Remaining life prediction device and method

Abstract

To provide a remaining life predicting device capable of accurately predicting remaining life of a DC-DC converter as compared with prior art based on measurement results of induced electromotive force generated in a transformer of a DC-DC converter in operation.SOLUTION: A remaining life predicting device 1 includes a switching frequency measuring unit 13, a voltage ripple measuring unit 15, and a remaining life predicting unit 16. The switching frequency measuring unit 13 measures a switching frequency based on induced electromotive force generated in auxiliary winding 213. The voltage ripple measuring unit 15 measures a voltage ripple of induced electromotive force generated in the auxiliary winding 213. The remaining life predicting unit 16 predicts remaining life of an input capacitor Ci based on a switching frequency f measured by the switching frequency measuring unit 13, and predicts remaining life of an output capacitor Co based on a voltage ripple Vr measured by the voltage ripple measuring unit 15.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a remaining life prediction device and a remaining life prediction method for predicting the remaining life of a DC-DC converter. [Background technology]

[0002] Patent Document 1 discloses a method and electronic device for calculating the remaining life of a capacitor at a specified temperature in accordance with an equation based on Arrhenius' law. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-243269 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the invention disclosed in Patent Document 1 detects the temperature around the capacitor in the power supply circuit and indirectly calculates the remaining life by applying the temperature to an equation based on Arrhenius' law, and does not directly predict the remaining life by observing the actual operation of the power supply circuit.

[0005] The object of the present invention is to provide a remaining life prediction device and a remaining life prediction method that can predict the remaining life of a DCDC converter with greater accuracy than the prior art, based on the measurement results of the induced electromotive force generated in the transformer of the DCDC converter during operation. [Means for solving the problem]

[0006] A remaining life prediction device according to an embodiment of the present disclosure is a remaining life prediction device for predicting a remaining life of a DC-DC converter, The DC-DC converter is a transformer having a primary winding, a secondary winding capable of being electromagnetically coupled to the primary winding, and an auxiliary winding capable of being electromagnetically coupled to the primary winding and the secondary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on an induced electromotive force generated in the auxiliary winding; a voltage ripple measuring unit for measuring a voltage ripple of an induced electromotive force generated in the auxiliary winding; a remaining life prediction unit that predicts a remaining life of the input capacitor based on the switching frequency measured by the switching frequency measurement unit, and predicts a remaining life of the output capacitor based on the voltage ripple measured by the voltage ripple measurement unit.

[0007] A remaining life prediction device according to another aspect of the present disclosure is a remaining life prediction device for predicting a remaining life of a DC-DC converter, The DC-DC converter is A transformer having a primary winding and a secondary winding that can be electromagnetically coupled to the primary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on a voltage of the primary winding; and a remaining life prediction unit that predicts a remaining life of the input capacitor based on the switching frequency measured by the switching frequency measurement unit.

[0008] A remaining life prediction device according to yet another aspect of the present disclosure is a remaining life prediction device for predicting a remaining life of a DC-DC converter, The DC-DC converter is A transformer having a primary winding and a secondary winding that can be electromagnetically coupled to the primary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: A switching circuit that switches an input voltage; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction device includes: a voltage ripple measuring unit for measuring a voltage ripple of an induced electromotive force generated in the secondary winding; and a remaining life prediction unit that predicts a remaining life of the output capacitor based on the voltage ripple measured by the voltage ripple measurement unit.

[0009] A remaining life prediction method according to one embodiment of the present disclosure is a remaining life prediction method for predicting a remaining life of a DC-DC converter, comprising: The DC-DC converter is a transformer having a primary winding, a secondary winding capable of being electromagnetically coupled to the primary winding, and an auxiliary winding capable of being electromagnetically coupled to the primary winding and the secondary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction method includes: a switching frequency measuring step of measuring the switching frequency based on an induced electromotive force generated in the auxiliary winding; a voltage ripple measuring step of measuring a voltage ripple of an induced electromotive force generated in the auxiliary winding; and a remaining life prediction step of predicting a remaining life of the input capacitor based on the switching frequency measured in the switching frequency measurement step, and predicting a remaining life of the output capacitor based on the voltage ripple measured in the voltage ripple measurement step. Effect of the Invention

[0010] According to the remaining life prediction device and remaining life prediction method of the present disclosure, the remaining life of a DCDC converter can be predicted more accurately than conventional techniques based on the measurement results of the induced electromotive force generated in the transformer of the DCDC converter during operation. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example configuration of a remaining life prediction device according to an embodiment of the present disclosure. [Diagram 2] 2 is a flowchart showing an example of a method for predicting a remaining life of an input capacitor, which is executed by the remaining life prediction device of FIG. 1. [Figure 3A] 11 is a graph showing a simulation result of the output voltage and switching frequency of an input capacitor with no degradation over time. [Figure 3B] 11 is a graph showing a simulation result of the output voltage and switching frequency of an input capacitor in a deteriorated state over time. [Figure 4] 2 is a flowchart showing an example of a method for predicting a remaining life of an output capacitor, which is executed by the remaining life prediction device of FIG. 1. [Figure 5A] 4 is a graph showing a voltage ripple measured by a voltage ripple measuring unit when there is no degradation in the output capacitor. [Figure 5B] 11 is a graph showing a voltage ripple measured by a voltage ripple measuring unit when there is degradation in an output capacitor. [Figure 5C] 13 is a table showing a simulation result of the relationship between the ESR of the output capacitor and the voltage ripple. [Figure 6] 2 is a block diagram showing an example of a hardware configuration of a remaining life prediction unit in FIG. 1. [Figure 7] 1 is a block diagram showing an example of the configuration of a remaining life prediction device according to a first modified example of an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a remaining life prediction device according to the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, the same or similar components are denoted by the same reference numerals.

[0013] 1 is a block diagram showing an example of the configuration of a remaining life prediction device 1 according to an embodiment of the present disclosure. The remaining life prediction device 1 predicts the remaining life of a DC-DC converter 2.

[0014] In the present disclosure, "predicting the remaining life" includes deriving the remaining life of the DCDC converter 2 as a numerical value, estimating the presence or absence and the degree of deterioration of the DCDC converter 2, etc. For example, when the remaining life prediction device 1 determines that the DCDC converter 2 has deteriorated and cannot perform its original performance, it predicts that the remaining life of the DCDC converter 2 is short.

[0015] 1, remaining life prediction device 1 includes an auxiliary circuit 11, a frequency-voltage conversion circuit 12, a switching frequency measurement unit 13, a voltage detection circuit 14, a voltage ripple measurement unit 15, and a remaining life prediction unit 16.

[0016] The DC-DC converter 2, which is the target of the remaining life prediction process by the remaining life prediction device 1, includes a transformer 21, a primary side circuit 22, a secondary side circuit 23, and a control circuit 24. The transformer 21 has a primary winding 211, secondary windings 212a and 212b that can be electromagnetically coupled to the primary winding 211, and an auxiliary winding (tertiary winding) 213 that can be electromagnetically coupled to the primary winding 211 and the secondary windings 212a and 212b.

[0017] The primary side circuit 22 of the DC-DC converter 2 includes a DC power source Vi, an input capacitor Ci, a switching circuit 221, and a resonant circuit 222. The input capacitor Ci is, for example, an electrolytic capacitor. One end of the input capacitor Ci is connected to one of a pair of terminals of the DC power source Vi, and the other end of the input capacitor Ci is connected to the other terminal of the DC power source Vi. As a result, an input voltage from the DC power source Vi is applied to the input capacitor Ci, and the input capacitor Ci is charged.

[0018] In the example of Fig. 1, the resonant circuit 222 includes a resonant capacitor Cr and a resonant reactor Lr connected in series with each other. The resonant circuit 222 is inserted between the switching circuit 221 and the primary winding 211. That is, one end of the resonant circuit 222 is connected to the primary winding 211 of the transformer 21. In the example of Fig. 1, one end of the resonant reactor Lr is connected to the primary winding 211 of the transformer 21. The other end of the resonant circuit 222 is connected to a connection point between a switching element Q1 and a switching element Q2, which will be described later.

[0019] In the example of FIG. 1, the switching circuit 221 includes switching elements Q1 and Q2 connected in series with each other. In the example of FIG. 1, the switching elements Q1 and Q2 are n-type MOSFETs. The control circuit 24 complementarily switches the switching elements Q1 and Q2 on and off at a predetermined switching frequency f. That is, the control circuit 24 alternately performs a first control of turning on the switching element Q1 and turning off the switching element Q2, and a second control of turning off the switching element Q1 and turning on the switching element Q2, at the switching frequency f. In this way, the switching circuit 221 alternately connects the other end of the resonant circuit 222 to a pair of terminals of the input capacitor Ci at a predetermined switching frequency f in accordance with a control signal from the control circuit 24, thereby switching the input voltage.

[0020] The secondary side circuit 23 of the DC-DC converter 2 includes diodes D1 and D2 for rectifying the voltage input from the secondary windings 212a and 212b, and an output capacitor Co for smoothing the rectified voltage. The smoothed voltage is supplied to the load R.

[0021] In the remaining life prediction device 1, the induced electromotive force generated in the auxiliary winding 213 is transmitted to the frequency-voltage conversion circuit 12 and the voltage detection circuit 14 via the auxiliary circuit 11. The auxiliary circuit 11 may include, for example, a frequency detection circuit that detects the frequency of the induced electromotive force generated in the auxiliary winding 213, a rectifier circuit, etc. Such a frequency detection circuit may be a zero-cross detection circuit.

[0022] 2 is a flowchart showing an example of a method for predicting the remaining life of the input capacitor Ci. The frequency-voltage conversion circuit 12 converts the frequency of the input signal into a voltage and outputs it to the switching frequency measurement unit 13 (step S1). The switching frequency measurement unit 13 measures the frequency of the induced electromotive force generated in the auxiliary winding 213 based on the signal input from the frequency-voltage conversion circuit 12 (step S2). The switching frequency measurement unit 13 performs frequency measurement according to, for example, the direct method. Since this frequency corresponds to the switching frequency f of the DC-DC converter 2, the switching frequency measurement unit 13 is configured to be able to measure the switching frequency f.

[0023] The remaining life prediction unit 16 predicts the remaining life of the input capacitor Ci based on the switching frequency f measured by the switching frequency measurement unit 13 (step S3). Figures 3A and 3B are graphs for explaining the process of predicting the remaining life of the input capacitor Ci based on the switching frequency f. Figure 3A is a graph showing the simulation results of the output voltage and switching frequency f of the input capacitor Ci in a non-degraded state over time. Figure 3B is a graph showing the simulation results of the output voltage and switching frequency f of the input capacitor Ci in a degraded state over time.

[0024] When the input capacitor Ci deteriorates, the equivalent series resistance (ESR) of the input capacitor Ci increases, and the fluctuation of the output voltage and the switching frequency f increases. In a state where there is no deterioration, the difference between the maximum and minimum values ​​of the switching frequency f is Δf0, as shown in FIG. 3A. In a state where there is deterioration and the ESR has increased, the difference Δf1 between the maximum and minimum values ​​of the switching frequency f is larger than Δf0, as shown in FIG. 3B. The remaining life prediction unit 16, for example, determines whether the ratio Δf(t) / Δf0 of the difference Δf(t) between the maximum and minimum values ​​of the switching frequency f at the time of measurement to the difference Δf0 between the maximum and minimum values ​​of the switching frequency f in a state where there is no deterioration is greater than a predetermined threshold value f th1When the number of input capacitors Ci reaches 2 or more, for example, it is determined that the input capacitor Ci has deteriorated or that the remaining life of the input capacitor Ci is short.

[0025] Δf0 is an example of a "prescribed value" in the present disclosure, and can be measured in advance by testing the DCDC converter 2, the input capacitor Ci, and the like. Δf0 may be a switching frequency measured by the switching frequency measurement unit 13 during the initial operation of the DCDC converter 2. Here, the initial operation of the DCDC converter 2 refers to the operation when the components such as the DCDC converter 2, the input capacitor Ci, and the output capacitor Co are not degraded, and specifically includes the initial operation of the DCDC converter 2, the operation when the total operation time from the initial startup does not exceed a predetermined time, and the operation when the number of startups from the initial startup does not exceed a predetermined number.

[0026] Alternatively, the remaining life prediction unit 16 may determine whether Δf(t) is greater than or equal to a predetermined threshold value f th2 When this occurs, it may be determined that the input capacitor Ci has deteriorated.

[0027] The above description of determining whether the input capacitor Ci has deteriorated based on the difference Δf0 between the maximum and minimum values ​​of the switching frequency f is merely an example, and the present embodiment is not limited thereto. The remaining life prediction unit 16 can determine whether the input capacitor Ci has deteriorated based on the change over time of the switching frequency f. For example, when the switching frequency f increases and decreases periodically, the remaining life prediction unit 16 may determine whether the input capacitor Ci has deteriorated based on an average value obtained by averaging the difference between the maximum and minimum values ​​of the switching frequency f in one period over a predetermined period. In this way, the remaining life prediction unit 16 may determine that the input capacitor Ci has deteriorated or that the remaining life of the input capacitor Ci is short when the ratio of the amount of change over time of the switching frequency f at the time of measurement to the amount of change over time of the switching frequency f in a state without deterioration is equal to or greater than a predetermined threshold value, for example, 2 or more.

[0028] The output voltage and switching frequency f of the input capacitor Ci can be detected by measuring the induced voltage developed in the auxiliary winding 213.

[0029] 4 is a flowchart showing an example of a method for predicting the remaining life of the output capacitor Co. The voltage detection circuit 14 detects an induced voltage occurring in the auxiliary winding 213 (step S4). The voltage ripple measurement unit 15 measures the voltage ripple of the voltage detected by the voltage detection circuit 14 (step S5).

[0030] The remaining life prediction unit 16 predicts the remaining life of the output capacitor Co based on the voltage ripple Vr measured by the voltage ripple measurement unit 15 (step S6). Figures 5A and 5B are graphs for explaining the process of predicting the remaining life of the output capacitor Co based on the voltage ripple Vr. When the output capacitor Co deteriorates, the ESR increases and the voltage ripple Vr increases. In a state where there is no deterioration, the voltage ripple is Vr0 as shown in Figure 5A, and in a state where the capacitor has deteriorated and the ESR has increased, the voltage ripple is Vr1 which is larger than Vr0 as shown in Figure 5B.

[0031] FIG. 5C is a table showing the results of a simulation of the relationship between the ESR of the output capacitor Co and the voltage ripple Vr. In the simulation, the ESR of the output capacitor Co in a non-degraded state is set to 22 mΩ, and the ESR of the output capacitor Co in a degraded state is set to 150 mΩ. The voltage ripple of the output voltage of the output capacitor Co in a non-degraded state is 29.021 V, and in a degraded state is 30.148 V. In FIG. 5C, the difference between the maximum voltage and the minimum voltage (Vp-p (peak to peak voltage)) is set to the voltage ripple Vr. This voltage ripple Vr can be measured by the voltage ripple measuring unit 15 by observing the induced electromotive force of the auxiliary winding 213.

[0032] The remaining life prediction unit 16 is configured to, for example, determine whether the ratio Vr(t) / Vr0 of the voltage ripple Vr(t) at the time of measurement to the voltage ripple Vr0 in a state without deterioration is greater than or equal to a predetermined threshold value V th1or more, for example, 1.05 or more, it is determined that the output capacitor Co has deteriorated or the remaining life of the output capacitor Co is short. Vr0 is an example of a "prescribed value" in the present disclosure, and can be measured in advance by testing the DC-DC converter 2, the output capacitor Co, etc. Vr0 may be a voltage ripple measured by the voltage ripple measuring unit 15 at the time of initial operation of the DC-DC converter 2. Alternatively, the remaining life predicting unit 16 determines whether Vr(t) is greater than or equal to a predetermined threshold value V th2 When this occurs, it may be determined that the output capacitor Co has deteriorated.

[0033] The remaining life of the DC-DC converter 2 can be predicted based on at least one of the remaining life of the input capacitor Ci and the output capacitor Co. Therefore, the remaining life prediction device 1 can predict the remaining life of the DC-DC converter 2 by estimating at least one of the remaining life of the input capacitor Ci and the output capacitor Co as described above.

[0034] Fig. 6 is a block diagram showing an example of a hardware configuration of remaining life prediction unit 16 in Fig. 1. For example, remaining life prediction unit 16 includes input unit 161, output unit 162, communication interface (I / F) 163, arithmetic circuit 164, and storage unit 165.

[0035] The input unit 161 is an interface circuit that connects the remaining life prediction unit 16 to external circuits such as the frequency-voltage conversion circuit 12 and the voltage detection circuit 14 in order to input information to the remaining life prediction unit 16. The output unit 162 is an interface circuit that connects the remaining life prediction unit 16 to an external device in order to output information from the remaining life prediction unit 16. The communication interface 163 includes an interface circuit that enables a communication connection between the remaining life prediction unit 16 and an external device. The communication interface 163 communicates according to an existing wired communication standard or wireless communication standard.

[0036] The arithmetic circuit 164 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and controls the operation of the remaining life prediction unit 16 in response to information processing. Such information processing is realized by the arithmetic circuit 164 executing a program. The arithmetic circuit 164 may be realized by one or more dedicated processors. Furthermore, regarding the components of the arithmetic circuit 164, functions may be omitted, replaced, or added as appropriate depending on the embodiment. The arithmetic circuit 164 may be configured with various semiconductor integrated circuits such as a CPU, an MPU, a GPU, a microcomputer, a DSP, an FPGA, an ASIC, etc.

[0037] The storage unit 165 is a medium that stores information such as a program by electrical, magnetic, optical, mechanical, or chemical action so that a computer or other device, machine, etc. can read the information such as the recorded program. The storage unit 165 is, for example, an auxiliary storage device such as a hard disk drive or a solid state drive.

[0038] The above components of remaining life prediction unit 16 do not need to be housed in one housing, and may be realized by multiple computer systems. Similarly to remaining life prediction unit 16, auxiliary circuit 11, frequency-voltage conversion circuit 12, switching frequency measurement unit 13, voltage detection circuit 14, and voltage ripple measurement unit 15 of remaining life prediction device 1 may also be configured by one or more semiconductor integrated circuits, computer systems, etc.

[0039] As described above, the remaining life prediction device 1 according to the present embodiment predicts the remaining life of the DCDC converter 2. The DCDC converter 2 includes a transformer 21, a primary side circuit 22, and a secondary side circuit 23. The transformer 21 has a primary winding 211, secondary windings 212a and 212b that can be electromagnetically coupled to the primary winding 211, and an auxiliary winding 213 that can be electromagnetically coupled to the primary winding 211 and the secondary windings 212a and 212b. The primary side circuit 22 is connected to the primary winding 211. The secondary side circuit 23 is connected to the secondary windings 212a and 212b. The primary side circuit 22 includes an input capacitor Ci to which an input voltage is applied, a switching circuit 221 that switches the input voltage at a predetermined switching frequency f, and a resonant circuit 222 inserted between the switching circuit 221 and the primary winding 211. The secondary side circuit 23 includes an output capacitor Co that smoothes the voltage input from the secondary windings 212a, 212b. The remaining life prediction device 1 includes a switching frequency measurement unit 13, a voltage ripple measurement unit 15, and a remaining life prediction unit 16. The switching frequency measurement unit 13 measures a switching frequency f based on an induced electromotive force generated in the auxiliary winding 213. The voltage ripple measurement unit 15 measures a voltage ripple Vr of the induced electromotive force generated in the auxiliary winding 213. The remaining life prediction unit 16 predicts the remaining life of the input capacitor Ci based on the switching frequency f measured by the switching frequency measurement unit 13, and predicts the remaining life of the output capacitor Co based on the voltage ripple Vr measured by the voltage ripple measurement unit 15.

[0040] According to this configuration, by measuring the induced electromotive force generated in the auxiliary winding 213, it is possible to directly observe the operation of the DCDC converter 2 and accurately predict the remaining life. From this remaining life, it is possible to determine the replacement timing of the DCDC converter 2, the input capacitor Ci, or the output capacitor Co and to develop a maintenance plan, thereby preventing a situation in which a device receiving power from the DCDC converter 2 stops due to the expiration of its life.

[0041] In addition, the remaining life prediction device 1 can predict the remaining life from outside the DCDC converter 2 via the auxiliary winding 213. Therefore, unlike the conventional technology, it is not necessary to incorporate a device for predicting the remaining life into the power supply device, and the size and cost of the DCDC converter 2 can be reduced. Furthermore, the primary side circuit of the DCDC converter is usually difficult to access easily, and even if it is possible to access it, there is a risk of harm to the body of the person measuring it, the measuring equipment, etc., due to the high voltage and high current. According to the remaining life prediction device 1, it is possible to predict the remaining life from outside the DCDC converter 2 without causing such difficulties and risks of harm.

[0042] Specifically, the remaining life prediction unit 16 may predict that the remaining life of the input capacitor Ci is short when the ratio of the amount of change in switching frequency at the current time to the amount of change in switching frequency at the initial operation is equal to or greater than a predetermined threshold. The remaining life prediction unit 16 may predict that the remaining life of the output capacitor Co is short when the ratio of the voltage ripple at the current time to the voltage ripple at the initial operation is equal to or greater than a predetermined threshold. This makes it possible to obtain the same effect as above.

[0043] Furthermore, the remaining life predictor 16 may predict that the remaining life of the input capacitor Ci is short when the amount of change over time in the switching frequency at the current time is equal to or greater than a predetermined threshold, and may predict that the remaining life of the output capacitor Co is short when the voltage ripple at the current time is equal to or greater than a predetermined threshold. This makes it possible to obtain the same effect as above based only on the measurement results at the current time.

[0044] (Modification) Although the embodiment of the present disclosure has been described in detail above, the above description is merely an example of the present disclosure in every respect. Various improvements and modifications can be made without departing from the scope of the present disclosure. For example, the following modifications are possible. In the following, the same reference numerals are used for the same components as in the above embodiment, and the description of the same points as in the above embodiment will be omitted as appropriate. The following modifications can be combined as appropriate.

[0045] (First Modification) 7 is a block diagram showing a configuration example of a remaining life prediction device 201 according to a first modified example of the embodiment of the present disclosure. Compared with the remaining life prediction device 1 of FIG. 1, the remaining life prediction device 201 does not include the auxiliary circuit 11, and further includes a frequency detection circuit 17. Moreover, the transformer 21 of the DCDC converter 2 does not have an auxiliary winding. In the first modified example, the remaining life prediction device 201 detects the frequency of the output voltage of the primary side circuit 22 by the frequency detection circuit 17 without using an auxiliary winding. Moreover, the voltage detection circuit 14 of the remaining life prediction device 201 detects the voltage between a pair of terminals of the output capacitor Co without using an auxiliary winding.

[0046] Even with this configuration, the remaining life prediction device 201 can accurately predict the remaining life by directly observing the operation of the DCDC converter 2. Since the replacement timing of the DCDC converter 2, the input capacitor Ci, or the output capacitor Co can be grasped from this remaining life and a maintenance plan can be made, it is possible to prevent a situation in which a device receiving power from the DCDC converter 2 stops due to the expiration of its life.

[0047] (Second Modification) In the above embodiment, as shown in FIG. 1, an example has been described in which the primary side circuit 22 of the DC-DC converter 2 includes the DC power supply Vi. However, the DC power may be input from outside the DC-DC converter 2.

[0048] (Third Modification) In the above embodiment, an example has been described in which it is determined that the input capacitor Ci has deteriorated or that the remaining life of the input capacitor Ci is short when Δf(t) / Δf0 or Δf(t) becomes equal to or greater than a predetermined threshold. However, the present disclosure is not limited to this. For example, the storage unit 165 (see FIG. 6) may store in advance a table showing the relationship between the difference Δf between the maximum value and the minimum value of the switching frequency f and the remaining life of the input capacitor Ci, and the remaining life prediction unit 16 may obtain the remaining life of the input capacitor Ci for the difference Δf(t) between the maximum value and the minimum value of the switching frequency f at the time of measurement from the table by a table lookup method. Such a remaining life of the input capacitor Ci is obtained in advance by testing the DC-DC converter 2, the input capacitor Ci, etc. This makes it possible to more accurately estimate the remaining life by the remaining life prediction unit 16, as well as to improve the processing speed and reduce the processing load.

[0049] (Fourth Modification) In the above embodiment, an example has been described in which it is determined that the output capacitor Co has deteriorated or that the remaining life of the output capacitor Co is short when Vr(t) / Vr0 or Vr(t) becomes equal to or greater than a predetermined threshold. However, the present disclosure is not limited to this. For example, the storage unit 165 (see FIG. 6) may store in advance a table showing the relationship between the voltage ripple Vr and the remaining life of the output capacitor Co, and the remaining life prediction unit 16 may obtain the remaining life of the output capacitor Co for the voltage ripple Vr(t) at the time of measurement from the table by a table lookup method. Such a remaining life of the output capacitor Co is obtained in advance by testing the DC-DC converter 2, the output capacitor Co, and the like. This allows the remaining life prediction unit 16 to estimate the remaining life with higher accuracy, while also improving the processing speed and reducing the processing load. [Explanation of symbols]

[0050] 1,201 Remaining life prediction device 2 DC-DC converter 11 Auxiliary circuit 12 Frequency-to-voltage conversion circuit 13 Switching frequency measurement section 14 Voltage detection circuit 15 Voltage ripple measurement section 16 Remaining life prediction section 17 Frequency detection circuit 21. Trans 22 Primary circuit 23 Secondary circuit 24 Control circuit 161 Input section 162 Output section 163 Communication Interface 164 Arithmetic circuit 165 Storage section 211 Primary Winding 212a Secondary Winding 212b Secondary Winding 213 Auxiliary Winding 221 Switching Circuits 222 Resonant circuit

Claims

1. A remaining life prediction device for predicting a remaining life of a DC-DC converter, The DC-DC converter comprises: a transformer having a primary winding, a secondary winding capable of being electromagnetically coupled to the primary winding, and an auxiliary winding capable of being electromagnetically coupled to the primary winding and the secondary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on an induced electromotive force generated in the auxiliary winding; a voltage ripple measuring unit for measuring a voltage ripple of an induced electromotive force generated in the auxiliary winding; a remaining life prediction unit that predicts deterioration of the input capacitor or the output capacitor based on the switching frequency measured by the switching frequency measurement unit and the voltage ripple measured by the voltage ripple measurement unit, thereby predicting a remaining life of the DC-DC converter, The remaining life prediction unit is A ratio of a change in the switching frequency at the present time to a change in the switching frequency at an initial operation time is equal to or greater than a predetermined threshold value, or When a ratio of the voltage ripple at the present time to the voltage ripple at the time of initial operation is equal to or greater than a predetermined threshold value, The remaining life of the DC-DC converter is predicted to be short. Remaining life prediction device.

2. A remaining life prediction device for predicting a remaining life of a DC-DC converter, comprising: The DC-DC converter comprises: a transformer having a primary winding, a secondary winding capable of being electromagnetically coupled to the primary winding, and an auxiliary winding capable of being electromagnetically coupled to the primary winding and the secondary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on an induced electromotive force generated in the auxiliary winding; a voltage ripple measuring unit for measuring a voltage ripple of an induced electromotive force generated in the auxiliary winding; a remaining life prediction unit that predicts deterioration of the input capacitor or the output capacitor based on the switching frequency measured by the switching frequency measurement unit and the voltage ripple measured by the voltage ripple measurement unit, thereby predicting a remaining life of the DC-DC converter, The remaining life prediction unit is When the current amount of change in the switching frequency over time is equal to or greater than a predetermined threshold value, or When the current voltage ripple is equal to or greater than a predetermined threshold, The remaining life of the DC-DC converter is predicted to be short. Remaining life prediction device.

3. A remaining life prediction device for predicting a remaining life of a DC-DC converter, The DC-DC converter comprises: A transformer having a primary winding and a secondary winding that can be electromagnetically coupled to the primary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on a voltage of the primary winding; a remaining life prediction unit that predicts a remaining life of the input capacitor based on the switching frequency measured by the switching frequency measurement unit, the remaining life prediction unit predicts that the remaining life of the input capacitor is short when a ratio of a current amount of change in the switching frequency to an amount of change in the switching frequency at an initial operation time is equal to or greater than a predetermined threshold value. Remaining life prediction device.

4. The transformer further includes an auxiliary winding that can be electromagnetically coupled to the primary winding, The switching frequency measurement unit measures the switching frequency based on an induced electromotive force generated in the auxiliary winding. The remaining life predicting device according to claim 3 .

5. A remaining life prediction device for predicting a remaining life of a DC-DC converter, comprising: The DC-DC converter comprises: A transformer having a primary winding and a secondary winding that can be electromagnetically coupled to the primary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, The remaining life prediction device includes: a switching frequency measurement unit that measures the switching frequency based on a voltage of the primary winding; a remaining life prediction unit that predicts a remaining life of the input capacitor based on the switching frequency measured by the switching frequency measurement unit, The remaining life prediction unit is predicting that the remaining life of the input capacitor is short when a current amount of change over time of the switching frequency is equal to or greater than a predetermined threshold value; Remaining life prediction device.

6. A remaining life prediction method for predicting a remaining life of a DC-DC converter, comprising: The DC-DC converter comprises: a transformer having a primary winding, a secondary winding capable of being electromagnetically coupled to the primary winding, and an auxiliary winding capable of being electromagnetically coupled to the primary winding and the secondary winding; a primary side circuit connected to the primary winding; a secondary side circuit connected to the secondary winding, The primary side circuit includes: an input capacitor to which an input voltage is applied; a switching circuit that switches the input voltage at a predetermined switching frequency; a resonant circuit inserted between the switching circuit and the primary winding, the secondary side circuit includes an output capacitor that smoothes a voltage input from the secondary winding; The remaining life prediction method includes: a switching frequency measuring step of measuring the switching frequency based on an induced electromotive force generated in the auxiliary winding; a voltage ripple measuring step of measuring a voltage ripple of an induced electromotive force generated in the auxiliary winding; a remaining life prediction step of predicting a remaining life of the DC-DC converter by predicting deterioration of the input capacitor or the output capacitor based on the switching frequency measured in the switching frequency measurement step and the voltage ripple measured in the voltage ripple measurement step, the remaining life prediction step includes predicting that the remaining life of the DC-DC converter is short when a ratio of a temporal change in the switching frequency at a current time to a temporal change in the switching frequency at an initial operation is equal to or greater than a predetermined threshold, or when a ratio of the voltage ripple at a current time to the voltage ripple at an initial operation is equal to or greater than a predetermined threshold. Remaining life prediction method.

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