A Method, System, Computer Readable Storage Medium and Product for Reducing Current Ripple of a Constant Current Source

Abstract

The present invention discloses a method, a system, a computer-readable storage medium and a product for reducing the current ripple of a constant current source, relating to the technical field of constant current source control, including: subtracting a set output current from a noise signal to obtain a first difference value; subtracting the first difference value from an actual output current value to obtain a second difference value and inputting the second difference value into a filter; inputting the filtered signal into a first PI controller to obtain two sets of buck inductor current setting values; sampling the inductor currents of the two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value; subtracting the first buck inductor current setting value from the first inductor current sampling value to obtain a third difference value; subtracting the second buck inductor current setting value from the second inductor current sampling value to obtain a fourth difference value; respectively inputting the third difference value and the fourth difference value into a second PI controller and a third PI controller to obtain two sets of duty cycles. By setting a filter, the present invention can reduce the current ripple of the constant current source.

Description

Technical Field

[0001] The present invention relates to the technical field of constant current source control, and particularly relates to a method, a system, a computer-readable storage medium and a product for reducing the current ripple of a constant current source. Background Art

[0002] In the application of fiber lasers, a constant current source is used as the power supply for pumping (LD), and the ripple magnitude of its output current affects the instability threshold of the laser mode. Currently, most constant current sources use a buck step-down topology. For a single buck topology, methods such as increasing the inductance of the filter inductor, increasing the capacitance of the filter capacitor, or adding a first-stage LC filter network are adopted.

[0003] To further reduce the output current ripple, according to the input voltage value, the number of series-connected LDs is reasonably selected, the output voltage value of the buck circuit is adjusted, and a large reduction in the ripple of the switching frequency component is achieved by the way of mutual cancellation of the inductor currents of multiple-phase interleaved buck.

[0004] In practical applications, to achieve a stable laser intensity, the constant current source should output a constant output current, so a closed-loop control method needs to be adopted. Its closed-loop control method can adopt single-loop control, hardware current sharing method, or double-loop control, with the outer loop for stable output current control and the inner loop for current sharing control.

[0005] In the interleaved buck double-loop control, the outer loop performs stable output current control, and its control input is the set output current value, and the actual output current of the interleaved buck is sampled. The set output current value is subtracted from the actual output current sampling value, and after passing through a PI controller, the set values of the inductor currents of the two buck circuits are obtained. The inner loop performs current sharing control, samples the inductor current values of the two buck circuits, subtracts the output of the outer-loop PI controller (which means the set values of the inductor currents of the two buck circuits) from the inductor current sampling values, and after passing through a PI controller, the duty cycle of each buck can be obtained.

[0006] If factors such as the switching oscillation of MOSFET devices and environmental noise are not considered, it is considered that the Buck circuit devices are ideal and linear. After adding current double-loop control, under ideal conditions, the output current ripple of the constant current source only contains the switching frequency sub-ripple, and the peak-to-peak value of the ripple is in the mA level.

[0007] In practical applications, due to the switching oscillation of components in the buck circuit itself, such as MOSFETs, and the large-area sampling and control circuits, which are affected by environmental noise, the sampled signal will contain environmental noise content. In addition, if an analog control scheme is selected, there is a quantization error in the current-given DAC. If a digital control scheme is selected, there is a quantization error in the ADC sampling, and there is an error caused by the resolution in the duty cycle of the PWM wave output by the controller. All of the above will cause the ripple of the output current to be much larger than the peak-to-peak value of the ripple under ideal conditions.

[0008] In the outer-loop current sampling, white noise is added for simulation. It can be obtained through simulation that after adding white noise, the ripple of the buck current output current increases significantly. Therefore, based on the current control method, the sampling and control loops cannot eliminate the noise generated by the circuit itself, environmental noise, and the quantization error existing in the chip itself, which results in a large ripple of the output current of the buck circuit. Summary of the Invention

[0009] The purpose of the present invention is to provide a method, system, computer-readable storage medium, and product for reducing the current ripple of a constant current source, so as to reduce the current ripple of the constant current source.

[0010] To achieve the above object, the present invention provides the following solutions:

[0011] In a first aspect, a method for reducing the current ripple of a constant current source includes:

[0012] Obtain an output current sampling signal; the current sampling signal includes: a noise signal and the actual value of the output current; the noise signal includes: environmental noise and the output current fluctuation caused by the quantization error of the chip;

[0013] Subtract the set output current from the noise signal to obtain a first difference;

[0014] Subtract the first difference from the actual output current value to obtain a second difference;

[0015] Input the second difference into a filter to obtain a filtered signal;

[0016] Input the filtered signal into a first PI controller to obtain two sets of buck inductor current setting values, denoted as the first buck inductor current setting value and the second buck inductor current setting value;

[0017] Sample the inductor currents of the two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value;

[0018] Subtract the first buck inductor current setting value from the first inductor current sampling value to obtain a third difference;

[0019] Subtract the second buck inductor current set value from the second inductor current sampled value to obtain a fourth difference;

[0020] Input the third difference into a second PI controller to obtain a first duty cycle;

[0021] Input the fourth difference into a third PI controller to obtain a second duty cycle.

[0022] Optionally, inputting the second difference into a filter to obtain a filtered signal specifically includes the following steps:

[0023] Obtain a threshold B;

[0024] If the second difference is greater than B, the filtered signal is equal to the second difference minus B;

[0025] If the second difference is less than -B, the filtered signal is equal to the second difference plus B;

[0026] If the second difference is greater than or equal to -B and less than or equal to B, the filtered signal is 0.

[0027] Optionally, the threshold B is half of the peak-to-peak value of the rated output current ripple.

[0028] Optionally, the filter is a filter circuit.

[0029] In a second aspect, the present invention provides a system for reducing the current ripple of a constant current source, including:

[0030] A current sampling signal acquisition module for acquiring an output current sampling signal; the current sampling signal includes: a noise signal and an actual output current value; the noise signal includes: environmental noise and output current fluctuations caused by quantization errors of the chip;

[0031] A first difference calculation module for subtracting the set output current from the noise signal to obtain a first difference;

[0032] A second difference calculation module for subtracting the first difference from the actual output current value to obtain a second difference;

[0033] A filtering module for inputting the second difference into a filter to obtain a filtered signal;

[0034] A first PI control module for inputting the filtered signal into a first PI controller to obtain two buck inductor current set values, denoted as a first buck inductor current set value and a second buck inductor current set value;

[0035] A sampling module for sampling the inductor currents of two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value;

[0036] A third difference module for subtracting the first buck inductor current set value from the first inductor current sampling value to obtain a third difference;

[0037] A fourth difference module for subtracting the second buck inductor current set value from the second inductor current sampling value to obtain a fourth difference;

[0038] A second PI control module for inputting the third difference into a second PI controller to obtain a first duty cycle;

[0039] A third PI control module for inputting the fourth difference into a third PI controller to obtain a second duty cycle.

[0040] Optionally, the filtering module includes:

[0041] A threshold acquisition unit for acquiring a threshold B;

[0042] A first judgment unit for determining that the filtered signal is equal to the second difference minus B when the second difference is greater than B;

[0043] A second judgment unit for determining that the filtered signal is equal to the second difference plus B when the second difference is less than -B;

[0044] A third judgment unit for determining that the filtered signal is 0 when the second difference is greater than or equal to -B and less than or equal to B.

[0045] Optionally, the threshold B is half of the peak-to-peak value of the rated output current ripple.

[0046] Optionally, the filtering module is a filter circuit.

[0047] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0048] In a fourth aspect, the present invention provides a computer program product including a computer program, and when the computer program / instruction is executed by a processor, the steps of the above method are implemented.

[0049] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0050] The present invention discloses a method, system, computer-readable storage medium and product for reducing the current ripple of a constant current source, including: subtracting a set output current from a noise signal to obtain a first difference; subtracting the first difference from an actual output current value to obtain a second difference; inputting the second difference into a filter to obtain a filtered signal; inputting the filtered signal into a first PI controller to obtain two sets of buck inductor current setting values, denoted as a first buck inductor current setting value and a second buck inductor current setting value; sampling the inductor currents of the two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value; subtracting the first buck inductor current setting value from the first inductor current sampling value to obtain a third difference; subtracting the second buck inductor current setting value from the second inductor current sampling value to obtain a fourth difference; inputting the third difference into a second PI controller to obtain a first duty cycle; inputting the fourth difference into a third PI controller to obtain a second duty cycle. By setting a filter, the present invention can reduce the current ripple of the constant current source. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0052] Figure 1 is a block diagram of a current double closed-loop control after adding a filter provided by the present invention;

[0053] Figure 2 is a schematic diagram of the output current waveform of the circuit after adding a filter provided by the present invention;

[0054] Figure 3 is a schematic diagram of the output signal of the filter provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0056] The purpose of the present invention is to provide a method, system, computer-readable storage medium and product for reducing the current ripple of a constant current source, so as to reduce the current ripple of the constant current source.

[0057] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Embodiment 1

[0059] Figure 1 This is the current double-loop control block diagram after adding a filter provided by the present invention. As shown in Figure 1 the figure, when the noise signal is taken into account, the sampled value of the interleaved buck output current contains not only the actual value of the output current but also the noise signal. Therefore, when calculating the current error, after subtracting the set output current value from the actual output current value, the noise signal needs to be further subtracted, and the result is err_orig.

[0060] The method in the present invention includes:

[0061] Step 1: Obtain the output current sampling signal; the current sampling signal includes: a noise signal and the actual value of the output current; the noise signal includes: environmental noise and the output current fluctuation caused by the quantization error of the chip.

[0062] Step 2: Subtract the noise signal from the set output current to obtain a first difference.

[0063] Step 3: Subtract the actual value of the actual output current from the first difference to obtain a second difference, that is, err_orig.

[0064] Step 4: Input the second difference into the filter to obtain a filtered signal, that is, err_final.

[0065] Specifically, it includes the following steps:

[0066] Refer to Figure 3 , where the horizontal axis represents time, the vertical axis represents amplitude, the thin solid line represents the input of the filter, and the thick solid line represents the output signal of the filter, specifically as follows:

[0067] Take half of the peak-to-peak value of the rated output current ripple as parameter B, and the filter output is err_final.

[0068] If err_orig is greater than B, then err_final = err_orig - B;

[0069] If err_orig is less than -B, then err_final = err_orig + B;

[0070] If err_orig ≥ -B and err_orig ≤ B, then err_orig = 0.

[0071] Step 4: Input the filtered signal into the first PI controller to obtain two sets of buck inductor current set values, denoted as the first buck inductor current set value and the second buck inductor current set value.

[0072] In addition, the filter in the present invention can also be a filter circuit. In this embodiment, the specific structure and model of the filter are not specifically limited as long as it can achieve filtering.

[0073] Step 5: Sample the inductor currents of the two buck circuits to obtain the first inductor current sampling value and the second inductor current sampling value.

[0074] Step 6: Subtract the first buck inductor current set value from the first inductor current sampling value to obtain a third difference.

[0075] Step 7: Subtract the second buck inductor current set value from the second inductor current sampling value to obtain a fourth difference.

[0076] Step 8: Input the third difference into the second PI controller to obtain a first duty cycle.

[0077] Step 9: Input the fourth difference into the third PI controller to obtain a second duty cycle.

[0078] In the embodiment, the peak-to-peak ripple of the rated output current is about 1A. Then B = 0.5A. Substitute 0.5A into the filter, and its output waveform is as Figure 2 shown.

[0079] After adding filtering, it can be seen that the peak-to-peak ripple of the output current is significantly reduced, its peak-to-peak value drops to about 0.5A, and the frequency content of the noise is also greatly reduced.

[0080] Embodiment 2

[0081] The present invention provides a system for reducing the current ripple of a constant current source, including:

[0082] A current sampling signal acquisition module for acquiring an output current sampling signal; the current sampling signal includes: a noise signal and an actual value of the output current; the noise signal includes: environmental noise and output current fluctuations caused by quantization errors of the chip;

[0083] A first difference module for subtracting the set output current from the noise signal to obtain a first difference;

[0084] A second difference module for subtracting the actual output current sampling value from the first difference to obtain a second difference;

[0085] A filtering module for inputting the second difference into a filter to obtain a filtered signal;

[0086] The first PI control module is configured to input the filtered signal into a first PI controller to obtain two sets of buck inductor current set values, denoted as the first buck inductor current set value and the second buck inductor current set value;

[0087] The sampling module is configured to sample the inductor currents of two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value;

[0088] The third difference module is configured to subtract the first inductor current sampling value from the first buck inductor current set value to obtain a third difference;

[0089] The fourth difference module is configured to subtract the second inductor current sampling value from the second buck inductor current set value to obtain a fourth difference;

[0090] The second PI control module is configured to input the third difference into a second PI controller to obtain a first duty cycle;

[0091] The third PI control module is configured to input the fourth difference into a third PI controller to obtain a second duty cycle.

[0092] Specifically, the filtering module includes:

[0093] A threshold acquisition unit configured to acquire a threshold B;

[0094] A first judgment unit configured to, when the second difference is greater than B, determine that the filtered signal is equal to the second difference minus B;

[0095] A second judgment unit configured to, when the second difference is less than -B, determine that the filtered signal is equal to the second difference plus B;

[0096] A third judgment unit configured to, when the second difference is greater than or equal to -B and less than or equal to B, determine that the filtered signal is 0.

[0097] Embodiment III

[0098] A computer-readable storage medium having a computer program stored thereon, where the computer program, when executed by a processor, implements the steps of the constant current source current ripple reduction method in Embodiment I.

[0099] Embodiment IV

[0100] A computer program product including a computer program, where the computer program, when executed by a processor, implements the steps of the constant current source current ripple reduction method in Embodiment I.

[0101] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memories can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided by the present invention can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided by the present invention can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0102] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0103] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present invention; at the same time, for those of ordinary skill in the art, according to the ideas of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for reducing the current ripple of a constant current source, characterized in that, Including: Obtain the output current sampling signal; The current sampling signal includes: a noise signal and the actual value of the output current; the noise signal includes: environmental noise and the output current fluctuation caused by the quantization error of the chip; Subtract the set output current from the noise signal to obtain a first difference; Subtract the actual value of the actual output current from the first difference to obtain a second difference; Input the second difference into a filter to obtain a filtered signal, which specifically includes the following steps: Obtain a threshold B; If the second difference is greater than B, the filtered signal is equal to the second difference minus B; If the second difference is less than -B, the filtered signal is equal to the second difference plus B; If the second difference is greater than or equal to -B and less than or equal to B, the filtered signal is 0; Input the filtered signal into a first PI controller to obtain two sets of buck inductor current setting values, denoted as the first buck inductor current setting value and the second buck inductor current setting value; Sample the inductor currents of the two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value; Subtract the first buck inductor current setting value from the first inductor current sampling value to obtain a third difference; Subtract the second buck inductor current setting value from the second inductor current sampling value to obtain a fourth difference; Input the third difference into a second PI controller to obtain a first duty cycle; Input the fourth difference into a third PI controller to obtain a second duty cycle.

2. The method for reducing the current ripple of the constant current source according to claim 1, wherein The threshold B is half of the peak-to-peak value of the rated output current ripple.

3. The method for reducing the current ripple of the constant current source according to claim 1, characterized in that The filter is a filter circuit.

4. A constant current source current ripple reduction system, characterized in that, Including: A current sampling signal acquisition module for obtaining the output current sampling signal; The current sampling signal includes: a noise signal and the actual value of the output current; the noise signal includes: environmental noise and the output current fluctuation caused by the quantization error of the chip; A first difference calculation module for subtracting the set output current from the noise signal to obtain a first difference; A second difference calculation module for subtracting the actual value of the actual output current from the first difference to obtain a second difference; A filtering module for inputting the second difference into a filter to obtain a filtered signal, and the filtering module includes: A threshold acquisition unit for obtaining the threshold B; A first judgment unit for determining that the filtered signal is equal to the second difference minus B when the second difference is greater than B; A second judgment unit for determining that the filtered signal is equal to the second difference plus B when the second difference is less than -B; A third judgment unit for determining that the filtered signal is 0 when the second difference is greater than or equal to -B and less than or equal to B; A first PI control module for inputting the filtered signal into a first PI controller to obtain two sets of buck inductor current setting values, denoted as the first buck inductor current setting value and the second buck inductor current setting value; A sampling module for sampling the inductor currents of the two buck circuits to obtain a first inductor current sampling value and a second inductor current sampling value; The third difference module is configured to subtract the first buck inductor current set value from the first inductor current sampled value to obtain a third difference value; The fourth difference module is configured to subtract the second buck inductor current set value from the second inductor current sampled value to obtain a fourth difference value; The second PI control module is configured to input the third difference value to a second PI controller to obtain a first duty cycle; The third PI control module is configured to input the fourth difference value to a third PI controller to obtain a second duty cycle.

5. The constant current source current ripple reduction system according to claim 4, wherein, The threshold B is half of the peak-to-peak value of the rated output current ripple.

6. The constant current source current ripple reduction system according to claim 4, wherein The filtering module is a filter circuit.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-3.

8. A computer program product, comprising a computer program, characterized in that, When the computer program / instructions are executed by a processor, it implements the steps of the method according to any one of claims 1-3.

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