TW202115953A - Method and system of controlling fuel cell hybrid power - Google Patents

Abstract

The present invention provides a method and system of controlling fuel cell hybrid power which disclose the following steps: Starting up the fuel cell, calculating the demanded air volume of the fuel cell according to the first variable load demand power of the variable load and the battery demand power of the energy storage battery; supplying the air to the fuel cell according to the required air volume; receiving the actual air volume value, and calculating the output current interval of the fuel cell according to the actual air volume value; finally, the output current of the fuel cell is controlled within the output current interval. Therefore, the present invention can provide an appropriate amount of air, so that the fuel cell can maintain a stable operating voltage, thereby improving the life of the fuel cell. Meanwhile, via controlling the state-of-charge (SOC) of the energy storage battery, the tolerance of the error of controlling the fuel cell can be relaxed.

Description

Fuel cell compound power control method and system

The present invention is a fuel cell composite power control method and system, in particular to a fuel cell and energy storage battery to provide variable load power. Before starting the fuel cell, it is calculated based on the power demand of the energy storage battery and the variable load A fuel cell compound power control method and system for fuel cell required air volume.

In recent years, sustainable development has become an important issue, and the world is therefore committed to the pursuit of a balanced development of energy, environmental protection and economy. In terms of transportation, gasoline is generally used as a source of power. However, the process of converting gasoline into energy will release a large amount of greenhouse gases, which undoubtedly violates the pursuit of environmental protection goals, especially under the pressure of greenhouse gas reduction after the entry into force of the Kyoto Protocol. Gradually release energy alternatives. Due to the recyclable nature of fuel cells, the application of fuel cell technology to transportation has become a solution that takes into account environmental protection and can respond to the current era of high energy prices.

In the process of fuel cell power generation, it is necessary to supply appropriate air to participate in the reaction. If the air involved in the reaction is excessive, it will cause the loss of moisture inside the fuel cell and affect the performance and life. On the contrary, if the air involved in the reaction is too little, it will lead to the fuel cell. The operating voltage drops, and the output power is therefore reduced. Therefore, how to control an appropriate amount of air to participate in the reaction is an important issue that the fuel cell needs to solve.

In the conventional technology, by detecting the current of the fuel cell load, the fuel cell controller calculates the air volume demand of the fuel cell according to the load current, and then transmits the air volume demand signal to the air compressor to make the air compressor Supply air to the fuel cell. However, the disadvantage of the conventional technology is that when the air compressor provides fuel cell air, it will increase the load demand of the fuel cell. As a result, the detected load current will change with the operation of the air compressor. This in turn causes the voltage of the fuel cell to oscillate during the feedback control, which in turn makes the current output of the fuel cell unstable.

In another conventional technology, when the fuel cell system is operating, the internal current consumption of the air compressor under different air volumes is pre-tested, and when the fuel cell system is actually operating, only the net output current of the system is detected. In this way, There will be no vibration of feedback control caused by the air compressor. However, in this method, the current of the fuel cell is the net output current plus the pre-tested internal consumption current value. Since the pre-tested internal consumption current value is the current value under a specific state, in actual operation, the gas during fuel cell operation The pressure is a dynamic oscillating state, so the internal current consumption value of the air compressor is bound to be in an oscillating state. If the internal current consumption is directly assumed to be a constant value, the actual air supply may exceed the acceptable value range, and if the internal components such as the air compressor follow Declining efficiency over time will make the air supply more and more insufficient over time, leading to accelerated decline in the performance of the fuel cell.

Based on the above-mentioned bottleneck of the conventional technology, the present invention provides a fuel cell hybrid power control method and system to provide an appropriate amount of air so that the fuel cell can maintain a stable current output, thereby improving the life of the fuel cell.

The present invention provides a fuel cell compound power control method and system thereof. The demand power of the variable load and the demand power of the energy storage battery are used to calculate the demand air volume of the fuel cell, instead of using the variable load current of the fuel cell to estimate the demand air volume in the prior art, so that the fuel cell can maintain a stable air intake.

The present invention provides a fuel cell compound power control method and system. By adjusting the current output between the fuel cell and the energy storage battery, a stable current can be output even when the required power changes instantaneously.

The present invention provides a fuel cell compound power control method and system, which determine whether to start the fuel cell based on the state of the energy storage battery and the power demand of the variable load, so that the error tolerance for controlling the fuel cell can be relaxed while avoiding Waste of energy.

The present invention provides a fuel cell hybrid power control method, which controls the fuel cell and the energy storage battery, and at least one of the fuel cell and the energy storage battery is used to provide power to the variable load. The method includes the following steps: first, start The fuel cell calculates the desired output current of the fuel cell based on the first variable load demand power of the variable load and the battery demand power of the energy storage battery; calculates the fuel cell demand air volume based on the output current; and then provides the air volume demand based on the demand air volume Signal to the blower to make the blower supply air to the fuel cell; continue, read the actual air volume value supplied to the fuel cell, and calculate the output current range of the fuel cell based on the actual air volume value; finally, provide the control current range signal according to the output current range To the DC/DC transformer to control the DC/DC transformer, so that the output current of the fuel cell can be controlled within the output current range. Among them, when the variable load generates the second variable load demand power, if it is determined that the second variable load demand power is less than the first variable load demand power, the output part of the output current is output to the energy storage battery, otherwise, when the second variable load demand is judged When the power is not less than the power required by the first variable load, the energy storage battery provides a supply current to the variable load.

In the process of implementing the fuel cell compound power control method, the maximum discharge power of the energy storage battery is read to determine the maximum discharge power of the energy storage battery, and the maximum discharge power is compared with the first variable load demand power. When the discharge power is less than the power required by the first variable load, the fuel cell can be started. On the contrary, when the maximum discharge power is not less than the power required by the first variable load, the energy storage battery provides power to the variable load.

Moreover, in the process of implementing the fuel cell hybrid power control method, the state-of-charge (SOC) of the energy storage battery is controlled between the first threshold and the second threshold. Once the state-of-charge is not greater than At the first threshold, the energy storage battery is charged, and when the state of charge is not less than the second threshold, the energy storage battery is discharged; wherein, the method of charging the energy storage battery is selected from independently charging the energy storage battery Charge, output part of the output current of the fuel cell to the energy storage battery and a combination of the above methods. The method of discharging the energy storage battery is selected from independently discharging the energy storage battery, providing power to the variable load through the energy storage battery, and A combination of the above methods.

The present invention provides a fuel cell composite power control system to provide power to a variable load. The system proposed by the present invention includes a fuel cell, a blower, an energy storage battery, and a control unit. The fuel cell provides output current, and the blower supplies air. To the fuel cell, the energy storage battery generates the battery demand power, the control unit reads the first variable load demand power, the second variable load demand power and the battery demand power, and generates an air volume demand signal and transmits the air volume demand signal to the blower, and , The control unit reads the actual air value supplied to the fuel cell to calculate the output current interval of the fuel cell, and controls the output current of the fuel cell within the output current interval. Wherein, when the variable load momentarily generates the second variable load demand power, the control unit determines that the second variable load demand power is less than the first variable load demand power, the output part of the output power The current is output to the energy storage battery. On the contrary, when the control unit determines that the power required by the second variable load is not less than the power required by the first variable load, the energy storage battery provides a supply current to the variable load.

The control system is also matched with the battery management system unit, which detects and controls the battery demand power, maximum discharge power, and state of charge of the energy storage battery.

Moreover, when the fuel cell hybrid power control system is executed, the battery management system further controls the state of charge of the energy storage battery between the first threshold and the second threshold.

Wherein, when the battery management system detects that the state of charge of the energy storage battery is not greater than the first threshold, the battery management system and/or the control unit causes the energy storage battery to charge; when the battery management system detects the state of charge of the energy storage battery If it is not less than the second threshold, the battery management system and/or the control unit discharges the energy storage battery.

Among them, the control system further includes a DC/DC transformer, and the control unit controls the DC/DC transformer so that the output current is within the output current range. The control system further includes an air volume meter, which measures the actual air volume value, and reads the actual air volume value through the control unit.

In summary, the present invention proposes a fuel cell hybrid power control method and system, which calculate the required air volume of the fuel cell by varying the required power of the load and the required power of the energy storage battery to overcome the existing problems in the prior art. The technical bottleneck makes it possible to supply an appropriate amount of air to the fuel cell. In addition, the current supply between the fuel cell and the energy storage battery is adjusted more timely, and the judgment of whether to start the energy storage battery as a buffer is also added, so that the fuel cell hybrid power control method and system of the present invention are stable The advantages of operating voltage, wide operating fault tolerance and reducing energy waste.

1‧‧‧Fuel cell compound power control system

10‧‧‧Control Unit

20‧‧‧Battery Management System Unit

30‧‧‧Blower

40‧‧‧Energy storage battery

50‧‧‧Fuel cell

60‧‧‧DC/DC Transformer

70‧‧‧Inverter

80‧‧‧Variable load

90‧‧‧Air Flow Meter

S01, S02, S03, S04, S05, S06‧‧‧Step

S21, S22, S23a, S23b‧‧‧Step

S31, S32, S33a, S33b‧‧‧Step

S41, S42, S43a, S43b, S43c‧‧‧Step

S51, S52, S53a, S53b‧‧‧Step

Figure 1 is a flowchart of a control method according to an embodiment of the present invention.

Figure 2 is a block diagram of a control system according to an embodiment of the present invention.

Figure 3 is a flowchart of a control method according to an embodiment of the present invention.

Figure 4 is a flowchart of a control method according to an embodiment of the present invention.

Figure 5 is a flowchart of a control method according to an embodiment of the present invention.

The advantages and spirit of the present invention can be further understood from the following detailed description and the accompanying drawings. The structure and use of the embodiment of the present invention are described in detail as follows. It must be understood that the present invention provides many applicable innovative concepts, which can be widely implemented under a specific background technology. This specific embodiment is only represented in a specific manner to make and use the present invention, but it does not limit the scope of the present invention.

The present invention provides a fuel cell compound power control method and system, which control a fuel cell and an energy storage battery, and at least one of the fuel cell and the energy storage battery is used to provide power to a variable load. Please refer to FIG. 1 and FIG. 2. FIG. 1 is a flowchart of a control method disclosed in the present invention, and FIG. 2 is a block diagram of a control system disclosed in the present invention.

As shown in Figure 1, the method of the present invention includes the following steps: First, in step S01, the control unit 10 in the fuel cell hybrid power control system 1 starts the fuel cell 50; in step S02, the control unit 10 reads changes The first variable load demand power of the load 90 reads the battery demand power of the energy storage battery 40 through the battery management system unit 20, and calculates the desired output current of the fuel cell 50 according to the first variable load demand power and the battery demand power; In step S03, the control unit 10 calculates the required air volume of the fuel cell 50 according to the output current of the fuel cell 50; in step S04, the control unit 10 provides an air volume demand signal to the blower according to the required air volume 30. Allow the blower 30 to supply air to the fuel cell 50; in step S05, the control unit 10 reads the air flow meter 80 to measure the actual air volume value supplied to the fuel cell 50, and calculates the output current range of the fuel cell 50 based on the actual air volume value Finally, in step S06, the control unit 10 provides a control current range signal to the DC/DC transformer 60 according to the output current interval to control the DC/DC transformer 60 so that the output current of the fuel cell 50 is within the output current interval. It should be noted that the power demand of the load can be learned by the inverter. In addition, when the vehicle is running, it can be obtained by reading the throttle position signal and analyzing it by the trip computer. In other words, it can be obtained by The inverter knows the real-time changing load power, and the trip computer can estimate the changing load power demand. Since in the actual operation of the fuel cell hybrid power system, the power demand of the variable load will inevitably change with the use situation, in the present invention, the control unit continuously reads the demand of the variable load through the inverter In addition, in practical applications, the fuel cell hybrid power system of the present invention will generate additional energy demand instantly or in a short time due to the power change of the variable load. Therefore, there will be a significant change in the demand power. Based on the above, the present invention also provides a method to deal with when the demand power of the variable load changes instantaneously. Please refer to Figures 2 and 3, and Figure 3 It is a flow chart of a control method disclosed in the present invention when the demand power of a variable load changes instantaneously.

When the demand power of the variable load changes in an instant or a short period of time, that is, step S21, the control unit 10 reads the second variable load demand power generated in an instant or a short period of time, and then proceeds to step S22, and the control unit 10 determines the second 2. Whether the variable load demand power is less than the first variable load demand power, if the second variable load demand power is not less than the first variable load demand power, as described in step S23a, the energy storage battery 40 provides a supply current to the variable load 90, Conversely, if the second variable load demand power is less than the first variable load demand power, proceed as in As described in step S23b, the control unit 10 controls the DC/DC transformer 60 to output part of the output current to the energy storage battery 40.

In addition, in order to reduce the waste of energy, the present invention further determines whether to start the fuel cell for power supply according to the demand power of the variable load and the maximum discharge power of the energy storage battery. Please refer to FIG. 2 and FIG. 4 at the same time. FIG. 4 is a flowchart of a control method according to an embodiment of the present invention.

When the fuel cell hybrid power control system 1 is executed, the battery management system 20 is further used to calculate the maximum discharge power of the energy storage battery 40, and the control unit 10 can read the first variable load demand power, and ascertain the energy storage battery 40 As shown in step S31, then, in step S32, the control unit 10 determines whether the maximum discharge power is less than the first variable load demand power, if the maximum discharge power is not less than the first variable load demand power, as in step S33a As described, the control unit 10 does not start the fuel cell 50, but is powered by the energy storage battery 40. On the contrary, if the maximum discharge power is less than the first variable load demand power, the control unit 10 starts the fuel cell as described in step S33b. 50.

In addition, the present invention further determines whether to start the fuel cell for power supply according to the state of charge of the energy storage battery. Please refer to Fig. 1, Fig. 2 and Fig. 5 at the same time. Fig. 5 is a flowchart of a control method according to an embodiment of the present invention.

When the fuel cell hybrid power control system 1 is executed, the battery management system 20 first controls the state of charge of the energy storage battery 40, and makes the control unit 10 know the state of charge of the energy storage battery 40, as shown in step S41, and then in step S42 When it is determined that the state of charge of the energy storage battery 40 is between the first threshold and the second threshold, as described in step S43a, the control unit 10 activates the fuel cell 50, and continues to perform the steps in Figure 1 above; on the contrary;地，The state of charge of the energy storage battery 40 When it is not greater than the first threshold, as described in step S43b, the battery management system 20 and/or the fuel cell hybrid power control system 1 controls the energy storage battery 40 to charge it, for example, it may independently charge the storage battery. The energy battery 40 is charged, a part of the output current of the fuel cell 50 is output to the energy storage battery 40, and a combination of the above methods, or as described in step S43c, when the state of charge is not less than the second threshold, the battery management system 20 and/ Or the fuel cell composite power control system 1 controls the energy storage battery 40 to discharge it. For example, the energy storage battery 40 can be discharged independently, or the energy storage battery 40 can be used to supply power to a variable load, and A combination of the above methods.

Among them, since the definition of the state of charge is mainly divided into two types, one is the absolute state of charge (Absolute State-Of-Charge; ASOC) and the relative state of charge (Relative State-Of-Charge; RSOC). Generally speaking, the relative charge Regardless of the battery type and usage status, the definition of state refers to 100% when the battery is fully charged and 0% when fully discharged. The absolute state of charge is determined by various factors such as battery material characteristics, manufacturing characteristics, etc. The value of is a reference value calculated according to the fixed capacity value of the battery. In other words, for the absolute state of charge, the absolute state of charge of a brand new fully charged battery is 100%. It can't reach 100% even during charging and discharging. Based on the above, if the first threshold and the second threshold in this case are described by taking the relative state of charge as an example, the first threshold may be between 80% and 90%, and the second threshold may be between 15% and 25%. %between.

It should be noted that in the fuel cell composite power control method of the present invention, the step of controlling the energy storage battery 40 by the fuel cell composite power control system 1 to charge and discharge is not the fuel cell composite power control. The control unit 10 in the system 1 is controlling the energy storage battery 40. In other words, the control unit 10 cannot control the energy storage battery 40. Instead, it controls the output power of the DC/DC transformer in the fuel cell hybrid power control system 1 to Reach control power Flow direction. More specifically, the present invention uses the DC/DC transformer as the current source and the energy storage battery as the voltage source. Therefore, the control unit only needs to control the output power of the DC/DC transformer to determine the current flow. When the output power is greater than the demand of the variable load, the current will naturally charge the energy storage battery, and when the output power is less than the demand of the variable load, the energy storage battery will naturally discharge.

It can be seen from the above that the fuel cell hybrid power control system of the present invention is shown in Figure 2. The fuel cell hybrid power control system 1 is used to provide power to a variable load 90. The system includes a control unit 10, a battery management system unit 20, and a blower. 30. Energy storage battery 40, fuel cell 50, DC/DC transformer 60, inverter 70, air flow meter 80. Among them, the battery management system unit 20 is used to calculate the battery required power, the maximum discharge power, and the state of charge of the energy storage battery 40. The blower 30 is used to supply air to the fuel cell 50. The air flow meter 80 is used to measure the actual air flow supplied to the fuel cell 50. The control unit 10 can read the variable load demand power of the variable load 80 through the inverter 70, and read the battery demand power of the energy storage battery 40 through the battery management system unit 20, and thereby calculate the output current of the fuel cell 50. The control unit 10 also calculates the required air volume according to the output current to provide an air volume demand signal to the blower 30. According to the actual air volume value measured by the read air flow meter 80, the control unit 10 can calculate the output current range of the fuel cell 50 and control DC/DC The transformer 60 controls the output current of the fuel cell 50 within the output current range.

In addition, the control unit 10 determines the second variable load demand power generated in an instant or a short time, and determines whether the second variable load demand power is less than the first variable load demand power, if the second variable load demand power is not less than When the first variable load requires power, the energy storage battery 40 provides supplementary current to the variable load 90. Conversely, if the second variable load demand power is less than the first variable load demand power, the control unit 10 controls the DC/DC transformer 60, Ambassador The divided output current is output to the energy storage battery 40.

Moreover, the control unit 10 further determines whether the maximum discharge power is less than the first variable load demand power after determining the first variable load demand power and the maximum discharge power of the energy storage battery 40, if the maximum discharge power is not less than the first variable load demand power , The control unit 10 does not start the fuel cell 50, and the energy storage battery 40 naturally supplies power. On the contrary, if the maximum discharge power is less than the first variable load demand power, the control unit 10 starts the fuel cell 50.

In summary, the present invention proposes a fuel cell composite power control method and system, which calculates the air demand of the fuel cell according to the demand power of the variable load and the demand power of the energy storage battery, so as to provide an appropriate amount of air to enable the fuel cell to perform Maintain good power and at the same time have good performance. When the demand power of the variable load changes instantaneously, according to the change of the demand power, part of the current output to the energy storage battery is controlled accordingly, or the energy storage battery supplies current to the variable load. In addition, it is based on the comparison between the maximum discharge power of the energy storage battery and the required power of the variable load, and the state of charge of the energy storage battery to determine whether to start the fuel cell. It can be seen from the above that the fuel cell hybrid power control method and system proposed in the present invention have the advantage of stabilizing the operating voltage of the fuel cell, thereby increasing the life of the fuel cell, and through the combination of the fuel cell and the energy storage battery , Can fully supply the power demand of the variable load, in order to achieve the benefits of reducing energy waste.

Although the present invention is disclosed in the foregoing embodiments as above, it is not intended to limit the present invention. Anyone familiar with similar art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of patent protection shall be determined by the scope of the patent application attached to this specification.

S21, S22, S23a, S23b‧‧‧Step

Claims (15)

A fuel cell composite power control method, which controls a fuel cell and an energy storage battery, and at least one of the fuel cell and the energy storage battery is used to provide power to a variable load, and the energy storage battery generates a battery demand The variable load generates a first variable load demand power and a second variable load demand power. The method includes the following steps: starting the fuel cell, and calculating the power according to the first variable load demand power and the battery demand power A desired output current of the fuel cell; calculate a demand air volume of the fuel cell according to the desired output current; provide an air volume demand signal according to the demand air volume so that air is supplied to the fuel cell; read an air volume supplied to the fuel cell Actual air volume value, and calculating an output current range of the fuel cell based on the actual air volume value; and providing a control current range signal to control the DC/DC transformer so that an output current of the fuel cell is within the output current range; , When the second variable load demand is generated instantaneously, and the second variable load demand power is less than the first variable load demand power, a part of the output current of the fuel cell is output to the energy storage battery, and when the second variable load demand When the load demand power is not less than the first variable load demand power, the energy storage battery provides a supply current to the variable load. The fuel cell compound power control method according to claim 1, wherein before the step of starting the fuel cell, the method further comprises: reading a maximum discharge power of the energy storage battery to ascertain the maximum discharge power of the energy storage battery ; And compare the maximum discharge power with the first variable load demand power, when the maximum discharge power is small When the first variable load requires power, the fuel cell is started. The fuel cell compound power control method according to claim 2, wherein when the maximum discharge power is not less than the power required by the first variable load, the fuel cell is not activated and the energy storage battery provides power to the variable load. The fuel cell hybrid power control method according to claim 1, which further controls a state of charge of the energy storage battery between a first threshold and a second threshold during execution. The fuel cell compound power control method according to claim 4, wherein when the state of charge is not greater than the first threshold, the energy storage battery is charged, and when the state of charge is not less than the second threshold, then The energy storage battery is discharged. The fuel cell hybrid power control method according to claim 4, wherein the method of charging the energy storage battery is selected from independently charging the energy storage battery, and outputting part of the output current of the fuel cell to the energy storage battery A combination of the battery and the above methods. The fuel cell compound power control method according to claim 4, wherein the method of discharging the energy storage battery is selected from independently discharging the energy storage battery, providing power to the variable load through the energy storage battery, and the above A combination of methods. A fuel cell compound power control system for providing electric power to a variable load that generates a first variable load demand power and a second variable load demand power. The system includes: a fuel cell that provides an output current; A blower to supply air to the fuel cell; an energy storage battery to generate a battery demand power; and a control unit to read the first variable load demand power and the second variable load demand power And the battery demand power, and the control unit generates an air volume demand signal and transmits the air volume demand signal to the blower, and reads an actual air volume value supplied to the fuel cell to calculate an output current interval of the fuel cell, And control the output current of the fuel cell within the output current interval; wherein, when the second variable load demand is generated instantaneously, and the second variable load demand power determined by the control unit is less than the first variable load demand power, Part of the output current is sent to the energy storage battery, and when the control unit determines that the second variable load demand power is not less than the first variable load demand power, the energy storage battery provides a supply current to the variable load. The fuel cell hybrid power control system described in claim 8 is further matched with a battery management system unit (Battery Management System), and the battery management system unit is directed to the battery demand power and a maximum discharge power of the energy storage battery , A state of charge (State-of-Charge, SOC) for detection and control. According to the fuel cell hybrid power control system according to claim 9, when it is executed, the battery management system further controls the state of charge of the energy storage battery between a first threshold and a second threshold. The fuel cell hybrid power control system according to claim 10, wherein when the battery management system detects that the state of charge of the energy storage battery is not greater than the first threshold, the battery management system and/or the fuel cell hybrid The power control system charges the energy storage battery. The fuel cell hybrid power control system according to claim 10, wherein when the battery management system detects that the state of charge of the energy storage battery is not less than the second threshold, the battery management system and/or the fuel cell hybrid The power control system discharges the energy storage battery. The fuel cell composite power control system according to claim 8, which further includes a DC/DC transformer, and the control unit controls the DC/DC transformer so that the output current is in the output power In the flow interval. The fuel cell hybrid power control system according to claim 8, which further includes an air flow meter for measuring the actual air flow value. The fuel cell hybrid power control system according to claim 8, wherein the variable load is a motor.

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