, which can be connected to the input end of the overcurrent protection circuit 300. Since the inductor current peak detection circuit is usually an existing circuit of the converter, no additional circuit needs to be added when implementing the converter inductance correction method. For example, the converter inductance correction method can be deployed in the existing PCBA functional test FCT (Functional Circuit Test) of the production line. At this time, the inductor element has been paired with the controller and welded on the same circuit board, which is convenient for one-to-one correction. No additional binding work is required, which is convenient for production management; accurate correction is achieved and the precise inductance measurement of the incoming inductance is avoided one by one, which improves the quality of mass production without reducing production efficiency.

[0065] Reference Fig. 9 , Fig. 9 Another converter circuit topology is shown. This embodiment proposes another example of an inductor current peak detection circuit. In this example, the output current of the sensor CT is rectified by diodes D21 and D22, forming a voltage signal on the resistor R21, which is filtered by the resistor R22 and the capacitor C21, and then amplified by the operational amplifier Amp21 and R23, R24, and finally outputs a DC signal to the overcurrent protection circuit 300. Figure 1 In comparison, the working principles are similar, except that the sensor CT output rectification circuit is different.

[0066] It can be understood that the switching frequency of the primary bridge arm circuit 100 when providing the excitation power source affects the frequency of the inductor current. When the cutoff frequency of the inductor current peak detection circuit is lower than the switching frequency, the capacitor in the inductor current peak detection circuit is easily filled with the peak current signal, and when the current signal decreases, the capacitor voltage attenuates very little, which facilitates the conversion of the high-frequency inductor current signal into a stable DC signal for ADC conversion and correction calculation, thereby improving the detection accuracy.

[0067] In some embodiments, the inductor to be measured L cal A resonant capacitor Cr is also connected in series. The switching frequency of the primary bridge arm circuit 100 when providing the excitation power supply is greater than the inductor L to be measured. cal And the resonant frequency of the resonant capacitor Cr.

[0068] In this embodiment, the converter is a resonant converter. Compared with the non-resonant converter, the inductor to be measured L cal There is resonance between the inductor and the resonant capacitor Cr, which has a certain influence on the waveform of the inductor current. During correction, the switching frequency f of the primary side wave sw Need to be much higher than the inductor L cal Resonant frequency with capacitor Cr The inductor current shape tends to be a non-resonant piecewise straight line, making the capacitance Cr have a significant effect on the inductance L. cal The effect of the correction is small.

[0069] In some embodiments, the loop includes an output capacitor C0 at the output side of the secondary bridge arm circuit 200, and the switching frequency of the primary bridge arm circuit 100 when providing the excitation power supply is greater than the inductor L to be measured. cal and the resonant frequency of the output capacitor C0.

[0070] In this embodiment, the output capacitor C0 is connected to the equivalent circuit. Due to its large capacitance, its natural frequency is the same as that of the inductor Lcal. Very low, the switching frequency fsw of the primary side wave during correction must be much higher than f0' to ensure that the output capacitor C0 does not affect the correction result. In addition, the grid-connected contactor on the AC side of the converter needs to be disconnected to ensure that the grid voltage is not connected to C0 and the correction process is not affected by the grid voltage.

[0071] Continue to refer to Figure 3-Figure 6 ,like Figure 3 In the equivalent circuit shown, the condition can be satisfied: f sw >>f filter ;like Figure 4 In the equivalent circuit shown, the condition can be satisfied: f sw >>f filter And f sw >>f0'; Figure 5 In the equivalent circuit shown, the condition can be satisfied: f sw >>f filter And f sw >>f0; Figure 6 In the equivalent circuit shown, the condition f can be satisfied sw >>f filter And f sw >>f0 and f sw >>f0' (Since f0>>f0', it is naturally satisfied).

[0072] An embodiment of the present application further provides a converter, the converter comprising a controller, a transformer T, a primary bridge arm circuit 100 connected to the primary side of the transformer T, and a secondary bridge arm circuit 200 connected to the secondary side of the transformer T, the controller is connected to the primary bridge arm circuit 100 and the secondary bridge arm circuit 200, and is configured to implement the converter inductance correction method according to the above. The specific process of the converter inductance correction method can refer to the above embodiments, which also have corresponding technical effects, and this embodiment will not be repeated here.

[0073] Reference Figure 10-Figure 19 , Figure 10-Figure 191 and 2 show a converter circuit topology. In each figure, the primary bridge arm circuit 100 is a full-bridge circuit. Figure 10-15 The secondary bridge arm circuit 200 is a half-bridge circuit. Since the half-bridge circuit requires a capacitor for DC isolation, the figures can be divided into a resonant converter including a resonant capacitor Cr or a non-resonant converter including a DC isolation capacitor Cb based on the capacitance of the capacitor C. Figure 16-Figure 19 The secondary bridge arm circuit 200 in the embodiment is a full-bridge circuit, which does not require capacitor isolation. Fig.16 and Fig.18 is a resonant converter including a resonant capacitor Cr, Fig.17 and Fig.19 It is a capacitor-free non-resonant converter. Fig.10 , Fig.12 , Fig.14 , Fig.16 and Fig.17 The inductor to be measured L cal Located on the secondary side of transformer T, Fig.11 , Fig.13 , Fig.15 , Fig.18 and Fig.19 The inductor to be measured L cal Located on the primary side of transformer T.

[0074] In this article, the term "comprises", "includes" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be noted that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0075] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for correcting converter inductance, characterized in that: The converter includes a transformer, a primary bridge arm circuit connected to the primary side of the transformer, and a secondary bridge arm circuit connected to the secondary side of the transformer, and the primary side or the secondary side of the transformer is provided with an inductance to be measured; the converter inductance correction method includes: Controlling the secondary bridge arm circuit to form a loop with the secondary side of the transformer; Controlling the primary bridge arm circuit to provide excitation power to the transformer; When the transformer is excited, obtaining the measured peak current of the inductor to be measured; The expected inductance value of the inductor to be measured is corrected according to the measured peak current and the expected peak current to obtain an actual inductance value.

2. The converter inductance correction method according to claim 1, characterized in that: The measured peak current is collected by an inductor current peak detection circuit, and the switching frequency of the primary bridge arm circuit when providing the excitation power supply is higher than the cutoff frequency of the inductor current peak detection circuit.

3. The converter inductance correction method according to claim 2, characterized in that: The inductor to be measured is also connected in series with a resonant capacitor, and the switching frequency of the primary bridge arm circuit when providing the excitation power supply is greater than the resonant frequency of the inductor to be measured and the resonant capacitor.

4. The converter inductance correction method according to claim 2, characterized in that: The loop includes an output capacitor at the output side of the secondary bridge arm circuit, and a switching frequency of the primary bridge arm circuit when providing the excitation power supply is greater than a resonant frequency of the inductor to be measured and the output capacitor.

5. The converter inductance correction method according to any one of claims 1 to 4, characterized in that: The expected peak current is determined based on the secondary-to-primary turns ratio of the transformer, the input side voltage of the primary bridge arm circuit, the positive or negative level duty cycle of the excitation power supply, the switching frequency of the primary bridge arm circuit when providing the excitation power supply, and the expected inductance.

6. The converter inductance correction method according to claim 4, characterized in that: The positive or negative level duty cycle of the excitation power supply is 1.

7. The converter inductance correction method according to any one of claims 1 to 4, characterized in that: The loop includes a short-circuit loop formed on the secondary side of the transformer, or the loop includes a loop in which the secondary side of the transformer is connected to an output capacitor on the output side of the secondary side bridge arm circuit.

8. The converter inductance correction method according to any one of claims 1 to 4, characterized in that: The secondary bridge arm circuit includes a half-bridge cyclic conversion circuit or a full-bridge cyclic conversion circuit, and the converter is a resonant type or a non-resonant type.

9. The converter inductance correction method according to any one of claims 1 to 4, characterized in that: The inductor to be measured is a discrete inductor element, or the inductor to be measured is a leakage inductance of the transformer.

10. A converter, characterized in that: It includes a controller, a transformer, a primary bridge arm circuit connected to the primary side of the transformer, and a secondary bridge arm circuit connected to the secondary side of the transformer, the controller is connected to the primary bridge arm circuit and the secondary bridge arm circuit, and is configured to implement the converter inductance correction method according to any one of claims 1-9.

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