JP2011130595A - Fuel cell system - Google Patents

Abstract

A fuel cell system having a resonance reactor having a saturable characteristic of an optimum configuration in a boost converter.
A coil La as a resonance reactor having a saturable characteristic used in such a fuel cell system is formed by winding a winding 20 around a center core 18 of a core 5 formed of a magnetic material. The center core 18 is formed with gaps 31, 32, 33 formed of a nonmagnetic material, and a core region formed of a magnetic material between the gaps 31, 32, 33 and the winding 20. 181a, 181b, 182a, 182b, 183a, 183b are provided.
[Selection] Figure 5

Description

  The present invention relates to a fuel cell system.

  In recent years, a fuel cell has attracted attention as a power source excellent in operating efficiency and environmental performance. Although the fuel cell can output the electric power according to the demand of the load by controlling the supply amount of the fuel gas, the output voltage of the fuel cell may not match the voltage required by the load. Therefore, a technique for matching the output voltage of the fuel cell with the voltage required by the load by converting the output voltage of the fuel cell with a DC / DC converter has been proposed (for example, see Patent Document 1).

  The DC / DC converter uses an electronic switch, a diode, and an inductance as basic elements, and converts a voltage by a switching operation of the electronic switch. The DC / DC converter includes a snubber circuit that absorbs the ripple generated by the switching operation of the electronic switch. The snubber circuit absorbs ripple with a capacitor. Since the energy conversion efficiency of the DC / DC converter is reduced unless the charge stored in the capacitor is effectively used, a technique for effectively using the charge stored in the capacitor is proposed (for example, Patent Document 2).

  Although it is known that a DC-DC converter can reduce switching loss by performing soft switching, if this is used for boosting a fuel cell, electric power stored for soft switching is input to the fuel cell. It is difficult to apply. Therefore, as a fuel cell system that can boost the output voltage of the fuel cell by soft switching, a technique described in Patent Document 3 below has been proposed.

  The fuel cell system described in Patent Document 3 includes a boost converter, which includes a first switch (configured by a switch element and a diode) and a first coil. A main booster that boosts the output voltage of the fuel cell with the back electromotive force of the first coil that is generated when the switch performs switching operation with respect to the first coil, and a capacitor that adjusts the potential difference between both poles of the first switch with the amount of charge And reducing the switching loss of the first switch by adjusting the amount of electricity stored in the capacitor during switching operation, and includes a second switch (configured by a switch element and a diode) and a secondary coil. Part.

  By the way, in such a boost converter, when both the first switch and the second switch are turned off, a reverse current instantaneously flows through the diode constituting the second switch and stops instantaneously, and this decrease generates a surge voltage. To do. In order to cope with this phenomenon, the present inventors conducted an experiment by adding a diode to the sub-boost unit and connecting the cathode between the second switch and the second coil. As a result, a phenomenon occurred in which the diode was broken down.

  For this phenomenon, it is considered useful to add a third coil as a saturable reactor, and the role of the saturable reactor to be added is assigned to the second coil as a resonant reactor. Can be considered. As described above, a technique in which a saturable reactor characteristic is assigned to a resonant reactor has also been proposed (see, for example, Patent Document 4 below).

JP 2003-217625 A JP 2005-143259 A JP 2009-165246 A JP 2003-018833 A

  By the way, the above-mentioned patent document 4 describes the resonance reactor as follows. Specifically, in the resonance reactor, the winding is a litz wire (stranded wire), and the core has a toroidal shape. The core of the resonance reactor has an outer diameter and an inner diameter that are equivalent to the core of the flyback transformer, and a thickness that is the same as or smaller than that of the flyback transformer. Further, the magnetization characteristics of the core of the resonance reactor are unsaturated when the current flowing through the resonance reactor is within a predetermined range. The core has an almost constant inductance value in this region and exceeds the predetermined range. In the region, it is described that the core is saturated and the inductance value decreases.

  As described above, in Patent Document 4, although there is a functional description of a resonant reactor having a saturable characteristic, there is no description clearly showing the configuration, and any saturable reactor is suitable for a boost converter of a fuel cell system. It is unknown whether it is.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a fuel cell system having a resonance reactor having a saturable characteristic of an optimum configuration in a boost converter.

  In order to solve the above problems, a fuel cell system according to the present invention is a fuel cell system including a fuel cell that is a direct current power source, and a boost converter that boosts an output voltage of the fuel cell and supplies power to a load. The step-up converter has a first switch and a first coil, and the output voltage of the fuel cell is generated by a back electromotive force of the first coil generated by the switching operation of the first switch with respect to the first coil. A main boosting unit that boosts the voltage and a capacitor that adjusts the potential difference between both electrodes of the first switch by the amount of charge, and reduces the switching loss of the first switch by adjusting the amount of charge of the capacitor during the switching operation. A sub-boost unit, the sub-boost unit includes a second switch and a second coil, and the second coil is formed of a magnetic material. The core is formed by winding a winding around at least a part of the core, and a gap formed by a non-magnetic material is formed in a portion of the core where the winding is wound. A core region formed of a magnetic material is provided between the coil and the winding.

  According to the present invention, the second coil functioning as the resonance reactor of the sub boosting unit in the boost converter is wound around at least a part of the core formed of the magnetic material, and further the winding is wound. Since the gap is formed in the core of the portion and the core region is provided between the gap and the winding, it can function as a saturable reactor having a saturable characteristic. More specifically, by forming a core region formed of a magnetic material adjacent to the part where the gap is formed, the core region becomes a path with a small magnetic resistance, and the inductance value is increased on the low current side. can do. Because the core region is adjacent to the gap, unlike the other core parts, the capacity of the path through which magnetism passes is small, so the core region is saturated on the high current side and the entire gap is formed In addition, the inductance value can be lowered. Therefore, when both the first switch and the second switch are turned off, the first switch and the second switch can function as a reactor that suppresses the surge voltage, and breakdown of other elements constituting the sub boosting unit can be prevented. Furthermore, in the present invention, since the gap is formed in the core portion around which the winding is wound, the magnetic flux confinement effect due to the current flowing in the winding is utilized to prevent the leakage of the magnetic flux to the outside. Can do. Specifically, the gap is made of a nonmagnetic material, the magnetic resistance is substantially equal to air, and the magnetic flux leaks to the outside at the portion where the gap is formed. Therefore, in the present invention, the leakage of magnetic flux to the outside is prevented by utilizing the magnetic flux confinement effect caused by the current flowing through the winding. Furthermore, since a core region formed of a magnetic material is provided between the gap and the winding, magnetic flux leakage to the winding can be reduced by the magnetic flux confinement effect by the core region, and eddy current can be reduced. Loss due to generation can also be reduced.

  In the present invention, it is also preferable that the core region is provided between the windings so as to surround the gap. In this preferred embodiment, since the gap is surrounded by the core region, the magnetic flux confinement effect by the core region can be further exerted, and the loss due to the generation of eddy current in the winding can be more effectively reduced.

  In the present invention, it is also preferable that the gap is constituted by a plurality of gap portions, and each gap portion is surrounded by the core region provided between the windings. In this preferred embodiment, by dividing the gap into a plurality of gap portions, the gap length in one gap portion can be shortened and magnetic flux leakage can be reduced. Further, since each gap portion is surrounded by the core region, the loss due to the generation of eddy current in the winding can be more effectively reduced by a synergistic effect with the magnetic flux confinement effect by the core region.

  In the present invention, it is also preferable that the gap is provided by forming a cavity in the core. As described above, since the gap is surrounded by the core region, even if the gap is hollow, it can be formed without requiring any special reinforcing means. Therefore, it is not necessary to use a member such as ceramics for forming the gap, and the loss due to the generation of eddy current in the winding can be more effectively reduced while reducing the cost.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which has a reactor for resonance provided with the saturable characteristic of the optimal structure in a boost converter can be provided.

It is a schematic block diagram which shows the fuel cell system with which the boost converter which is embodiment of this invention is used. It is a figure which shows the circuit structure of the boost converter used for the fuel cell system shown in FIG. It is a figure which shows the characteristic of the resonance reactor which has a saturable characteristic used for the boost converter shown in FIG. It is a perspective view which shows the external appearance of the resonance reactor which has a saturable characteristic used for the boost converter shown in FIG. It is sectional drawing which shows the longitudinal cross-section of the center vicinity of the resonance reactor which has a saturable characteristic shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same components are denoted by the same reference numerals as much as possible in the drawings, and redundant descriptions are omitted.

  First, a fuel cell system FCS mounted on a fuel cell vehicle according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a system configuration of a fuel cell system FCS that functions as an in-vehicle power supply system for a fuel cell vehicle. The fuel cell system FCS can be mounted on a vehicle such as a fuel cell vehicle (FCHV), an electric vehicle, or a hybrid vehicle.

  The fuel cell system FCS includes a fuel cell FC, an oxidizing gas supply system ASS, a fuel gas supply system FSS, a power system ES, a cooling system CS, and a controller EC. The fuel cell FC is configured to generate electric power upon receiving a supply of reaction gas (fuel gas, oxidizing gas). The oxidizing gas supply system ASS is a system for supplying air as an oxidizing gas to the fuel cell FC. The fuel gas supply system FSS is a system for supplying hydrogen gas as fuel gas to the fuel cell FC. The power system ES is a system for controlling charge / discharge of power. The cooling system CS is a system for cooling the fuel cell FC. The controller EC (control unit) is a controller that performs overall control of the entire fuel cell system FCS.

  The fuel cell FC is configured as a solid polymer electrolyte type cell stack in which a large number of cells (a single battery (power generator) including an anode, a cathode, and an electrolyte) are stacked in series. In a normal operation, the fuel cell FC undergoes an oxidation reaction of formula (1) at the anode and a reduction reaction of formula (2) at the cathode. The fuel cell FC as a whole undergoes an electromotive reaction of the formula (3).

H ₂ → 2H ⁺ + 2e ⁻ (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
H ₂ + (1/2) O ₂ → H ₂ O (3)

  The oxidizing gas supply system ASS has an oxidizing gas passage AS3 and an oxidizing off gas passage AS4. The oxidizing gas flow path AS3 is a flow path through which oxidizing gas supplied to the cathode of the fuel cell FC flows. The oxidation off gas flow path AS4 is a flow path through which the oxidation off gas discharged from the fuel cell FC flows.

  The oxidizing gas flow path AS3 is provided with an air compressor AS2 and a humidifier AS5. The air compressor AS2 is a compressor for taking in the oxidizing gas from the atmosphere via the filter AS1. The humidifier AS5 is a humidifier for humidifying the oxidizing gas pressurized by the air compressor AS2.

  A pressure sensor S6, a back pressure adjustment valve A3, and a humidifier AS5 are provided in the oxidation off gas flow path AS4. The back pressure adjustment valve A3 is a valve for adjusting the oxidizing gas supply pressure. The humidifier AS5 is provided for exchanging moisture between the oxidizing gas (dry gas) and the oxidizing off gas (wet gas).

  The fuel gas supply system FSS has a fuel gas supply source FS1, a fuel gas passage FS3, a circulation passage FS4, a circulation pump FS5, and an exhaust / drain passage FS6. The fuel gas channel FS3 is a channel through which the fuel gas supplied from the fuel gas supply source FS1 to the anode of the fuel cell FC flows. The circulation flow path FS4 is a flow path for returning the fuel off-gas discharged from the fuel cell FC to the fuel gas flow path FS3. The circulation pump FS5 is a pump that pressure-feeds the fuel off-gas in the circulation flow path FS4 to the fuel gas flow path FS3. The exhaust drainage channel FS6 is a channel that is branched and connected to the circulation channel FS4.

  The fuel gas supply source FS1 is composed of, for example, a high-pressure hydrogen tank or a hydrogen storage alloy, and stores high-pressure (for example, 35 MPa to 70 MPa) hydrogen gas. When the shutoff valve H1 is opened, the fuel gas flows out from the fuel gas supply source FS1 to the fuel gas flow path FS3. The fuel gas is decompressed to about 200 kPa, for example, by the regulator H2 and the injector FS2, and supplied to the fuel cell FC.

  The fuel gas flow path FS3 is provided with a cutoff valve H1, a regulator H2, an injector FS2, a cutoff valve H3, and a pressure sensor S4. The shutoff valve H1 is a valve for shutting off or allowing the supply of the fuel gas from the fuel gas supply source FS1. The regulator H2 adjusts the pressure of the fuel gas. The injector FS2 controls the amount of fuel gas supplied to the fuel cell FC. The shutoff valve H3 is a valve for shutting off the fuel gas supply to the fuel cell FC.

  The regulator H2 is a device that regulates the upstream side pressure (primary pressure) to a preset secondary pressure, and includes, for example, a mechanical pressure reducing valve that reduces the primary pressure. The mechanical pressure reducing valve has a housing in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. It has a configuration for the next pressure. By arranging the regulator H2 on the upstream side of the injector FS2, the upstream pressure of the injector FS2 can be effectively reduced.

  The injector FS2 is an electromagnetically driven on-off valve capable of adjusting the gas flow rate and the gas pressure by driving the valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from the valve seat. The injector FS2 moves in an axial direction (gas flow direction) with respect to a valve seat having an injection hole for injecting gaseous fuel such as fuel gas, a nozzle body for supplying and guiding the gaseous fuel to the injection hole, and the nozzle body. And a valve body that is stored and held so as to open and close the injection hole.

  The valve body of the injector FS2 is driven by a solenoid that is an electromagnetic drive device, and is configured such that the gas injection time and gas injection timing of the injector FS2 can be controlled by a control signal output from the controller EC. Injector FS2 changes downstream by changing at least one of the opening area (opening) and the opening time of the valve provided in the gas flow path of injector FS2 in order to supply the required gas flow rate downstream. The gas flow rate (or hydrogen molar concentration) supplied to the side is adjusted.

  The circulation flow path FS4 is provided with a shutoff valve H4, and an exhaust / drain flow path FS6 is connected thereto. An exhaust / drain valve H5 is provided in the exhaust / drain flow path FS6. The exhaust / drain valve H5 is a valve for discharging the fuel off-gas containing impurities in the circulation flow path FS4 and moisture to the outside by operating according to a command from the controller EC. By opening the exhaust / drain valve H5, the concentration of impurities in the fuel off-gas in the circulation flow path FS4 is reduced, and the hydrogen concentration in the fuel off-gas circulating in the circulation system can be increased.

  The fuel off-gas discharged through the exhaust / drain valve H5 is mixed with the oxidizing off-gas flowing through the oxidizing off-gas passage AS4 and diluted by a diluter (not shown). The circulation pump FS5 circulates and supplies the fuel off gas in the circulation system to the fuel cell FC by driving the motor.

  The power system ES includes a DC / DC converter ES1, a battery ES2, a traction inverter ES3, a traction motor ES4, auxiliary machinery ES5, and an FC boost converter ES6. The fuel cell system FCS is configured as a parallel hybrid system in which a DC / DC converter ES1 and a traction inverter ES3 are connected to the fuel cell FC in parallel. The DC / DC converter ES1 and the traction inverter ES3 constitute a PCU (Power Control Unit).

  The FC boost converter ES6 is a DC / DC converter having a function of boosting the output voltage of the fuel cell FC and outputting it to the traction inverter ES3 and the traction motor ES4. The DC / DC converter ES1 boosts the DC voltage supplied from the battery ES2 and outputs it to the traction inverter ES3, and the DC power generated by the fuel cell FC or the regenerative power recovered by the traction motor ES4 by regenerative braking. It has a function of stepping down and charging the battery ES2. The charging / discharging of the battery ES2 is controlled by these functions of the DC / DC converter ES1. Further, the operating point (output terminal voltage, output current) of the fuel cell FC is controlled by voltage conversion control by the DC / DC converter ES1. A voltage sensor S1 and a current sensor S2 are attached to the fuel cell FC. The voltage sensor S1 is a sensor for detecting a voltage obtained by boosting the output terminal voltage of the fuel cell FC by the FC boost converter ES6. The current sensor S2 is a sensor for detecting the output current of the fuel cell FC. A temperature sensor S7 is attached between the boost converter ES6 and the traction inverter ES3.

  The battery ES2 functions as a surplus power storage source, a regenerative energy storage source during regenerative braking, and an energy buffer during load fluctuations associated with acceleration or deceleration of the fuel cell vehicle. As the battery ES2, for example, a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery is preferable. An SOC sensor S3 for detecting SOC (State of charge) is attached to the battery ES2.

  The traction inverter ES3 is, for example, a PWM inverter driven by a pulse width modulation method. The traction inverter ES3 converts the DC voltage output from the fuel cell FC or the battery ES2 into a three-phase AC voltage according to a control command from the controller EC, and controls the rotational torque of the traction motor ES4. The traction motor ES4 is a three-phase AC motor, for example, and constitutes a power source of the fuel cell vehicle.

  Auxiliary machinery ES5 includes motors (for example, power sources such as pumps) arranged in each part in the fuel cell system FCS, inverters for driving these motors, and various in-vehicle auxiliary machinery ( For example, an air compressor, an injector, a cooling water circulation pump, a radiator, etc.) are collectively referred to.

  The cooling system CS includes a radiator CS1, a coolant pump CS2, a coolant forward path CS3, and a coolant return path CS4. The radiator CS1 radiates and cools the coolant for cooling the fuel cell FC. The coolant pump CS2 is a pump for circulating the coolant between the fuel cell FC and the radiator CS1. The coolant forward path CS3 is a channel connecting the radiator CS1 and the fuel cell FC, and is provided with a coolant pump CS2. When the coolant pump CS2 is driven, the coolant flows from the radiator CS1 to the fuel cell FC through the coolant forward path CS3. The coolant return path CS4 is a flow path connecting the fuel cell FC and the radiator CS1, and is provided with a water temperature sensor S5. When the coolant pump CS2 is driven, the coolant that has cooled the fuel cell FC returns to the radiator CS1.

  The controller EC (control unit) is a computer system including a CPU, a ROM, a RAM, and an input / output interface, and controls each unit of the fuel cell system FCS. For example, the controller EC starts the operation of the fuel cell system FCS when receiving the start signal IG output from the ignition switch. Thereafter, the controller EC obtains the required power of the entire fuel cell system FCS based on the accelerator opening signal ACC output from the accelerator sensor, the vehicle speed signal VC output from the vehicle speed sensor, and the like. The required power of the entire fuel cell system FCS is the total value of the vehicle travel power and the auxiliary power.

  Here, auxiliary electric power includes electric power consumed by in-vehicle auxiliary equipment (humidifier, air compressor, hydrogen pump, cooling water circulation pump, etc.), and equipment required for vehicle travel (transmission, wheel control device, steering) Power consumed by devices, suspension devices, etc.), power consumed by devices (air conditioners, lighting equipment, audio, etc.) disposed in the passenger space, and the like.

  Then, the controller EC determines the distribution of output power between the fuel cell FC and the battery ES2. The controller EC controls the oxidizing gas supply system ASS and the fuel gas supply system FSS so that the power generation amount of the fuel cell FC matches the target power. Further, the controller EC outputs an instruction signal to the DC / DC converter ES1, causes the DC / DC converter ES1 to execute converter control, and controls the operating point (output terminal voltage, output current) of the fuel cell FC. Further, the controller EC outputs, for example, each U-phase, V-phase, and W-phase AC voltage command value to the traction inverter ES3 as a switching command so that a target torque according to the accelerator opening is obtained. Controls the output torque and rotation speed of the motor ES4. Further, the controller EC controls the cooling system CS so that the fuel cell FC has an appropriate temperature.

  Here, the characteristics of the electric circuit of the FC boost converter ES6 will be described with reference to FIG. FIG. 2 is a diagram showing the electrical configuration of the fuel cell system FCS with the FC boost converter ES6 as the center, but for the sake of simplicity, description of the battery ES2 and the DC / DC converter ES1 as a battery boost converter, etc. Is omitted.

  The FC boost converter ES6 includes a main boost circuit LN1 for performing a boost operation as a DC / DC converter and a sub boost circuit LN2 for performing a soft switching operation.

  The main booster circuit LN1 converts the energy stored in the coil L1 (first coil) to the traction motor ES4 side (traction inverter ES3 side) by the switching operation of the switching circuit composed of the switch element S1 (first switch) and the diode D4. ) Is released via the diode D3 to boost the output voltage of the fuel cell FC. Specifically, one end of the coil L1 is connected to the terminal on the high potential side of the fuel cell FC. The pole at one end of the switch element S1 is connected to the other end of the coil L1, and the pole at the other end of the switch element S1 is connected to the low potential side terminal of the fuel cell FC. The cathode terminal of the diode D6 is connected to the other end of the coil L1, and the capacitor C3 is connected between the anode terminal of the diode D5 and the other end of the switch element S1. In this main booster circuit LN1, the capacitor C3 functions as a smoothing capacitor for the boosted voltage. The main booster circuit LN1 is also provided with a smoothing capacitor C1 on the fuel cell FC side, which makes it possible to reduce the ripple of the output current of the fuel cell FC. The voltage applied to the smoothing capacitor C3 becomes the outlet voltage of the FC boost converter ES6. Further, the power supply voltage of the fuel cell FC is a voltage applied to the smoothing capacitor C1, and is an inlet voltage of the FC boost converter ES6.

  Next, the sub booster circuit LN2 includes a first series connection body including a diode D2 connected in parallel to the switch element S1 and a snubber capacitor C2 connected in series thereto. In the first series connection body, the cathode terminal of the diode D2 is connected to the other end of the coil L1, and the anode terminal thereof is connected to one end of the snubber capacitor C2. Furthermore, the other end of the snubber capacitor C2 is connected to a terminal on the low potential side of the fuel cell FC. In addition, a coil L2 (second coil), which is an inductive element, a diode D1, and a switching circuit composed of a switch element S2 (second switch) and a diode D5 are connected in series to the sub booster circuit LN2. A second series connection is included. In this second series connection body, one end of the switch element S2 is connected to a connection site between the diode D2 and the snubber capacitor C2 of the first series connection body. Further, the cathode terminal of the diode D1 is connected to one end of the coil L2, and the anode terminal is connected to the other end of the switch element S2. The other end of the coil L2 is connected to one end side of the coil L1. The sub-boost circuit LN2 is provided with a diode D6, the anode terminal of which is connected to the connection part between the coil L2 and the diode D1 of the second series connection body, and the cathode terminal of which is the low potential of the fuel cell FC. It is connected to the terminal on the side.

  The FC boost converter ES6 configured as described above adjusts the switching duty ratio of the switch element S1, thereby increasing the boost ratio by the FC boost converter ES6, that is, the output voltage of the fuel cell FC input to the FC boost converter ES6. The ratio of the output voltage of the FC boost converter ES6 applied to the traction inverter ES3 is controlled. Further, by interposing the switching operation of the switch element S2 of the sub boost circuit LN2 in the switching operation of the switch element S1, so-called soft switching is realized, and the switching loss in the FC boost converter ES6 can be greatly reduced. Become.

  Subsequently, a resonant reactor having a saturable characteristic used as the coil L2 will be described. FIG. 3 is a diagram showing the inductance characteristics of a resonant reactor having such saturable characteristics. As shown in FIG. 3, the low current region has an inductance value of 30 μH, and the high current region has an inductance value of 0.9 μH. In general, a coil having an inductance value of 30 μH in a low current region and a coil having an inductance value of 0.9 μH in a high current region are arranged in series. However, in this embodiment, a saturable characteristic is provided in a resonant reactor. This is realized by one coil.

  FIG. 4 shows a configuration of a coil La that is a coil used as the coil L2 and is a resonant reactor having a saturable characteristic. As shown in FIG. 4, the coil La is composed of a core 5 made of a magnetic material and a winding 20 formed by winding a copper wire. The core 5 includes an upper core 10 and a lower core 12. The upper core 10 and the lower core 12 are each formed in a plate shape so as to form a rectangular parallelepiped shape. A side core 14 is provided so as to connect the vicinity of one side of the upper core 10 and the vicinity of one side of the lower core 12 facing the one side. A side core 16 is provided so as to connect the vicinity of the other side opposite to the one side of the upper core 10 and the vicinity of the other side of the lower core 12 facing the other side. Therefore, the side core 14 and the side core 16 are erected so as to face each other.

  A center core 18 is provided between the side core 14 and the side core 16. The center core 18 is erected so as to connect the vicinity of the center of the upper core 10 and the vicinity of the center of the lower core 12. The winding 20 is wound around the center core 18.

  Next, FIG. 5 shows a longitudinal section near the center of the center core 18, and the description will be continued with reference to FIG. As shown in FIG. 5, gap portions 31, 32, and 33 are formed in the center core 18, and a gap is formed as a whole. The gap portions 31, 32, and 33 are each formed of a nonmagnetic material. Specifically, it may be formed of a ceramic material or may be a cavity. If the gap portions 31, 32, and 33 are formed of a ceramic material, high dimensional accuracy can be maintained. Further, even if the gap portions 31, 32, 33 are formed by cavities, the gap portions 31, 32, 33 are sandwiched by the core region as will be described later in the case of the present embodiment. Can keep.

  The gap portion 31 is sandwiched at both ends by a core region 181a and a core region 181b made of a magnetic material. The gap portion 32 is also sandwiched at both ends by a core region 182a and a core region 182b made of a magnetic material. The gap portion 33 is also sandwiched at both ends by a core region 183a and a core region 183b made of a magnetic material. Therefore, magnetic flux leakage from the gap portions 31, 32, 33 can be confined by the core regions 181a, 181b, 182a, 182b, 183a, 183b.

  The core region 181 a and the core region 181 b may be provided independently so as to sandwich the gap portion 31, but are preferably provided continuously so as to surround the gap portion 31. If the core region 181a and the core region 181b are continuously provided so as to surround the gap portion 31, magnetic flux leakage from the gap portion 31 can be more effectively suppressed. The same applies to the core regions 182a and 182b corresponding to the gap portion 32 and the core regions 183a and 183b corresponding to the gap portion 33.

FCS: fuel cell system EC: controller FC: fuel cell FSS: fuel gas supply system FS1: fuel gas supply source FS2: injector FS3: fuel gas channel FS4: circulation channel FS5: circulation pump FS6: exhaust drainage channel H1: Cutoff valve H2: Regulator H3: Cutoff valve H4: Cutoff valve H5: Exhaust drain valve ASS: Oxidation gas supply system AS1: Filter AS2: Air compressor AS3: Oxidation gas flow path AS4: Oxidation off gas flow path AS5: Humidifier A3: Back Pressure regulating valve CS: Cooling system CS1: Radiator CS2: Coolant pump CS3: Coolant forward path CS4: Coolant return path ES: Power system ES1: Converter ES2: Battery ES3: Traction inverter ES4: Traction motor ES5: Auxiliary equipment ES6: FC boost converter S1: Voltage sensor S2: Current sensor S3: OC sensor S4: a pressure sensor S5: the water temperature sensor S6: pressure sensor S7: Temperature sensor IG: activation signal VC: vehicle speed signal ACC: an accelerator opening signal

Claims (4)

A fuel cell system comprising a fuel cell that is a DC power source, and a boost converter that boosts the output voltage of the fuel cell and supplies power to a load,
The boost converter includes:
A main booster that has a first switch and a first coil, and boosts the output voltage of the fuel cell with a back electromotive force of the first coil generated by the switching operation of the first switch with respect to the first coil. And
A capacitor that adjusts a potential difference between both poles of the first switch by a storage amount, and a sub boosting unit that reduces a switching loss of the first switch by adjusting a storage amount of the capacitor during the switching operation. And
The sub boosting unit has a second switch and a second coil,
The second coil is formed by winding a winding around at least a part of a core formed of a magnetic material, and a non-magnetic material is formed on a portion of the core where the winding is wound. The fuel cell system is characterized in that a gap formed by the magnetic material is formed, and a core region formed of a magnetic material is provided between the gap and the winding.   The fuel cell system according to claim 1, wherein the core region is provided between the winding and the winding so as to surround the gap. The gap is composed of a plurality of gap portions,
The fuel cell system according to claim 2, wherein each gap portion is surrounded by the core region provided between the windings.   The fuel cell system according to claim 2, wherein the gap is provided by forming a cavity in the core.

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