JPS6240830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control method for a fuel cell power generation device.

Conventional fuel cell power generation equipment has two independent control systems: a temperature control system that controls the internal temperature of the fuel cell and a voltage control system that controls the output voltage from the fuel cell. The abnormal temperature rise could not be directly controlled due to the oversupply of fuel caused by the control system.

The present invention eliminates the above-mentioned drawbacks by inserting a switch element between the temperature control system and the voltage control system, so that the output signal from the PID temperature adjustment circuit of the temperature control system increases in the direction of temperature increase by more than a predetermined value. When the temperature reaches this value, the switch element is closed and the amount of fuel supplied is reduced in response to a temperature control signal to prevent an abnormal temperature rise due to excessive fuel supply.

That is, between the fuel supply device and the fuel cell,
It has a valve to adjust the amount of fuel flowing into the fuel cell, and compares the output voltage from the fuel cell with the voltage signal generated by the voltage setting circuit and amplifies the difference.
a control system including a PID voltage adjustment circuit and a valve drive circuit that drives a valve that has obtained a drive signal suitable for the valve based on a signal from the PID voltage adjustment circuit;
A PID temperature control circuit that compares the temperature of the fuel cell with the setting signal from the temperature setting circuit and amplifies the difference.
a control system including a fuel cell cooling pump or fan driven by a signal from the PID temperature control circuit, and a comparator that operates when the output value of the PID temperature control circuit exceeds a predetermined value; This fuel cell power generation device is characterized in that it includes a switch element that conducts a signal from a PID temperature control circuit so as to add the signal from the PID voltage control circuit to the signal from the PID voltage control circuit based on the output signal of the comparator.

An embodiment of the present invention will be described.

1 is a fuel supply device including a fuel supply pump for supplying fuel to the fuel cell 2; 31 is a main valve for adjusting the amount of fuel sent from the fuel supply device 1 into the fuel cell 2; 32 is fuel cell 2
4 is a temperature detector for detecting the temperature inside the fuel cell 2; 41 is a temperature setting value and a temperature sensor for controlling the temperature of the fuel cell 2; Detects and amplifies temperature differences within the system and compensates for the control system.
PID temperature control circuit; 42 is a temperature setting circuit for setting the temperature inside the fuel cell 2; 43 is a drive circuit for driving a cooling pump or fan; 44 is cooling water or cooling for cooling the fuel cell 2. A cooling pump or fan that sends air into the fuel cell 2; 51 is a comparator that operates when the output value from the PID temperature control circuit 41 exceeds a predetermined value; 52 is a comparator that operates when the comparator 51 operates;
A switch element 61 is used to connect the signal from the PID temperature control circuit 41 to the adder circuits 63 and 72 according to the signal. A PID voltage adjustment circuit that detects and amplifies the voltage difference and also compensates for the control system; 62 is the fuel cell 2;
a voltage setting circuit for setting the output voltage from the
63 is an addition circuit that adds the output signal of the PID temperature adjustment circuit 41 so as to subtract it from the signal output from the PID voltage adjustment circuit 61; 64 is a comparator 81;
65 is an auxiliary valve drive circuit that drives the auxiliary valve 32; 7 is a shunt that detects the output current from the fuel cell 2;
Reference numeral 1 denotes a compensation amplifier circuit that amplifies the output signal from the shunt circuit 7 and performs a compensation operation for the control system; 72 subtracts the output signal of the PID temperature adjustment circuit 41 from the output signal of the compensation amplifier circuit 71; An addition circuit that adds the output signal of the PID voltage adjustment circuit 61; 73 is a switch element that connects the output of the PID voltage adjustment circuit 61 and the addition circuit 72 by the operation of the comparator 81; 74 is a comparator 8;
When 1 is activated, a switch element connects between the adder circuit 72 and the main valve drive circuit 75, 75 is a main valve drive circuit that drives the main valve 31, and 81 is a switch element that connects the adder circuit 72 and the main valve drive circuit 75. 9 is the electrical output.

The amount of fuel sent out from the fuel supply device 1 is adjusted by either the main valve 31 or the auxiliary valve 32, and then the fuel is delivered to the fuel cell 2.
It is converted into electrical output commensurate with the amount of fuel supplied. At this time, due to the chemical reaction that occurs to convert the fuel into electrical output and the electrical loss caused by the voltage drop due to the internal resistance of the battery, heat is generated inside the battery, raising the internal temperature of the battery. In order to prevent the abnormally high temperature inside the battery from occurring in this way, it is necessary to cool the inside of the battery. For temperature control, the temperature detector 4 detects the internal temperature of the fuel cell 2, the PID temperature control circuit 41 compares it with the temperature setting signal generated by the temperature setting circuit 42, and the difference is amplified. Ru. This amplified signal is transmitted to the cooling pump or fan drive circuit 4.
3, the signal is converted into an electrical output suitable for the cooling pump or fan 44, drives the cooling pump or fan 44, and adjusts the amount of cooling water or air that flows into the fuel cell 2 to keep the internal temperature of the battery constant. Keep the temperature at .

The output voltage from the fuel cell 2 is compared by a PID voltage adjustment circuit 61 with a voltage setting signal generated by a voltage setting circuit 62, and the difference therebetween is amplified. This amplified signal passes through an adder circuit 63, is supplied to an auxiliary valve drive circuit 65, and is converted into a drive signal suitable for the auxiliary valve 32.
The output voltage from the fuel cell 2 is kept constant by controlling the inflow amount of fuel. Regarding the output power from the fuel cell 2, in order to make the amount of fuel inflow commensurate with the output voltage, the current from the fuel cell 2 is detected by the shunt 7, and after this signal is amplified by the compensation amplifier 71, Passes through the adder circuit 72,
Supplied to the main valve drive circuit 75, the main valve 31
After being converted into a drive signal suitable for the main valve 3
The inflow amount of fuel is adjusted to match the output power of the fuel cell 2.

In addition to the above-mentioned circuit, when controlling the fuel cell 2, it is necessary to take into consideration the state of excess fuel supply, where the amount of fuel supplied is large relative to the output power of the fuel cell 2, and such excessive fuel supply In this state, the internal temperature of the fuel cell 2 shows an abnormal temperature rise, so in order to prevent such an abnormal temperature rise,
When the signal output from the PID temperature control circuit 41 exceeds a predetermined level in the direction of temperature increase, the comparator 51 detects this, closes the interlocking switch element 52, and outputs the signal from the PID temperature control circuit 41. The signals are led to adder circuits 63 and 72.
By subtracting the output signals from the PID voltage adjustment circuit 61 and the compensation amplifier circuit 71, the main valve 3
1 and the auxiliary valve 32 to reduce the amount of fuel supplied to prevent excessive fuel supply.

Furthermore, if the auxiliary valve 32 of the voltage regulation system and the main valve 31 of the power regulation system are operated at the same time, the voltage regulation system and the power regulation system will interfere with each other and the control system will become unstable. It is necessary to operate only one of 32. For this purpose, a switch element 64 is inserted between the adder circuit 63 and the auxiliary valve drive circuit 65, and a switch element 7 is inserted between the adder circuit 72 and the main valve drive circuit 75.
4, and PID voltage adjustment circuit 61 and addition circuit 7
A switch element 73 is inserted between the two. These switch elements 64, 73 and 74 are interlocked with a comparator 81, and the comparator 81 is set to operate when the magnitude of the output signal from the compensation amplifier circuit 71 reaches a predetermined value or more. Due to the operation of the comparator 81, the switch element 64 is opened and the auxiliary valve 32, which had been operating before the operation of the comparator 81, is closed.
On the other hand, when the switch element 74 is closed, the main valve 31, which was closed before the comparator 81 operates, is switched to operate in place of the auxiliary valve 32. At the same time, the comparator 81 operates to close the switch element 73, and the signal from the PID voltage adjustment circuit 61 is added to the addition circuit 72, thereby causing the main valve 31 to have a voltage adjustment function.

FIG. 2 shows the relationship between the valve openings of the main valve 31 and the auxiliary valve 32 with respect to the electrical output of the fuel cell 2. Characteristic A indicates the valve opening characteristic of the auxiliary valve 32, and characteristic B indicates the valve opening characteristic of the main valve 32. The valve opening characteristics of 31 are shown respectively. These valves control the amount of fuel supplied by the auxiliary valve 32 when the electrical output from the fuel cell 2 is low, and the fuel cell 2
When the electrical output from the main valve 31 is greater than a predetermined value, the main valve 31 controls the amount of fuel supplied. The main valve 31 and the auxiliary valve 32 are selected to be switched when the electrical output of the fuel cell 2 reaches a value of 5 to 20%. As a result, the fuel supply to the fuel cell 2 can be controlled consistently and accurately from a small electrical output to a large electrical output.

As described above, according to the present invention, it is possible to prevent an abnormal rise in the internal temperature of the fuel cell due to excessive supply of fuel, thereby eliminating the adverse effect on the cell reaction, and reducing the cooling capacity for cooling the fuel cell. As a result, the cooling pump or cooling fan can be replaced with a smaller one and the fuel cell can be made smaller and lighter, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the electrical output of a fuel cell and the opening degree of a valve for supplying fuel. 1 is a fuel supply device, 2 is a fuel cell, 31 is a main valve, 32 is an auxiliary valve, 4 is a temperature detector, 41
is a PID temperature control circuit, 42 is a temperature setting circuit, 43
5 is a cooling pump or fan drive circuit; 44 is a cooling pump or fan; 51 is a comparator;
2 is a switch element, 61 is a PID voltage adjustment circuit, 6
2 is a voltage setting circuit, 63 is an adder circuit, 64 is a switch element, 65 is an auxiliary valve drive circuit, 7 is a shunt, 71 is a compensation amplifier circuit, 72 is an adder circuit, 73
is a switch element, 74 is a switch element, 75 is a main valve drive circuit, 81 is a comparator, 9 is an electric output, A is a characteristic of the auxiliary valve, and B is a characteristic of the main valve.

Claims (1)

[Claims] 1. A valve is provided between the fuel supply device and the fuel cell to adjust the amount of fuel flowing into the fuel cell,
A PID voltage adjustment circuit that compares the output voltage from the fuel cell with a voltage signal generated by a voltage setting circuit and amplifies the difference; and a drive signal suitable for the valve is obtained from the signal from the PID voltage adjustment circuit to operate the valve. A control system including a valve drive circuit that drives the fuel cell, a PID temperature control circuit that compares the temperature of the fuel cell with a setting signal from the temperature setting circuit and amplifies the difference, and a fuel that is driven by the signal from the PID temperature control circuit. A control system including a battery cooling pump or fan, a comparator that operates when the output value of the PID temperature control circuit exceeds a predetermined value, and a signal of the PID temperature control circuit based on the output signal of the comparator. A fuel cell power generation device characterized by comprising a switch element that makes conductive so as to add to a signal from the PID voltage adjustment circuit.