# US 10,120,037 B2 · Power inductor evaluation apparatus and power inductor evaluation program

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- Number: US 10,120,037 B2
- Document ID: US10120037B2
- Status: Granted
- Kind: B2
- Application number: 15/009,202
- Filed: 2016-01-28
- Published: 2016-08-04
- Granted: 2018-11-06
- Earliest claimed: 2015-02-02
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Ko Yamanaga
- Web page: https://patentgrep.com/patent/US10120037B2

## CPC

- G01R 31/40: Testing power supplies (testing photovoltaic devices H02S50/10)
- G01R 31/2848: {using simulation}
- G06F 30/36: Circuit design at the analogue level
- G06F 30/367: Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
- G06F 30/373: Design optimisation
- H02M 3/04: by static converters
- G06F 30/00: Computer-aided design [CAD]
- G06F 2119/06: Power analysis or power optimisation
- G06F 2119/16: Equivalence checking
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

A power inductor evaluation apparatus includes a storage unit and a determination unit. The storage unit stores the simulation model of a DC-DC converter. The simulation model includes the equivalent circuit model of a power inductor, including a DC superimposition characteristics slope α and a saturation current Isat as parameters. The determination unit inputs the DC superimposition characteristics slope α and the saturation current Isat into the simulation model of the DC-DC converter and performs simulation, and determines whether or not the power inductor having the DC superimposition characteristics slope α and the saturation current Isat is usable on the basis of whether or not the simulation results satisfy design requirements (e.g, a permissible ripple voltage and a peak current).

## Claims

### Claim 1

A power inductor evaluation apparatus comprising:
a storage unit storing a circuit model that includes an equivalent circuit model of a power inductor and simulates a Direct Current to Direct Current (DC-DC) converter, the equivalent circuit model including a Direct Current (DC) superimposition characteristics slope and a saturation current as parameters;
a reception unit receiving input of the DC superimposition characteristics slope and the saturation current of the power inductor to be a determination object and input of a requirement including at least one of a permissible ripple voltage and a peak current; and
a determination unit that performs an arithmetic operation by inputting the DC superimposition characteristics slope and saturation current received by the reception unit into the circuit model of the DC-DC converter including the equivalent circuit model of the power inductor and determines whether or not the power inductor having the DC superimposition characteristics slope and saturation current is usable on a basis of whether or not a result of the arithmetic operation satisfies the requirement thus providing a basis for power inductor optimization based upon DC superimposition characteristics slope and/or saturation current margins.

### Claim 2 (depends on 1)

The power inductor evaluation apparatus according to claim 1,
wherein the power inductor is one of a plurality of power inductors and the storage unit stores, for each of the plurality of power inductors, the DC superimposition characteristics slope and the saturation current in association with a corresponding power inductor,
wherein the reception unit receives, instead of the DC superimposition characteristics slope and saturation current of the power inductor to be a determination object, input of information identifying the power inductor, and
wherein the determination unit acquires the DC superimposition characteristics slope and the saturation current corresponding to the information identifying the power inductor from the storage unit, and determines whether or not the power inductor is usable.

### Claim 3 (depends on 1)

The power inductor evaluation apparatus according to claim 1, wherein the equivalent circuit model of the power inductor approximates the DC superimposition characteristics slope by using a Fermi distribution function.

### Claim 4 (depends on 1)

The power inductor evaluation apparatus according to claim 1, further comprising an acquisition unit that integrates results of usable/unusable determination performed regarding combinations of a plurality of DC superimposition characteristics slopes and respective saturation currents, and acquires a list of the combinations of DC superimposition characteristics slopes and respective saturation currents determined to be usable.

### Claim 5 (depends on 1)

A power inductor evaluation program that resides in a non-transitory computer-readable storage medium and that causes a computer to function as the power inductor evaluation apparatus according to claim 1.

### Claim 6 (depends on 1)

The power inductor evaluation apparatus according to claim 1, wherein the power inductor is one of a plurality of power inductors and the storage unit stores, for each of the plurality of power inductors, the DC superimposition characteristics slope and the saturation current in association with a corresponding power inductor, and the power inductor evaluation apparatus provides DC superimposition characteristics slope and saturation current margin criteria for selecting an optimal power inductor.

### Claim 7

A power inductor evaluation apparatus comprising:
a storage unit storing a circuit model that includes an equivalent circuit model of a power inductor and simulates a Direct Current to Direct Current (DC-DC) converter, the equivalent circuit model including measured Direct Current (DC) superimposition characteristics data as a parameter;
a reception unit receiving input of the measured DC superimposition characteristics data of the power inductor to be a determination object component, an operation condition of the DC-DC converter, and a requirement including at least one of a permissible ripple voltage and a peak current; and
a determination unit that performs an arithmetic operation by inputting the measured DC superimposition characteristics data received by the reception unit into the circuit model of the DC-DC converter including the equivalent circuit model of the power inductor and determines whether or not the power inductor is usable on a basis of whether or not a result of the arithmetic operation satisfies the requirement in the operation condition thus providing a basis for power inductor optimization based upon DC superimposition characteristics slope and/or saturation current margins.

### Claim 8 (depends on 7)

The power inductor evaluation apparatus according to claim 7,
wherein the power inductor is one of a plurality of power inductors and the storage unit stores, for each of the plurality of power inductors, the measured DC superimposition characteristics data in association with a corresponding power inductor,
wherein the reception unit receives, instead of the measured DC superimposition characteristics data of the power inductor to be a determination object, input of information identifying the power inductor, and
wherein the determination unit acquires the measured DC superimposition characteristics data corresponding to the received information identifying the power inductor from the storage unit, and determines whether or not the power inductor is usable.

### Claim 9 (depends on 7)

The power inductor evaluation apparatus according to claim 7, further comprising an acquisition unit that integrates a plurality of results of usable/unusable determination performed by changing an operation condition of the DC-DC converter, and acquires a range of operation conditions of the DC-DC converter determined to be usable.

### Claim 10 (depends on 9)

The power inductor evaluation apparatus according to claim 9, wherein the operation conditions of the DC-DC converter include at least one of an input voltage, an output voltage, an operating frequency, and an output current.

### Claim 11 (depends on 7)

The power inductor evaluation apparatus according to claim 7, wherein the power inductor is one of a plurality of power inductors and the storage unit stores, for each of the plurality of power inductors, the DC superimposition characteristics slope and the saturation current in association with a corresponding power inductor, and the power inductor evaluation apparatus provides DC superimposition characteristics slope and saturation current margin criteria for selecting an optimal power inductor.