CN101786413B - Energy management system of hybrid power plant based on fuel cell - Google Patents

Abstract

The energy management system of the hybrid power device based on the fuel cell comprises an energy management controller which is formed by connecting a load energy demand model unit, a fuel cell auxiliary energy demand model unit, a charge state calculation unit and a charge state regulator through signal lines, wherein the energy management controller collects load control signals, a charge state calculation module collects and calculates an instant charge state value of the power cell, and the energy management controller is connected with a fuel cell controller and a direct current converter of the fuel cell system through a CAN network and sends control signals. The invention has the advantages that: the cost can be reduced, and the reliability of the system can be improved; the energy balance matching of a fuel cell power system and the follow-up control of the charging current of a power battery pack are realized; the dynamic performance of the fuel cell system during the operation of the power device is improved, the service life of the power battery pack is prolonged, and the safety of the power battery is enhanced; the method has the advantages of intellectualization, high reliability, low cost and the like.

Description

Energy management system of hybrid power plant based on fuel cell

technical field

The invention belongs to the technical field of hybrid power devices, in particular relates to a fuel cell-based electric-electric hybrid power device, and in particular relates to energy management of the hybrid power device.

Background technique

Due to the low emission characteristics of the hybrid power plant, it has become the focus of research in the power field. There are currently two types of hybrid power devices: according to the type of energy, they are divided into electric-electric hybrid and oil-electric hybrid; according to the form of the drive system, they are divided into parallel type and series type.

At present, most fuel cell-based hybrid power devices are electric-electric hybrid series. The fuel cell system adopts a passive control method to control the working power of the fuel cell and the output of the DC converter according to the load current. The disadvantage of this hybrid power device based on fuel cells is that the control has hysteresis, which often causes excessive changes in the discharge current of the power battery, resulting in short life and low safety of the power battery pack.

Contents of the invention

The object of the present invention is to provide an energy management system of a hybrid power device based on a fuel cell, so as to realize predictive control of the fuel cell system and follow-up control of the charging current of the power battery pack, and overcome the deficiencies of the prior art.

The technical solution of the present invention is: the energy management system of a hybrid power device based on a fuel cell, including a fuel cell system connected by a power line and a signal line, a power battery system and a DC converter, and is characterized in that the fuel cell-based The energy management system of the hybrid power plant also includes an energy management controller, and the energy management controller includes a load energy demand model unit and a fuel cell auxiliary energy demand model unit, a state-of-charge calculation unit and a state-of-charge regulator, the state-of-charge regulator pre-sets Input the expected state of charge value, load energy demand and fuel cell auxiliary energy demand model unit, state of charge calculation unit and state of charge regulator belong to different program modules in the energy controller, and coordinate operation of each module according to the interrupt response, the energy The management controller collects the load control signal from the outside and transmits it to the load energy demand and the auxiliary energy demand model unit of the fuel cell. The state of charge calculation unit collects the input and output current of the power battery from the power battery system to calculate the instantaneous state of charge value of the power battery, and the energy The management controller is connected with the fuel cell controller (FCS) and DC converter (DCDC) of the fuel cell system through the CAN network, and sends control signals.

The energy management system of the fuel cell-based hybrid power device according to the present invention is characterized in that the program flow of the energy management system operation is: the energy management controller (VMS) collects the load control signal from the outside, the load energy demand and the fuel The battery-assisted energy demand model unit calculates the energy demand of the power plant based on the collected load control signal, and the state-of-charge calculation unit calculates the current state-of-charge of the power battery from the measured cumulative charge and discharge current and current voltage of the power battery value (SOC value), the state of charge regulator performs charge and discharge judgments according to the preset expected state of charge value and the current state of charge value: when the current state of charge value (SOC value) of the power battery is lower than the expected state of charge value state value, the command is sent to the fuel cell system to charge the power battery, and the fuel cell system charges the power battery with a fixed value. When the current state of charge of the power battery reaches the expected state of charge value of the power battery, the charging is stopped. The current charged by the fuel cell system to the power battery is zero; when the state of charge value of the power battery is higher than the expected state of charge value, the fuel cell system does not charge the power battery, that is, the current charged by the fuel cell system to the power battery is zero , the energy management controller (VMS) calculates the energy demand of the power plant and the state of charge regulator according to the load energy demand and the fuel cell system energy demand model according to the preset expected state of charge value and the current state of charge value of the power battery The result of charging and discharging judgments calculates the overall energy demand, and transmits the calculated overall energy demand to the fuel cell control system and the DC converter (DCDC), and the DC converter (DCDC) controls the output of the DC converter according to the calculated overall energy demand.

The energy management system of the fuel cell-based hybrid power device of the present invention is characterized in that the fan of the fuel cell system of the hybrid power device is a fan powered by a DC brushless motor, and the driver of the fan is equipped with a CAN communication interface .

The energy management system of a hybrid power device based on a fuel cell according to the present invention is characterized in that the DC brushless motor of the fan of the fuel cell system of the hybrid power device is a 48V~96V, 2.2kw, 3500RPM DC brushless motor .

The energy management system of the fuel cell-based hybrid power device of the present invention, the hybrid power device belongs to the electric-electric hybrid series power device, and the energy management system adopts the least square method (RLS) to respectively establish the load energy demand and the auxiliary energy demand of the fuel cell system The black-box model; the power accumulation method is used to calculate the state of charge (SOC) value of the power battery pack. According to the established load energy demand and auxiliary energy demand model of the fuel cell system, through the collected load control signal and the current state of charge (SOC) value of the power battery pack, the total energy demand is predicted, and the work of the fuel cell system is controlled in advance State, to reduce the dynamic response time of the fuel cell system, and control the output of the DC converter (Buck DCDC), to meet the energy demand of the load system, fuel cell system and the state of charge of the power battery pack.

The advantages of the present invention are:

1. A DC brushless motor is used to assemble a DC fan to replace an asynchronous motor. In the system, a DC motor driver is used instead of a frequency converter, which can reduce a boost DC converter (Boost DCDC), which can reduce costs and increase system reliability.

2. The management system of the present invention realizes the follow-up control of the charging current of the power battery pack.

3. The present invention can realize the energy balance matching of the fuel cell power system, predict the energy demand according to the model, control the fuel cell working power and DCDC output current in advance, improve the dynamic performance of the fuel cell system when the power device is running, and prolong the life of the power battery pack. The service life is improved and the safety of the power battery is enhanced.

4. CAN network is used to realize the communication of energy management controller (VMS), fuel cell system controller (FCS), Buck DCDC and vehicle system, which has the advantages of intelligence, high reliability and low cost.

Description of drawings

The present invention has three accompanying drawings:

Fig. 1 is a schematic diagram of the power supply system of the present invention, in which solid line arrows represent positive lines, and dotted line arrows represent negative lines;

Fig. 2 is a structural diagram of the energy management system of the present invention, in which the thin solid line arrows indicate the control signal flow direction, and the thick solid line arrows indicate the energy flow direction;

Fig. 3 is a flow chart of the control program of the energy management system of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the embodiment of accompanying drawing.

Accompanying drawing 1 provided is electric-electric hybrid serial power plant. It consists of connecting various subsystems as shown in Figure 1. In this embodiment, when the switch K1 is closed, it is a pure electric mode, and when the switches K1 and K2 are closed simultaneously, it is a hybrid mode.

Figure 2 is a system structure diagram. The load energy demand and fuel cell auxiliary energy demand model unit of its energy management controller (VMS) adopts the least square method (RLS) to establish the energy demand model of the load and fuel cell system. The state-of-charge calculation unit and the state-of-charge regulator are functional modules in the energy management controller, which are specifically implemented by programs.

The energy management controller (VMS) collects the load control signal from the outside, and the load energy demand and fuel cell auxiliary energy demand model unit calculates the energy demand of the power plant according to the collected load control signal, and the state of charge calculation unit calculates the power from the measured power The accumulated charging and discharging current and voltage of the battery pack are used to calculate the current state of charge value (SOC value) of the power battery, and the state of charge regulator performs charging according to the preset expected state of charge value and the current state of charge value of the power battery. Discharge judgment: When the current state of charge (SOC value) of the power battery is lower than the expected state of charge value, a command to charge the power battery is sent to the fuel cell system, and the fuel cell system charges the power battery with a fixed value. When the charging of the battery reaches the expected state of charge value of the power battery, the charging is stopped, that is, the current charged by the fuel cell system to the power battery is zero; when the state of charge value of the power battery is higher than the expected state of charge value, the fuel cell system does not charge Power battery charging means that the fuel cell system charges the power battery with zero current. The formula for calculating the total required energy of the power plant is:

E= _Eload + _{Efuel cell auxiliary system} + _{Epower battery pack charging}

In the above formula, E is the total energy demand, E _load is the load energy demand, E _{fuel cell auxiliary system} is the energy demand of the fuel cell auxiliary system, E _{power battery pack charging} is the power battery pack charging energy demand.

The formula for calculating the state of charge is:

$\mathrm{<span\; class="notranslate">\; soc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; BC</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; soc</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; BC</span>}$

In the above calculation formula, BC represents the battery capacity, soc(k) represents the SOC value of the battery pack at the current moment, soc(k-1) represents the SOC value at the previous moment, i _out represents the discharge current of the power battery, and i _in represents the power Battery pack charging current. The SOC value is stored in the controller's internal electrically erasable programmable read-only memory (E ² PROM) at regular intervals, so that the value can be read as the initial value at the next startup; when the power battery is used for the first time, it is assumed that the soc(k -1) is 90%. When calculating the SOC of the power battery pack, first read the SOC value in the E ² PROM as soc(k-1), and then perform the calculation of the power battery pack according to the SOC calculation formula. SOC calculation. The control program flow of the energy management controller is shown in Figure 3. The energy management controller (VMS) calculates the energy demand of the power plant and the state of charge regulator according to the load energy demand and the fuel cell auxiliary energy demand model unit. The result of charge and discharge judgment calculates the overall energy demand, and transmits the calculated overall energy demand to the fuel cell control system and the DC converter (DCDC) through the CAN network, and the DC converter (DCDC) controls the output of the DC converter according to the calculated overall energy demand . The fuel cell controller (FCS) controls the working conditions of the fuel cell system in advance according to the overall energy demand to improve the dynamic response performance of the fuel cell system. The energy demand of each sub-unit in the power plant. The calculation of the SOC value of the power battery pack adopts the power accumulation method. When using the power battery pack for the first time, fully charge the power battery pack with the charger first, assuming that the SOC of the power battery pack is 90%, then calculate the current power value of the SOC as the total power x 0.9. Every time the SOC calculation of the power battery pack is performed in the future, the SOC value in the E ² PROM is first read as the current SOC value, and then the SOC calculation of the power battery pack is performed according to the SOC calculation formula. The experimental data of the energy management system shows that the DCDC output current is approximately equal to the sum of the fuel cell auxiliary system current and the load current. This is because the power unit is completely powered by fuel cells, and the initial use of the power battery pack, its SOC is approximately 85%, so the charging and discharging current of the power battery is close to zero.

Claims (1)

1. based on the energy management system of the mixed power plant of fuel cell, energy management system comprises the fuel cell system that is connected with signal wire (SW) by power line, electrokinetic cell system, direct current transducer and energy management controller, the energy management controller comprises load energy demand and fuel cell auxiliary energy demand model unit, state-of-charge calculating unit and state-of-charge regulating control, load energy demand and fuel cell auxiliary energy demand model unit, state-of-charge calculating unit and state-of-charge regulating control are the program modules in the energy management controller, according to each module coordinated operation of interrupt response, the energy management controller is connected DCDC by CAN network and the fuel cell controller (FCS) of fuel cell system with DC converter) be connected, transmit control signal, the program circuit that it is characterized in that the operation of described energy management system is: energy management controller (VMS) gathers load control signal and is transferred to load energy demand and fuel cell auxiliary energy demand model unit from the outside, load energy demand and fuel cell auxiliary energy demand model unit calculate the energy requirement of engine installation according to the load control signal that collects, state-of-charge calculating unit driven force battery system gathers the instant state-of-charge value of the input and output Current calculation electrokinetic cell of electrokinetic cell, the state-of-charge calculating unit is from accumulative total charging and discharging currents and the current voltage of the electrokinetic cell that records, calculate the current state-of-charge value of electrokinetic cell (SOC value), the state-of-charge regulating control pre-enters expectation state-of-charge value, the state-of-charge regulating control discharges and recharges judgement according to the expectation state-of-charge value and the current state-of-charge value of electrokinetic cell that preset: when the current state-of-charge value of electrokinetic cell (SOC value) when expecting the state-of-charge value, send to the power battery charging instruction to fuel cell system, fuel cell system with definite value to power battery charging, when the current state-of-charge value of electrokinetic cell reaches expectation state-of-charge value, stop charging, be fuel cell system be zero to the electric current of power battery charging, when the state-of-charge value of electrokinetic cell during higher than expectation state-of-charge value, fuel cell system is not to power battery charging, be fuel cell system be zero to the electric current of power battery charging, energy management controller (VMS) discharges and recharges the energy requirement of calculated population as a result of judgement according to energy requirement and the state-of-charge regulating control that load energy demand and fuel cell auxiliary energy demand model unit calculate engine installation according to the current state-of-charge value of the expectation state-of-charge value that presets and electrokinetic cell, the total energy demand of calculating is transferred to Fuel Cell Control System and DC converter (DCDC), DC converter (DCDC) is controlled direct current transducer output according to the total energy demand of calculating.

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