Hydrogen injector control device

Abstract

To provide a hydrogen injector control device which can improve the accuracy of injection amount control.SOLUTION: A control device 100 comprises a MOSFET 20 disposed at a downstream side of a coil, and connected to prescribed potential, a current monitor circuit 40, and a CPU 10. The current monitor circuit includes a shunt resistor 41 disposed at a current path between the coil and the MOSFET, and an operational amplifier 42 for amplifying a both-side voltage of the shunt resistor, and outputting voltage correlated with a current value which flows in the coil. The CPU acquires a current monitor value from an input voltage which has monitored an output voltage, and controls a current amount by changing a pulse width of a PWM signal for controlling on / off-operations of the MOSFET on the basis of the current monitor value. Also, when it is determined that an error occurs between the last-time value and a this-time value of the input voltage, the CPU collects the input voltage by a correction value corresponding to the error, and acquires a post-correction input voltage for acquiring the current monitor value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a hydrogen injector control device.

Background Art

[0002] As an example of a hydrogen injector control device, there is a hydrogen injector disclosed in Patent Document 1. The hydrogen injector includes a solenoid valve connected to a high-pressure hydrogen tank and a controller that supplies current to the coil of the solenoid valve. The controller monitors the current flowing through the coil while supplying a first current to the coil. When the rate of change of the current increases, the controller reduces the current supplied from the first current to the second current.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a configuration in which a hydrogen injector control device controls the hydrogen injection amount by the opening degree of a valve is conceivable. In this case, the hydrogen injector control device monitors the current flowing through the coil and controls the opening degree of the valve according to the amount of current flowing through the coil.

[0005] In this case, in order for the hydrogen injector control device to monitor the current flowing through the coil, a shunt resistor is provided in the current path between the coil and the switching element on the low side of the coil. The switching element is connected to a power supply via a diode. Then, the hydrogen injector control device amplifies the voltage across the shunt resistor generated by the current flowing through the coil with an operational amplifier and inputs it to a processing device, and the processing device monitors the current.

[0006] In a hydrogen injector control device, the voltage across the shunt resistor is high when the switching element is off. Therefore, the input voltage to the operational amplifier in the hydrogen injector control device becomes large. Consequently, if an error occurs in the input voltage of the hydrogen injector control device, the error is also amplified by the operational amplifier, resulting in a larger error when the switching element is off compared to when it is on, and a decrease in the accuracy of the current monitoring in the processing unit. Therefore, the hydrogen injector control device has a problem in that the accuracy of injection amount control decreases due to errors in the input voltage.

[0007] One of the objectives disclosed is to provide a hydrogen injector control device that can improve the accuracy of injection volume control. [Means for solving the problem]

[0008] The hydrogen injector control device disclosed herein is A hydrogen injector control device that controls the amount of hydrogen injected by controlling the valve opening degree by the amount of current supplied to the coil of the hydrogen injector, A switching element (20) is provided downstream of the coil and connected to a predetermined potential, A current monitor circuit (40) includes a current sensing resistor (41) provided in the current path between the coil and the switching element, and an amplifier (42) that amplifies the voltage across the current sensing resistor and outputs a voltage correlated with the current value flowing through the coil. The system includes a processing unit (10) that obtains a current monitor value from the input voltage which monitors the output voltage of the amplifier, and controls the amount of current by changing the pulse width of a control signal that controls the on / off state of a switching element based on the current monitor value, If the processing unit determines that there is an error between the previous and current values ​​of the input voltage, it considers that the current monitor value deviates from the actual current flowing through the coil, corrects the input voltage with a correction value corresponding to the error, and obtains a corrected input voltage for acquiring the current monitor value.

[0009] In this way, the hydrogen injector control device assumes that the current monitor value deviates from the actual current flowing through the coil and corrects the input voltage with a correction value corresponding to the error. Therefore, the hydrogen injector control device can improve the accuracy of the current monitor value. As a result, the hydrogen injector control device can improve the accuracy of hydrogen injection amount control.

[0010] Furthermore, other embodiments of the hydrogen injector control device disclosed herein include: A hydrogen injector control device that controls the amount of hydrogen injected by controlling the valve opening degree by the amount of current supplied to the coil of the hydrogen injector, A switching element (20) is provided downstream of the coil and connected to a predetermined potential, A current monitor circuit (40) includes a current sensing resistor (41) provided in the current path between the coil and the switching element, and an amplifier (42) that amplifies the voltage across the current sensing resistor and outputs a voltage correlated with the current value flowing through the coil. The system includes a processing unit (10) that obtains a current value from the input voltage which monitors the output voltage of the amplifier, and controls the amount of current by changing the pulse width of the control signal that controls the on / off state of the switching element based on the obtained current value, which is the current monitor value, The processing unit controls the amount of current using the input voltage during the on-period of the switching element, without using the input voltage during the off-period of the switching element.

[0011] In this way, the hydrogen injector control device can improve the accuracy of hydrogen injection amount control by using the output voltage during the ON period to control the current amount.

[0012] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses in this section are illustrative in their correspondence with the embodiments described later and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings.

Brief Description of the Drawings

[0013] [Figure 1] It is a block diagram showing a schematic configuration of a fuel cell system. [Figure 2] It is a circuit diagram showing a schematic configuration of a control device. [Figure 3] It is a flowchart showing the processing operation of the control device. [Figure 4] It is a timing chart showing the processing operation of the control device. [Figure 5] It is a flowchart showing the processing operation of the control device of a modification example. [Figure 6] It is a timing chart showing the processing operation of the control device of a modification example. [Figure 7] It is a flowchart showing the processing operation of the control device of the second embodiment. [Figure 8] It is a timing chart showing the processing operation of the control device of the second embodiment. [Figure 9] It is a flowchart showing the processing operation of the control device of a modification example. [Figure 10] It is a timing chart showing the processing operation of the control device of a modification example.

Modes for Carrying Out the Invention

[0014] Hereinafter, a plurality of modes for carrying out the present disclosure will be described while referring to the drawings. In each mode, parts corresponding to those described in the preceding mode may be denoted by the same reference numerals and redundant descriptions may be omitted. In each mode, when only a part of the configuration is described, other parts of the configuration may be applied by referring to other modes described previously.

[0015] (First Embodiment) The control device 100 of the present embodiment will be described with reference to FIGS. 1 to 4. In the present embodiment, a hydrogen injector control device is applied to the control device 100. The control device 100 is configured to be mounted on a fuel cell vehicle.

[0016] <Fuel Cell System Configuration> As shown in FIG. 1, the control device 100 is a part of the fuel cell system. The fuel cell system is a system that supplies hydrogen (hydrogen gas) and oxygen to the fuel cell stack 300 for power generation of the fuel cell stack 300. In addition to the control device 100, the fuel cell system includes a hydrogen injector 200, a plurality of valve bodies 201 to 204, a fuel cell stack 300, an air compressor 400, a hydrogen tank 500, and the like. In FIG. 1, the control device is abbreviated as ECU, the fuel cell stack as FCS, and the hydrogen tank as HDT.

[0017] The fuel cell stack 300 is a laminate of cells that generate electricity by the electrochemical reaction of hydrogen and oxygen. Each cell has a configuration in which a hydrogen electrode and an oxygen electrode are arranged with an electrolyte membrane interposed therebetween. The hydrogen electrode may also be referred to as an anode. The oxygen electrode may also be referred to as a cathode.

[0018] A plurality of pipes are connected to the fuel cell stack 300. The cathode is connected to the air compressor 400 via an oxygen supply pipe. A supply valve 201 is provided in the oxygen supply pipe. Oxygen compressed by the air compressor 400 is supplied to the cathode via the supply valve 201. It can also be said that compressed air is supplied to the cathode as a gas containing oxygen. Oxygen is used for the electromotive reaction at the cathode. Oxygen that is not used for the electromotive reaction at the cathode is discharged from the oxygen exhaust pipe. A pressure regulating valve 202 is provided in the oxygen exhaust pipe. The supply valve 201 and the pressure regulating valve 202 are controlled to open and close by the control device 100.

[0019] The anode is connected to a hydrogen tank 500 via a hydrogen supply pipe. A hydrogen injector 200 is provided in the hydrogen supply pipe. The hydrogen tank 500 is connected to the hydrogen supply pipe via a tank main shut-off valve 204. Hydrogen is supplied to the anode from the hydrogen tank 500 via the hydrogen injector 200. The hydrogen is used in the electromotive reaction at the anode. Hydrogen not used in the electromotive reaction at the anode is discharged from the hydrogen exhaust pipe. A discharge path shut-off valve 203 is provided in the hydrogen exhaust pipe. In addition to hydrogen not used in the electromotive reaction, water (water vapor) and other substances are also discharged from the hydrogen exhaust pipe. The hydrogen injector 200, the discharge path shut-off valve 203, and the tank main shut-off valve 204 are controlled to open and close by a control device 100.

[0020] The configuration of the piping and valve bodies 201-204 connected to the fuel cell stack 300 is not limited to the above. Therefore, the fuel cell system may include components other than those described above.

[0021] The hydrogen injector 200 is equipped with a linear solenoid valve. The linear solenoid valve includes a coil 210 and a plunger. When current is supplied to the coil 210, the magnetic force of the coil 210 causes the plunger to move in the direction that opens the flow path, i.e., the direction that opens the valve. The linear solenoid valve injects hydrogen when the valve opens. The amount of hydrogen injected by the hydrogen injector 200 is controlled by the valve opening. The valve opening is controlled by the amount of current (current value I) flowing through the coil 210.

[0022] The linear solenoid valve closes its flow path when the current flowing to the coil 210 does not reach a predetermined value. The flow path is connected to the fuel cell stack 300. One end of the coil 210 is connected to the battery 600, and the other end is connected to terminal 50 of the control device 100.

[0023] <Control device configuration> As shown in Figure 2, the control device 100 includes a CPU 10, a MOSFET 20, an internal power supply 30, a current monitoring circuit 40, and the like. The control device 100 controls the valve opening degree by the amount of current supplied to the coil 210 of the hydrogen injector 200. In this way, the control device 100 controls the amount of hydrogen injected by the hydrogen injector 200. In other words, the control device 100 controls the amount of hydrogen supplied to the fuel cell stack 300.

[0024] The CPU 10 is an arithmetic processing unit equipped with memory 11. In other words, the CPU 10 comprises an arithmetic unit that performs arithmetic processing and memory 11 that stores various data. Note that the memory 11 may be located outside the CPU 10. The CPU 10 corresponds to a processing unit.

[0025] The CPU 10 performs predetermined arithmetic processing. The CPU 10 (arithmetic unit) is configured to access information stored in the memory 11. The CPU 10 receives the output voltage Vout output from the operational amplifier 42 as input. In other words, the CPU 10 monitors the output voltage Vout as the input voltage Vin. The CPU 10 obtains (calculates) the current value I from the input voltage Vin. The obtained current value I corresponds to the current monitoring value.

[0026] Furthermore, the CPU 10 also has a function to correct the input voltage Vin, which is used to calculate the current monitor value, with a correction value Vco. Therefore, the CPU 10 can obtain a corrected input voltage Vin1, which is the corrected input voltage Vin. In this case, the CPU 10 calculates the current monitor value from the corrected input voltage Vin1. The correction will be explained in more detail later.

[0027] The CPU 10 generates a PWM signal as a control signal to control the on / off state of the MOSFET 20 based on the current monitor value. The CPU 10 controls the amount of current supplied to the coil 210 by changing the pulse width of the PWM signal. In other words, the CPU 10 controls the current of the coil 210 (hydrogen injector 200) by outputting a PWM signal. The memory 11 stores information such as the correction value Vco, threshold Vth, and variables X1 and X2, which will be explained later.

[0028] MOSFET20 is located downstream of coil 210. Therefore, MOSFET30 can also be described as a low-side MOS or low-side switching element. The drain terminal of MOSFET20 is connected to coil 210. Also, the drain terminal of MOSFET20 is connected to the internal power supply 30 via a diode. Therefore, MOSFET20 can be said to be connected to a predetermined potential. The gate terminal of MOSFET20 is connected to CPU10. A PWM signal is input to the gate terminal. The source terminal of MOSFET20 is connected to ground, for example. MOSFET20 corresponds to a switching element. In the following, "ON" indicates that MOSFET20 is ON, and "OFF" indicates that MOSFET20 is OFF.

[0029] The current monitoring circuit 40 includes a shunt resistor 41 and an operational amplifier 42. The shunt resistor 41 is located in the current path between the coil 210 and the MOSFET 20. The operational amplifier 42 amplifies the voltage across the shunt resistor 41 (potential difference V2-V1) and outputs an output voltage Vout that correlates with the current I flowing through the coil 210. The potential difference V2-V1 is the difference between the voltage value at the second terminal V2 and the voltage value at the first terminal V1. The resistance value of the shunt resistor 41 is R1. The operational amplifier 42 corresponds to an amplifier.

[0030] The current monitoring circuit 40 also includes several resistors 43-48 for determining the multiplier of the voltage across the shunt resistor 41. The first resistor 43, the second resistor 44, and the third resistor 45 are connected to the second terminal V2 and the + terminal of the operational amplifier 42. The fourth resistor 46, the fifth resistor 47, and the sixth resistor 48 are connected to the first terminal V1 and the - terminal of the operational amplifier 42. The shunt resistor 41 corresponds to the current sensing resistor.

[0031] As described above, the hydrogen injector 200 is equipped with a linear solenoid valve. Therefore, the hydrogen injector 200 differs from an injector equipped with an on / off valve. The injector controls the amount of hydrogen injected by the time the valve is open. Thus, the current accuracy requirement for the injector is sufficient to allow transitions between the on and off states.

[0032] In contrast, the hydrogen injector 200 controls the amount of hydrogen injected by the current value I flowing through the coil 210, as described above. In other words, the hydrogen injector 200's hydrogen injection amount is directly linked to the current value I flowing through the coil 210. For this reason, the control device 100 needs to accurately detect (monitor) the current value I.

[0033] When the current monitor circuit 40 is off, the voltage value of the first terminal V1 rises to +B+Vf. The voltage value of the second terminal V2 is based on the voltage value of the first terminal V1. Therefore, the voltage value of the second terminal V2 also increases when the current monitor circuit 40 is off. The voltage value of the first terminal V1 is 0[V] when on and +B+Vf[V] when off. The voltage value of the second terminal V2 is I×R1[V] when on and (+B+Vf)+I×R1[V] when off. Therefore, the input voltages to the + and - terminals of the operational amplifier 42 will have an error compared to the voltage corresponding to the actual current value flowing through the coil 210.

[0034] Furthermore, the input voltage error to the operational amplifier 42 is affected by the ratio of resistors 43 to 48. Therefore, as the voltages applied to the first terminal V1 and the second terminal V2 increase, the absolute value of the error increases. The input voltage error is amplified by the operational amplifier 42 and input to the CPU 10. Consequently, the error of the current monitor circuit 40 is larger when it is off than when it is on. In other words, the current value I calculated from the output voltage Vout deviates more from the actual current value flowing through the coil 210 when it is off than when it is on. The CPU 10 calculates a corrected input voltage Vin1 to reduce this deviation. For this reason, the CPU 10 may correct the input voltage Vin with a correction value Vco only during the off period.

[0035] <Control device processing operation> Here, we will explain the processing operation of the control device 100 using Figures 3 and 4.

[0036] When power is supplied, the CPU 10 executes the process shown in the flowchart of Figure 3 at predetermined intervals. The CPU 10 may also execute the process shown in the flowchart of Figure 3 when current control for the coil 210 is required. Figure 4 shows the waveform in the control device 100 during current control.

[0037] In Figure 4, the waveform of the output voltage Vout is shown by a solid line representing the output voltage Vout due to the input voltage error of the operational amplifier 42, and the dashed-dotted line representing the output voltage Vout corresponding to the actual current value flowing through the coil 210. Furthermore, the waveform of the corrected input voltage Vin1 is shown by a solid line representing the corrected Vin1, and the dashed-dotted line representing the input voltage Vin corresponding to the actual current value flowing through the coil 210.

[0038] Furthermore, Figure 4 illustrates two patterns for the output voltage Vout. In the first pattern, the output voltage Vout is labeled as output voltage Vout1. In the second pattern, the output voltage Vout is labeled as output voltage Vout2. The first pattern represents the case where the deviation is on the upper side relative to the actual current value. The second pattern represents the case where the deviation is on the lower side relative to the actual current value.

[0039] In step S10, CPU 10 monitors the input voltage Vin and saves it to variable X1. Variable X1 can be considered the current value of the input voltage Vin. CPU 10 then saves variable X1 to memory 11. If variable 1 is already saved, CPU 10 overwrites it with the X1 monitored in step S10.

[0040] In step S12, the CPU 10 determines whether the variable X2 > 0. If the CPU 10 determines that the variable X2 > 0, it proceeds to step S14; otherwise, it proceeds to step S24. The variable X2 can also be considered the previous value of the input voltage Vin.

[0041] In step S14, the CPU 10 determines whether |X1-X2|>Vth. Vth is a threshold value used to determine whether correction is necessary. The threshold value Vth corresponds to a predetermined value. The CPU 10 determines whether correction is necessary in step S14. It can also be said that the CPU 10 determines in step S14 whether there is an error between the previous value and the current value of the input voltage Vin. The error between the previous value and the current value can also be considered as the error between the voltage corresponding to the actual current value flowing through the coil 210 and the input voltage to the operational amplifier 42.

[0042] When CPU 10 determines that |X1-X2|>Vth, it considers that the current value has increased or decreased by more than a predetermined value from the previous value. In this case, CPU 10 considers that there is an error and correction is necessary, and proceeds to step S16. In other words, CPU 10 determines that an error of a magnitude requiring correction has occurred. Furthermore, if CPU 10 determines that there is an error between the previous value and the current value of the input voltage Vin, it can also be said that it determines that the current monitor value deviates from the actual current value flowing through coil 210.

[0043] On the other hand, if the CPU 10 does not determine that |X1-X2| > Vth, it assumes that the current value has not increased or decreased by more than a predetermined value from the previous value. In this case, the CPU 10 assumes that there is no error and therefore no correction is necessary, and proceeds to step S22. In other words, the CPU 10 determines that no error has occurred that would require correction. It can also be said that if the CPU 10 does not determine that there is an error between the previous value and the current value of the input voltage Vin, it determines that the current monitor value does not deviate from the actual current value flowing through the coil 210. Note that the CPU 10 may also determine that correction is necessary when |X1-X2| ≥ Vth, and that no correction is necessary when |X1-X2| ≥ Vth.

[0044] In step S22, CPU 10 sets the correction value Vco to 0. In other words, CPU 10 sets the correction value Vco to 0. CPU 10 saves the correction value Vco to memory 11. If the correction value Vco is already saved, CPU 10 overwrites it with 0. Note that correction value Vco = 0 indicates that the correction value Vco is not set.

[0045] In step S16, CPU 10 determines whether Vco = 0. In other words, CPU 10 determines whether a correction value Vco is set. If CPU 10 determines that Vco = 0, it assumes that the correction value Vco is not set and proceeds to step S18. If CPU 10 does not determine that Vco = 0, it assumes that the correction value Vco is set and proceeds to step S20.

[0046] In step S18, CPU 10 executes Vco = X1 - X2. In other words, CPU 10 sets the result of the calculation X1 - X2 as the correction value Vco. As shown in Figure 4, the correction value Vco is the difference between the output voltage Vout due to the input voltage error of the operational amplifier 42 and the output voltage Vout corresponding to the actual current value flowing through the coil 210.

[0047] Furthermore, as described above, the CPU 10 performs step S18 only if it determines that the correction value Vco has not been set in step S16. This reduces the processing load required for the CPU 10 to set the correction value Vco. However, the disclosure is not limited thereto. The CPU 10 may omit step S16. The CPU 10 then overwrites and saves the correction value Vco set in step S18 to memory 11.

[0048] In step S20, CPU10 executes X1 = X1 - Vco. That is, CPU10 sets the result of the calculation X1 - Vco as the variable X1. CPU10 sets the value obtained by subtracting the correction value Vco from the variable X1 saved in step S10 as the corrected variable X1. The corrected variable X1 corresponds to the corrected input voltage Vin1. In other words, if CPU10 determines that there is an error between the previous value and the current value of the input voltage Vin, it corrects the input voltage Vin with a correction value Vco corresponding to the error and obtains the corrected input voltage Vin1 for acquiring the current monitor value.

[0049] In this way, the CPU 10 corrects the input voltage Vin with the correction value Vco. As shown in Figure 4, the CPU 10 can correct in either positive or negative direction by steps S18 and S20. Furthermore, when the CPU 10 sets the variable X1 (corrected input voltage Vin1) in step S20, it uses that variable X1 to perform current control. In other words, if the deviation between the previous value and the current value of the input voltage Vin increases or decreases beyond the threshold Vth, the CPU 10 corrects that deviation as a deviation from the actual current value and uses it for control. Alternatively, the CPU 10 can be said to correct the sampling value (Vin) during the off period with Vco to perform current control.

[0050] In step S24, CPU 10 executes X2 = X1. CPU 10 sets the variable X2 to the variable X1 set in step S20. Then, CPU 10 overwrites and saves the variable X2 to memory 11. As a result, the variable X1 set in step S20 becomes the previous value.

[0051] In step S26, the CPU 10 determines whether or not current control has ended. If the CPU 10 determines that current control has ended, it terminates the flowchart in Figure 3; otherwise, it returns to step S10. For example, the CPU 10 determines that current control has ended when it receives a signal indicating that the valve of the hydrogen injector 200 is closed. The signal indicating valve closure is received from another control device, etc. The CPU 10 will continue to perform correction while the MOSFET 20 is off. In other words, the CPU 10 performs injection control while correcting the correction value Vco while the MOSFET 20 is off.

[0052] <Effects> As described above, the control device 100 assumes that the current monitor value deviates from the actual current value flowing through the coil 210 and corrects the input voltage Vin with a correction value Vco corresponding to the error. Therefore, the control device 100 can improve the accuracy of the current monitor value. As a result, the control device 100 can improve the accuracy of current control. Therefore, the control device 100 can improve the accuracy of hydrogen injection amount control. In other words, the control device 100 can improve the accuracy of hydrogen injection amount control even during the off period of the MOSFET 20, which is prone to errors.

[0053] Furthermore, the control device 100 can correct and use the input voltage Vin during the off period of the MOSFET 20 for injection amount control. Therefore, the control device 100 can reduce the influence of noise when the voltage is averaged.

[0054] Furthermore, the hydrogen injector 200 can correct the input voltage Vin and improve the accuracy of the current monitor value, even when installed in a fuel cell vehicle. The hydrogen injector 200 can improve the accuracy of injection amount control even if the error deviates from the factory setting.

[0055] <Variation> Here, a modified version of the control device 100 of the first embodiment will be described using Figures 5 and 6. The modified version will mainly describe the differences from the above embodiment. The modified version differs from the above embodiment in its processing operation. In Figure 5, the same process as in Figure 3 uses the same step numbers as in Figure 3.

[0056] Figure 6 is a diagram corresponding to Figure 4. In Figure 6, the final value during the ON period is denoted as ONFV, the initial value during the ON period as ONIV, the final value during the OFF period as OFFFV, and the initial value during the OFF period as OFFIV. The final value during the ON period, ONFV, is the final value of the output voltage Vout during the ON period of MOSFET 20. The initial value during the ON period, ONIV, is the initial value of the output voltage Vout during the ON period of MOSFET 20. The final value during the OFF period, OFFFV, is the final value of the output voltage Vout during the OFF period of MOSFET 20. The initial value during the OFF period, OFFIV, is the initial value of the output voltage Vout during the OFF period of MOSFET 20. In Figure 6, white circles indicate sampling timing, and black circles indicate values ​​after linear interpolation.

[0057] If CPU 10 determines YES in step S16, it proceeds to step S17. In step S17, CPU 10 performs linear interpolation (X11, X12). As shown in Figure 6, CPU 10 estimates the final ON-period value ONFV, initial ON-period value ONIV, final OFF-period value OFFFV, and initial OFF-period value OFFIV of the output voltage Vout by linear interpolation, synchronized with the PWM signal.

[0058] The CPU 10 then obtains the estimated current value X11 and the estimated previous value X12, which are obtained through linear interpolation. For control purposes, the final and initial values ​​deviate from the actual current values. Therefore, the CPU 10 determines the numerical values ​​(X11, X12) by performing linear interpolation, including the previous data. In the modified example, the estimated current value X11 and estimated previous value X12 obtained by linear interpolation are considered the true values.

[0059] In step S18a, CPU 10 executes Vco = X11 - X12. CPU 10 uses the difference between the estimated previous value X12 and the estimated current value X11 in the estimated value as a correction value Vco according to the error.

[0060] The CPU 10 determines the final ON-period value ONFV and the initial ON-period value ONIV in synchronization with the timing of the PWM signal, and determines the linearly interpolated value to be the true value. It can also be said that the CPU 10 uses the difference between the true value and the actual current value during the off-period as a correction value Vco for control.

[0061] In this way, the modified control device 100 determines the correction value Vco using a linearly interpolated value. Therefore, the control device 100 can improve the accuracy of the correction.

[0062] Preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure. A second embodiment, as another form of the present disclosure, is described below. The above embodiments and the second embodiment can be implemented individually, or they can be implemented in combination as appropriate. The present disclosure can be implemented in various combinations, not limited to the combinations shown in the embodiments.

[0063] (Second Embodiment) The control device 100 of the second embodiment will be described with reference to Figures 7 and 8. The control device 100 of this embodiment has the same configuration as the control device 100 of the above embodiment. The processing operation of this embodiment differs from that of the above embodiment. In Figure 7, the same processing as in Figure 3 is used, and the same step numbers as in Figure 3 are used. Figure 8 is a drawing corresponding to Figure 4. In Figure 8, hatching is applied to periods when the output voltage Vout is not used for current control.

[0064] When power is supplied, the CPU 10 executes the processes shown in the flowchart of Figure 7 at predetermined intervals. The CPU 10 may also execute the processes shown in the flowchart of Figure 7 when current control for the coil 210 is required.

[0065] In step S1, the CPU 10 determines whether the PWM is on or off. The CPU 10 determines the off and on periods of the MOSFET 20 from the PWM signal. If the CPU 10 determines that the PWM signal is PWM on, it considers this to be the on period of the MOSFET 20 and proceeds to step S10. In step S10, the CPU 10 performs current control using the saved variable X1 (monitored input voltage Vin).

[0066] On the other hand, if the CPU 10 does not determine that the PWM signal is PWM ON, it does not consider the MOSFET 20 to be ON for the duration of the ON period and proceeds to step S26. In other words, if the CPU 10 does not determine that the PWM signal is PWM ON, it proceeds to step S26 without proceeding to step S10.

[0067] Therefore, as shown in the hatched period in Figure 8, the CPU 10 does not use the input voltage Vin during the off period of the MOSFET 20. In other words, the CPU 10 performs current control using only the input voltage Vin during the on period of the MOSFET 20.

[0068] As described above, in the current monitoring circuit 40 using the operational amplifier 42, when the MOSFET 20 is off, the voltages at the first terminal V1 and the second terminal V2 increase, and the output error of the operational amplifier 42 increases proportionally. Therefore, the control device 100 performs current control without using the input voltage Vin during the off period when the output error is large. Thus, the control device 100 can achieve the same effects as in the above embodiment. Furthermore, the control device 100 can simplify the processing operation of the CPU 10 compared to the above embodiment.

[0069] <Variation> Here, a modified version of the control device 100 of the second embodiment will be described using Figures 9 and 10. The modified version differs from the second embodiment in its processing operation. The modified version will mainly be described in terms of the differences from the second embodiment. In Figure 9, the same processing as in Figures 1 and 3 is used, along with the same step numbers as in Figures 1 and 3. Figure 10 is a drawing corresponding to Figure 8.

[0070] The CPU 10 determines in step S14 that |X1-X2|>Vth is an off period. That is, as shown in D1 of Figure 10, the CPU 10 determines that it is an off period when the difference between the current value and the previous value of the output voltage Vout exceeds the threshold Vth.

[0071] If CPU 10 determines YES in step S14, it proceeds to step S151. In step S151, CPU 10 executes X2 = X1. CPU 10 sets the variable X2 to the variable X1 saved in step S10. Then, CPU 10 overwrites memory 11 with the value of variable X2. As a result, the variable X1 saved in step S10 becomes the previous value.

[0072] In step S152, CPU 10 monitors the input voltage Vin again and saves it to variable X1. CPU 10 then overwrites variable X1 in memory 11.

[0073] In step S152, CPU 10 determines again whether |X1-X2|>Vth. If CPU 10 does not determine that |X1-X2|>Vth, it assumes that the off period is continuing and returns to step S151.

[0074] Furthermore, when the CPU 10 determines that |X1-X2|>Vth, it considers this to be an ON period and proceeds to step S24. That is, as shown in D2 of Figure 10, after determining that it is an OFF period, the CPU 10 determines that it is an ON period if the difference between the current value and the previous value of the output voltage Vout exceeds the threshold Vth. Also, after determining that it is an OFF period, the CPU 10 determines that it has switched from an OFF period to an ON period if the difference exceeds the threshold Vth again.

[0075] If the CPU 10 determines YES in step S153, it performs current control using the variable X1 saved in step S152. Therefore, as shown in the hatched period in Figure 10, the CPU 10 does not use the input voltage Vin during the off period of the MOSFET 20. In other words, the CPU 10 performs current control using only the input voltage Vin during the on period of the MOSFET 20.

[0076] This disclosure is described in accordance with embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the scope of equivalents. In addition, while various combinations and forms are shown in this disclosure, other combinations and forms that include one, more, or fewer of those elements also fall within the scope and idea of ​​this disclosure. [Explanation of symbols]

[0077] 10...CPU, 11...Memory, 20...MOSFET, 30...Internal power supply, 40...Current monitor circuit, 41...Shunt resistor, 42...Operational amplifier, 43...First resistor, 44...Second resistor, 45...Third resistor, 46...Fourth resistor, 47...Fifth resistor, 48...Sixth resistor, 50...Terminal, 100...Control device, 200...Hydrogen injector, 300...Fuel cell stack, 400...Air compressor, 500...Hydrogen tank, 600...Battery

Claims

1. A hydrogen injector control device that controls the amount of hydrogen injected by controlling the valve opening degree by the amount of current supplied to the coil of the hydrogen injector, A switching element (20) is provided downstream of the coil and connected to a predetermined potential, A current monitoring circuit (40) includes a current sensing resistor (41) provided in the current path between the coil and the switching element, and an amplifier (42) that amplifies the voltage across the current sensing resistor and outputs a voltage correlated with the current value flowing through the coil. The processing unit (10) includes an input voltage that monitors the output voltage of the amplifier, which obtains a current monitor value from the input voltage, and controls the amount of current by changing the pulse width of a control signal that controls the on / off state of the switching element based on the current monitor value, The processing device determines that there is an error between the previous value and the current value of the input voltage, considers that the current monitor value deviates from the actual current value flowing through the coil, corrects the input voltage with a correction value corresponding to the error, and obtains a corrected input voltage for acquiring the current monitor value.

2. The hydrogen injector control device according to claim 1, wherein the processing device determines that there is an error when the current value increases or decreases by more than a predetermined value from the previous value.

3. The hydrogen injector control device according to claim 1 or 2, wherein the processing device, in synchronization with the control signal, estimates the final value and initial value of the output voltage during the ON period of the switching element, and the final value and initial value of the output voltage during the OFF period of the switching element by linear interpolation, and sets the deviation between the previously estimated value and the currently estimated value in the estimated values ​​as the correction value according to the error.

4. A hydrogen injector control device that controls the amount of hydrogen injected by controlling the valve opening degree by the amount of current supplied to the coil of the hydrogen injector, A switching element (20) is provided downstream of the coil and connected to a predetermined potential, A current monitoring circuit (40) includes a current sensing resistor (41) provided in the current path between the coil and the switching element, and an amplifier (42) that amplifies the voltage across the current sensing resistor and outputs a voltage correlated with the current value flowing through the coil. The processing unit (10) includes an input voltage that monitors the output voltage of the amplifier, which acquires the current value from the input voltage, and controls the amount of current by changing the pulse width of the control signal that controls the on / off state of the switching element based on the acquired current value, which is the current monitor value, The processing apparatus is a hydrogen injector control device that controls the amount of current using the input voltage during the on period of the switching element, without using the input voltage during the off period of the switching element.

5. The hydrogen injector control device according to claim 4, wherein the processing device determines the off period and the on period from the control signal.

6. The hydrogen injector control device according to claim 4, wherein the processing device determines the off period to occur when the difference between the current value and the previous value of the output voltage exceeds a predetermined value, and determines the on period to occur when the difference exceeds the predetermined value again.

Images