A fuel cell self-heating device, method and system

Abstract

The application discloses a fuel cell self-heating device, method and system, which comprises a master control module, a power module, and a multi-channel selector. The master control module is used for generating a control signal and sending the control signal to the connected power module. The power module is used for receiving the control signal and determining the state of the multi-channel selector. When the multi-channel selector is in a target state, the input source of a first circuit is determined as a power battery, the first circuit is a heating circuit, the heating circuit is operated to make an inductor in the heating circuit charge and discharge, so that a power device generates heat, and the power device comprises the inductor, a first switch tube, a first conducting tube, a second switch tube and a second conducting tube. The fuel cell self-heating device can more conveniently realize self-heating of the fuel cell, and can reduce the complexity and cost of the fuel cell system by controlling the power module to operate the heating circuit, making the inductor charge and discharge, and making the power device generate heat and transmit the heat to the fuel cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy, in particular to a fuel cell self-heating device, method and system. BACKGROUND

[0002] At present, with the increasing awareness of carbon neutralization, environmental protection and emission reduction, and the continuous rise of oil prices, new energy such as hydrogen fuel cells has attracted widespread attention due to its zero pollution, renewable and high efficiency. Since the fuel cell can only produce a low output voltage in a low temperature environment of about 0℃, it is necessary to heat the fuel cell in a low temperature environment to achieve normal operation of the battery. At present, the commonly used heating methods include electric heating and catalytic combustion heating. Among them, the electric heating technology heats the cooling liquid locally by increasing the heating device such as electric heating wire to bring heat into the battery stack. This method is difficult to control the temperature and will reduce the efficiency of the fuel cell system; the catalytic combustion heating technology increases the cost and complexity of the fuel cell system by installing a burner for catalytic reaction.

[0003] Therefore, how to conveniently heat the fuel cell without affecting the efficiency and cost of the fuel cell system is a problem to be solved. SUMMARY

[0004] The present application provides a fuel cell self-heating device, method and system. The main control module controls the power module to run the heating circuit, charges and discharges the power device in the heating circuit, generates heat, and transmits the heat to the fuel cell, which can realize self-heating of the fuel cell, is convenient and fast, and does not need to install additional equipment.

[0005] The first aspect of the present application provides a fuel cell self-heating device, which comprises a main control module and a power module, wherein the power module comprises a multiplexer and a first circuit: the main control module is used to generate a control signal and send the control signal to the connected power module; the power module is used to receive the control signal and determine the state of the multiplexer according to the control signal; in the case that the multiplexer is in the target state, the input source of the first circuit is determined to be the power battery, the first circuit is the heating circuit, the heating circuit is run to make the inductance in the heating circuit charge and discharge, so that the power device generates heat, wherein the power device comprises a first switch tube, a first conduction tube, a second switch tube and a second conduction tube; in the case that the multiplexer is in a non-target state, the input source of the first circuit is determined to be the fuel cell, the first circuit is a boost-buck cascade topology circuit, and the power battery is charged.

[0006] The fuel cell self-heating device provided by the application generates a control signal indicating the state of the multiplexer by the master module and sends the control signal to the power module. The power module determines the input source of the first circuit according to the control signal. In the case that the input source of the first circuit is the power battery, the power module determines to run the heating circuit. The power device in the power module generates heat through the charging and discharging of the inductor, and transmits the heat to the fuel cell, thereby achieving the heating of the fuel cell. The inductor is also part of the power device. In the case that the power module determines that the input source of the first circuit is the fuel cell, the first circuit is a boost-buck cascaded topology circuit. The device does not need to install a heating device in the fuel cell system, and can realize the functions of charging the power battery and self-heating of the fuel cell, thereby reducing the cost and the complexity of the fuel cell system.

[0007] In a possible implementation of the first aspect, the master module is further configured to generate a first signal for controlling the state of the first switch tube and a second signal for controlling the state of the second switch tube, wherein the first signal and the second signal are the same.

[0008] In a possible implementation of the first aspect, the master module comprises a sampling circuit, a digital control chip and a driving circuit. The sampling circuit is configured to acquire a current signal of the inductor. The digital control chip is configured to acquire an external communication signal and generate a control signal according to the external communication signal and the current signal, wherein the external communication signal is used to indicate a target current value of the inductor, and the control signal comprises a multiplexer control signal for indicating the state of the multiplexer, the first signal and the second signal. The driving circuit is configured to send the control signal to the power module. In the above process, the external communication signal can be a signal sent by an external host computer through a controller area network (CAN) protocol, which is used to control the current of the inductor. The master module generates a control signal for indicating the state of the multiplexer, the state of the first switch tube and the state of the second switch tube according to the external communication signal and the current signal of the inductor acquired by sampling, and controls the current of the inductor by controlling the multiplexer, the first switch tube and the second switch tube, and further controls the speed of heat generation, temperature transition and the like.

[0009] In a possible implementation of the first aspect, the power module is specifically configured to receive the multiplexer control signal, the first signal and the second signal. In the case that the multiplexer is in the target state, and the first signal and the second signal each indicate that the first switch tube and the second switch tube are turned on, the inductor is charged, so that the power device generates heat. In the above process, the first switch tube and the second switch tube are turned on, the power battery charges the inductor as the input end in the heating circuit, the current of the inductor continuously increases, the power device generates heat, and the heat is transmitted to the fuel cell, thereby achieving the self-heating of the fuel cell.

[0010] Or, in the case of the multiplexer is in the target state, the first signal and the second signal each indicate that the first switch tube and the second switch tube are off, the inductor is discharged, so that the power device generates heat. In the above process, the first switch tube and the second switch tube are off, and the inductor charges the power battery at the input end because the current of the inductor does not change abruptly, and the current of the inductor decreases continuously. In the process of charging the power battery by the inductor, the power device generates heat, which is transmitted to the fuel cell to achieve self-heating of the fuel cell.

[0011] According to the above two possible embodiments, in the fuel cell self-heating device, the master control module determines the conduction or off of the first switch tube and the second switch tube through the control signal, controls the current of the inductor by controlling the duty cycle of each switch tube, controls the amount of heat generated by the power device, and further controls the heating speed and temperature of the fuel cell. The above process can reduce the problem of reduced fuel cell working efficiency caused by unstable temperature transition during fuel cell heating.

[0012] In a possible implementation of the first aspect, the inductor is a single-phase inductor or a parallel multi-phase inductor. Because the current of the inductor does not change abruptly and can freewheel, the inductor can charge and discharge in the case of the conduction or off of the first switch tube and the second switch tube, so that the power device generates heat and transmits the heat to the fuel cell.

[0013] The second aspect of the application provides a fuel cell self-heating method. The method is applied to the fuel cell self-heating device provided in the first aspect, and the fuel cell self-heating device includes a master control module and a power module. The power module includes a multiplexer and a first circuit. The method includes: the master control module generates a control signal and sends the control signal to the power module; the power module receives the control signal and determines the state of the multiplexer according to the control signal; in the case of the multiplexer being in the target state, the input source of the first circuit is determined to be the power battery, the first circuit is a heating circuit, and the heating circuit is operated to make the inductor in the heating circuit charge and discharge, so that the power device generates heat. The power device includes a first switch tube, a first conduction tube, a second switch tube, and a second conduction tube; in the case of the multiplexer being in the non-target state, the input source of the first circuit is determined to be the fuel cell, and the first circuit is a boost-buck cascaded topology circuit to charge the power battery.

[0014] In a possible implementation of the second aspect, the above method further includes: the master control module generates a first signal for controlling the state of the first switch tube and a second signal for controlling the state of the second switch tube, wherein the first signal and the second signal are the same.

[0015] In a possible implementation of the second aspect, the master module comprises a sampling circuit, a digital control chip, and a driving circuit; the sampling circuit acquires a current signal of the power device; the digital control chip acquires an external communication signal, and generates a control signal according to the external communication signal and the current signal, wherein the external communication signal is used to indicate a target current value of the inductor, and the control signal comprises a multiplexer control signal indicating a state of the multiplexer, a first signal, and a second signal; and the driving circuit sends the control signal to the power module.

[0016] In a possible implementation of the second aspect, the power module receives the multiplexer relay control signal, the first signal, and the second signal; and the power module charges the inductor so that the power device generates heat when the multiplexer is in the target state and the first signal and the second signal each indicate that the first switch tube and the second switch tube are turned on; or the power module discharges the inductor so that the power device generates heat when the multiplexer is in the target state and the first signal and the second signal each indicate that the first switch tube and the second switch tube are turned off.

[0017] The third aspect provides a fuel cell self-heating system, which comprises a fuel cell self-heating device and a temperature sensing device, the temperature sensing device is used to acquire a temperature of the fuel cell, and send a temperature signal to the fuel cell self-heating device, the temperature signal is used to indicate the temperature of the fuel cell; the fuel cell self-heating device is used to receive the temperature signal, and execute the fuel cell self-heating method provided in the second aspect according to the temperature signal, and can realize the function of the fuel cell self-heating device in the first aspect.

[0018] On the basis of the implementation manners provided in the aspects above, the application can be further combined to provide more implementation manners. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced.

[0020] Figure 1 is a structural schematic diagram of a fuel cell self-heating device provided by the embodiments of the application;

[0021] Figure 2 is a structural schematic diagram of a boost-buck cascaded topology circuit in which the power module operates in a non-target state provided by the embodiments of the application;

[0022] Figure 3 is a structural schematic diagram of a heating circuit in which the power module operates in a target state provided by the embodiments of the application;

[0023] Figure 4is an equivalent circuit structure schematic diagram provided by the embodiment of the application when the first switch tube and the second switch tube in the heating circuit are in the on state;

[0024] Figure 5 is an equivalent circuit structure schematic diagram provided by the embodiment of the application when the first switch tube and the second switch tube in the heating circuit are in the off state;

[0025] Figure 6 is a flow chart of a fuel cell self-heating method provided by the embodiment of the application;

[0026] Figure 7 is a structure schematic diagram of a fuel cell self-heating system provided by the embodiment of the application. DETAILED DESCRIPTION

[0027] At present, fuel cells are widely used in automobile and other industrial industries due to their zero pollution, renewable and high efficiency characteristics. However, the fuel cell has a high requirement on the environmental temperature. In the case that the fuel cell system is in a low temperature environment, the fuel cell can only output a low voltage. At present, when the fuel cell system is in a low temperature environment, heat can be generated by using an electric heating technology or a catalytic heating technology to improve the temperature of the fuel cell. The electric heating technology heats the cooling liquid locally by adding a heating device such as an electric heating wire in the fuel cell system, and transmits the heat to the inside of the fuel cell. This method needs to strictly control the temperature transition. When the temperature is too high, the fuel cell electrode will be damaged, and the working efficiency of the fuel cell will be reduced. The catalytic combustion heating technology adds a burner for catalytic reaction in the fuel cell system to generate heat and heat the fuel cell. This method increases the cost and complexity of the fuel cell system.

[0028] Therefore, in order to solve the above problems, the application provides a fuel cell self-heating device. A main control module controls a power module, so that the power module operates a heating circuit in a low temperature environment. The inductor in the heating circuit is charged or discharged to generate heat for the power device, and the heat is transmitted to the fuel cell to realize self-heating of the fuel cell. Figure 1 As shown in the formula (1), the power module is controlled by the main control module to operate the heating circuit in the low temperature environment. The inductor in the heating circuit is charged or discharged to generate heat for the power device, and the heat is transmitted to the fuel cell to realize self-heating of the fuel cell. Figure 1is a structural schematic diagram of a fuel cell self-heating device. The fuel cell self-heating device 100 includes a master control module 110 and a power module 120, wherein the power module 120 includes a multiplexer S1 and a first circuit: the master control module 110 is used to generate a control signal and send the control signal to the connected power module; the power module 120 is used to receive the control signal and determine the state of the multiplexer according to the control signal; in the case that the multiplexer is in the target state, the input source of the first circuit is determined to be the power battery, the first circuit is a heating circuit, and the heating circuit is operated to make the inductor L1 in the heating circuit charge and discharge, so that the power device generates heat, wherein the power device includes a first switch tube Q1, a first conducting tube D1, a second switch tube Q2 and a second conducting tube D2; in the case that the multiplexer is in a non-target state, the input source of the first circuit is determined to be a fuel cell DC, and the first circuit is a boost-buck cascaded topology circuit, which realizes charging of the power battery.

[0029] The master control module includes a sampling circuit 111, a digital control chip 112 and a driving circuit 113. The multiplexer in the power module can be a multi-contact switch such as a relay, Figure 1 The specific type of multiplexer is not limited in the application. The power battery as the input source is not limited in the application. Figure 1 C2 is taken as an example for illustration.

[0030] The first switch tube and the second switch tube included in the power device can be silicon carbide mosfet tubes, the on-resistance and switching loss of which are greatly reduced compared to other types, and the working stability can be improved due to the high-temperature working characteristics. The first switch tube and the second switch tube can also be other types of switch tubes, which are not limited in the application. Figure 1 Diodes are taken as an example for illustration, which are not limited in the application.

[0031] The inductor L1 in the heating circuit also belongs to the power device, and generates heat together with the first switch tube Q1, the first conducting tube D1, the second switch tube Q2 and the second conducting tube D2. The inductor can be a single-phase inductor or a parallel connection of multiple-phase inductors, which are not limited in the application. The capacitor C1 and the power battery C2 in the power module are connected in parallel, and the corresponding voltages at both ends are the same. The moving contact of the relay S1 is connected with the first switch tube Q1, the first stationary contact is connected with the second conducting tube D2, and the second stationary contact is connected with the fuel cell.

[0032] The power module determines the state of the relay according to the control signal generated by the master module, and determines the input source corresponding to the first circuit included in the power module. In the case where the first static contact of the relay is closed (i.e., the first static contact is connected with the second conducting tube D2, and the relay is in the target state), the input source of the first circuit is determined to be the power battery, the first circuit is determined to be a heating circuit, the heating circuit is operated, the inductor performs charging and discharging, and the power device generates heat. In the process of operating the heating circuit in the power module described above, the inductor, the first switch tube, the second switch tube, the first conducting tube and the second conducting tube included in the power device can collectively generate a large amount of heat, and the device generating heat in the heating circuit is not specifically limited in the present application. Therefore, the power module can generate sufficient heat without adding a heating device to the fuel cell system, thereby realizing self-heating of the fuel cell. In the case where the second static contact of the relay is closed (i.e., the second static contact is connected with the fuel cell, and the relay is in a non-target state), the input source of the first circuit is the fuel cell, and the first circuit is a boost-buck cascade topology circuit, which can enable the power module to realize normal boost-buck function, adjust the voltage across the output side power battery, i.e., realize the power battery charging function.

[0033] In a possible implementation, one temperature sensor is connected with the fuel cell and the master module respectively, wherein the temperature sensor can be collectively integrated in the fuel cell self-heating device together with the fuel cell and the master module, or separately integrated in a temperature sensing device, which is not specifically limited in the present application. In the case where the temperature sensor obtains the temperature of the fuel cell below the first temperature threshold, the temperature sensor sends a low-temperature signal to the master module. In the case where the temperature sensor obtains the temperature of the fuel cell above the second temperature threshold, the temperature sensor sends a high-temperature signal to the master module, wherein the second temperature threshold is greater than or equal to the first temperature threshold, which is not specifically limited in the present application. The fuel cell can work at a normal efficiency in the case where the temperature thereof is greater than or equal to the first temperature threshold and less than or equal to the second temperature threshold, at this time, the temperature sensor can obtain the temperature value at which the fuel cell can normally work, and send a normal temperature signal to the master module.

[0034] In one possible implementation, in the case that the temperature sensor sends a normal temperature signal to the master module, the digital control chip in the master module generates a control signal according to an external communication signal sent by the upper computer through a controller area network (CAN) protocol, a current inductance current signal sampled by the sampling circuit from the power module, and the normal temperature signal, wherein the control signal includes a relay control signal indicating a state of a relay, a first signal indicating a state of a first switch tube Q1, and a second signal indicating a state of a second switch tube Q2. The master module sends the above signals to the power module through a driving circuit. The relay control signal indicates that the second stationary contact of the relay is closed, the fuel cell is taken as an input source of the first circuit, the first circuit is determined as a boost-buck cascade topology circuit, and the boost-buck cascade topology circuit is operated. The first signal and the second signal control the conduction and the turn-off of the first switch tube and the second switch tube in the normal control circuit, adjust the voltage across the output end of the first circuit, and realize the function of charging the power battery.

[0035] The first signal and the second signal are two pulse width modulation (PWM) signals, PWM-Q1 and PWM-Q2, which are generated by a proportional integral (PI) regulator according to the external communication signal and the current inductance current signal sampled, and are the same. Because the first signal PWM-Q1 and the second signal PWM-Q2 are the same, the first switch tube and the second switch tube only have two states of common conduction or common turn-off. The PI regulator determines a given inductance current value according to the external communication signal sent by the upper computer, and generates the first signal and the second signal for controlling the inductance current value according to the current inductance current signal sampled. After the first signal and the second signal are generated by the PI regulator, the problem of temperature being too high due to inertia and hysteresis characteristics of the current, and reducing the efficiency of the fuel cell can be avoided.

[0036] As shown in Figure 2 , the first signal PWM-Q1 and the second signal PWM-Q2 are the same, and the first switch tube Q1 and the second switch tube Q2 only have two states of common conduction or common turn-off. Figure 2This is a schematic diagram of a buck-boost cascaded topology circuit for power module operation in a non-target state, provided by an embodiment of this application. The connection relationship between the devices in the buck-boost cascaded topology circuit is as follows. The first terminal of the fuel cell DC is connected to the second stationary contact of relay S1, and the second stationary contact is connected to the moving contact of relay S1. The relay is in a non-target state. The moving contact of the relay is connected to the first terminal of the first switch Q1. The second terminal of the first switch Q1 is connected to the first terminal of the first conducting tube D1 and the first terminal of the inductor L1. The second terminal of the first conducting tube D1 is connected to the second terminal of the fuel cell DC and the second terminal of the second switch Q2. The first terminal of the second switch Q2 is connected to the second terminal of the inductor L1. The second terminal of the inductor L1 is connected to the second terminal of the second conducting tube D2. The first terminal of the second conducting tube is connected to the first terminal of the power battery C2 at the output terminal. The second terminal of the power battery C2 is also connected to the second terminal of the second switch Q2. The capacitor C1 and the power battery C2 are connected in parallel. The first terminal of the capacitor C1 is connected to the first terminal of the power battery C2, and the second terminal of the capacitor C1 is connected to the second terminal of the power battery C2.

[0037] In another possible implementation, the power module, in addition to operation Figure 2 In addition to the buck-boost cascaded topology circuit shown, another circuit can also be operated. When the temperature of the fuel cell is below the first temperature threshold, the temperature sensor sends a low-temperature signal to the main control module. The digital control chip in the main control module generates a relay control signal to close the first stationary contact of the relay based on external communication signals, the current signal of the inductor obtained by the sampling circuit, and the low-temperature signal. The power module determines that the input source in the first circuit is the power battery and that the first circuit is the heating circuit based on the relay control signal, and then operates the heating circuit.

[0038] like Figure 3 As shown, Figure 3Fig. 1 is a structural schematic diagram of a heating circuit in which a power module operates in a target state according to an embodiment of the present application. A main control module is connected to the power module, and the power module includes a heating circuit which operates. The heating circuit can further include a capacitor C1. The connection relationship is as follows: a moving contact of a relay S1 is connected to a first stationary contact of the relay, and the relay is in a target state; the capacitor C1 and a power battery C2 are connected in parallel, a first terminal of the capacitor C1 is connected to a first terminal of the power battery C2, and a second terminal of the capacitor C1 is connected to a second terminal of the power battery C2; the first terminal of the capacitor C1 is connected to a first terminal of a second conducting tube D2 and the first stationary contact of the relay S1 respectively; a second terminal of the second conducting tube D2 is connected to a second terminal of an inductor L1 and a first terminal of a second switch tube Q2 respectively; a second terminal of a first switch tube Q1 is connected to a first terminal of the inductor L1 and a first terminal of a first conducting tube D1 respectively; a first terminal of the first switch tube Q1 is connected to the moving contact of the relay S1; and the second terminal of the capacitor C1 is connected to a second terminal of the first conducting tube D1 and a second terminal of the second switch tube Q2 respectively. In the above feedback circuit, the power module further controls the first switch tube Q1 and the second switch tube Q2 to be turned on or turned off at the same time according to the received first signal and second signal, so as to control the inductor to charge and discharge, to make the power device generate heat in the charging and discharging process, and to transmit the heat to the fuel cell, thereby realizing self-heating of the fuel cell.

[0039] In a possible implementation, the digital control chip generates a first signal indicating that the first switch tube is turned on and a second signal indicating that the second switch tube is turned on according to the received external communication signal indicating the target current value of the inductor and the sampled current signal of the inductor, and the first signal and the second signal are both high level.

[0040] As shown in Fig. 2, the first switch tube Q1 and the second switch tube Q2 are in the turned-on state. Figure 4 Figure 4 Fig. 3 is an equivalent circuit structural schematic diagram in which the first switch tube and the second switch tube in the heating circuit are in the turned-on state according to an embodiment of the present application. In the turned-on state, the first switch tube and the second switch tube are equivalent to short circuit, a first terminal of the inductor L1 is connected to a first terminal of the power battery, a second terminal of the inductor L1 is connected to a second terminal of the power battery, the power battery is connected in parallel with a capacitor, a first terminal of the capacitor C1 is connected to a first terminal of the power battery C2, and a second terminal of the capacitor C1 is connected to a second terminal of the power battery C2. Figure 4 In the above, since the capacitor can store voltage, the capacitor and the power battery are connected in parallel, and the power battery charges the inductor L1, which is actually that the capacitor C1 charges the inductor L1. With the increase of the turned-on time of the first switch tube and the second switch tube, the charging time of the inductor L1 is prolonged, and the current of the inductor L1 is continuously increased. The inductor, the first switch tube and the second switch tube generate heat according to the inductor current, and the heat is transmitted to the fuel cell through the cooling liquid, so as to heat the fuel cell.

[0041] ​In another possible implementation, the digital control chip generates a first signal indicating that the first switch is off and a second signal indicating that the second switch is off according to an external communication signal indicating the target current value of the inductor and a current signal of the inductor sampled in real time, and both the first signal and the second signal are low.

[0042] As shown in Figure 5 , Figure 5 is an equivalent circuit structure diagram when the first switch and the second switch are in an off state in a heating circuit provided by an embodiment of the present application. In the off state, the first switch and the second switch are equivalent to an open circuit. The first end of the inductor L1 is connected to the first end of the first conducting tube. The second end of the first conducting tube is connected to the second end of the capacitor. The first end of the capacitor is connected to the first end of the second conducting tube. The second end of the second conducting tube is connected to the second end of the inductor L1. Since the power supply inputs a direct current, the current of the inductor increases linearly at a certain ratio. In the discharging process, the current of the inductor does not change abruptly. At this time, the current on the inductor flows through the first conducting tube and the second conducting tube to charge the capacitor. With the increase of the off time of the switch, the magnetic field on the magnetic core of the inductor gradually decreases, and the inductor current also decreases. In the above process, the heat generated by the inductor is transmitted to the fuel cell through the cooling liquid, so as to heat the fuel cell.

[0043] In the above Figure 4 , Figure 5 , the power device generating heat is only taken as an example of one inductor shown in the figure. In the charging process of the inductor, the power device generating heat can be the inductor, and can also be the first switch and the second switch, the first conducting tube and the second conducting tube in the circuit. In actual application, in addition to the single-phase inductor shown in the figure, the device generating heat can also be a multi-phase inductor in parallel, for example, a four-phase inductor, a six-phase inductor, etc. In the charging process of the inductor, the multiple inductors and the corresponding switches of each inductor can generate heat at the same time. In the discharging process of the inductor, the multiple inductors can also generate heat. In a possible implementation, the power module can include more types or more quantities of devices generating heat, which are not limited in the present application.

[0044] In the two possible implementations described above, the power module determines the duration of a complete charge / discharge cycle based on the frequencies of the first and second switching transistors. Typically, the duty cycle of the switching transistors is 50-55%. The power module can control the charging and discharging durations of the inductor based on the duty cycle. The duty cycle is the percentage of the on-time of the first and second switching transistors within a complete charge / discharge cycle, i.e., the percentage of the inductor charging time within a complete charge / discharge cycle. This application does not specifically limit the magnitude of the duty cycle. When the duty cycle increases, the on-time of the first and second switching transistors increases, the charging time of inductor L1 increases, the current corresponding to inductor L1 increases, and the heat generated by the power device increases accordingly. When the duty cycle decreases, the off-time of the first and second switching transistors increases, the discharging time of inductor L1 increases, the current corresponding to inductor L1 decreases, and the heat generated by the power device gradually decreases. In summary, the power module controls the inductor current by controlling the duty cycle to control the charging or discharging duration of the inductor. Controlling the magnitude of the inductor current can control the heat generated by the inductor, the first switching transistor, the first conducting transistor, the second switching transistor, and the second conducting transistor, thereby controlling the temperature transition of the fuel cell. This can avoid the problem of the fuel cell being difficult to regulate its temperature, leading to damage to the membrane electrode and reduced fuel cell efficiency due to excessive temperature.

[0045] In one specific implementation, when the fuel cell is in a low-temperature environment and cannot operate normally, the main control module generates a relay control signal to close the first stationary contact of the relay based on the low-temperature signal received from the temperature sensor, and sends the relay control signal to the power module. The power module, based on the relay control signal, determines that the input source of the first circuit is the power battery and operates the heating circuit. The main control module also generates a first signal indicating the state of the first switch and a second signal indicating the state of the second switch based on the sampled current signal of the inductor from external communication signals and the PI regulator. At this time, both the first and second signals are high-level, and the power module determines that the first and second switches are turned on based on the first and second signals. With the first and second switches on, the inductor in the heating circuit is in a charging state, and the inductor, the first switch, and the second switch together generate heat. This heat is transferred to the fuel cell through the coolant, causing the fuel cell to heat up.

[0046] If the sampled current signal of the current inductor is too high, the main control module, based on the external communication signal, the sampled current signal of the current inductor, and the PI regulator, generates a low-level first signal and a second signal. The power module determines to turn off the first and second switches based on the first and second signals. With the first and second switches off, the inductor in the heating circuit is in a discharging state, generating heat from the inductor, the first conducting transistor, and the second conducting transistor. The generated heat gradually decreases as the discharge time increases. The power module continues to transfer the generated heat to the fuel cell through the coolant until the fuel cell reaches its normal operating temperature through self-heating.

[0047] When the fuel cell is operating at its normal operating temperature, the main control module generates a relay control signal to close the second stationary contact of the relay based on the normal temperature signal received from the temperature sensor, and sends this signal to the power module. The power module, based on the relay control signal, determines that the fuel cell is the input source of the circuit and runs a buck-boost cascaded topology circuit to achieve either a boost or buck voltage adjustment.

[0048] In one possible implementation, the main control module and the power module can be integrated into a single device, such as... Figure 1 As shown. Alternatively, the main control module and the power module can be integrated into two different devices to achieve all the above functions, and this application does not specifically limit this.

[0049] The aforementioned fuel cell self-heating device can be applied to stationary generators, transportation vehicles (such as automobiles, airplanes, ships, etc.), and portable power systems, etc., and this application does not specifically limit it.

[0050] In summary, the fuel cell self-heating device provided in this application utilizes the existing power devices of the fuel cell system to generate heat through a main control module, thereby achieving self-heating of the fuel cell system. Compared to current external heating technologies, this is more convenient and does not increase the cost or complexity of the fuel cell. Furthermore, the fuel cell self-heating device provided in this application can generate two identical PWM signals based on external communication signals and sampled inductor current signals. The states of the first and second switching transistors are controlled according to these PWM signals, thereby flexibly controlling the inductor current and further controlling the amount of heat generated by the power devices, preventing excessively high temperatures from affecting fuel cell efficiency.

[0051] like Figure 6 As shown, Figure 6 This is a flowchart of a self-heating method for a fuel cell provided in this application. This method is applied to... Figure 1 The self-heating device for the fuel cell shown includes the following steps.

[0052] S610: The main control module generates control signals and sends them to the power module.

[0053] The main control module generates control signals based on the external communication signals sent by the host computer and the current signals of the inductors in the power module. The external communication signals sent by the host computer can be used to indicate the magnitude of the inductor current and can be signals sent via the CAN protocol. This application does not specifically limit this.

[0054] The control signals generated by the main control module include a multiplexer control signal indicating the state of the multiplexer, a first signal indicating the state of the first switch, and a second signal indicating the state of the second switch.

[0055] In one possible implementation, in addition to receiving external communication signals and the sampled current signal from the inductor in the power module, the main control module also receives the current temperature signal of the fuel cell from the temperature sensor. Based on the received temperature signal, the main control module generates a multiplexer control signal indicating the state of the multiplexer.

[0056] When the fuel cell temperature falls below a first temperature threshold, the temperature sensor sends a low-temperature signal to the main control module. This first temperature threshold is the minimum temperature at which the fuel cell operates normally. Based on the low-temperature signal, the main control module determines that the fuel cell needs self-heating, generates a multiplexer control signal indicating that the multiplexer is in the target state, and sends this signal to the power module to instruct it to operate the heating circuit.

[0057] When the temperature of the fuel cell is higher than the first temperature threshold and the fuel cell is operating normally, the temperature sensor sends a normal temperature signal to the main control module. The main control module determines that the fuel cell is operating normally, generates a multiplexer control signal indicating that the multiplexer is in a non-target state, and sends the multiplexer control signal to the power module to instruct the power module to run the buck-boost cascaded topology circuit.

[0058] In one possible implementation, the main control module uses the received external communication signal and the sampled current signal from the power module to generate two identical PWM signals through a PI regulator. The two PWM signals are the first signal and the second signal, respectively.

[0059] S620: The power module receives a control signal and determines the state of the multiplexer based on the control signal. If the multiplexer is determined to be in the target state, the power module executes step S630; if the multiplexer is determined to be in a non-target state, the power module executes step S640.

[0060] The power module receives control signals sent by the main control module and determines the state of the multiplexer based on the multiplexer control signal in the control signals.

[0061] S630: The power module determines that the input source of the first circuit is the power battery, and the first circuit is the heating circuit. It runs the heating circuit to charge and discharge the inductor.

[0062] When the multiplexer control signal indicates that the multiplexer is in the target state, the power module determines that the input source of the first circuit is the power battery, and that the first circuit is the heating circuit, and then operates the heating circuit. Based on the first and second signals in the received control signals, the power module determines the states of the first and second switching transistors respectively, causing the inductor in the heating circuit to charge or discharge, thereby generating heat in the power devices of the heating circuit and transferring the heat to the fuel cell.

[0063] In one possible implementation, when the first and second signals are at high levels, the first and second switching transistors are in a conducting state, and the inductor and capacitor are connected, with the capacitor charging the inductor. As the conduction time of the first and second switching transistors increases, the inductor charging time increases, and the inductor current increases. The inductor, the first switching transistor, and the second switching transistor generate heat based on the inductor current, and this heat is transferred to the fuel cell through the coolant, causing the fuel cell to heat up. The larger the inductor current, the more heat is generated, and the faster the heating occurs.

[0064] In another possible implementation, when the first and second signals are at low levels, the first and second switching transistors are in the off state. Since the inductor current does not change abruptly, the current in the inductor freewheels through the first and second conducting transistors, charging the capacitor. As the off time of the first and second switching transistors increases, the magnetic field on the inductor core gradually decreases, and the inductor current also decreases. During this process, the inductor, the first conducting transistor, and the second conducting transistor generate heat based on the inductor current, and transfer this heat to the fuel cell through the coolant, causing the fuel cell to heat up. The smaller the inductor current, the less heat is generated by the power devices, and the slower the fuel cell heats up.

[0065] In the above process, the power module controls the state of the first and second switching transistors according to the first and second signals, and controls the charging and discharging state of the inductor. This allows for flexible control of the inductor current, thereby controlling the amount of heat generated by the power devices. This avoids the problem of excessive heat generation by the power devices damaging the membrane electrode assembly of the fuel cell and reducing the working efficiency of the fuel cell.

[0066] S640: The power module determines that the input source of the first circuit is the fuel cell. The first circuit is a buck-boost cascaded topology circuit to charge the power battery.

[0067] When the multiplexer is in a non-target state, the power module determines that the input source of the circuit is the fuel cell, and the first circuit is a buck-boost cascaded topology circuit. The power module operates this buck-boost cascaded topology circuit. When the power module is operating the buck-boost cascaded topology circuit, the power module determines the states of the first and second switches in the power module according to the first and second signals in the control signals, respectively, and adjusts the voltage across the output side to realize the charging function of the power battery.

[0068] In the specific implementation, Figure 1 The fuel cell system shown and Figure 2 The main control module 110 in the fuel cell self-heating device shown is used to execute the above step S610, and the power module 120 is used to execute the above steps S620 to S640.

[0069] In summary, the fuel cell self-heating method provided in this application controls the input source of the first circuit in the power module through a control signal generated by the main control module, thereby controlling the operating circuit in the power module. When the input source of the first circuit is a power battery, the power module operates the heating circuit, utilizing inductive charging and discharging to generate heat from the power devices. This more conveniently achieves self-heating of the fuel cell, enabling normal operation of the fuel cell in low-temperature environments and avoiding the problem of reduced fuel cell efficiency. Furthermore, this fuel cell self-heating method eliminates the need for an additional heating device in the fuel cell system, thus controlling the cost and complexity of the fuel cell system.

[0070] like Figure 7 As shown, Figure 7 This is a schematic diagram of a fuel cell self-heating system provided in an embodiment of this application. The fuel cell self-heating system 700 includes at least... Figure 1 The diagram shows a fuel cell self-heating device 100 and a temperature sensing device 720 including a temperature sensor 721. The temperature sensing device is used to acquire the temperature of the fuel cell and send a temperature signal to the fuel cell self-heating device, the temperature signal indicating the temperature of the fuel cell; the fuel cell self-heating device is used to receive the temperature signal and perform actions based on the temperature signal. Figure 6 The self-heating method for fuel cells shown can be implemented. Figure 1 The diagram shows all the functions of the fuel cell self-heating device.

[0071] In one possible implementation, the temperature sensor, the main control module, and the power module can be integrated in the same or different devices to achieve the above functions. Therefore, the fuel cell self-heating system may include more or fewer devices, which is not specifically limited in this application.

Claims

1. A fuel cell self-heating device, characterized in that, The device includes a main control module and a power module. The main control module includes a sampling circuit, a digital control chip, and a drive circuit. The power module includes a multiplexer and a first circuit. The first circuit includes at least an inductor and a power device. The power device includes a first switching transistor, a first conducting transistor, a second switching transistor, and a second conducting transistor. The main control module is used to acquire external communication signals through the digital control chip, generate control signals, a first signal, and a second signal based on the inductor current signal acquired by the sampling circuit and the external communication signals, and send the control signals, the first signal, and the second signal to the connected power module through the driving circuit. The external communication signal is used to indicate the target current value of the inductor, the first signal is used to control the state of the first switch, and the second signal is used to control the state of the second switch. The first signal and the second signal are the same. The power module is used to receive the control signal and determine the state of the multiplexer based on the control signal; When the multiplexer is in the target state, the input source of the first circuit is determined to be a power battery, and the first circuit is a heating circuit. The heating circuit is operated so that the inductor in the heating circuit charges and discharges according to the first signal and the second signal, causing the power device to generate heat. When the first signal controls the first switch and the second signal controls the second switch to increase the on-time, the charging time of the inductor increases and the current of the inductor increases. When the first signal controls the first switch and the second signal controls the second switch to increase the off-time, the discharging time of the inductor increases and the current of the inductor decreases. When the multiplexer is in a non-target state, the input source of the first circuit is determined to be the fuel cell, and the first circuit is a buck-boost cascaded topology circuit to charge the power battery.

2. The apparatus according to claim 1, characterized in that, The power module is specifically used for: Receive the multiplexer control signal, the first signal, and the second signal; When the multiplexer is in the target state and the first signal and the second signal respectively indicate that the first switch and the second switch are turned on, the inductor is charged, causing the power device to generate heat; or, when the first signal and the second signal respectively indicate that the first switch and the second switch are turned off, the inductor is discharged, causing the power device to generate heat.

3. The apparatus according to claim 1 or 2, characterized in that, The inductor is a single-phase inductor or a multi-phase inductor connected in parallel.

4. A self-heating method for a fuel cell, applied to a fuel cell self-heating device, characterized in that, The fuel cell self-heating device includes a main control module and a power module. The main control module includes a sampling circuit, a digital control chip, and a drive circuit. The power module includes a multiplexer and a first circuit. The first circuit includes at least an inductor and power devices. The power devices include a first switching transistor, a first conducting transistor, a second switching transistor, and a second conducting transistor. The method includes: The main control module acquires external communication signals through the digital control chip, and generates control signals, a first signal, and a second signal based on the inductor current signal acquired by the sampling circuit and the external communication signals. The main control module then sends the control signals, the first signal, and the second signal to the power module through the drive circuit. The external communication signal is used to indicate the target current value of the inductor, the first signal is used to control the state of the first switch, and the second signal is used to control the state of the second switch. The first signal and the second signal are the same. The power module receives the control signal and determines the state of the multiplexer based on the control signal; When the multiplexer is in the target state, the input source of the first circuit is determined to be a power battery, and the first circuit is a heating circuit. The heating circuit is operated so that the inductor in the heating circuit charges and discharges according to the first signal and the second signal, causing the power device to generate heat. When the first signal controls the first switch and the second signal controls the second switch to increase the on-time, the charging time of the inductor increases and the current of the inductor increases. When the first signal controls the first switch and the second signal controls the second switch to increase the off-time, the discharging time of the inductor increases and the current of the inductor decreases. When the multiplexer is in a non-target state, the input source of the first circuit is determined to be the fuel cell, and the first circuit is a buck-boost cascaded topology circuit to charge the power battery.

5. The method according to claim 4, characterized in that, After the drive circuit sends the control signal to the power module, the method further includes: The power module receives the multiplexer relay control signal, the first signal, and the second signal; When the multiplexer is in the target state and the first and second signals respectively indicate that the first and second switches are turned on, the power module charges the inductor, causing the power device to generate heat; or... When the multiplexer is in the target state and the first signal and the second signal respectively indicate that the first switch and the second switch are turned off, the power module discharges the inductor, causing the power device to generate heat.

6. A fuel cell self-heating system, characterized in that, The system includes a fuel cell self-heating device and a temperature sensing device. The temperature sensing device is used to acquire the temperature of the fuel cell and send a temperature signal to the fuel cell self-heating device. The temperature signal is used to indicate the temperature of the fuel cell. The fuel cell self-heating device is used to receive the temperature signal and perform the method according to claim 4 or 5 based on the temperature signal.

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