JP5535689B2 - Fuel cell system and method for adjusting fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system and an adjustment method thereof.

  As a conventional fuel cell system, one having a power conditioner that boosts and converts electric power from a fuel cell is known (for example, see Patent Document 1). In this system, electric power is supplied to an external load through a power conditioner connected to the fuel cell, and surplus power (DC heater) is supplied as surplus power as surplus power through the power conditioner. ) Is energized.

JP 2008-53039 A

  By the way, when surplus power is consumed using a surplus heater as in the conventional fuel cell system, it is necessary to adjust the surplus heater in advance. For example, supplying all rated power, which is the target power supply during rated operation, to the external load and not supplying any power to the surplus heater, and supplying all rated power to the surplus heater without supplying any power to the external load. In the above, the input current value to the power conditioner is adjusted to be the same.

  However, even when the current adjustment to the surplus heater described above is performed, the power supplied from the fuel cell to the surplus heater may increase due to the influence of external factors. When the power output from the fuel cell exceeds the power value in the rated operation, the fuel cell is overloaded. In order to avoid such a situation, a method is conceivable in which the supply current to the surplus heater is adjusted in advance to be smaller than the supply current to the external load. However, if it is set too small, the surplus power, which is a function of the surplus heater, cannot be sufficiently consumed, so that it is difficult to stably supply power from the fuel cell against fluctuations in the external load.

  Therefore, the present invention provides a fuel cell system capable of appropriately achieving both suppression of overload of the fuel cell and stabilization of supply power, and appropriate balance of suppression of overload of the fuel cell and stabilization of supply power. It is an object of the present invention to provide a method for adjusting a fuel cell system that can be adjusted as described.

In order to solve the above-described problems, a fuel cell system according to the present invention boosts and converts electric power from a fuel cell by a power conditioner and supplies it to an external load, and the surplus fuel cell via the power conditioner. A fuel cell system for supplying electric power to a surplus heater, comprising a waste heat recovery system for recovering exhaust heat of the surplus heater, wherein the power conditioner measures a current supplied to the surplus heater A current value to the surplus heater is smaller than the current value to the external load by the sum of the maximum error current value due to the temperature error of the current sensor and the current value to the exhaust heat recovery system. It is configured to be adjusted in advance so as to become.

  This fuel cell system is preset so that the current value supplied to the surplus heater is smaller than the current value to the external load based on the error current value due to the temperature error of the current sensor. With this configuration, when the surplus heater operates, the supply current to the surplus heater becomes a value smaller than the current value to the external load in consideration of the error current value caused by the temperature error of the current sensor. . For this reason, it is possible to avoid that the supply current to the surplus heater becomes larger than the current value to the external load even when the temperature sensor causes an error due to an external factor and the supply current to the surplus heater increases. It is possible to suppress the fuel cell from being overloaded. Furthermore, since the amount of decrease in the current value supplied to the surplus heater can be set based on the error current value of the current sensor, it is possible to minimize the influence of the surplus heater on surplus power consumption. Therefore, suppression of the overload of the fuel cell and stabilization of the supplied power can be appropriately achieved.

Further, with this configuration, the current value to the current sensor is smaller than the current value to the external load based on the error current value due to the temperature error of the current sensor and the supply current value to the exhaust heat recovery system. . For this reason, even when a temperature error of the current sensor occurs and the load of the fuel cell increases due to the operation of the exhaust heat recovery system, it is possible to suppress the fuel cell from being overloaded and to stabilize the supply power. Can be achieved.

In addition, the fuel cell system adjustment method according to the present invention boosts and converts power from the fuel cell by a power conditioner and supplies it to an external load, and supplies surplus power of the fuel cell via the power conditioner. A method for adjusting a fuel cell system including an exhaust heat recovery system for supplying to an excess heater and recovering the exhaust heat of the excess heater , wherein the fuel cell is connected to the external load via the power conditioner. A load-side measurement step of measuring an input current value of the power conditioner when supplying predetermined power; and the power condition when supplying the predetermined power from the fuel cell to the surplus heater via the power conditioner. Measured at the heater side measurement step that measures the input current value of the na and the heater side measurement step The force current value is adjusted to be smaller than the input current value measured in the load side measurement step, and the input current value measured in the heater side measurement step and the input measured in the load side measurement step. An adjustment step of setting a difference with a current value based on an error current value due to a temperature error of a current sensor included in the power conditioner and measuring a current value to the surplus heater, and the adjustment step includes: The difference between the input current value measured in the heater-side measurement step and the input current value measured in the load-side measurement step is expressed as the maximum error current value due to the temperature error of the current sensor and the current to the exhaust heat recovery system. Set the value to be the sum of the values .

  According to the adjustment method of the fuel cell system according to the present invention, the same effect as the above-described fuel cell system can be obtained.

  According to the present invention, it is possible to appropriately achieve both suppression of overload of the fuel cell and stabilization of supplied power. Moreover, it can adjust so that the balance of suppression of the overload of a fuel cell and stabilization of supplied power may become appropriate.

1 is a schematic configuration diagram of an embodiment of a fuel cell system according to the present invention. 2 is a flowchart showing an adjustment operation of the fuel cell system of FIG. 1. It is a schematic diagram explaining the adjustment method of the fuel cell system of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  The fuel cell system according to the present embodiment is suitably employed as a household fuel cell system, for example. FIG. 1 is a schematic configuration diagram of an embodiment of a fuel cell system according to the present invention. As shown in FIG. 1, the fuel cell system 1 includes a fuel cell 2. The fuel cell 2 is a direct current power supply (DC power supply) and supplies power to an external load (home load) 9. As the fuel cell 2, for example, a polymer electrolyte fuel cell that generates power using a reformed gas generated by reforming raw fuel is used.

  A power conditioner (PCS: Power Conditioning Subsystem) 3 is connected to the fuel cell 2, and power output from the fuel cell 2 is supplied to the power conditioner 3. The power conditioner 3 is a device that adjusts the output power of the fuel cell 2 so that it can be used at home and the like, and includes a booster 30 and a converter 31. The booster 30 has a function of boosting the electric power output from the fuel cell 2. The converter 31 is connected to the booster 30 and has a function of converting DC power output from the booster 30 into AC power. The output side of the power conditioner 3 is connected to the external load 9. With this configuration, the electric power of the fuel cell 2 is boosted by the booster 30 of the power conditioner 3, converted into AC power by the converter 31, and supplied to the external load 9. The external load 9 is connected to a system power supply 8 that is an AC power supply, and is configured such that the power from the system power supply 8 and the power from the fuel cell 2 can be used together.

  Here, when the power consumption of the external load 9 is drastically reduced, it is difficult for the fuel cell 2 to change the output suddenly. Therefore, the generated power of the fuel cell 2 exceeds the power consumption of the external load 9, and surplus Electric power may be generated. Regarding the surplus power, a method of causing a reverse power flow to the system power supply side is also conceivable, but here, a surplus heater 4 is provided in order to consume the surplus power generated. The surplus heater 4 is connected to the output side of the power controller 33 inside the power conditioner 3 and is operated in accordance with the generation of surplus power. For example, an electric heater is used as the surplus heater 4.

  Further, the fuel cell system 1 includes an exhaust heat recovery system that recovers heat generated by the surplus heater 4. The exhaust heat recovery system includes a hot water storage tank 7 in which household water is stored, a water pump 6 that circulates water in the hot water storage tank in a circulation path, and a heat exchanger 5 that is provided on the downstream side of the water pump 6. I have. The heat exchanger 5 is configured so that circulating water in the circulation path can exchange heat of the excess heater 4. For this reason, the water in the hot water storage tank 7 is circulated in the circulation path by the water pump 6, the heat of the surplus heater 4 is recovered by the heat exchanger 5, and is stored in the hot water storage tank 7 again. The exhaust heat recovery system uses the fuel cell 2 as a power source. Further, a heat radiating fan or the like may be provided as the exhaust heat recovery system.

  The operation of the components of the fuel cell system 1 described above is controlled by the system controller 11 that is an electrical component. The system control device 11 performs control of constituent devices (for example, control of the fuel supply pump 10) according to the sensors provided in the fuel cell system 1, the usage status of the user, and the like. Note that the system control device 11 performs bidirectional communication with the PCS control device 32 of the power conditioner 3 and obtains information on the current value and power value of each part necessary for system control. In the power conditioner 3, the current sensor 36 that measures the current value of the fuel cell, the current sensor 35 that measures the output current value of the power conditioner 3, the current sensor 12 that measures the current value of the system power supply 8, and the surplus heater 4 A current sensor 34 or the like that measures the current value is used, and the PCS control device 32 obtains a power value from the current value of each part to control the AC output and the surplus heater output.

  When the power consumption of the external load 9 rapidly decreases during the rated operation of the fuel cell 2, the PCS control device 32 supplies the power of the fuel cell 2 to the surplus heater 4 side to consume the surplus power. When the surplus heater 4 operates, the system controller 11 operates the water pump 6 to recover heat. Here, the current value supplied to the surplus heater 4 is adjusted in advance before operation. Hereinafter, the adjustment operation of the current value supplied to the surplus heater 4 will be described with reference to FIG. FIG. 2 is a flowchart showing the adjustment operation of the power conditioner 3. The control process shown in FIG. 2 is executed at the time of adjustment inspection of the power conditioner 3, for example. In consideration of ease of understanding, the control process shown in FIG. 2 will be described with reference to the schematic diagram shown in FIG. 3 as appropriate. FIG. 3 is a schematic diagram illustrating a method for adjusting the fuel cell system 1.

  As shown in FIG. 2, the PCS control device 32 measures the input current value Ap1 of the power conditioner 3 when power is supplied to the external load 9 during rated operation (S10: load side measurement step). The PCS control device 32 supplies electric power from the fuel cell 2 to the external load 9 through the power conditioner 3 along the supply path indicated by A1 in FIG. 3 and determines the input current value of the power conditioner 3 from the current sensor 36. Measure with The measurement conditions at this time are the measurement conditions 1 shown in FIG. That is, the surplus heater 4 is turned off, and the power output from the power conditioner 3 to the surplus heater 4 is 0 [W]. And the electric power which the power conditioner 3 outputs to the external load 9 side is X [W]. This X [W] is the target power (rated power) at the rated operation of the fuel cell, and for example, 750 [W] is used.

  Next, the PCS control device 32 measures the input current value of the power conditioner 3 when power is supplied to the surplus heater 4 during the rated operation (S12: heater side measurement step). The PCS control device 32 supplies electric power from the fuel cell 2 to the surplus heater 4 through the power conditioner 3 along the supply path indicated by A2 in FIG. 3, and the input current value Ap2 of the power conditioner 3 is a current sensor. 36. The measurement conditions at this time are the measurement conditions 2 shown in FIG. That is, the surplus heater 4 is turned on, and the power output from the power conditioner 3 to the surplus heater 4 is X + α [W]. This X [W] is the target power at the rated operation of the fuel cell, and for example, 750 [W] is used. Further, α is the electric power generated from the resistance difference (loss difference) between the supply path A1 and the supply path A2, and is specifically determined based on the resistance value of the converter 31 and the power controller 33. On the other hand, the power output from the power conditioner 3 to the external load 9 is 0 [W].

Next, the PCS control device 32 compares the input current value Ap1 measured in the process of S10 with the input current value Ap2 measured in the process of S12, and adjusts the input current value Ap2 (S14, S16: adjustment). Step). The PCS control device 32 supplies power to the surplus heater 4 from the fuel cell 2 via the power conditioner 3 along the supply path indicated by A2 in FIG. 3 and measures the input current value Ap2, while the power conditioner 3 The input current value Ap2 is adjusted to be smaller than the input current value Ap1. This adjustment is performed by, for example, an adjustment mechanism provided in the power conditioner 3. The PCS control device 32 determines the temperature drift (temperature error) of the current sensor 34 provided in the power conditioner 3 with respect to the difference between the input current value Ap2 and the input current value Ap1 (that is, a decrease amount that is decreased compared to the input current value Ap1). Determine in consideration of For example, the PCS control device 32 acquires a temperature drift curve indicating the temperature dependence of the measured value of the current sensor 34 in advance, and the temperature of the current sensor 34 based on the assumed temperature range when the power conditioner 3 is operating. Identify the error. Then, for example, the PCS control device 32 determines the amount of deviation of the current value at the maximum temperature error, which is the maximum value of the temperature error, as a reduction amount that is reduced compared to the input current value Ap1. More preferably, the PCS control device 32 determines a reduction amount to be reduced as compared with the input current value Ap1 in consideration of the power of the electrical equipment (here, the water pump 6) constituting the exhaust heat recovery system. Also good. For example, the PCS control device 32 measures the current value necessary for the operation of the water pump 6 in advance, and based on the value obtained by adding the measured current value and the current value due to the maximum temperature error (maximum error current value). The amount of reduction is determined. For example, the PCS control device 32 sets the amount of decrease G using Equation 1 below, where ± W _{1 is the} deviation due to temperature drift, and W ₂ is the power required for the operation of the exhaust heat recovery system.
G = | ± W ₁ + W ₂ | (1)
When the PCS control device 32 finishes adjusting the input current value Ap2, the control process shown in FIG.

  By executing the control process shown in FIG. 2, the input current value Ap2 of the power conditioner 3 when the surplus heater 4 is ON is smaller than the input current value Ap1 of the power conditioner 3 when the surplus heater 4 is OFF. The amount of decrease is set based on the amount of current value deviation due to the temperature error of the current sensor 34 for the surplus heater 4 and the power consumption of the exhaust heat recovery system that operates when the surplus heater 4 is turned on. By adjusting in this way, the influence of the temperature error of the current sensor 34 can be reduced in advance, so that the power supplied from the fuel cell 2 when the surplus heater 4 is turned on increases compared to when the surplus heater 4 is turned off. As a result, the fuel cell 2 can be prevented from being overloaded. Furthermore, since the power consumption of the exhaust heat recovery system that operates when the surplus heater 4 is ON can be reduced in advance, the fuel cell 2 is overloaded by the load of the equipment that is operated to recover the exhaust heat. Can be avoided. Then, by setting the amount of decrease as described above, it is possible to suppress the overload of the fuel cell 2 without significantly disturbing the surplus power consumption capability of the surplus heater 4.

  As described above, according to the fuel cell system 1 or the adjustment method of the fuel cell system 1 according to the present embodiment, the current value supplied to the surplus heater 4 is supplied to the external load based on the error current value due to the temperature error of the current sensor 34. It is set in advance so as to be smaller than the current value. With this configuration, when the surplus heater 4 operates, the supply current to the surplus heater 4 is larger than the current value to the external load 9 in consideration of the error current value caused by the temperature error of the current sensor 34. Small value. For this reason, even when an error occurs in the current sensor 34 due to an external factor and the supply current to the surplus heater 4 increases, the supply current to the surplus heater 4 becomes larger than the current value to the external load 9. Since it can avoid, it becomes possible to suppress that the fuel cell 2 becomes overloaded. Furthermore, since the amount of decrease in the current value supplied to the surplus heater 4 can be set based on the error current value of the current sensor 34, it is possible to minimize the influence of the surplus heater 4 on surplus power consumption. It becomes. Therefore, the suppression of the overload of the fuel cell 2 and the stabilization of the supplied power can be appropriately made compatible.

  The present invention is not limited to the embodiment described above.

  Although what was arrange | positioned inside the power conditioner 3 was demonstrated as the current sensors 34, 35, and 36, you may arrange | position outside the power conditioner 3. FIG.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 3 ... Power conditioner, 4 ... Surplus heater, 5 ... Heat exchanger (exhaust heat recovery system), 6 ... Water pump (exhaust heat recovery system), 7 ... Hot water storage tank (Exhaust heat recovery system), 8 ... system power supply, 9 ... external load, 10 ... fuel supply pump, 11 ... system controller, 12, 34, 35, 36 ... current sensor, 30 ... booster, 31 ... converter, 32 ... PCS control device, 33 ... Power controller.

Claims (2)

A fuel cell system that boosts and converts electric power from a fuel cell by a power conditioner and supplies it to an external load, and supplies surplus power of the fuel cell to an excess heater through the power conditioner,
An exhaust heat recovery system for recovering the exhaust heat of the surplus heater;
The power conditioner includes a current sensor that measures a current supplied to the surplus heater,
The current value to the surplus heater is previously set to be smaller than the current value to the external load by the sum of the maximum error current value due to the temperature error of the current sensor and the current value to the exhaust heat recovery system. Being adjusted,
A fuel cell system. The power from the fuel cell is boosted / converted by a power conditioner and supplied to an external load, and the surplus power of the fuel cell is supplied to the surplus heater via the power conditioner , and the exhaust heat of the surplus heater A method for adjusting a fuel cell system including an exhaust heat recovery system for recovering
A load-side measurement step of measuring an input current value of the power conditioner when supplying predetermined power from the fuel cell to the external load via the power conditioner;
A heater-side measurement step of measuring an input current value of the power conditioner when supplying the predetermined power from the fuel cell to the surplus heater via the power conditioner;
The input current value measured in the heater side measurement step is adjusted to be smaller than the input current value measured in the load side measurement step, and the input current value measured in the heater side measurement step and the An adjustment step for setting a difference from the input current value measured in the load side measurement step based on an error current value due to a temperature error of a current sensor included in the power conditioner and measuring a current value to the surplus heater; ,
With
In the adjustment step, the difference between the input current value measured in the heater-side measurement step and the input current value measured in the load-side measurement step is calculated as a maximum error current value due to a temperature error of the current sensor and the exhaust heat. Set the current value to the recovery system to be the sum of the values ,
A fuel cell system adjustment method comprising:

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