Suspension control power supply circuit based on hydrogen fuel cells

Abstract

The application discloses a suspension control power supply circuit based on a hydrogen fuel cell. A timer circuit in the circuit is connected with a hydrogen fuel cell module, a voltage stabilizing unit is connected with the hydrogen fuel cell module, an energy storage module and a suspension control module. When the suspension system is in a rated working condition, the hydrogen fuel cell module is switched to a constant power mode, and the working state of the hydrogen fuel cell module is selected according to the capacity of the energy storage module. When the working state is switched, the timer circuit is reset to start timing to obtain the corresponding working state duration, the working state duration and the corresponding output voltage change value are controlled to ensure that the power supply voltage of the suspension system is in a stable state. In addition, the working state of the hydrogen fuel cell is selected according to the capacity of the energy storage module, so that the energy storage module and the hydrogen fuel cell module are prevented from frequently switching states due to suspension control fluctuations. In a peak working condition, the energy storage module is switched to a discharging state to adapt to the suspension system in real time, and the defect that the hydrogen fuel cell has a slow dynamic response is compensated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of suspension control, in particular to a suspension control power supply circuit based on a hydrogen fuel cell. BACKGROUND

[0002] In order to realize the real ground-hugging flight of the maglev train, reduce the line resistance caused by the contact between the current collector shoe and the contact rail, reduce the construction cost of the line, and eliminate the safety hazards of the exposed contact rail, the medium and low speed maglev train needs to cancel the current rail power supply scheme and provide power through on-board energy storage or on-board power generation.

[0003] When the fuel cell is applied in the magnetic suspension control system, because the output load is the suspension electromagnet, which belongs to a typical inductive load, when the suspension controller controls the electromagnet in a closed loop, the dynamic changes of the load and the suspension gap cause large power fluctuations of the suspension controller, and the input power under the rated working condition and the peak working condition differs by more than 6 times, while the fuel cell is a rated power supply system, and when used in the suspension controller field, it needs to be configured according to the peak power, which will result in very low utilization efficiency and energy density ratio of the fuel cell and high cost, and the dynamic response of the hydrogen fuel cell system output is very slow, which cannot meet the demand of the high current change rate of the suspension control system. The above problems directly hinder the promotion and application of hydrogen fuel cells in the suspension control field. SUMMARY

[0004] Therefore, it is necessary to provide a suspension control power supply circuit based on a hydrogen fuel cell to improve the utilization efficiency of the fuel cell and adapt to the high change rate of the suspension control in view of the above technical problems.

[0005] A suspension control power supply circuit based on a hydrogen fuel cell, the circuit comprising:

[0006] a hydrogen fuel cell module, a voltage stabilizing unit, an energy storage module, a timer circuit, and a suspension control module; the timer circuit is connected to the hydrogen fuel cell module;

[0007] The voltage stabilizing unit is connected to the hydrogen fuel cell module, the energy storage module, and the suspension control module, and is used to stabilize the unstable direct current power output by the hydrogen fuel cell module to output to the suspension control module and / or the energy storage module;

[0008] When the suspension system is in the rated working condition, the hydrogen fuel cell module is switched to the constant power output mode, and the working state of the hydrogen fuel cell module is controlled to be switched according to the capacity condition of the energy storage module; the working state includes a first working state in which the output power is not less than the suspension power and a second working state in which the output power is less than the suspension power;

[0009] When switching the working state, the timer circuit is reset and starts timing to obtain the corresponding working state duration and the output voltage variation value of the voltage stabilizing unit in the working state duration, which is used to calculate the ratio of the suspension single cycle control working time to the working state duration, so that the product of the ratio and the output voltage variation value is less than one ten-thousandth of the suspension control working voltage;

[0010] When the suspension system is in the peak working condition, the hydrogen fuel cell module switches to the current-limiting output mode, and the energy storage module switches to the discharging state, so that the hydrogen fuel cell module and the energy storage module output voltage to the voltage stabilizing unit together power the suspension control module.

[0011] The above-mentioned suspension control power supply circuit based on the hydrogen fuel cell first adds the energy storage module. When the suspension system is in the rated working condition, the hydrogen fuel cell module switches to the constant power output mode, and the working state of the hydrogen fuel cell module is selected according to the capacity of the energy storage module, that is, the output power of the hydrogen fuel cell is controlled within a certain range, and the output power of the hydrogen fuel cell module is selected to be not less than or less than the suspension power according to the capacity of the energy storage module. When switching the working state, the timer circuit is reset and starts timing to obtain the corresponding working state duration and the output voltage variation value of the voltage stabilizing unit in the working state duration, and the ratio of the suspension single cycle control working time to the working state duration is calculated, so that the product of the ratio and the output voltage variation value is less than one ten-thousandth of the current suspension control working voltage. Because in the rated working condition, the capacity of the energy storage module is fully considered, and the working state of the hydrogen fuel cell module is switched, the actual working voltage of the voltage stabilizing unit will fluctuate periodically within a certain time interval. The working state duration and the output voltage variation value are controlled to ensure that the input power supply voltage of the suspension system is in a stable working state. In addition, the working state of the hydrogen fuel cell is selected according to the capacity of the energy storage module, which avoids the frequent switching of the energy storage module between charging and discharging states and the frequent switching of the hydrogen fuel cell module between working states caused by the suspension control fluctuation, and improves the service life. In the peak working condition, in order to improve the utilization rate of the battery, the rated power of the hydrogen fuel cell is less than the peak power of the suspension system, and the hydrogen fuel cell module cannot meet the power demand of the suspension system alone. At this time, the energy storage module can switch to the discharging state to adapt to the high change rate of the suspension system in real time, and make up for the defect of slow dynamic output response of the hydrogen fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Module schematic diagram of the suspension control power supply circuit based on the hydrogen fuel cell;

[0013] Figure 2 Schematic diagram of the suspension control power supply circuit based on the hydrogen fuel cell. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0015] As shown in Figure 1 A hydrogen fuel cell based levitation control power supply circuit is provided, comprising:

[0016] a hydrogen fuel cell module, a voltage stabilizing unit, an energy storage module, a timer circuit and a levitation control module. The timer circuit is connected to the hydrogen fuel cell module.

[0017] The voltage stabilizing unit is connected to the hydrogen fuel cell module, the energy storage module and the levitation control module, and is used to stabilize the unstable direct current power output by the hydrogen fuel cell module to output to the levitation control module and / or the energy storage module.

[0018] When the levitation system is in a rated operating condition, the hydrogen fuel cell module switches to a constant power output mode, and the working state of the hydrogen fuel cell module is controlled according to the capacity condition of the energy storage module. The working state includes a first working state in which the output power is not less than the levitation power and a second working state in which the output power is less than the levitation power.

[0019] When the levitation system is in a peak operating condition, the hydrogen fuel cell module switches to a current limiting output mode, and the energy storage module switches to a discharging state, so that the hydrogen fuel cell module and the energy storage module output voltage to the voltage stabilizing unit to supply power to the levitation control module.

[0020] It can be seen that the actual operating condition of the levitation system is different, the output mode of the hydrogen fuel cell module is different, and the addition of the energy storage module greatly reduces the power configuration requirement of the hydrogen fuel cell. Especially in the peak operating condition, the hydrogen fuel cell module and the energy storage module work cooperatively, and it is not necessary to configure a hydrogen fuel cell that meets more than 6 times the peak power of the levitation system, but only slightly larger than the rated power of the levitation system, which can also provide peak power for the levitation system. In the peak operating condition, in order to improve the utilization rate of the battery, the rated power of the hydrogen fuel cell is less than the peak power of the levitation system, and the hydrogen fuel cell module cannot meet the power requirement of the levitation system alone. At this time, the energy storage module can be switched to a discharging state to adapt to the levitation system with high change rate in real time, and make up for the defect that the dynamic output response of the hydrogen fuel cell is slow. Here, it can be set to be greater than 1.2 times the rated power of the levitation system (determined according to the operating condition of the levitation system, generally the total power is 1.1 times the rated power), which can greatly reduce the system cost.

[0021] The fuel cell supplies power to a system with rated power. The maximum output power is limited, but the output power can be adjusted. In normal design, the output power of the fuel cell is greater or less than the rated power of the suspension system. Therefore, when the suspension system is operating at rated power, the fuel cell controls the output power by controlling the inlet and outlet valves. At this time, the output power of the fuel cell does not reach its limit. When the suspension system is operating at peak power, the control system detects the output voltage of the fuel cell and limits the output current according to the limit of the output power to ensure that the fuel cell is operating at the limit of the output power. The advantage is that the output power can be maximized to reduce the capacity fluctuation of the energy storage module and avoid affecting the reliability and service life of the fuel cell due to over-power operation.

[0022] In the method, when the hydrogen fuel cell module switches the working state, the timer circuit is reset and starts timing to obtain the corresponding working state duration and the output voltage variation value of the voltage stabilizing unit within the working state duration, which are used to calculate the ratio of the suspension single cycle control working time to the working state duration, so that the product of the ratio and the output voltage variation value is less than one ten-thousandth of the suspension control working voltage.

[0023] Specifically, when the capacity of the energy storage module is lower than a preset value, the hydrogen fuel cell module is controlled to switch to the first working state, the ratio of the suspension single cycle control working time to the first working state duration is calculated, and the corresponding output voltage rising value is calculated, so that the product of the ratio and the output voltage rising value is less than one ten-thousandth of the suspension control working voltage. When the capacity of the energy storage module is not lower than the preset value, the hydrogen fuel cell module is controlled to switch to the second working state, the ratio of the suspension single cycle control working time to the second working state duration is calculated, and the corresponding output voltage falling value is calculated, so that the product of the ratio and the output voltage falling value is less than one ten-thousandth of the suspension control working voltage.

[0024] It can be understood that, in the rated working condition, the energy storage module tracks the suspension power in real time, switches the charging and discharging state according to the actual working condition, adjusts the insufficient or excessive output power of the hydrogen fuel cell module, and thus the output voltage of the voltage stabilizing unit fluctuates periodically within a certain time range. Therefore, the timer circuit is added to time each working state duration, the ratio of the suspension single cycle control working time to the working state duration is calculated, and the corresponding output voltage variation value of the voltage stabilizing unit within the working state duration is calculated, so that the product of the ratio and the output voltage variation value is less than one ten-thousandth of the current suspension control working voltage. The working state duration and the output voltage variation value are controlled to ensure that the input power supply voltage of the suspension system is in a stable working state.

[0025] In addition, the working state of the hydrogen fuel cell is selected according to the capacity of the energy storage module, which avoids frequent switching of the charging and discharging state of the energy storage module and the working state of the hydrogen fuel cell module caused by suspension control fluctuation, and improves the service life.

[0026] In one embodiment, the energy storage module comprises an energy storage element and an energy storage power switch device. The energy storage power switch device is connected to the energy storage element, and when turned on, the energy storage module and the hydrogen fuel cell module together output stable DC power to the suspension control module, and when turned off, the hydrogen fuel cell module outputs stable DC power to the energy storage module through the voltage stabilizing unit for charging.

[0027] The circuit introduces an energy storage power switch device, which is used to switch the charging and discharging state of the energy storage module according to actual needs. In particular, the dynamic output response of the hydrogen fuel cell is slow, and it cannot adapt to the high change rate of the suspension system in real time. When the energy storage power switch device is turned on, the energy storage module can track the suspension power in real time and supply power, which makes up for the defect of slow dynamic output response of the hydrogen fuel cell.

[0028] In one embodiment, the voltage stabilizing unit comprises a battery power switch module, an inductor, and a battery filter capacitor.

[0029] The battery power switch module comprises a first battery power switch device and a second battery power switch device; the first battery power switch device is connected to the second battery power switch device.

[0030] The battery filter capacitor comprises a first battery filter capacitor and a second battery filter capacitor; the first battery filter capacitor is connected to the positive terminal and the ground terminal of the hydrogen fuel cell module, and the first battery power switch device and the second battery power switch device are respectively connected to both ends of the battery filter capacitor.

[0031] The first port of the inductor is connected to the first common connection point between the first battery power switch device and the second battery power switch device, and the second port of the inductor is connected to the first port of the positive terminal of the intermediate DC loop.

[0032] The second port of the positive terminal of the intermediate DC loop is connected to the second common connection point between the energy storage power switch device and the second battery filter capacitor.

[0033] It can be understood that the first battery filter capacitor, the first battery power switch device, the second battery power switch device, the inductor, the second battery filter capacitor, and the energy storage module constitute a voltage-stabilized DC power supply with energy storage function.

[0034] In one embodiment, the suspension control module comprises a control power switch module and a suspension electromagnet.

[0035] The control power switch module comprises a first control power switch device and a second control power switch device; the first control power switch device is connected to the second common connection point.

[0036] The first control power switch device is connected with the second control power switch device, and the second control power switch device is connected with the third common connection point between the levitation electromagnet and the first control power switch device.

[0037] The first control power switch device is used for adjusting a duty cycle to control an output current of the levitation electromagnet, and the second control power switch device is used for providing a freewheeling loop for the levitation electromagnet.

[0038] When the hydrogen fuel cell module is in the constant power output mode and the positive electrode terminal voltage value of the hydrogen fuel cell module is higher than the positive electrode terminal voltage value of the intermediate direct current loop, the first battery power switch device, the second battery power switch device, the inductor and the second battery filter capacitor constitute a voltage reduction and stabilization circuit, and the inductor and the second battery filter capacitor constitute a voltage reduction and filtering circuit; the first battery power switch device and the second battery power switch device are complementary operated at a rated switching frequency, and the output voltage and the output current of the first battery power switch device are controlled by adjusting the duty cycle of the first battery power switch device, so that the hydrogen fuel cell is kept in the constant power output mode.

[0039] When the positive electrode terminal voltage value of the intermediate direct current loop is higher than the positive electrode terminal voltage value of the energy storage module, the energy storage power switch device is turned off to charge the energy storage element.

[0040] When the positive electrode terminal voltage value of the energy storage module is higher than the positive electrode terminal voltage value of the intermediate direct current loop, the energy storage power switch device is turned on to output the voltage from the energy storage element and the hydrogen fuel cell module to the levitation control module.

[0041] As shown in Figure 2 , a schematic diagram of a levitation control power supply circuit based on a hydrogen fuel cell is provided. Among them, F_BAT is a hydrogen fuel cell module, EA1 and EA2 are a first battery filter capacitor and a second battery filter capacitor respectively, LA1 is an inductor, E1 is an energy storage module, which can be selected from supercapacitors, lithium batteries and the like, QA1, QA2 and QA3 are a first battery power switch device, a second battery power switch device and an energy storage power switch device respectively, which can be selected from MOS, IGBT and the like, QB1 and QB2 are a first control power switch device and a second control power switch device respectively, which constitute a levitation electromagnet control chopper circuit, and can be selected from MOS, IGBT and the like, YA1 is a levitation electromagnet, and DC+ end is a positive electrode terminal of an intermediate direct current loop.

[0042] Because the hydrogen fuel cell voltage fluctuation period is far lower than the suspension electromagnet control period, the suspension system uses constant power operation mode when in rated working condition, and at this time the F_BAT output DC F_BAT+ end voltage is higher than the DC+ end voltage, QA1, QA2, LA1, EA2 constitute a voltage reduction stabilizing circuit, wherein QA1, QA2 work complementarily at the rated switching frequency, through adjusting the QA1 duty cycle to control the output voltage and output current, so that the hydrogen fuel cell is kept in constant power operation mode, LA1, EA2 constitute a voltage reduction filter circuit, and QA2 is the LA1 inductance freewheeling; QB1, QB2 constitute a suspension control chopper circuit, YA1 is the suspension electromagnet, and when working, the output current is controlled by controlling the QB1 duty cycle, and QB2 provides a freewheeling circuit for YA1; When the system works, the DC+ end voltage is higher than the BAT+ voltage, and the QA3 built-in diode is automatically charged; under normal working condition, the BAT+ end voltage is basically equal to the DC+ end voltage.

[0043] When the suspension control works in the peak condition, at this time the hydrogen fuel cell output power cannot meet the suspension control demand, then the DC+ end voltage will decrease, when the system detects that the DC+ end voltage is lower than the BAT+ end voltage, QA3 is turned on, E1 and F_BAT are connected in parallel to output together, and provide power for the suspension control; when the suspension system returns to normal working condition, at this time the fuel cell output power is greater than the suspension control required power, then the DC+ end voltage rises, when it is detected that there is a forward current from the DC+ end to the BAT+ end, then QA3 is turned off, and the system returns to the suspension rated working condition.

Claims

1. A levitation control power supply circuit based on a hydrogen fuel cell, characterized in that, The circuit includes: The system includes a hydrogen fuel cell module, a voltage regulator unit, an energy storage module, a timer circuit, and a levitation control module; the timer circuit is connected to the hydrogen fuel cell module. The voltage stabilizing unit is connected to the hydrogen fuel cell module, the energy storage module, and the levitation control module, and is used to stabilize the unstable DC power output by the hydrogen fuel cell module so that it can be output to the levitation control module and / or the energy storage module. When the suspension system is in rated operating condition, the hydrogen fuel cell module switches to constant power output mode, and the operating state of the hydrogen fuel cell module is controlled to switch according to the capacity status of the energy storage module; the operating state includes a first operating state in which the output power is not less than the suspension power and a second operating state in which the output power is less than the suspension power. When switching working states, the timer circuit is reset and starts timing to obtain the corresponding working state duration and the output voltage change value of the voltage regulator unit during the working state duration. This is used to calculate the ratio of the floating single-cycle control working time to the working state duration, such that the product of the ratio and the output voltage change value is less than one ten-thousandth of the floating control working voltage. When the suspension system is under peak operating conditions, the hydrogen fuel cell module switches to current-limited output mode, and the energy storage module switches to discharge state, so that the output voltage of the hydrogen fuel cell module and the energy storage module is supplied to the voltage regulator unit to power the suspension control module.

2. The circuit according to claim 1, characterized in that, The energy storage module includes energy storage elements and energy storage power switching devices; The energy storage power switching device is connected to the energy storage element and is used to enable the energy storage module and the hydrogen fuel cell module to output a stable DC power supply to the levitation control module when the switch is turned on, and to enable the hydrogen fuel cell module to output a stable DC power supply to the energy storage module through the voltage regulator unit for charging when the switch is turned off.

3. The circuit according to claim 2, characterized in that, The voltage regulation unit includes a battery power switch module, an inductor, and a battery filter capacitor; The battery power switch module includes a first battery power switch device and a second battery power switch device; the first battery power switch device is connected to the second battery power switch device. The battery filter capacitor includes a first battery filter capacitor and a second battery filter capacitor; the first battery filter capacitor is connected to the positive terminal and the ground terminal of the hydrogen fuel cell module, and the first battery power switch and the second battery power switch are respectively connected to the two ends of the battery filter capacitor; The first port of the inductor is connected to the first common terminal between the first battery power switch and the second battery power switch, and the second port of the inductor is connected to the first port of the positive terminal of the intermediate DC circuit. The second port of the positive terminal of the intermediate DC circuit is connected to the second common connection point between the energy storage power switching device and the second battery filter capacitor.

4. The circuit according to claim 3, characterized in that, The levitation control module includes a control power switch module and a levitation electromagnet; The control power switch module includes a first control power switch device and a second control power switch device; the first control power switch device is connected to the second common terminal. The levitation electromagnet is connected to the first control power switch device and the second control power switch device, and the second control power switch device is connected to the third common connection point between the levitation electromagnet and the first control power switch device. The first control power switching device is used to adjust the duty cycle to control the output current of the levitation electromagnet, and the second control power switching device is used to provide a freewheeling circuit for the levitation electromagnet. When the hydrogen fuel cell module is in constant power output mode and the positive terminal voltage of the hydrogen fuel cell module is higher than the positive terminal voltage of the intermediate DC circuit, the first battery power switch, the second battery power switch, the inductor, and the second battery filter capacitor constitute a step-down voltage regulator circuit, and the inductor and the second battery filter capacitor constitute a step-down filter circuit. The first battery power switch and the second battery power switch operate complementaryly at the rated switching frequency. By adjusting the duty cycle of the first battery power switch, the output voltage and output current of the first battery power switch are controlled, so that the hydrogen fuel cell remains in constant power output mode. When the voltage value at the positive terminal of the intermediate DC circuit is higher than the voltage value at the positive terminal of the energy storage module, the energy storage power switch device is turned off to charge the energy storage element. When the positive terminal voltage of the energy storage module is higher than the positive terminal voltage of the intermediate DC circuit, the energy storage power switch is turned on, so that the energy storage element and the hydrogen fuel cell module can output voltage to the suspension control module together.

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