Current Detection Device, Current Detection Method, Current Control Device, and Current Control Method

Abstract

Current detection device, current detection method, current control device, and current control method. Improve the detection accuracy of current. The current detection device includes a first current detection unit, a second current detection unit, a storage unit, a synthesis unit, an estimation unit, and an output unit. The first current detection unit detects the current flowing through a wire to be detected based on a shunt resistor. The second current detection unit detects the current based on a Hall element. The storage unit stores probability distributions respectively representing the uncertainties of the respective detection values of the first current detection unit and the second current detection unit. The synthesis unit synthesizes the probability distributions corresponding to the respective detection values. The estimation unit performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis unit. The output unit outputs the current estimated by maximum likelihood estimation.

Description

Technical Field

[0001] The disclosed embodiments relate to a current detection device, a current detection method, a current control device, and a current control method. Background Art

[0002] Conventionally, a current detection device that uses a shunt resistor to detect current and a current detection device that uses a Hall element to detect current are known. In addition, a current control device that controls an output current by using the current detected by the current detection device as a feedback value is also known.

[0003] In addition, a current detection device having both a shunt resistor and a Hall element has been proposed (for example, see Patent Document 1).

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-281774

[0005] However, in the conventional current detection device having both a shunt resistor and a Hall element, the detection value of the Hall element is corrected by using the detection value of the shunt resistor. That is, in the conventional current detection device, it cannot be said that both the detection value of the shunt resistor and the detection value of the Hall element are fully utilized, and there is room for improvement in the detection accuracy of the current. Summary of the Invention

[0006] An object of one aspect of the embodiments is to provide a current detection device, a current detection method, a current control device, and a current control method that can improve the detection accuracy of current.

[0007] A current detection device according to one aspect of the embodiments includes a first current detection unit, a second current detection unit, a storage unit, a synthesis unit, an estimation unit, and an output unit. The first current detection unit detects a current flowing through a wire to be detected based on a shunt resistor. The second current detection unit detects the current based on a Hall element. The storage unit stores probability distributions representing uncertainties of the respective detection values of the first current detection unit and the second current detection unit. The synthesis unit synthesizes the probability distributions corresponding to the respective detection values. The estimation unit performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis unit. The output unit outputs the current estimated by maximum likelihood estimation.

[0008] The current detection method of one aspect of the embodiment includes a first current detection step, a second current detection step, a storage step, a synthesis step, an estimation step, and an output step. The first current detection step detects the current flowing through the wire to be detected based on a shunt resistor. The second current detection step detects the current based on a Hall element. The storage step stores probability distributions respectively representing the uncertainties of the detection values of the first current detection step and the second current detection step. The synthesis step synthesizes the probability distributions corresponding to the respective detection values. The estimation step performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis step. The output step outputs the current obtained by maximum likelihood estimation.

[0009] The current control device of one aspect of the embodiment includes the above-described current detection device and an output control unit. The output control unit controls the output current based on the current output from the current detection device.

[0010] The current control method of one aspect of the embodiment includes a first current detection step, a second current detection step, a storage step, a synthesis step, an estimation step, an output step, and an output control step. The first current detection step detects the current flowing through the wire to be detected based on a shunt resistor. The second current detection step detects the current based on a Hall element. The storage step stores probability distributions respectively representing the uncertainties of the detection values of the first current detection step and the second current detection step. The synthesis step synthesizes the probability distributions corresponding to the respective detection values. The estimation step performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis step. The output step outputs the current obtained by maximum likelihood estimation. The output control step controls the output current according to the current output from the output step.

[0011] Advantageous Effects of the Invention

[0012] According to one aspect of the embodiment, it is possible to provide a current detection device, a current detection method, a current control device, and a current control method that improve the detection accuracy of the current. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram showing an outline of the current detection device of the embodiment.

[0014] Figure 2 It is a schematic diagram showing a structural example of a circuit.

[0015] Figure 3 It is a block diagram showing the structure of the current detection device.

[0016] Figure 4A It is one of the schematic diagrams showing the processing content of the synthesis unit.

[0017] Figure 4B It is the second schematic diagram showing the processing content of the synthesizing unit.

[0018] Figure 5 It is a schematic diagram showing the processing content of the estimating unit and the predicting unit.

[0019] Figure 6 It is a flowchart showing the processing steps executed by the current detection device.

[0020] Figure 7 It is a diagram showing a combination example of detection elements.

[0021] Figure 8 It is a block diagram showing the structure of the current control device.

[0022] Figure 9 It is a flowchart showing the processing steps executed by the current control device.

[0023] Reference Numeral Explanation

[0024] 5 Wire; 10 Control unit (CPU); 11 First current detection unit; 12 Second current detection unit; 13 Synthesizing unit; 14 Estimating unit; 15 Predicting unit; 16 Output unit; 20 Storage unit (memory); 21 Probability distribution information (probability distribution); 22 Learning information; 30 Shunt resistor; 31 First output line; 31a Isolation amplifier; 31b First phase shifter; 31c AD converter; 40 Hall element; 41 Second output line; 41a Amplifier; 41b Second phase shifter; 41c AD converter; 100 Current detection device; 200 Current control device; 210 Output control unit; D Probability distribution; MD Maximum likelihood distribution; PD Prediction distribution; SD Synthesis distribution. Detailed Embodiment

[0025] Hereinafter, embodiments of the current detection device, the current detection method, the current control device, and the current control method disclosed in the present application will be described in detail with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below.

[0026] First, use Figure 1 to describe the current detection device 100 of the embodiment. Figure 1 It is a schematic diagram showing the outline of the current detection device 100 of the embodiment. In addition, use Figure 2 and Figure 3 to describe the specific structure of the current detection device 100 later.

[0027] As Figure 1 shown, the current detection device 100 detects the current flowing through the wire to be detected by the first element and the second element having different characteristics respectively. The first element is, for example, a shunt resistor, and the second element is, for example, a Hall element. In addition, in Figure 1In each of the steps (step S1, step S2, and step S3), the horizontal axis of each curve graph represented by a dashed box is current (I), and the vertical axis is probability (P).

[0028] Here, the shunt resistor measures the voltage difference across the resistor and detects the current according to Ohm's law. However, there is a drawback that noise caused by the ambient temperature or self-heating is superimposed on the output. In addition, the Hall element measures the magnetic motive force generated around the current and detects the current in a non-contact manner according to Ampere's law. However, there is a drawback that ambient electromagnetic noise is superimposed on the output.

[0029] Thus, the shunt resistor and the Hall element each have the above-mentioned drawbacks. Therefore, when they are used alone, it cannot be said that the detection accuracy of the current is high enough, and there is room for improvement in terms of detection accuracy.

[0030] Therefore, in the current detection device 100 of the embodiment, the current flowing through the wire is detected by the first element and the second element having different characteristics respectively, and the detected values are processed as probability distributions respectively. Then, maximum likelihood estimation is performed on the current according to the combined distribution obtained by combining the respective probability distributions.

[0031] Here, as the first element and the second element, it is preferable to adopt a combination of elements with different reasons for accuracy degradation, such as a combination of a shunt resistor and a Hall element. By using elements with different characteristics in this way, the defects can be mutually compensated, and it is easy to improve the detection accuracy.

[0032] In addition, the above-mentioned "probability distribution" corresponds to a statistical distribution assumed to be a normal distribution, which takes the current value measured by each element as the mean (μ) and has a deviation with a standard deviation (σ). That is, it can be said that the probability distributions respectively represent the uncertainty of each detected value of each element. In addition, regarding the standard deviation (σ) of the current value measured by each element, it can be obtained from the catalog values of each element or based on experiments. In addition, the probability distribution can also be called a "probability distribution function".

[0033] Furthermore, in the current detection device 100 of the embodiment, in addition to performing maximum likelihood estimation on the current according to the combined distribution, maximum likelihood estimation is also performed on the current according to the updated distribution obtained by Bayesian updating of the latest combined distribution in the past combined distributions.

[0034] Hereinafter, the above processing content will be specifically described. First, the current detection device 100 regards each detection value of the current of the first element and the second element as a probability distribution D (step S1). Specifically, as shown by the dashed box in "step S1", the current value detected by the first element is "i1". At this time, the current detection device 100 processes the detection value of the first element as "probability distribution D1", and this "probability distribution D1" sets i1 as the average (μ) and has a standard deviation (σ) corresponding to the first element.

[0035] In addition, similarly, let the current value detected by the second element be "i2". At this time, the current detection device 100 processes the detection value of the second element as "probability distribution D2", and this "probability distribution D2" sets i2 as the average (μ) and has a standard deviation (σ) corresponding to the second element. In this way, by processing each detection value as a probability distribution representing the uncertainty of each detection value instead of processing each detection value as a simple value, the detection values of each element can be statistically synthesized in a proper form.

[0036] Next, the current detection device 100 generates a combined distribution SD for the current axis (I axis) (step S2). Specifically, as shown by the dashed box in "step S2", the probability distribution D1 and the probability distribution D2 shown in step S1 are combined, that is, the probability distribution D1 and the probability distribution D2 are combined for the probability axis (P axis) to generate the combined distribution SD. Here, the average (μ) of the combined distribution SD is set as "i3". In addition, the current detection device 100 may also use "i3" as the output value.

[0037] Next, the current detection device 100 performs Bayesian update on the combined distribution SD for the time axis (T axis) (step S3). Specifically, as shown by the dashed box in "step S3", an updated distribution MD is sequentially generated by performing Bayesian update on the latest combined distribution SD in the past combined distribution SD. And the current detection device 100 outputs the current value that is the average (μ) of the updated distribution MD as the result of the Bayesian update.

[0038] Here, Bayesian Updating is a known method in which the estimated value is updated accordingly when the information is updated at any time, thereby improving the estimation accuracy. In addition, Bayesian update is sometimes also called sequential Bayesian estimation.

[0039] In addition, in step S3, the latest time is exemplified as t0, the previous time is exemplified as t1, and the time before the previous time is exemplified as t2. Explaining in time series, the composite distribution MD of t2 is the composite distribution MD(t2), the composite distribution MD of t1 is the composite distribution MD(t1), and the composite distribution MD of t0 is the composite distribution MD(t0). In addition, the output value of t2 is i(t2), the output value of t1 is i(t1), and the output value of t0 is i(t0).

[0040] As shown in step S3, the standard deviation (σ) in each composite distribution MD becomes smaller through repeated Bayesian updates, that is, the spread in the current axis (I-axis) direction of the normal distribution becomes smaller. Therefore, the accuracy of current detection can be improved. In this way, by performing maximum likelihood in the time axis direction, the detection accuracy of the current can be further improved.

[0041] Next, use Figure 2 to illustrate Figure 1 an example of the circuit structure of the current detection device 100 shown. Figure 2 is a schematic diagram showing an example of the circuit structure. As Figure 2 shown, a shunt resistor 30 is provided on the wire 5 to be detected for current, and a Hall element 40 is provided non-contact with the wire 5. In addition, in Figure 2 the shown case, the shunt resistor 30 and the Hall element 40 are arranged closely. By arranging them in this way, miniaturization of the current detection device 100 can be achieved.

[0042] In addition, it is not necessary to arrange the Hall element 40 near the shunt resistor 30. That is, if the two elements are arranged along the wire 5 to be detected, the same current value can be obtained. Therefore, the shunt resistor 30 and the Hall element 40 can be separated significantly in appearance. Here, the Hall element 40 is an IC type Hall element, which can detect not only alternating current but also direct current.

[0043] On the first output line 31 which is the output line of the shunt resistor 30, an isolation amplifier 31a, a first phase shifter 31b, and an AD converter 31c are arranged in sequence from the upstream side. The isolation amplifier 31a is an amplifier that electrically insulates between the analog input signal and the output signal, and amplifies the voltage difference across the shunt resistor 30.

[0044] The first phase shifter 31b delays the phase of the output waveform of the isolation amplifier 31a by an arbitrary time in order to make the phase of the output waveform of the amplifier 41a on the second output line 41 consistent. The AD converter 31c converts the analog input signal into a digital output signal.

[0045] On the output line of the Hall element 40, i.e., the second output line 41, an amplifier 41a, a second phase shifter 41b, and an AD converter 41c are provided in sequence from the upstream side. The amplifier 41a amplifies the output value of the Hall element 40. The second phase shifter 41b delays the phase of the output of the amplifier 41a by an arbitrary time so as to match the phase of the output waveform of the isolation amplifier 31a of the first output line 31. The AD converter 41c converts the analog input signal into a digital output signal.

[0046] Thus, in the current detection device 100, phase shifters are respectively provided on both the first output line 31 corresponding to the shunt resistor 30 and the second output line 41 corresponding to the Hall element 40. Therefore, regardless of which of the systems of the shunt resistor 30 and the Hall element 40 has a phase delay, phase matching can be performed. So, it can be not only applied to DC current detection without any problem, but also applied to AC current detection. In addition, when the detection object is DC, the phase shifter on one of the first output line 31 and the second output line 41 can be omitted.

[0047] In addition, as Figure 2 shown, the first output line 31 and the second output line 41 merge on the downstream side, and a CPU (Central Processing Unit) 10 and a memory 20 are provided at the merge destination. Then, the output value generated by the CPU 10 is output to the outside. In addition, the CPU 10 and the memory 20 respectively correspond to the control unit 10 and the storage unit 20 described later. Figure 3

[0048] In addition, as Figure 2 shown, the first output line 31 and the second output line 41 do not include noise filters respectively. This is because, as described above, the current detection device 100 performs maximum likelihood estimation on the output value by synthesizing the probability distributions of two systems, so the influence of noise can be suppressed. In this way, by omitting the noise filters, cost reduction and miniaturization of the current detection device 100 can be achieved.

[0049] Next, Figure 3 is used to explain the structure of the current detection device 100. Figure 3 is a block diagram showing the structure of the current detection device 100. In addition, in Figure 3 , the description of the first output line 31 and the second output line 41 shown in Figure 2 is omitted.

[0050] As Figure 3 shown, the current detection device 100 includes a control unit 10, a storage unit 20, a shunt resistor 30, and a Hall element 40. In addition, regarding the shunt resistor 30 and the Hall element 40, Figure 2has been described, and thus, the description here is omitted.

[0051] The control unit 10 includes a first current detection unit 11, a second current detection unit 12, a synthesis unit 13, an estimation unit 14, a prediction unit 15, and an output unit 16. The storage unit 20 stores probability distribution information 21 and learning information 22.

[0052] Here, the control unit 10 includes, for example, a computer or various circuits having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), input / output ports, and the like.

[0053] The CPU of the computer functions as the first current detection unit 11, the second current detection unit 12, the synthesis unit 13, the estimation unit 14, the prediction unit 15, and the output unit 16 of the control unit 10, for example, by reading and executing a program stored in the ROM.

[0054] In addition, at least one or all of the first current detection unit 11, the second current detection unit 12, the synthesis unit 13, the estimation unit 14, the prediction unit 15, and the output unit 16 of the control unit 10 may be configured by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0055] The storage unit 20 corresponds to, for example, a RAM or an HDD. The RAM or HDD can store the probability distribution information 21 and the learning information 22. In addition, the control unit 10 may also acquire the above program or various information via another computer or a removable recording medium connected by a wired or wireless network.

[0056] The first current detection unit 11 outputs the current value of the shunt resistor 30 system to the synthesis unit 13. In addition, the second current detection unit 12 outputs the current value of the Hall element 40 system to the synthesis unit 13. In addition, as long as the shunt resistor 30 and the Hall element 40 are on the wire 5 to be the current detection object, there is no limitation on their positional relationship with each other.

[0057] Based on the probability distribution information 21 of the storage unit 20, the synthesis unit 13 transforms the current value of the shunt resistor 30 system into a probability distribution, and also converts the current value of the Hall element 40 system into a probability distribution. Then, the synthesis unit 13 generates a combined distribution by combining the respective probability distributions, and outputs the generated combined distribution to the estimation unit 14. In addition, use Figure 4A and Figure 4BThe more specific processing content of the synthesizing unit 13 will be described later.

[0058] Based on the synthesis distribution of the synthesizing unit 13, the estimating unit 14 performs maximum likelihood estimation on the current. Specifically, the estimating unit 14 generates a maximum likelihood distribution by synthesizing the prediction distribution of the predicting unit 15 and the synthesis distribution received from the synthesizing unit 13. Then, the estimating unit 14 outputs the average value (μ) of the generated maximum likelihood distribution as the estimated current to the output unit 16, associates the generated maximum likelihood distribution with time information, and stores it in the storage unit 20 as learning information 22.

[0059] Based on the learning information 22, the predicting unit 15 generates a prediction distribution that predicts the latest synthesis distribution, and outputs the generated prediction distribution to the estimating unit 14. In addition, use Figure 5 The more specific processing content of the estimating unit 14 and the predicting unit 15 will be described later. In addition, the output unit 16 outputs the estimated current received from the estimating unit 14 to the outside.

[0060] The probability distribution information 21 is information including the variance (σ) of the current value measured via the shunt resistor 30 and the variance (σ) of the current value measured via the Hall element 40. Here, the probability distribution information 21 may also be simply referred to as "probability distribution 21". The learning information 22 is information that associates the maximum likelihood distribution generated by the estimating unit 14 in the past with time. In addition, the learning information 22 may be only the information of the most recently generated maximum likelihood distribution, or may include information of multiple maximum likelihood distributions in a time series.

[0061] Next, use Figure 4A and Figure 4B to illustrate Figure 3 the processing content of the synthesizing unit 13 shown. Figure 4A and Figure 4B are one and two of the schematic diagrams showing the processing content of the synthesizing unit 13.

[0062] As Figure 4A shown, when the current value detected by the system of the shunt resistor 30 is i1, the synthesizing unit 13 generates a probability distribution Ds, which is a normal distribution having i1 as the mean (μ) and the standard deviation (σ) corresponding to the shunt resistor 30 in the probability distribution information 21.

[0063] In addition, when the current detected by the system of the Hall element 40 is i2, the synthesizing unit 13 generates a probability distribution Dh, which is a normal distribution having i2 as the mean (μ) and the standard deviation (σ) corresponding to the Hall element 40 in the probability distribution information 21.

[0064] Next, as Figure 4BAs shown, the synthesizing unit 13 generates a synthesized distribution SD for the current axis (I axis). Specifically, by synthesizing the Figure 4A probability distributions Ds and Dh shown, the synthesized distribution SD is generated. Then, the synthesizing unit 13 outputs the generated synthesized distribution SD to the estimating unit 14. Additionally, the average (μ) of the synthesized distribution SD, i.e., i3, can be used as the output value of the current detection device 100.

[0065] Next, the Figure 5 description Figure 3 of the processing contents of the estimating unit 14 and the predicting unit 15 shown will be given. Figure 5 is a schematic diagram showing the processing contents of the estimating unit 14 and the predicting unit 15. Additionally, Figure 5 the synthesized distribution SD shown is the latest synthesized distribution SD received by the estimating unit 14 from the synthesizing unit 13. Additionally, Figure 5 the predicted distribution PD shown is the latest predicted distribution PD received from the predicting unit 15.

[0066] The estimating unit 14 synthesizes the synthesized distribution SD received from the synthesizing unit 13 and the predicted distribution PD received from the predicting unit 15 for the probability axis (P axis) to generate the maximum likelihood distribution MD. Then, the estimating unit 14 stores the generated maximum likelihood distribution MD as the learning information 22 in the storage unit 20 and outputs the average (μ) of the maximum likelihood distribution MD, i.e., im, to the output unit 16.

[0067] In this way, the estimating unit 14 synthesizes the synthesized distribution SD corresponding to the latest current value and the predicted distribution PD corresponding to the predicted current value predicted based on the past synthesized distribution SD. Therefore, a possible current value reflecting the change history from the past can be obtained.

[0068] Next, the Figure 6 description of the processing steps executed by the current detection device 100 will be given. Figure 6 is a flowchart showing the processing steps executed by the current detection device 100. Additionally, the current detection device 100 repeats the Figure 6 processing procedure shown at each sampling timing.

[0069] As Figure 6 shown, the current detection device 100 detects the current via the shunt resistor 30 (step S101) and converts the detected value into a probability distribution based on the probability distribution information 21 (step S102). Additionally, the current detection device 100 detects the current via the Hall element 40 (step S103) and converts the detected value into a probability distribution based on the probability distribution information 21 (step S104). Additionally, steps S101 to S102 and steps S103 to S104 are executed in parallel.

[0070] Next, the synthesizing unit 13 generates the latest synthesized distribution (step S105) by synthesizing the probability distribution in step S102 and the probability distribution in step S104. Then, the predicting unit 15 generates a predicted distribution based on the learning information 22 (step S106). In addition, the estimating unit 14 generates a maximum likelihood distribution by combining the latest combined distribution in step S105 and the predicted distribution in step S106 (step S107).

[0071] In addition, the estimating unit 14 stores the maximum likelihood distribution in step S107 into the learning information 22 (step S108), and the output unit 16 outputs the current value based on the maximum likelihood distribution in step S107 (step S109), ending the process.

[0072] So far, the case where the current detection device 100 detects current through the combination of the shunt resistor and the Hall element has been described, but different combinations of detection elements can also be used.

[0073] Therefore, the following is used Figure 7 to illustrate the change in the combination of detection elements. Figure 7 is a diagram showing an example of the combination of detection elements. In addition, Figure 7 the combination shown in Example 1 is the combination corresponding to the current detection device 100 described Figures 2 to 6 above.

[0074] As Figure 7 shown, in "Example 1", a shunt resistor is used as the first detection element and a Hall element is used as the second detection element. In the case of the combination of Example 1, as described above, the detection object of the current is both AC and DC. In addition, the performance such as responsiveness and accuracy is also good.

[0075] "Example 2" is an example in which a "current transformer" is used instead of the Hall element in Example 1. That is, a shunt resistor is used as the first detection element and a current transformer is used as the second detection element. In the case of the combination of Example 2, different from the case of Example 1, the detection object is limited to AC. In addition, the performance such as responsiveness and accuracy is as good as that of Example 1.

[0076] "Example 3" is an example in which a "current transformer" is used instead of the shunt resistor in Example 1. That is, a current transformer is used as the first detection element and a Hall element is used as the second detection element respectively. In addition, in the case of the combination of Example 3, similar to the case of Example 2, the detection object is limited to AC. In addition, since both elements are of the type affected by electromagnetic noise, the performance such as responsiveness and accuracy is worse than that of Example 1 and Example 2.

[0077] However, a current control device 200 including the above current detection device 100 can also be configured. Therefore, the following is used Figure 8 andFigure 9 A description will be given of a current control device 200 having a current detection device 100. Figure 8 FIG. is a block diagram showing the structure of the current control device 200, Figure 9 and FIG. is a flowchart showing the processing steps executed by the current control device 200.

[0078] As Figure 8 shown, the current control device 200 includes a current detection device 100 and an output control unit 210. In addition, since the structure of the current detection device 100 has been described using Figure 3 etc., the description here is omitted. The output control unit 210 controls the output current based on the current output from the current detection device 100.

[0079] For example, the output control unit 210 performs control to make the output current approach the target current by using the current value detected by the current detection device 100 as a feedback value. Here, the output control unit 210 performs PI (proportional integral) control. Alternatively, P (proportional) control or PID (proportional integral derivative) control may be performed instead of PI control.

[0080] In this way, the current control device 200 performs current control using the detected current of the current detection device 100 with high detection accuracy of the current, and thus can improve the accuracy of current control. In addition, in Figure 8 , the case where the current detection device 100 is one has been illustrated, but the current control device 200 may also include a plurality of current detection devices 100.

[0081] As Figure 9 shown, the current control device 200 executes the processing steps of the current detection device 100 (refer to steps S101 to S109 of Figure 6 ) (step S201). Next, the output control unit 210 performs output control using the output value of the current detection device 100 as a feedback value (step S202), and ends the processing.

[0082] As described above, the current detection device 100 of the embodiment includes a first current detection unit 11, a second current detection unit 12, a storage unit 20, a synthesis unit 13, an estimation unit 14, and an output unit 16. The first current detection unit 11 detects the current flowing through the wire 5 to be detected via a shunt resistor 30. The second current detection unit 12 detects the current via a Hall element 40. The storage unit 20 stores probability distributions representing the uncertainties of the respective detection values of the first current detection unit 11 and the second current detection unit 12. The synthesis unit 13 synthesizes the probability distributions corresponding to the respective detection values. The estimation unit 14 performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis unit 13. The output unit 16 outputs the current estimated by maximum likelihood.

[0083] Thus, in the current detection device 100 according to the embodiment, the detection value of the shunt resistor 30 and the detection value of the Hall element 40 are respectively processed as probability distributions, and the current value is estimated based on the combined distribution obtained by combining the two distributions. That is, maximum likelihood in the current axis direction of the probability distribution (estimation of the most probable current value) is performed, so that the accuracy of current detection can be improved.

[0084] In addition, the current control device 200 according to the embodiment includes the current detection device 100 and the output control unit 210. The output control unit 210 controls the output current based on the current output from the current detection device 100. Thus, in the current control device 200 according to the embodiment, the output current is controlled based on the current output from the current detection device 100, so that the accuracy of current control can be improved.

[0085] In addition, in the above embodiment, the case where the number of the shunt resistors 30 or the Hall elements 40 is 1 is exemplified, but the current detection device 100 or the current control device 200 including a plurality of shunt resistors 30 or Hall elements 40 can also be configured.

[0086] Those skilled in the art can easily derive further effects and modification examples. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Claims

1. A current detection device, characterized in that, it has: a first current detection unit that detects the current flowing through a wire to be detected based on a shunt resistor; a second current detection unit that detects the current based on a Hall element; a storage unit that stores a probability distribution representing the uncertainty of each detection value of the first current detection unit and the second current detection unit respectively; a synthesis unit that synthesizes the probability distributions corresponding to the respective detection values; an estimation unit that performs maximum likelihood estimation of the current based on the synthesized distribution of the synthesis unit; and an output unit that outputs the current obtained by maximum likelihood estimation, wherein the estimation unit estimates the current based on an updated distribution obtained by Bayesian updating of the latest synthesized distribution among the past synthesized distributions.

2. The current detection device according to claim 1, characterized in that, the storage unit further stores the past synthesized distributions as learning information, the current detection device further has a prediction unit that predicts the next synthesized distribution based on the learning information, and the estimation unit estimates the current by synthesizing the predicted distribution of the prediction unit and the latest synthesized distribution.

3. The current detection device according to any one of claims 1 to 2, characterized in that, the current detection device further has: a first phase shifter provided on the output line of the shunt resistor; and a second phase shifter provided on the output line of the Hall element.

4. The current detection device according to claim 1, characterized in that, the output lines of the shunt resistor and the Hall element do not have a noise filter as a constituent element respectively.

5. A current detection method, characterized in that, it includes: a first current detection step of detecting the current flowing through a wire to be detected based on a shunt resistor; a second current detection step of detecting the current based on a Hall element; a storage step of storing a probability distribution representing the uncertainty of each detection value of the first current detection step and the second current detection step respectively; a synthesis step of synthesizing the probability distributions corresponding to the respective detection values; an estimation step of performing maximum likelihood estimation of the current based on the synthesized distribution of the synthesis step; and an output step of outputting the current obtained by maximum likelihood estimation, wherein in the estimation step, the current is estimated based on an updated distribution obtained by Bayesian updating of the latest synthesized distribution among the past synthesis steps.

6. A current control device, characterized in that, it has: the current detection device according to any one of claims 1 to 4; and an output control unit that controls the output current based on the current output from the current detection device.

7. A current control method, characterized in that, it includes: a first current detection step of detecting the current flowing through a wire to be detected based on a shunt resistor; a second current detection step of detecting the current based on a Hall element; A storage step of storing a probability distribution that respectively represents the uncertainties of the detection values of the first current detection step and the second current detection step; A synthesis step of synthesizing the probability distributions respectively corresponding to the detection values; An estimation step of performing maximum likelihood estimation on the current according to the synthesized distribution of the synthesis step; An output step of outputting the current estimated by maximum likelihood; And An output control step of controlling the output current according to the current output by the output step, wherein, in the estimation step, the current is estimated according to an updated distribution which is obtained by performing Bayesian update on the latest synthesized distribution in the past synthesis step.

Images