Power supply calibration system and working method thereof

Abstract

The invention relates to the technical field of power supply calibration, and discloses a power supply calibration system and a working method thereof, the power supply calibration system comprises a reference source calibration circuit, a sampling calibration circuit, a power calibration circuit and a main control unit; and during the continuous normal operation period of the power supply, the control unit regularly controls the change-over switch to switch one of the main sampling circuit and the auxiliary sampling circuit which are currently in an idle state to a calibration state so as to update the second mapping relation corresponding to the sampling circuit, and corrects the sampling voltage based on the updated second mapping relation. And meanwhile, the other sampling circuit is kept in a normal output sampling state, and the output voltage of the power calibration circuit is finely adjusted in real time in combination with the third mapping relation. On the premise of maintaining normal and continuous operation of the power supply, the sampling circuits can be calibrated automatically and regularly, any temperature drift and time drift generated by each sampling circuit since last calibration can be compensated reliably, and long-term and continuous high-precision output of the power supply can be maintained.

Description

Technical Field

[0001] This application belongs to the field of power supply calibration technology, specifically relating to power supply calibration systems and their operating methods. Background Technology

[0002] Multi-channel high-precision power supplies are core power supply units commonly used in various precision electronic systems. The stability and accuracy of their output voltage directly determine the performance of the entire system. Therefore, power supply calibration is the key to ensuring the performance of multi-channel high-precision power supplies.

[0003] Currently, for the calibration of multi-channel power supplies, such as Figure 5 As shown, the standard reference voltage output from the reference source is generally used as the calibration benchmark for primary calibration. After primary calibration, this calibration voltage is provided to the secondary regulator, which performs secondary calibration based on this reference voltage, and then provides feedback adjustment to the final output voltage. While this calibration scheme can theoretically ensure that the final output voltage accuracy matches the initial calibration accuracy, it ignores the impact of "temperature drift" caused by changes in ambient temperature affecting electronic components during operation, as well as "time drift" caused by the aging of the components themselves, on the output accuracy. After prolonged operation, the output accuracy of the reference source and the detection accuracy of the sampling circuit will gradually deviate from the initial calibration value, eventually leading to a continuous accumulation and increase in power supply output error, making it impossible to maintain high-precision output over a long period.

[0004] In the prior art, in order to reduce the impact of temperature drift and time drift during long-term operation of power supplies, high-precision power supplies used in fields such as high-precision optical power supplies usually use high-precision stability devices to construct the core circuit of the power supply. However, such components are expensive and cannot completely eliminate temperature drift and time drift. They can only extend the accuracy maintenance time, resulting in limited high-precision output time and low reliability. In addition, in order to prevent accuracy decay, the power supply needs to be disconnected for initial calibration after running for a period of time, which seriously affects the continuous operation of the powered system and reduces production efficiency. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a power supply calibration system and its operating method. Under the premise of maintaining the normal and continuous operation of the power supply, it can automatically and periodically calibrate the sampling circuit, reliably compensate for any temperature drift or time drift generated by each sampling circuit since the last calibration, and correct the sampling accuracy attenuation caused by temperature drift and time drift in real time. It can effectively eliminate the system error introduced by the temperature drift and time drift of the sampling circuit, so as to maintain the long-term and continuous high-precision output of the power supply.

[0006] The first aspect of this application provides a power calibration system, including a reference source calibration circuit, a sampling calibration circuit, a power calibration circuit, and a main control unit; The reference source calibration circuit is electrically connected to the main control unit and is used to establish the first mapping relationship between the set output voltage and the actual output voltage of the reference source, providing a precise reference voltage for the sampling calibration circuit across the entire range. The sampling calibration circuit is electrically connected to the main control unit and the reference source calibration circuit. It includes at least one set of main sampling circuits and sub-sampling circuits, as well as a switching switch controlled by the control unit. The sampling terminal of each sampling circuit is connected to the switching switch. In the calibration state, the switching switch is switched to be connected to the output terminal of the reference source calibration circuit. Based on the accurate reference voltage provided by the first mapping relationship, a second mapping relationship is established between the sampling voltage of each sampling circuit and the actual output voltage of the reference source calibration circuit, so as to obtain the accurate sampling value of the power supply and prepare for adjusting the actual output voltage of the power supply. The power calibration circuit is electrically connected to the main control unit and the sampling calibration circuit. It is used to establish a third mapping relationship between the power supply's set output voltage and the actual output voltage, and to fine-tune the power supply's actual output voltage based on the accurate sampled value. The control unit is configured to: establish and store a first mapping relationship, a second mapping relationship, and a third mapping relationship during the initial calibration phase; during continuous normal operation of the power supply, a timed control switch switches one of the main sampling circuit and the secondary sampling circuit that is currently in an idle state to the calibration state, so as to update the second mapping relationship corresponding to the sampling circuit, and correct the sampling voltage based on the updated second mapping relationship, while keeping the other sampling circuit in a normal output sampling state, and finely adjusting the output voltage of the power calibration circuit in real time in combination with the third mapping relationship.

[0007] In one alternative scheme, the number of main sampling circuits, sub-sampling circuits, and switching switches is matched with the number of power output channels, and the sampling terminals of the main sampling circuits and sub-sampling circuits of each channel are connected to the corresponding switching switches. In calibration mode, the main control unit controls the switching switch to connect the input terminals of the main sampling circuit or sub-sampling circuit corresponding to each channel to the output terminal of the reference source calibration circuit of the corresponding channel, thereby completing their respective calibrations. In normal power supply mode, the main control unit controls the switching switch to connect the input terminals of the main sampling circuit or sub-sampling circuit corresponding to each channel to the output terminal of the power calibration circuit of the corresponding channel.

[0008] In one alternative, the reference source calibration circuit acquires the actual output voltage of the reference source across its full range using a high-precision multimeter, and establishes a first mapping relationship between the set output voltage and the actual output voltage of the reference source. This first mapping relationship is represented by a piecewise approximation function. The relationship is: Vrt = krn × Vref + brn; In the formula, Vrt is the actual output voltage of the reference source measured by a high-precision multimeter, Vref is the set output voltage of the reference source, krn and brn are the parameters of the piecewise function, and the main control unit stores the parameters, segmentation points, and number of segments of each segment function in this relation.

[0009] In one alternative scheme, the sampling calibration circuit switches the main sampling circuit and the sub-sampling circuit to the output terminal of the reference source via a switching switch, and performs polling sampling on the full-range output voltage of the reference source to establish a second mapping relationship between the sampling voltage of each channel's main sampling circuit and sub-sampling circuit and the actual output voltage of the reference source calibration circuit. The second mapping relationship is represented by a piecewise approximation function. The relation is: Vt1 = Vs×Ksn + Bsn; In the formula, Vt1 is the actual output voltage of the reference source calibration circuit, Vs is the sampling voltage of the sampling circuit, Ksn and Bsn are the piecewise function parameters, and the main control unit stores the parameters, segmentation points and number of segments of each segment function in this relation.

[0010] In one alternative, the power calibration circuit acquires the actual output voltage of the power supply across its full range using a high-precision multimeter, and establishes a third mapping relationship between the power supply's set output voltage and the actual output voltage. This third mapping relationship is represented by a piecewise approximation function. The relationship is: Vpt = Vc×Kpn + Bpn; In the formula, Vpt is the actual output voltage of the power supply, Vc is the set output voltage of the power supply, Kpn and Bpn are the piecewise function parameters, and the main control unit stores the parameters, segmentation points and number of segments of each segment function in this relation.

[0011] In one alternative, the switch is either a relay switch or a multiplexer.

[0012] The second aspect of this application provides a method for operating a power supply calibration system, used in the aforementioned power supply calibration system, comprising the following steps: S1: Establishment of reference source mapping relationship: The main control unit controls the reference source calibration circuit to start calibration, controls the reference source to output full-range voltage, and collects the actual output voltage of the reference source across the full range through a high-precision multimeter, establishing and storing the first mapping relationship between the set output voltage and the actual output voltage of the reference source. S2: Establishment of sampling circuit mapping relationship: The main control unit controls the sampling calibration circuit to start calibration. Based on the accurate reference voltage provided by the first mapping relationship, the main sampling circuit and the sub-sampling circuit are switched to the output terminal of the reference source in sequence by the switching switch. The full-range output voltage of the reference source is polled and sampled. The second mapping relationship between the sampling voltage of each channel's main sampling circuit and sub-sampling circuit and the actual output voltage of the reference source calibration circuit is established and stored. S3: Sampling calibration circuit timed online calibration: During the continuous normal operation of the power supply, the main control unit controls the switching switch to switch one of the main sampling circuit and the auxiliary sampling circuit that is currently in the idle state to the output of the reference source for calibration. The corresponding second mapping relationship is updated based on the first mapping relationship, and the sampling voltage is corrected based on the updated second mapping relationship to obtain accurate sampling values ​​and feed them back to the main control unit. At the same time, the other sampling circuit is kept in the normal output sampling state. S4: Power output mapping relationship establishment: The main control unit controls the power calibration circuit to start calibration, controls the power calibration circuit to output full-range voltage, collects its actual output voltage through a high-precision multimeter, and establishes and stores the third mapping relationship between the power supply's set output voltage and the actual output voltage. S5: Real-time fine-tuning of the power supply output voltage: The main control unit performs real-time fine-tuning of the output voltage of the power calibration circuit based on the accurate sampled value and the third mapping relationship between the power calibration circuit and the power calibration circuit.

[0013] The beneficial effects of this application are: This application constructs a three-level calibration architecture controlled by the main control unit, consisting of a reference source calibration circuit, a sampling calibration circuit, and a power calibration circuit. This forms a timed online calibration mechanism, ensuring that at least one sampling circuit is always in the latest calibration state and provides high-precision feedback, while the other is in a normal output sampling state. The output is fine-tuned based on the accurate sampling values ​​fed back by each channel sampling circuit. This allows for automatic and timed calibration of the sampling circuits while maintaining the normal and continuous operation of the power supply. It reliably compensates for any temperature drift or time drift generated by each sampling circuit since the last calibration, and can correct the sampling accuracy attenuation caused by temperature drift and time drift in real time. It can effectively eliminate system errors introduced by temperature drift and time drift of the sampling circuit, so as to maintain the long-term, continuous high-precision output of the power supply. The calibration process does not require high-precision stability devices or power outages, which effectively reduces hardware costs and greatly improves the operational continuity and production efficiency of the powered system.

[0014] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of 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 based on these drawings without creative effort.

[0016] Figure 1 This is a block diagram of a single-channel function implementation of a power calibration system in one embodiment of this application; Figure 2 This is a schematic diagram of the sampling and calibration circuit of a power calibration system in one embodiment of this application; Figure 3 This is a schematic diagram of the basic structure of a power calibration system in one embodiment of this application; Figure 4 This is a schematic diagram of the segmented approximation of the calibration system in one embodiment of this application; Figure 5 This is a basic structural diagram of a multi-channel power calibration system in the prior art. Detailed Implementation

[0017] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application. Similarly, the following examples are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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, an electrical connection, or a connection that allows communication between components; 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, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0019] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0020] To address the aforementioned problems, this application proposes improvements and innovations, including the following embodiments.

[0021] In one implementation, please refer to Figure 1-4The first aspect of this application provides a power calibration system, including a reference source calibration circuit, a sampling calibration circuit, a power calibration circuit, and a main control unit.

[0022] The main control unit is a microcontroller with a built-in timing module for triggering the sampling and calibration process at regular intervals. It receives and processes data collected from a high-precision multimeter, the main sampling circuit, and the secondary sampling circuit, executes a piecewise linear approximation algorithm, and updates the three-level mapping parameters. A built-in storage module stores relevant data for the first, second, and third mapping relationships. Based on the updated second mapping relationship, it corrects the sampling data, calculates the power output adjustment based on the third mapping relationship, and outputs a control signal to the power calibration circuit to achieve closed-loop stable control of the output voltage. Therefore, it serves as the core of the system, undertaking the functions of timing coordination, parameter storage, data processing, and closed-loop regulation.

[0023] In this embodiment, the reference source calibration circuit is electrically connected to the main control unit. The reference source calibration circuit acquires the actual output voltage of the reference source across its full range using a high-precision multimeter, establishes a first mapping relationship between the set output voltage and the actual output voltage of the reference source, and sends this first mapping relationship to the main control unit for storage. This provides the sampling calibration circuit with a precise reference voltage across its full range. The first mapping relationship is represented by a piecewise approximation function, with the formula: Vrt = krn × Vref + brn, where Vrt is the actual output voltage of the reference source measured by the high-precision multimeter, Vref is the set output voltage of the reference source, and krn and brn are the piecewise function parameters. Figure 4 As shown, the curve is represented by four straight lines of different ranges. The curve has four segments, where (x1, y1), (x2, y2), (x3, y3), and (x4, y4) are the segmentation points. The main control unit stores the parameters, segmentation points, and number of segments of each segment of the relational function.

[0024] Specifically, in calibration mode, the main control unit controls the reference source in the reference source calibration circuit to output a series of set voltage values ​​Vref covering its full range. At the same time, it accurately measures its actual output voltage Vrt using an external high-precision multimeter. The main control unit establishes a first mapping relationship between the collected (Vref, Vrt) data pairs through a piecewise approximation function, which can be expressed in general form as Vrt = krn × Vref + brn, where krn and brn are the slope and intercept parameters of the nth segment, respectively. The main control unit stores the parameters, segment points, and number of segments of all segments in the built-in storage module. After calibration, the reference source becomes a voltage reference with known accuracy, thus providing a full-range accurate reference voltage Vt1 (Vt1 = Vrt) for subsequent calibration.

[0025] In this embodiment, the sampling calibration circuit is electrically connected to the main control unit and the reference source calibration circuit. It includes several sets of main sampling circuits and sub-sampling circuits that match the number of power supply output channels, as well as switching switches controlled by the control unit. The sampling terminals of the main sampling circuit and sub-sampling circuit of each channel are respectively connected to the corresponding switching switches. In the calibration state, the main sampling circuit and sub-sampling circuit are switched to the output terminal of the reference source calibration circuit through the relay switch to poll and sample the full-range output voltage of the reference source. Based on the accurate reference voltage provided by the first mapping relationship, a second mapping relationship is established between the sampling voltage of each main sampling circuit and sub-sampling circuit of each channel and the actual output voltage of the reference source calibration circuit, so as to obtain the accurate sampling value of the power supply and prepare for adjusting the actual output voltage of the power supply. The second mapping relationship is represented by a piecewise approximation function, and the relationship is: Vt1 = Vs×Ksn + Bsn, where Vt1 is the actual output voltage of the reference source calibration circuit, Vs is the sampling voltage of the sampling circuit, and Ksn and Bsn are the piecewise function parameters. The main control unit stores the parameters, segment points and number of segments of each segment function of the relationship.

[0026] Specifically, the sampling calibration circuit is set up for each power output channel. Each channel contains two independent main sampling circuits and a secondary sampling circuit. The input terminals of the main and secondary sampling circuits are switched via a relay switch. Each channel's relay switch has three connection points: a common terminal connected to the input terminal of the sampling circuit, a set of normally open contacts connected to the power output terminal, and another set of normally closed contacts connected to the reference source output terminal. The main control unit commands the reference source calibration circuit to output multiple known precise voltages Vt1 and records the corresponding raw sampling values ​​Vs of the sampling circuit. Based on multiple sets of (Vt1, Vs) data pairs, a second mapping relationship is independently established for each sampling circuit through a piecewise approximation function. Its general form can be expressed as Vt1 = Ksn × Vs + Bsn, where Ksn and Bsn are the slope and intercept parameters of the nth segment, respectively. The parameters, segment points, and segment numbers of all segments are stored in the built-in storage module.

[0027] In this embodiment, the power calibration circuit is electrically connected to the main control unit and the sampling calibration circuit. It collects the actual output voltage of the power supply across its entire range using a high-precision multimeter, establishes a third mapping relationship between the power supply's set output voltage and the actual output voltage, and fine-tunes the actual output voltage of the power supply based on the accurate sampled values. The third mapping relationship is represented by a piecewise approximation function, with the following formula: Vpt = Vc×Kpn + Bpn, where Vpt is the actual output voltage of the power supply, Vc is the set output voltage of the power supply, and Kpn and Bpn are the piecewise function parameters. The main control unit stores the parameters, segmentation points, and number of segments of each segment of the function in this formula.

[0028] Specifically, during the initial calibration, the main control unit outputs a full-range set voltage value Vc through the power calibration circuit and uses a high-precision multimeter to measure the actual output voltage Vpt on the power output terminal. A third mapping relationship is established through the (Vc, Vpt) data, which can be expressed in general form as Vpt = Vc×Kpn + Bpn, where Kpn and Bpn are the slope and intercept parameters of the nth segment, respectively. The parameters, segment points, and number of segments of all segments are stored in the built-in storage module.

[0029] The control unit is configured to: establish and store a first mapping relationship, a second mapping relationship, and a third mapping relationship during the initial calibration phase; during continuous normal operation of the power supply, a timed control switch switches one of the main sampling circuit and the secondary sampling circuit that is currently in an idle state to the calibration state, so as to update the second mapping relationship corresponding to the sampling circuit, and correct the sampling voltage based on the updated second mapping relationship, while keeping the other sampling circuit in a normal output sampling state, and finely adjusting the output voltage of the power calibration circuit in real time in combination with the third mapping relationship.

[0030] It should be noted that the reference source calibration circuit only performs full-range reference voltage calibration when the power supply sampling circuit is calibrated. Since the reference source temperature is stable, the reference source circuit does not have time drift or temperature drift issues, and it does not need to be updated after the first mapping relationship is determined.

[0031] Corresponding to the aforementioned embodiments of the power supply calibration system, a second aspect of this application provides a method for operating a power supply calibration system, comprising the following steps: S1: Establishment of reference source mapping relationship: The main control unit controls the reference source calibration circuit to start calibration, controls the reference source to output full-range voltage, and collects the actual output voltage of the reference source across the full range through a high-precision multimeter, establishing and storing the first mapping relationship between the set output voltage and the actual output voltage of the reference source. S2: Establishment of sampling circuit mapping relationship: The main control unit controls the sampling calibration circuit to start calibration. Based on the accurate reference voltage provided by the first mapping relationship, the main sampling circuit and the sub-sampling circuit are switched to the output terminal of the reference source in sequence through the relay switch. The full-range output voltage of the reference source is polled and sampled. The second mapping relationship between the sampling voltage of each channel's main sampling circuit and sub-sampling circuit and the actual output voltage of the reference source calibration circuit is established and stored. S3: Sampling calibration circuit timed online calibration: During the continuous normal operation of the power supply, the main control unit controls the relay switch at regular intervals to switch one of the main sampling circuit and the auxiliary sampling circuit that is currently in the idle state to the output of the reference source for calibration. Based on the first mapping relationship, the corresponding second mapping relationship is updated, and the sampling voltage is corrected through the updated second mapping relationship to obtain an accurate sampling value and feed it back to the main control unit. At the same time, the other sampling circuit is kept in the normal output sampling state. S4: Power output mapping relationship establishment: The main control unit controls the power calibration circuit to start calibration, controls the power calibration circuit to output full-range voltage, collects its actual output voltage through a high-precision multimeter, and establishes and stores the third mapping relationship between the power supply's set output voltage and the actual output voltage. S5: Real-time fine-tuning of the power supply output voltage: The main control unit performs real-time fine-tuning of the output voltage of the power calibration circuit based on the accurate sampled value and the third mapping relationship between the power calibration circuit and the power calibration circuit.

[0032] For example, suppose a high-precision power supply system has completed the initial establishment of the first, second, and third mapping relationships and is in normal working condition, supplying power to an external load. After the system is powered on, the main control unit loads the stored first, second, and third mapping relationship parameters.

[0033] Initially, the main sampling circuit operates as the working path, connected to the power output terminal, and is in normal operation. The secondary sampling circuit operates as the idle path, connected to the output terminal of the reference source, and is in calibration mode. When the main control unit's timer expires, it initiates the calibration process. First, the main control unit controls the reference source to output a precise reference voltage Vt1 that closely approximates the current actual output voltage Vrt. Subsequently, it controls a relay switch to disconnect the input terminal of the main sampling circuit from the power output and switch it to the reference source. Simultaneously, it disconnects the input terminal of the secondary sampling circuit from the reference source and switches it to the power output. This switching action achieves a seamless transition of the sampling entity, with the secondary sampling circuit seamlessly taking over the sampling feedback task of the output voltage, ensuring uninterrupted control loop operation.

[0034] Idle path calibration. After switching, the main sampling circuit becomes the idle path and enters calibration mode, while the secondary sampling circuit becomes the working path. The main control unit uses a reference source to calibrate the main sampling circuit that was just switched off and updates the second mapping parameters of the main sampling circuit. After calibration, the system enters a new stable state: the secondary sampling circuit becomes the working path, and the main sampling circuit becomes the calibrated standby path. Subsequently, the main control unit resets the timer and waits for the next calibration cycle. When the next calibration cycle arrives, the connection states of the main and secondary circuits are swapped again to begin a new process.

[0035] Working path feedback correction. While the main sampling circuit is calibrated as an idle path, the newly switched secondary sampling circuit continues to sample. The main control unit calls the second mapping relationship parameters established by the previous calibration of the secondary sampling circuit to correct the sampled voltage value to an accurate sampled value in real time, and feeds it back to the main control unit to ensure stable output voltage.

[0036] Thus, the power supply calibration system and its working method of this application, by constructing a three-level calibration architecture controlled by the main control unit—a reference source calibration circuit, a sampling calibration circuit, and a power calibration circuit—forms a timed online calibration mechanism. This ensures that at least one sampling circuit is always in the latest calibration state and provides high-precision feedback, while the other is in a normal output sampling state and performs output fine-tuning based on the accurate sampling values ​​fed back by each channel sampling circuit. This allows for automatic and timed calibration of the sampling circuits while maintaining normal and continuous power supply operation. It reliably compensates for any temperature drift or time drift generated by each sampling circuit since the last calibration, and can correct the sampling accuracy attenuation caused by temperature drift and time drift in real time. It can effectively eliminate system errors introduced by temperature drift and time drift of the sampling circuit, so as to maintain long-term and continuous high-precision output of the power supply. The calibration process does not require high-precision stability devices or power outages, effectively reducing hardware costs and greatly improving the operational continuity and production efficiency of the powered system.

[0037] Finally, it should be noted that although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, all of which should be included within the protection scope of this application.

Claims

1. A power calibration system, characterized in that: The power calibration system includes a reference source calibration circuit, a sampling calibration circuit, a power calibration circuit, and a main control unit; The reference source calibration circuit is electrically connected to the main control unit and is used to establish a first mapping relationship between the set output voltage and the actual output voltage of the reference source, providing a precise reference voltage for the full range of the sampling calibration circuit. The sampling calibration circuit is electrically connected to the main control unit and the reference source calibration circuit. It includes at least one set of main sampling circuits and sub-sampling circuits, as well as a switching switch controlled by the control unit. The sampling terminal of each sampling circuit is connected to the switching switch. In the calibration state, the switching switch is switched to be connected to the output terminal of the reference source calibration circuit. Based on the accurate reference voltage provided by the first mapping relationship, a second mapping relationship is established between the sampling voltage of each sampling circuit and the actual output voltage of the reference source calibration circuit, so as to obtain the accurate sampling value of the power supply and prepare for adjusting the actual output voltage of the power supply. The power calibration circuit is electrically connected to the main control unit and the sampling calibration circuit, and is used to establish a third mapping relationship between the set output voltage and the actual output voltage of the power supply, and to fine-tune the actual output voltage of the power supply based on the precise sampling value. The control unit is configured to: establish and store the first mapping relationship, the second mapping relationship, and the third mapping relationship during the initial calibration phase; During continuous normal operation of the power supply, the switching switch is periodically controlled to switch one of the main sampling circuit and the secondary sampling circuit that is currently in an idle state to the calibration state, so as to update the second mapping relationship corresponding to the sampling circuit, and correct the sampling voltage based on the updated second mapping relationship. At the same time, the other sampling circuit is kept in the normal output sampling state, and the output voltage of the power calibration circuit is finely adjusted in real time in combination with the third mapping relationship.

2. The power calibration system according to claim 1, characterized in that: The number of main sampling circuits, the number of auxiliary sampling circuits, and the number of switching switches are matched with the number of power output channels. The sampling terminals of the main sampling circuits and auxiliary sampling circuits of each channel are respectively connected to the corresponding switching switches. In calibration mode, the main control unit controls the switching switch to connect the input terminals of the main sampling circuit or sub-sampling circuit corresponding to each channel to the output terminal of the reference source calibration circuit of the corresponding channel, thereby completing their respective calibrations. In normal power supply mode, the main control unit controls the switching switch to connect the input terminals of the main sampling circuit or sub-sampling circuit corresponding to each channel to the output terminal of the power calibration circuit of the corresponding channel.

3. The power calibration system according to claim 2, characterized in that: The reference source calibration circuit acquires the actual output voltage of the reference source across its full range using a high-precision multimeter, and establishes a first mapping relationship between the set output voltage and the actual output voltage of the reference source. This first mapping relationship is represented by a piecewise approximation function, and the relationship is: Vrt = krn×Vref + brn; In the formula, Vrt is the actual output voltage of the reference source measured by a high-precision multimeter, Vref is the set output voltage of the reference source, krn and brn are the piecewise function parameters, and the main control unit stores the parameters, segmentation points, and number of segments of each segment function in the relation.

4. The power calibration system according to claim 2, characterized in that: The sampling calibration circuit switches the main sampling circuit and the sub-sampling circuit to the output terminal of the reference source through a switching switch, and performs polling sampling on the full-range output voltage of the reference source to establish a second mapping relationship between the sampling voltage of each channel's main sampling circuit and sub-sampling circuit and the actual output voltage of the reference source calibration circuit. The second mapping relationship is represented by a piecewise approximation function, and the relationship is: Vt1 = Vs×Ksn + Bsn; In the formula, Vt1 is the actual output voltage of the reference source calibration circuit, Vs is the sampling voltage of the sampling circuit, Ksn and Bsn are the piecewise function parameters, and the main control unit stores the parameters, segmentation points and number of segments of each segment function of the relation.

5. The power calibration system according to claim 2, characterized in that: The power calibration circuit acquires the actual output voltage of the power supply across its full range using a high-precision multimeter, and establishes a third mapping relationship between the power supply's set output voltage and the actual output voltage. This third mapping relationship is represented by a piecewise approximation function, and the formula is: Vpt = Vc×Kpn + Bpn. In the formula, Vpt is the actual output voltage of the power supply, Vc is the set output voltage of the power supply, Kpn and Bpn are the piecewise function parameters, and the main control unit stores the parameters, segmentation points and number of segments of each segment function in the formula.

6. The power calibration system according to claim 1, characterized in that: The switching switch is a relay switch or a multiplexer.

7. The working method of the power supply calibration system, characterized in that, The power calibration system according to any one of claims 1-6 comprises the following steps: S1: Establishment of reference source mapping relationship: The main control unit controls the reference source calibration circuit to start calibration, controls the reference source to output full-range voltage, and collects the actual output voltage of the reference source across the full range through a high-precision multimeter, establishing and storing the first mapping relationship between the set output voltage and the actual output voltage of the reference source. S2: Establishment of sampling circuit mapping relationship: The main control unit controls the sampling calibration circuit to start calibration. Based on the accurate reference voltage provided by the first mapping relationship, the main sampling circuit and the sub-sampling circuit are switched to the output terminal of the reference source in sequence by the switching switch. The full-range output voltage of the reference source is polled and sampled. The second mapping relationship between the sampling voltage of each channel's main sampling circuit and sub-sampling circuit and the actual output voltage of the reference source calibration circuit is established and stored. S3: Timed online calibration of sampling calibration circuit: During the continuous normal operation of the power supply, the main control unit controls the switching switch to connect one of the main sampling circuit and the auxiliary sampling circuit that is currently in the idle state to the output of the reference source for calibration. Based on the first mapping relationship, the corresponding second mapping relationship is updated, and the sampling voltage is corrected based on the updated second mapping relationship to obtain an accurate sampling value and feed it back to the main control unit. At the same time, the other sampling circuit is kept in the normal output sampling state. S4: Power output mapping relationship establishment: The main control unit controls the power calibration circuit to start calibration, controls the power calibration circuit to output full-range voltage, collects its actual output voltage through a high-precision multimeter, and establishes and stores the third mapping relationship between the power supply's set output voltage and the actual output voltage. S5: Real-time fine-tuning of the power supply output voltage: The main control unit performs real-time fine-tuning of the output voltage of the power calibration circuit based on the precise sampled value and the third mapping relationship between the power calibration circuit.

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