Controllable current converter

Abstract

The invention, which belongs to the converter field, discloses a controllable current converter comprising a processor, a digital adjusting module, a voltage sampling resistor, a voltage conversion resistor, a first current transformer and a second current transformer. The processor is electrically connected with the digital adjusting module through the communication control end; the voltage sampling resistor is connected in series between secondary windings of the first current transformer; the voltage conversion resistor is connected in series between the secondary winding and the compensation winding of the first current transformer; the secondary winding and the compensation winding of the first current transformer are respectively connected with the output of the second current transformer in parallel; the primary head end of the second current transformer is connected with the digital adjusting module, and the primary tail end is connected with the common terminal potential. The processor is used for calculating an amplitude adjusting quantity and a phase adjusting quantity; and the digital adjusting module is used for controlling the amplitude of the output current and the phase of the output current according to the amplitude adjusting quantity and the phase adjusting quantity. Therefore, through the processor and the digital adjusting module, the problem that the accuracy of the current converter is not high can be solved.

Description

Technical Field

[0001] This invention relates to the field of converter technology, and in particular to a controllable current converter. Background Technology

[0002] Precise measurement of power and electrical energy based on quantum voltage relies on three key technologies: a quantum voltage generator, a precision voltage converter, and a precision current-to-voltage converter. The precision current-to-voltage converter typically employs a precision shunt or a precision current converter to transform a large current into a small current before converting it to voltage via a resistor. However, for large currents, precision shunts are very expensive, and achieving very high accuracy is difficult. Therefore, the current mainstream approach is to use a precision current converter to transform the large current into a small current before converting it to voltage via a resistor.

[0003] However, after the secondary current of the current converter is converted into voltage through a precision resistor, the inductance and distributed capacitance of the resistor itself, as well as the resistive load effect, will cause amplitude and phase errors, resulting in a decrease in the accuracy of the current converter. Summary of the Invention

[0004] This invention provides a controllable current converter that can solve the problem of low accuracy in existing current converters.

[0005] To solve the above-mentioned technical problems, the present invention provides a controllable current converter, comprising: a processor, a digital adjustment module, a voltage sampling resistor, a voltage transformation resistor, a first current transformer, and a second current transformer.

[0006] The communication control terminal of the digital adjustment module is electrically connected to the processor; the positive input terminal of the compensation voltage of the digital adjustment module is electrically connected to the second terminal of the voltage sampling resistor; the negative input terminal of the first compensation voltage of the digital adjustment module is electrically connected to the first terminal of the voltage sampling resistor; the negative input terminal of the second compensation voltage of the digital adjustment module is electrically connected to the tail terminal of the primary current transformer; and the output terminal of the compensation voltage of the digital adjustment module is electrically connected to the head terminal of the primary current transformer.

[0007] The first terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the second current transformer; the second terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the first current transformer.

[0008] The first terminal of the voltage conversion resistor is electrically connected to the secondary tail terminal of the second current transformer; the second terminal of the voltage conversion resistor is electrically connected to the first terminal of the voltage sampling resistor.

[0009] The secondary terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the second terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor.

[0010] The processor is used to calculate the amplitude adjustment amount based on the amplitude error of the output current of the current converter, and to calculate the phase adjustment amount based on the phase error of the output current of the current converter.

[0011] The digital adjustment module is used to control the output current amplitude of the current converter according to the amplitude adjustment amount, and to control the output current phase of the current converter according to the phase adjustment amount.

[0012] As a preferred embodiment, the digital adjustment module includes: a digital amplitude adjustment submodule and a digital phase adjustment submodule;

[0013] The communication control terminal of the digital amplitude adjustment submodule is the communication control terminal of the digital adjustment module; the positive compensation voltage input terminal of the digital amplitude adjustment submodule is the positive compensation voltage input terminal of the digital adjustment module; the first negative compensation voltage input terminal of the digital amplitude adjustment submodule is the first negative compensation voltage input terminal of the digital adjustment module; the second negative compensation voltage input terminal of the digital amplitude adjustment submodule is the second negative compensation voltage input terminal of the digital adjustment module; the compensation voltage output terminal of the digital amplitude adjustment submodule is the compensation voltage output terminal of the digital adjustment module.

[0014] The communication control terminal of the digital phase adjustment submodule is electrically connected to the communication control terminal of the digital amplitude adjustment submodule; the positive input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the positive input terminal of the compensation voltage of the digital amplitude adjustment submodule; the first negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the first negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; the second negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the second negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; and the compensation voltage output terminal of the digital phase adjustment submodule is electrically connected to the compensation voltage output terminal of the digital amplitude adjustment submodule.

[0015] As a preferred embodiment, the digital amplitude adjustment submodule includes: a digital amplitude regulator and a non-inverting compensation resistor;

[0016] The communication control terminal of the digital amplitude regulator is the communication control terminal of the digital amplitude regulation submodule;

[0017] The positive input terminal of the compensation voltage of the digital amplitude regulator is the positive input terminal of the compensation voltage of the digital amplitude regulation submodule;

[0018] The first compensation voltage negative input terminal of the digital amplitude regulator is the first compensation voltage negative input terminal of the digital amplitude regulation submodule;

[0019] The second compensation voltage negative input terminal of the digital amplitude regulator is the second compensation voltage negative input terminal of the digital amplitude regulation submodule;

[0020] The compensation voltage output terminal of the digital amplitude regulator is electrically connected to the first terminal of the in-phase compensation resistor;

[0021] The second terminal of the in-phase compensation resistor is the compensation voltage output terminal of the digital amplitude adjustment submodule.

[0022] As a preferred embodiment, the digital phase adjustment submodule includes: a digital phase adjuster and a quadrature compensation capacitor;

[0023] The communication control terminal of the digital phase adjuster is the communication control terminal of the digital phase adjustment submodule;

[0024] The positive input terminal of the compensation voltage of the digital phase adjuster is the positive input terminal of the compensation voltage of the digital phase adjustment submodule;

[0025] The first compensation voltage negative input terminal of the digital phase adjuster is the first compensation voltage negative input terminal of the digital phase adjustment submodule;

[0026] The second compensation voltage negative input terminal of the digital phase adjuster is the second compensation voltage negative input terminal of the digital phase adjustment submodule;

[0027] The compensation voltage output terminal of the digital phase adjuster is electrically connected to the first terminal of the quadrature compensation capacitor;

[0028] The second terminal of the quadrature compensation capacitor is the compensation voltage output terminal of the digital phase adjustment submodule.

[0029] As a preferred embodiment, the first current transformer includes a primary winding, a secondary winding, a compensating winding, a main core, and an auxiliary core.

[0030] The primary winding and the secondary winding are wound on the main iron core;

[0031] The auxiliary iron core is wound with the primary winding, the secondary winding, and the compensation winding.

[0032] As a preferred embodiment, the amplitude adjustment amount meets the following requirements:

[0033]

[0034] In the formula, ΔKp is the amplitude adjustment amount; R1 is the resistance value of the voltage sampling resistor; R3 is the resistance value of the in-phase compensation resistor; K T2 is the turns ratio of the second current transformer; ferr is the current amplitude error.

[0035] As a preferred embodiment, the phase adjustment amount meets the following requirements:

[0036]

[0037] In the formula, R1 is the phase adjustment value; C1 is the resistance value of the voltage sampling resistor; K is the capacitance value of the quadrature compensation capacitor; T2 The transformation ratio of the second current transformer is given; f is the frequency of the AC signal. This represents the current phase error.

[0038] As a preferred embodiment, the output current amplitude is determined based on the amplitude adjustment amount;

[0039] The formula for calculating the output current amplitude is:

[0040] Kp NEW =Kp+ΔKp

[0041] In the formula, Kp NEW Kp represents the amplitude of the output current; Kp represents the amplitude of the previous output current.

[0042] As a preferred embodiment, the output current phase is determined based on the phase adjustment amount;

[0043] Kφ NEW =Kφ+ΔKφ

[0044] In the formula, Kφ NEW Kφ is the phase of the output current; Kφ is the phase of the previous output current.

[0045] As a preferred embodiment, the output current amplitude error and the output current phase error are measured by a standard current-voltage converter.

[0046] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0047] This invention provides a controllable current converter, including a processor, a digital regulation module, a voltage sampling resistor, a voltage transformation resistor, a first current transformer, and a second current transformer. The processor is electrically connected to the digital regulation module via a communication control terminal. The voltage sampling resistor is connected in series between the secondary windings of the first current transformer. The voltage transformation resistor is connected in series between the secondary winding and the compensation winding of the first current transformer. The secondary winding and the compensation winding of the first current transformer are connected in parallel with the output of the second current transformer, respectively. The first terminal of the second current transformer is connected to the digital regulation module, and the last terminal is connected to a common potential. The processor is used to calculate the amplitude and phase regulation values. The digital regulation module is used to control the output current amplitude and phase based on the amplitude and phase regulation values. This invention incorporates a processor in the current converter, which can calculate the amplitude and phase regulation values ​​based on the output current amplitude error and the output current phase error. It also incorporates a digital regulator in the current converter, which can control the output current amplitude and phase based on the amplitude and phase regulation values, thereby reducing amplitude and phase errors and improving the accuracy of the current converter. Attached Figure Description

[0048] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments 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 from these drawings without creative effort.

[0049] Figure 1 A schematic diagram of one embodiment of the controllable current converter provided by the present invention;

[0050] Figure 2 A schematic diagram of another embodiment of the controllable current converter provided by the present invention;

[0051] Figure 3 This is a flowchart illustrating one embodiment of the current regulation method provided by the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0054] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0055] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0056] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0057] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0058] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0059] See Figure 1To address the problem of low accuracy in existing current converters, an embodiment of the present invention provides a controllable current converter, comprising: a processor, a digital adjustment module, a voltage sampling resistor, a voltage transformation resistor, a first current transformer, and a second current transformer.

[0060] The communication control terminal of the digital adjustment module is electrically connected to the processor; the positive input terminal of the compensation voltage of the digital adjustment module is electrically connected to the second terminal of the voltage sampling resistor; the negative input terminal of the first compensation voltage of the digital adjustment module is electrically connected to the first terminal of the voltage sampling resistor; the negative input terminal of the second compensation voltage of the digital adjustment module is electrically connected to the tail terminal of the primary current transformer; and the output terminal of the compensation voltage of the digital adjustment module is electrically connected to the head terminal of the primary current transformer.

[0061] The first terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the second current transformer; the second terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the first current transformer.

[0062] The first terminal of the voltage conversion resistor is electrically connected to the secondary tail terminal of the second current transformer; the second terminal of the voltage conversion resistor is electrically connected to the first terminal of the voltage sampling resistor.

[0063] The secondary terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the second terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor.

[0064] The processor is used to calculate the amplitude adjustment amount based on the amplitude error of the output current of the current converter, and to calculate the phase adjustment amount based on the phase error of the output current of the current converter.

[0065] The digital adjustment module is used to control the output current amplitude of the current converter according to the amplitude adjustment amount, and to control the output current phase of the current converter according to the phase adjustment amount.

[0066] The controllable current transformer of the present invention comprises a processor U1, a digital adjustment module, a voltage sampling resistor R1, a voltage transformation resistor R2, a first current transformer T1, and a second current transformer T2. The processor U1 is connected to the digital adjustment module via a communication control terminal SPI; the voltage sampling resistor R1 is connected in series between the secondary start terminal K1 and the secondary end terminal K2 of the secondary winding of the first current transformer T1; the voltage transformation resistor R2 is connected in series between the secondary winding K1K2 and the compensation winding B1B2 of the first current transformer T1; the secondary winding K1K2 and the compensation winding B1B2 of the first current transformer T1 are connected in parallel with the output of the second current transformer T2; the primary start terminal of the second current transformer T2 is connected to the digital adjustment module to realize the primary current injection, and the primary end terminal is connected to the common terminal potential.

[0067] Since the current converter needs to convert current into voltage at the secondary output, the secondary output current needs to be connected in series with the voltage conversion resistor R2. The voltage conversion resistor R2 can be set to about 50Ω to convert the secondary current into a precise voltage of about 1V.

[0068] Since secondary loads increase the error of current transformers, even high-precision resistors cannot completely avoid the influence of distributed inductance on phase error. To maintain stability, this invention connects the secondary windings K1 and K2 in series with a voltage sampling resistor R1. R1 can be set to 5Ω. The voltage across R1 is then adjusted via a digital adjustment module to regulate the output voltage. This adjusted current is injected into the second current transformer T2, and its output is connected in parallel to the voltage conversion resistor R2. This achieves digital adjustment of the errors in both the first current transformer T1 and the voltage conversion resistor R2.

[0069] The above digital adjustments are stored in non-volatile memory via a processor, ensuring retention even after power loss, thus realizing a digitally adjustable current converter.

[0070] Therefore, by incorporating a processor into the current converter, the amplitude adjustment amount can be calculated based on the output current amplitude error, and the phase adjustment amount can be calculated based on the output current phase error. Furthermore, by incorporating a digital adjustment module into the current converter, the output current amplitude can be controlled based on the amplitude adjustment amount, and the output current phase can be controlled based on the phase adjustment amount. Thus, by incorporating a processor and a digital adjustment module into the current converter, this invention effectively adjusts the current error, thereby improving the accuracy of the current converter.

[0071] In this embodiment of the invention, to improve the accuracy of the current converter, the processor U1 needs to have a computing power of not less than 1 MSPS, not less than two SPI serial interfaces, and not less than one UART communication interface. The first current transformer T1 needs to achieve an accuracy better than 5 ppm at 50 Hz. The second current transformer T2 needs to achieve an accuracy better than 0.1% at 50 Hz, and its turns ratio can be set to 50:1. The voltage sampling resistor R1 needs to achieve an accuracy better than 0.1%. The voltage conversion resistor R2 needs to achieve an accuracy of not less than 3 ppm.

[0072] As a preferred embodiment, the digital adjustment module includes: a digital amplitude adjustment submodule and a digital phase adjustment submodule;

[0073] The communication control terminal of the digital amplitude adjustment submodule is the communication control terminal of the digital adjustment module; the positive compensation voltage input terminal of the digital amplitude adjustment submodule is the positive compensation voltage input terminal of the digital adjustment module; the first negative compensation voltage input terminal of the digital amplitude adjustment submodule is the first negative compensation voltage input terminal of the digital adjustment module; the second negative compensation voltage input terminal of the digital amplitude adjustment submodule is the second negative compensation voltage input terminal of the digital adjustment module; the compensation voltage output terminal of the digital amplitude adjustment submodule is the compensation voltage output terminal of the digital adjustment module.

[0074] The communication control terminal of the digital phase adjustment submodule is electrically connected to the communication control terminal of the digital amplitude adjustment submodule; the positive input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the positive input terminal of the compensation voltage of the digital amplitude adjustment submodule; the first negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the first negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; the second negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the second negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; and the compensation voltage output terminal of the digital phase adjustment submodule is electrically connected to the compensation voltage output terminal of the digital amplitude adjustment submodule.

[0075] In this embodiment of the invention, the digital adjustment module includes a digital amplitude adjustment submodule and a digital phase adjustment submodule. The digital amplitude adjustment submodule and the digital phase adjustment submodule are connected in parallel in the circuit. The digital amplitude adjustment submodule is used to adjust the amplitude of the output current, and the digital phase adjustment submodule is used to adjust the phase of the output current.

[0076] As a preferred embodiment, the digital amplitude adjustment submodule includes: a digital amplitude regulator and a non-inverting compensation resistor;

[0077] The communication control terminal of the digital amplitude regulator is the communication control terminal of the digital amplitude regulation submodule;

[0078] The positive input terminal of the compensation voltage of the digital amplitude regulator is the positive input terminal of the compensation voltage of the digital amplitude regulation submodule;

[0079] The first compensation voltage negative input terminal of the digital amplitude regulator is the first compensation voltage negative input terminal of the digital amplitude regulation submodule;

[0080] The second compensation voltage negative input terminal of the digital amplitude regulator is the second compensation voltage negative input terminal of the digital amplitude regulation submodule;

[0081] The compensation voltage output terminal of the digital amplitude regulator is electrically connected to the first terminal of the in-phase compensation resistor;

[0082] The second terminal of the in-phase compensation resistor is the compensation voltage output terminal of the digital amplitude adjustment submodule.

[0083] See Figure 2 This is a schematic diagram of another embodiment of the controllable current converter provided by the present invention. The digital amplitude adjustment submodule includes a digital amplitude regulator U2 and a non-in-phase compensation resistor R3. The compensation voltage output terminal of the digital amplitude regulator U2 is electrically connected to the first terminal of the non-in-phase compensation resistor R3 to realize the injection of non-in-phase current, thereby compensating for amplitude error.

[0084] In this embodiment of the invention, the digital amplitude regulator U2 can digitally set the ratio of the output voltage to the input voltage according to a ratio of -1ˉ0, 0ˉ+1; the digital amplitude regulator U2 can use a device with an accuracy of 0.1% and a resolution of 0.1%. The resistance value of the in-phase compensation resistor R3 can be set to 10kΩ, with an accuracy of not less than 0.1%.

[0085] As a preferred embodiment, the digital phase adjustment submodule includes: a digital phase adjuster and a quadrature compensation capacitor;

[0086] The communication control terminal of the digital phase adjuster is the communication control terminal of the digital phase adjustment submodule;

[0087] The positive input terminal of the compensation voltage of the digital phase adjuster is the positive input terminal of the compensation voltage of the digital phase adjustment submodule;

[0088] The first compensation voltage negative input terminal of the digital phase adjuster is the first compensation voltage negative input terminal of the digital phase adjustment submodule;

[0089] The second compensation voltage negative input terminal of the digital phase adjuster is the second compensation voltage negative input terminal of the digital phase adjustment submodule;

[0090] The compensation voltage output terminal of the digital phase adjuster is electrically connected to the first terminal of the quadrature compensation capacitor;

[0091] The second terminal of the quadrature compensation capacitor is the compensation voltage output terminal of the digital phase adjustment submodule.

[0092] In this embodiment of the invention, the digital phase adjustment submodule includes a digital phase adjuster U3 and a quadrature compensation capacitor C1. The compensation voltage output terminal of the digital phase adjuster U3 is electrically connected to the first terminal of the quadrature compensation capacitor C1 to inject quadrature current, thereby compensating for phase error.

[0093] In this embodiment of the invention, the digital phase regulator U3 can digitally set the ratio of the output voltage to the input voltage according to a ratio of -1ˉ0, 0ˉ+1; the digital amplitude regulator U2 can use a device with an accuracy of 0.1% and a resolution of 0.1%. The capacitance value of the quadrature compensation capacitor C1 can be set to 31.83nF with an accuracy of not less than 0.1%, and can be composed of multiple capacitors connected in series or in parallel.

[0094] As a preferred embodiment, the first current transformer includes a primary winding, a secondary winding, a compensating winding, a main core, and an auxiliary core.

[0095] The primary winding and the secondary winding are wound on the main iron core;

[0096] The auxiliary iron core is wound with the primary winding, the secondary winding, and the compensation winding.

[0097] In this embodiment of the invention, the first current transformer T1 is a bipolar current transformer, including a primary winding L1L2, a secondary winding K1K2, a compensation winding B1B2, a main core 1, and an auxiliary core 2. The main core 1 is wound with the primary winding L1L2 and the secondary winding K1K2, while the auxiliary core 2 is wound with the primary winding L1L2, the secondary winding K1K2, and the compensation winding B1B2.

[0098] For the main core 1, there are only two windings: a primary winding L1L2 and a secondary winding K1K2. Its error is the ratio of the transformer's excitation current to the primary current. For the auxiliary core 2, the primary excitation current of the primary winding L1L2 forms the primary coil of the auxiliary core 2. The output of its secondary compensation winding B1B2 is used to offset the error of the primary excitation current. This type of transformer is a bipolar transformer. The error of a bipolar transformer is the error of the main core multiplied by the error of the auxiliary core 2, which typically reaches over 2 ppm. The current is generally designed to be around 20 mA.

[0099] As a preferred embodiment, the amplitude adjustment amount meets the following requirements:

[0100]

[0101] In the formula, ΔKp is the amplitude adjustment amount; R1 is the resistance value of the voltage sampling resistor; R3 is the resistance value of the in-phase compensation resistor; K T2 is the turns ratio of the second current transformer; ferr is the current amplitude error.

[0102] In this embodiment of the invention, the processor is used to calculate the amplitude adjustment amount, which is calculated based on the voltage sampling resistor and the in-phase compensation resistor. Specifically, assuming the current amplitude error of the current converter is ferr, and the amplitude error compensation value of the compensated second current transformer T2 is Id_f, then the following relationship can be derived:

[0103]

[0104] Wherein, I2 is the secondary current of the main core 1 of the first current transformer T1.

[0105] As a preferred embodiment, the phase adjustment amount meets the following requirements:

[0106]

[0107] In the formula, R1 is the phase adjustment value; C1 is the resistance value of the voltage sampling resistor; K is the capacitance value of the quadrature compensation capacitor; T2 The transformation ratio of the second current transformer is given; f is the frequency of the AC signal. This represents the current phase error.

[0108] In this embodiment of the invention, the processor is further configured to calculate the phase adjustment amount, which is derived based on the voltage sampling resistor and the quadrature compensation capacitor. Specifically, it is assumed that the current phase error of the current converter is... The phase error compensation value of the second current transformer T2 is Therefore, the following relationship can be derived:

[0109]

[0110] Where f is the AC signal frequency, which is generally the frequency of the power frequency signal, and the frequency is fixed at 50Hz.

[0111] As a preferred embodiment, the output current amplitude is determined according to the amplitude adjustment amount;

[0112] The formula for calculating the output current amplitude is:

[0113] Kp NEW =Kp+ΔKp

[0114] In the formula, Kp NEWKp represents the output current amplitude; Kp is the adjustment amount for the previous amplitude.

[0115] In this embodiment of the invention, after calculating the amplitude adjustment amount based on the voltage sampling resistor and the in-phase compensation resistor, the current output current amplitude can be calculated by combining it with the previous output current amplitude stored in the processor, and then written into the non-volatile memory by the processor. Specifically, the current output current amplitude is the sum of the previous output current amplitude and the amplitude adjustment amount.

[0116] As a preferred embodiment, the output current phase is determined according to the phase adjustment amount;

[0117] Kφ NEW =Kφ+ΔKφ

[0118] In the formula, Kφ NEW Kφ is the phase of the output current; Kφ is the phase of the previous output current.

[0119] In this embodiment of the invention, after calculating the phase adjustment amount based on the voltage sampling resistor and the quadrature compensation capacitor, the current output current phase can be calculated by combining it with the previous output current phase stored in the processor, and then written into the non-volatile memory by the processor. Specifically, the current output current phase is the sum of the previous output current phase and the phase adjustment amount.

[0120] As a preferred embodiment, the output current amplitude error and output current phase error are measured by a standard current-voltage converter.

[0121] In this embodiment of the invention, the output current amplitude error and output current phase error can be measured using a standard current-voltage converter with higher accuracy testing instruments. Specifically, by comparing the output current amplitude and current phase of the controllable current converter with the output signal of the standard current-voltage converter, the output current amplitude error and output current phase error of the controllable current converter can be obtained. Generally, the accuracy of the standard current-voltage converter is two levels higher than that of the basic current converter in the controllable current converter.

[0122] As an example of an embodiment of the present invention, see Figure 3This is a flowchart illustrating an embodiment of the current regulation method provided by the present invention. First, the amplitude and phase errors of the controllable current converter are tested using a standard current-voltage converter. Then, based on the tested amplitude and phase errors, the amplitude adjustment amount for amplitude compensation and the phase adjustment amount for phase compensation are calculated respectively. Finally, the current output current amplitude and phase are calculated by combining the amplitude and phase adjustment amounts, and written to a non-volatile memory. This allows the digital amplitude regulator U2 and digital phase regulator U3 to be controlled via SPI to adjust the amplitude and phase of the current converter's output current, ensuring that the controllable current converter meets the error threshold.

[0123] Implementing the above embodiments has the following effects:

[0124] This invention provides a controllable current converter, including a processor, a digital regulation module, a voltage sampling resistor, a voltage transformation resistor, a first current transformer, and a second current transformer. The processor is electrically connected to the digital regulation module via a communication control terminal. The voltage sampling resistor is connected in series between the secondary windings of the first current transformer. The voltage transformation resistor is connected in series between the secondary winding and the compensation winding of the first current transformer. The secondary winding and the compensation winding of the first current transformer are connected in parallel with the output of the second current transformer, respectively. The first terminal of the second current transformer is connected to the digital regulation module, and the last terminal is connected to a common potential. The processor is used to calculate the amplitude and phase regulation values. The digital regulation module is used to control the output current amplitude and phase based on the amplitude and phase regulation values. This invention incorporates a processor in the current converter, which can calculate the amplitude and phase regulation values ​​based on the output current amplitude error and the output current phase error. It also incorporates a digital regulator in the current converter, which can control the output current amplitude and phase based on the amplitude and phase regulation values, thereby reducing amplitude and phase errors and improving the accuracy of the current converter.

[0125] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A controllable current converter, characterized in that, include: Processor, digital regulation module, voltage sampling resistor, voltage transformation resistor, first current transformer and second current transformer; The communication control terminal of the digital adjustment module is electrically connected to the processor; the positive input terminal of the compensation voltage of the digital adjustment module is electrically connected to the second terminal of the voltage sampling resistor; the negative input terminal of the first compensation voltage of the digital adjustment module is electrically connected to the first terminal of the voltage sampling resistor. The second compensation voltage negative input terminal of the digital adjustment module is electrically connected to the primary tail terminal of the second current transformer. The compensation voltage output terminal of the digital adjustment module is electrically connected to the primary winding terminal of the second current transformer; The first terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the second current transformer; the second terminal of the voltage sampling resistor is electrically connected to the first secondary terminal of the first current transformer. The first terminal of the voltage conversion resistor is electrically connected to the secondary tail terminal of the second current transformer; the second terminal of the voltage conversion resistor is electrically connected to the first terminal of the voltage sampling resistor. The secondary terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the second terminal of the voltage conversion resistor; the compensation terminal of the first current transformer is electrically connected to the first terminal of the voltage conversion resistor. The processor is used to calculate the amplitude adjustment amount based on the amplitude error of the output current of the current converter, and to calculate the phase adjustment amount based on the phase error of the output current of the current converter. The digital adjustment module is used to control the output current amplitude of the current converter according to the amplitude adjustment amount, and to control the output current phase of the current converter according to the phase adjustment amount.

2. The controllable current converter according to claim 1, characterized in that, The digital adjustment module includes: a digital amplitude adjustment submodule and a digital phase adjustment submodule; The communication control terminal of the digital amplitude adjustment submodule is the communication control terminal of the digital adjustment module; the positive compensation voltage input terminal of the digital amplitude adjustment submodule is the positive compensation voltage input terminal of the digital adjustment module; the first negative compensation voltage input terminal of the digital amplitude adjustment submodule is the first negative compensation voltage input terminal of the digital adjustment module; the second negative compensation voltage input terminal of the digital amplitude adjustment submodule is the second negative compensation voltage input terminal of the digital adjustment module; the compensation voltage output terminal of the digital amplitude adjustment submodule is the compensation voltage output terminal of the digital adjustment module. The communication control terminal of the digital phase adjustment submodule is electrically connected to the communication control terminal of the digital amplitude adjustment submodule; the positive input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the positive input terminal of the compensation voltage of the digital amplitude adjustment submodule; the first negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the first negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; the second negative input terminal of the compensation voltage of the digital phase adjustment submodule is electrically connected to the second negative input terminal of the compensation voltage of the digital amplitude adjustment submodule; and the compensation voltage output terminal of the digital phase adjustment submodule is electrically connected to the compensation voltage output terminal of the digital amplitude adjustment submodule.

3. The controllable current converter according to claim 2, characterized in that, The digital amplitude adjustment submodule includes: a digital amplitude regulator and a non-inverting compensation resistor; The communication control terminal of the digital amplitude regulator is the communication control terminal of the digital amplitude regulation submodule; The positive input terminal of the compensation voltage of the digital amplitude regulator is the positive input terminal of the compensation voltage of the digital amplitude regulation submodule; The first compensation voltage negative input terminal of the digital amplitude regulator is the first compensation voltage negative input terminal of the digital amplitude regulation submodule; The second compensation voltage negative input terminal of the digital amplitude regulator is the second compensation voltage negative input terminal of the digital amplitude regulation submodule; The compensation voltage output terminal of the digital amplitude regulator is electrically connected to the first terminal of the in-phase compensation resistor; The second terminal of the in-phase compensation resistor is the compensation voltage output terminal of the digital amplitude adjustment submodule.

4. The controllable current converter according to claim 2, characterized in that, The digital phase adjustment submodule includes: a digital phase adjuster and a quadrature compensation capacitor; The communication control terminal of the digital phase adjuster is the communication control terminal of the digital phase adjustment submodule; The positive input terminal of the compensation voltage of the digital phase adjuster is the positive input terminal of the compensation voltage of the digital phase adjustment submodule; The first compensation voltage negative input terminal of the digital phase adjuster is the first compensation voltage negative input terminal of the digital phase adjustment submodule; The second compensation voltage negative input terminal of the digital phase adjuster is the second compensation voltage negative input terminal of the digital phase adjustment submodule; The compensation voltage output terminal of the digital phase adjuster is electrically connected to the first terminal of the quadrature compensation capacitor; The second terminal of the quadrature compensation capacitor is the compensation voltage output terminal of the digital phase adjustment submodule.

5. The controllable current converter according to claim 1, characterized in that, The first current transformer includes a primary winding, a secondary winding, a compensating winding, a main core, and an auxiliary core; The primary winding and the secondary winding are wound on the main iron core; The auxiliary iron core is wound with the primary winding, the secondary winding, and the compensation winding.

6. The controllable current converter according to claim 3, characterized in that, The amplitude adjustment amount must meet the following requirements: In the formula, ΔKp is the amplitude adjustment amount; R1 is the resistance value of the voltage sampling resistor; R3 is the resistance value of the in-phase compensation resistor; K T2 is the turns ratio of the second current transformer; ferr is the current amplitude error.

7. The controllable current converter according to claim 4, characterized in that, The phase adjustment amount must meet the following requirements: In the formula, R1 is the phase adjustment value; C1 is the resistance value of the voltage sampling resistor; K is the capacitance value of the quadrature compensation capacitor; T2 The transformation ratio of the second current transformer is given; f is the frequency of the AC signal. This represents the current phase error.

8. The controllable current converter according to claim 6, characterized in that, The output current amplitude is determined according to the amplitude adjustment amount; The formula for calculating the output current amplitude is: Kp. NEW =Kp+ΔKp In the formula, Kp NEW Kp represents the amplitude of the output current; Kp represents the amplitude of the previous output current.

9. The controllable current converter according to claim 7, characterized in that, The phase of the output current is determined according to the phase adjustment amount; Kφ NEW =Kφ+ΔKφ In the formula, Kφ NEW Kφ is the phase of the output current; Kφ is the phase of the previous output current.

10. The controllable current converter according to claim 1, characterized in that, The output current amplitude error and the output current phase error are measured by a standard current-voltage converter.

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