WO2011024707A1 - Electric industrial vehicle - Google Patents

Electric industrial vehicle Download PDF

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Publication number
WO2011024707A1
WO2011024707A1 PCT/JP2010/064012 JP2010064012W WO2011024707A1 WO 2011024707 A1 WO2011024707 A1 WO 2011024707A1 JP 2010064012 W JP2010064012 W JP 2010064012W WO 2011024707 A1 WO2011024707 A1 WO 2011024707A1
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WO
WIPO (PCT)
Prior art keywords
power
power storage
electric motor
electric
storage unit
Prior art date
Application number
PCT/JP2010/064012
Other languages
French (fr)
Japanese (ja)
Inventor
悟 金子
高志 伊君
枝穂 泉
秀一 森木
信夫 正野
Original Assignee
日立建機株式会社
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Publication of WO2011024707A1 publication Critical patent/WO2011024707A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M16/00—Structural combinations of different types of electrochemical generators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/40—Electric propulsion with power supplied within the vehicle using propulsion power supplied by capacitors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/20—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having different nominal voltages
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/06—Lead-acid accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/46—Accumulators structurally combined with charging apparatus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2200/00—Type of vehicles
    • B60L2200/40—Working vehicles
    • B60L2200/42—Fork lift trucks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/60—Electric or hybrid propulsion means for production processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • the present invention relates to an electric industrial vehicle such as a battery-type forklift, and more particularly to a power supply system device that supplies power to a drive source of each part of the vehicle.
  • FIG. 6 shows the configuration of a power supply system device for a general battery-type forklift that is conventionally known.
  • the power supply system device 3 of the present example includes an inverter 10, a lead battery 2, and a controller 11 that gives a command to the inverter 10.
  • the energy source of the battery-type forklift is only the lead battery 2, and the DC power of the lead battery 2 is converted into AC power by the inverter 10 to drive the electric motor 4 for traveling and the electric motor 6 for cargo handling.
  • the inverter 10 constituting the power supply system device 3 has two power converters in order to drive the two motors 4 and 6 independently.
  • the controller 11 outputs power according to the power required by the driver from the motors 4 and 6 (the operation amount determined by the accelerator, the brake pedal, and the cargo handling lever, although not particularly shown).
  • the motors 4 and 6 are controlled via the inverter 10.
  • the battery-type forklift frequently repeats acceleration / deceleration during traveling operation, and an electric brake is applied by the traveling electric motor 4 during braking. Therefore, a considerable amount of regenerative power is generated during traveling operation.
  • the hydraulic oil in the hydraulic cylinder is released and the potential energy stored in the lift is discarded. If it is set as the structure which rotates a generator using, it is also possible to collect
  • a battery-type forklift can generate a considerable amount of regenerative power from its operation.
  • lead batteries used in battery-powered forklifts are not excellent in charging characteristics with short-time high currents such as regenerative power of electric motors, so apply regenerative power of electric motors directly to lead batteries. However, most of them are lost, and regenerative power cannot be used effectively. Therefore, recently, in order to compensate for the low rapid charging characteristics of the lead battery, a technique for improving the recovery amount of regenerative electric power from an electric motor or a lift by using a large-capacity capacitor has been proposed.
  • Non-Patent Document 1 There have been several examples of technology that uses large capacity capacitors in combination with lead batteries. Among them, in a system device in which a large-capacity capacitor is connected in parallel to a battery via a DCDC converter, a current command is calculated so that the internal resistance of the capacitor can be regarded as zero, and control is performed so that the current flows through the capacitor. In particular, it is attracting attention as a technique for efficiently recovering regenerative power (see Non-Patent Document 1).
  • Non-Patent Document 1 uses a differential operation on the battery voltage as a method for calculating the current command flowing through the capacitor during regeneration, it is required to include a controller having high calculation performance.
  • Non-Patent Document 1 does not disclose a control method during power discharge, and it cannot be said that efficient driving is possible even during discharge, so there is room for improvement in this respect.
  • the present invention has been made in view of the current state of the prior art, and an object of the present invention is to make the drive unit highly efficient both during regeneration (charging) and during power running (discharging) by a simple calculation method.
  • An object of the present invention is to provide an electric industrial vehicle equipped with a drivable power supply system device.
  • the present invention is an electric industrial vehicle including an electric motor that drives a drive unit of a vehicle, and a power supply system device that supplies motor drive power to the electric motor, the power supply system device A first power storage means that is inferior in charging characteristics at a short time and a large current, a second power storage means that is excellent in charging characteristics at a short time and a large current, a DCDC converter that performs voltage control of the second power storage means,
  • the controller is configured to operate the first power storage means and the first power during a power running operation of the electric motor. 2 Based on each internal resistance of the power storage means and the load demand power of the electric motor, the first power storage means and the second power storage means And the configuration of determining the flow distribution.
  • the first power storage unit is configured so that the loss of the power supply system device is minimized based on the internal resistances of the first and second power storage units and the required load power of the electric motor during the power running operation of the electric motor. Since the current distribution of the second power storage means is determined, the power supply system apparatus can be used with high efficiency. Therefore, by combining with a technique for improving the amount of recovered regenerative power by the second power storage means during regeneration, it is possible to increase the drive efficiency of the drive unit during both regeneration and power running. Further, since the current distribution of the first power storage means and the second power storage means is determined based on the internal resistances of the first and second power storage means and the load demand power of the electric motor, the first power storage means is performed without performing a differential operation. And the current distribution of the second power storage means can be determined, and the burden on the controller can be reduced.
  • the controller controls the DCDC converter so that the regenerative power from the electric motor flows only in the second power storage unit during the regenerative operation of the electric motor. It was configured as follows.
  • the second power storage means is excellent in charging characteristics with a large current for a short time, by adopting such a configuration, it is possible to efficiently recover regenerative power.
  • the controller sets a current command value to be supplied to the first power storage unit during the regenerative operation of the electric motor to zero, and sets the current command value and the first power storage unit to
  • the DCDC converter is configured to be feedback-controlled so that the deviation from the flowing current value becomes zero.
  • the DCDC converter can be feedback controlled simply by adding or subtracting the current value flowing through the first power storage unit with respect to the current command value flowing through the first power storage unit, so that the burden on the controller can be reduced.
  • the first power storage unit is a lead battery
  • the second power storage unit is a large capacity capacitor
  • a battery-type forklift 1 includes a driving wheel (tire) 5 driven by an electric motor 4 for traveling, a pump 7 driven by an electric motor 6 for cargo handling, and a pump 7.
  • a hydraulic cylinder 8 driven by the discharged pressure oil and a lift 9 that rises or falls according to the expansion and contraction of the hydraulic cylinder 8 are provided.
  • the battery-type forklift 1 is provided with a lead battery 2 as an energy source for the electric motor 4 for traveling and the electric motor 6 for cargo handling, and the electric power stored in the lead battery 2 is traveled by the power supply system device 3.
  • the electric motor 4 and the cargo handling electric motor 6 are distributed in accordance with their respective required powers.
  • the battery-type forklift 1 can travel by rotating the drive wheels 5 with the electric motor 4 for traveling, and the pump 7 is rotationally driven with the electric motor 6 for cargo handling and discharged from the pump 7.
  • the flow of the pressurized oil is switched by a direction switching valve (not shown) or the like, and the hydraulic cylinder 8 can be extended or contracted to raise or lower the load.
  • the power supply system device 3 includes a lead battery 2 and a large capacity capacitor 13 connected in parallel to the inverter 10, and a DCDC converter 12 that adjusts a voltage value applied to the large capacity capacitor 13.
  • the current sensor 14 detects the current flowing through the lead battery 2 and the controller 11 controls the DCDC converter 12 according to the current flowing through the current sensor 14 and gives a command to the inverter 10.
  • the power supply system apparatus collects the power only in the large capacity capacitor 13 without flowing the regenerative power through the lead battery 2.
  • the controller 11 detects the current Ib flowing through the lead battery 2 by the current sensor 14, feeds it back to the control system of the DCDC converter 12, and performs regenerative power regenerative control. That is, when the controller 11 determines that the current operation is “regenerative operation”, the current command Ib * to be passed through the lead battery 2 is set to zero, and the detection value Ib of the current sensor 14 is fed back to the current command Ib * .
  • the controller 20 performs a control operation such as proportional integration so that the deviation ⁇ Ib between the current command Ib * and the detected value Ib becomes zero, and calculates the target voltage VC * of the large-capacitance capacitor 13. Further, the target voltage VC * of the large-capacity capacitor 13 is input to the DCDC converter voltage control system 21, and the voltage control of the large-capacity capacitor 13 by the DCDC converter 12 is performed.
  • the above is an example of the control operation of the power supply system apparatus 3 using the large-capacitance capacitor 13 in the regeneration mode.
  • the control operation of the power supply system apparatus 3 using the large-capacitance capacitor 13 in the regeneration mode is controlled by controlling the voltage of the large-capacity capacitor 13 using the DCDC converter 12 so that the current flowing through the lead battery 2 becomes zero, in the regeneration mode of the electric motor 4 for traveling and the electric motor 6 for cargo handling, All the regenerative power can be collected on the large-capacity capacitor 13 side.
  • the lead battery 2 having low regenerative power acceptance characteristics is used as the energy source of the traveling electric motor 4 and the cargo handling electric motor 6, the regenerative power can be recovered with high efficiency.
  • the electric motor 6 and the inverter 10 request the controller 11 for electric power necessary for the operation (work) at that time.
  • the controller 11 takes out power from the lead battery 2 and the large-capacity capacitor 13 in accordance with the required power. At that time, also in the power running operation, it is necessary to control the power supply system device 3 with high efficiency as in the above-described regenerative operation.
  • the lead battery 2 has a discharge characteristic equivalent to that of the large-capacitance capacitor 13, and thus, the lead battery 2 and the large-capacitance capacitor 13 are used together to drive the electric motor 4 for traveling and the electric motor 6 for cargo handling.
  • the required power from the inverter 10 is covered. At this time, it is naturally preferable to distribute the power between the lead battery 2 and the large-capacitance capacitor 13 so that the loss during discharging is minimized.
  • the controller 11 estimates the internal resistance of each of the lead battery 2 and the large-capacitance capacitor 13, and satisfies the required power of the electric motor 4 for traveling, the electric motor 6 for cargo handling, and the inverter 10, The burden electric power of the large capacity capacitor 13 is determined.
  • FIG. 4 shows the configuration of the current distribution unit 30 that calculates the power distribution between the lead battery 2 and the large-capacitance capacitor 13 during the power running operation.
  • the current distribution unit 30 of this example includes a required power calculation unit 25, an internal resistance calculation unit 26, and a power distribution unit 27.
  • the current distribution unit 30 is provided in the controller 11.
  • the required power calculation unit 25 inputs the rotation speed and temperature of the electric motor 4 for traveling and the electric motor 6 for cargo handling, the torque command value output from an unillustrated accelerator pedal, lift lift lever, etc., and the temperature of the inverter 10, Calculate the power required from time to time.
  • a more specific configuration of the required power calculation unit 25 is shown in FIG. As is apparent from this figure, the required power calculation unit 25 of this example calculates the output for each of the traveling electric motor 4 and the cargo handling electric motor 6 based on the multiplication of the motor rotational speed and the torque command value.
  • the loss at each motor operating point is calculated by the loss calculators 31 and 32 from the motor temperature and the temperature of the inverter 10, and the motors 4, 6 are calculated. Total output and loss are calculated to obtain the total required power.
  • the internal resistance calculation unit 26 inputs the temperatures of the lead battery 2 and the large capacity capacitor 13 and calculates the internal resistance value for each power storage device.
  • the internal resistance value calculation unit 26 stores internal resistance characteristics with respect to temperature for each of the power storage devices 2 and 13, and the internal resistance value is calculated based on the stored characteristics.
  • the lead battery 2 and the large-capacitance capacitor 13 are connected using the total required power obtained by the required power calculation unit 25 and the internal resistance value obtained by the internal resistance calculation unit 26. Determine power distribution.
  • the loss of the power supply system apparatus 3 is minimized.
  • a loss W loss that occurs when a current is passed through a resistor is expressed by Equation 1 where I is the current and R is the resistance.
  • Equation 1 the loss W loss is proportional to the square of the current I and the resistance value R, respectively. Therefore, in order to minimize the loss W loss , the power share of the power storage device having the smallest resistance R is increased.
  • the capacity of the large-capacity capacitor 13 is on the order of 1/100 of a lead battery, and the power that can be used is limited. Therefore, the condition for enabling power distribution that can minimize loss is when the large-capacitance capacitor 13 stores enough power to cover it, and when the power stored in the large-capacity capacitor 13 decreases. Is the power distribution that minimizes the loss as much as possible in the remaining power range.
  • the DCDC converter 12 is controlled based on the control block of FIG. 3 as in the above-described regenerative operation. That is, the current Ib flowing through the lead battery 2 is detected by the current sensor 14 and fed back to the control system of the DCDC converter 12.
  • the current command Ib * for the lead battery is determined based on the power distribution amount of the lead battery 2 calculated by the power distribution unit 27. For example, a value obtained by dividing the power distribution amount of the lead battery 2 by the voltage value of the lead battery 2 may be used for the current command Ib *.
  • a value obtained by dividing the power distribution amount of the lead battery 2 by the voltage value of the lead battery 2 may be used for the current command Ib *.
  • the electric industrial vehicle of this example is configured such that the internal resistance of the lead battery 2 and the large-capacitance capacitor 13 and the required load power of the electric motors 2 and 4 during the power running operation of the traveling electric motor 4 and the cargo handling electric motor 6. Therefore, the current distribution of the lead battery 2 and the large-capacity capacitor 13 is determined so that the loss of the power supply system device 3 is minimized, so that the power supply system device 3 can be used with high efficiency. Therefore, by combining with a technique for improving the amount of recovered regenerative power by the second power storage means during regeneration, it is possible to increase the drive efficiency of the drive unit during both regeneration and power running. In addition, since the current distribution of the lead battery 2 and the large-capacitance capacitor 13 can be determined without performing a differentiation operation, the burden on the controller can be reduced.
  • the DCDC converter 12 a step-up converter or a step-up / step-down converter can be used.
  • the step-up converter when the voltage of the large-capacitance capacitor 13 becomes equal to or lower than the voltage of the lead battery 2, the upper arm element of the DCDC converter 12 is switched ON, and the electric motors 4, 6 Is switched to the lead battery 2.
  • the DCDC converter 12 when a step-up / step-down converter is used as the DCDC converter 12, the DCDC converter 12 is operated so that the large-capacitance capacitor 13 operates within a predetermined voltage range when the electric motors 4 and 6 are powered. To control.
  • the power supply system device 3 using the lead battery 2 and the large-capacitance capacitor 13 in combination has been described as an example.
  • the combination of the two power storage devices provided in the power supply system device 3 is not limited to this.
  • a combination of the first power storage unit that is inferior in charging characteristics at a short time and a large current and the second power storage unit that is excellent in charging characteristics at a short time and a large current is sufficient.
  • the present invention can be used for an electric industrial vehicle such as a battery-type forklift.

Abstract

Disclosed is an electric industrial vehicle that is provided with a power supply system device that can drive a drive unit in a highly efficient manner during both regeneration and powering by means of a simple computation method. The power supply system device (3) of the electric industrial vehicle is configured from a lead battery (2), a high-capacitance capacitor (13), a DC/DC converter that controls the voltage of the high-capacitance capacitor (13), and a controller (11) that controls the charge and discharge power of the lead battery (2) and the high-capacitance capacitor (13). When the electric motors (4, 6) that are the drive sources of the electric industrial vehicle are performing a powering operation, the controller (11) decides the current distribution of the lead battery (2) and the high-capacitance capacitor (13) on the basis of the internal resistance of the lead battery (2) and the high-capacitance capacitor (13) and the required power load of the electric motors (4, 6) such that losses are minimized in the power supply system device (3).

Description

電動産業車両Electric industrial vehicle
　本発明は、バッテリ式フォークリフト等の電動産業車両に係り、特に、車両各部の駆動源に電源を供給する電源システム装置に関する。 The present invention relates to an electric industrial vehicle such as a battery-type forklift, and more particularly to a power supply system device that supplies power to a drive source of each part of the vehicle.
　近年、環境問題や原油高騰の問題などに対処するため、各工業製品に対して省エネ志向が強まっている。これを受けて、これまでエンジンによる油圧駆動システム装置が中心であった建設や荷役などの各種産業分野で使用される産業車両についても、電動化による高効率化、省エネルギ化の事例が増加してきている。産業車両を電動化した場合、すなわち産業車両の動力源として電動モータを用いた場合、排気ガスの低減のほか、エンジンの高効率駆動（ハイブリッドの場合）、伝達効率の向上、回生電力の回収などの省エネルギ効果が期待できる。 In recent years, in order to cope with environmental problems and the problem of soaring crude oil, energy-saving intentions are increasing for each industrial product. As a result, there have been an increasing number of cases of high efficiency and energy saving by electrification of industrial vehicles used in various industrial fields such as construction and cargo handling, where hydraulic drive system devices using engines have been the main focus. ing. When an industrial vehicle is electrified, that is, when an electric motor is used as a power source for an industrial vehicle, exhaust gas is reduced, the engine is driven with high efficiency (in the case of a hybrid), transmission efficiency is improved, regenerative power is recovered, etc. The energy saving effect can be expected.
　産業車両の中では、倉庫内や工場内で使用されることが多く、排ガスを出さないことが要求されるフォークリフトの電動化がいち早く進んでおり、バッテリの電力を用いて電動モータを駆動する「バッテリ式フォークリフト」が他の産業車両に先駆けて実用化されている。現在既に製品化されているバッテリ式フォークリフトは、電力源に鉛バッテリを使用し、この鉛バッテリの電力を用いて、直接走行用タイヤを電動モータで駆動し、走行を行う。また、荷物の昇降作業を行う荷役装置部分（リフト）においては、電動油圧システム装置が採用されており、専用の荷役モータで油圧ポンプを駆動し、発生した油圧でマスト部に設置された左右の油圧シリンダを作動させる構成となっている。 Among industrial vehicles, they are often used in warehouses and factories, and forklifts that are required not to emit exhaust gas are rapidly becoming electrified. Electric motors are driven using battery power. Battery-powered forklifts have been put into practical use ahead of other industrial vehicles. Battery-type forklifts that have already been commercialized use a lead battery as a power source, and use the electric power of the lead battery to directly drive a driving tire with an electric motor for running. In addition, in the cargo handling device part (lift) that lifts and lowers the cargo, an electro-hydraulic system device is adopted, and the hydraulic pump is driven by a dedicated cargo handling motor, and the left and right installed in the mast part with the generated hydraulic pressure The hydraulic cylinder is activated.
　図６に、従来知られている一般的なバッテリ式フォークリフトの電源システム装置の構成を示す。この図に示すように、本例の電源システム装置３はインバータ１０、鉛バッテリ２、ならびにインバータ１０に指令を与えるコントローラ１１で構成される。バッテリ式フォークリフトのエネルギ源は鉛バッテリ２のみであり、この鉛バッテリ２の直流電力をインバータ１０にて交流電力に変換して、負荷となる走行用電動モータ４及び荷役用電動モータ６を駆動する。電源システム装置３を構成するインバータ１０は、２つのモータ４，６をそれぞれ独立して駆動するため、２つの電力変換器を有している。コントローラ１１は、各モータ４，６から運転者の要求するパワー（特に図示していないが、アクセルやブレーキペダル、ならびに荷役用レバーにより決定される操作量）通りに動力が出力されるように、インバータ１０を介して各モータ４，６を制御する。 FIG. 6 shows the configuration of a power supply system device for a general battery-type forklift that is conventionally known. As shown in this figure, the power supply system device 3 of the present example includes an inverter 10, a lead battery 2, and a controller 11 that gives a command to the inverter 10. The energy source of the battery-type forklift is only the lead battery 2, and the DC power of the lead battery 2 is converted into AC power by the inverter 10 to drive the electric motor 4 for traveling and the electric motor 6 for cargo handling. . The inverter 10 constituting the power supply system device 3 has two power converters in order to drive the two motors 4 and 6 independently. The controller 11 outputs power according to the power required by the driver from the motors 4 and 6 (the operation amount determined by the accelerator, the brake pedal, and the cargo handling lever, although not particularly shown). The motors 4 and 6 are controlled via the inverter 10.
　バッテリ式フォークリフトは、走行動作時に加減速を頻繁に繰り返しており、制動時には走行用電動モータ４により電気ブレーキがかけられるので、走行動作時において、かなりの量の回生電力を発生している。また、現状では、リフトを用いて持ち上げられた荷物を下降する際、油圧シリンダ内の圧油をリリースして、リフトに蓄えられた位置エネルギを廃棄してしまっているが、このリフトの位置エネルギを利用して発電機を回す構成とすれば、回生電力としてエネルギを回収することも可能である。このように、バッテリ式フォークリフトでは、その動作内容からかなりの量の回生電力が発生できることがわかる。 The battery-type forklift frequently repeats acceleration / deceleration during traveling operation, and an electric brake is applied by the traveling electric motor 4 during braking. Therefore, a considerable amount of regenerative power is generated during traveling operation. At present, when lowering a load lifted using a lift, the hydraulic oil in the hydraulic cylinder is released and the potential energy stored in the lift is discarded. If it is set as the structure which rotates a generator using, it is also possible to collect | recover energy as regenerative electric power. Thus, it can be seen that a battery-type forklift can generate a considerable amount of regenerative power from its operation.
　しかしながら、バッテリ式フォークリフトに使用されている鉛バッテリは、電動モータの回生電力等の短時間大電流での充電特性には優れていないので、電動モータの回生電力等を直接鉛バッテリに印加しても、ほとんどが損失になってしまい、回生電力等を有効利用することができない。そこで、最近では、鉛バッテリの低急速充電特性を補うために、大容量のキャパシタなどを併用して、電動モータやリフトからの回生電力の回収量を改善する技術が提案されている。 However, lead batteries used in battery-powered forklifts are not excellent in charging characteristics with short-time high currents such as regenerative power of electric motors, so apply regenerative power of electric motors directly to lead batteries. However, most of them are lost, and regenerative power cannot be used effectively. Therefore, recently, in order to compensate for the low rapid charging characteristics of the lead battery, a technique for improving the recovery amount of regenerative electric power from an electric motor or a lift by using a large-capacity capacitor has been proposed.
　鉛バッテリに大容量のキャパシタを併用する技術は、これまでいくつかの事例が報告されている。その中でも、バッテリに対しＤＣＤＣコンバータを介して大容量キャパシタを並列接続したシステム装置において、キャパシタの内部抵抗をゼロとみなせるような電流指令を演算し、その電流がキャパシタに流れるように制御するものが、効率よく回生電力を回収する技術として特に注目される（非特許文献１参照。）。 There have been several examples of technology that uses large capacity capacitors in combination with lead batteries. Among them, in a system device in which a large-capacity capacitor is connected in parallel to a battery via a DCDC converter, a current command is calculated so that the internal resistance of the capacitor can be regarded as zero, and control is performed so that the current flows through the capacitor. In particular, it is attracting attention as a technique for efficiently recovering regenerative power (see Non-Patent Document 1).
　しかしながら、非特許文献１に記載の技術は、回生を行う際のキャパシタに流れる電流指令の演算方法として、バッテリ電圧に対する微分演算を用いているので、高い演算性能を有するコントローラを備えることが要求される。また、非特許文献１には、電力放電時の制御方法が開示されておらず、放電時にも効率のよい駆動が可能になるとはいえないので、この点に改良の余地がある。 However, since the technique described in Non-Patent Document 1 uses a differential operation on the battery voltage as a method for calculating the current command flowing through the capacitor during regeneration, it is required to include a controller having high calculation performance. The Further, Non-Patent Document 1 does not disclose a control method during power discharge, and it cannot be said that efficient driving is possible even during discharge, so there is room for improvement in this respect.
　本発明は、このような従来技術の現状に鑑みてなされたものであり、その目的は、簡便な演算方法により、回生（充電）時及び力行（放電）時の双方において駆動部を高効率に駆動可能な電源システム装置を備えた電動産業車両を提供することにある。 The present invention has been made in view of the current state of the prior art, and an object of the present invention is to make the drive unit highly efficient both during regeneration (charging) and during power running (discharging) by a simple calculation method. An object of the present invention is to provide an electric industrial vehicle equipped with a drivable power supply system device.
　本発明は、前記課題を解決するため、車両の駆動部を駆動する電動モータと、該電動モータにモータ駆動電力を供給する電源システム装置とを備えた電動産業車両であって、前記電源システム装置が、短時間大電流での充電特性に劣る第１蓄電手段と、短時間大電流での充電特性に優れた第２蓄電手段と、該第２蓄電手段の電圧制御を行うＤＣＤＣコンバータと、前記第１蓄電手段及び前記第２蓄電手段の充放電電力を制御するコントローラとを備えたものからなる電動産業車両において、前記コントローラは、前記電動モータの力行動作時に、前記第１蓄電手段及び前記第２蓄電手段の各内部抵抗と前記電動モータの負荷要求電力に基づいて、前記電源システム装置の損失が最小となるように、前記第１蓄電手段及び前記第２蓄電手段の電流配分を決定するという構成にした。 In order to solve the above problems, the present invention is an electric industrial vehicle including an electric motor that drives a drive unit of a vehicle, and a power supply system device that supplies motor drive power to the electric motor, the power supply system device A first power storage means that is inferior in charging characteristics at a short time and a large current, a second power storage means that is excellent in charging characteristics at a short time and a large current, a DCDC converter that performs voltage control of the second power storage means, In an electric industrial vehicle comprising a controller for controlling charge / discharge power of the first power storage means and the second power storage means, the controller is configured to operate the first power storage means and the first power during a power running operation of the electric motor. 2 Based on each internal resistance of the power storage means and the load demand power of the electric motor, the first power storage means and the second power storage means And the configuration of determining the flow distribution.
　かかる構成によると、電動モータの力行動作時に、第１及び第２の蓄電手段の内部抵抗と電動モータの負荷要求電力に基づいて、電源システム装置の損失が最小となるように、第１蓄電手段及び第２蓄電手段の電流配分を決定するので、電源システム装置の高効率な利用が可能になる。よって、回生時における第２蓄電手段による回生電力の回収量を改善する技術と組合わせることにより、回生時と力行時、双方における駆動部の駆動を高効率化することができる。また、第１及び第２の蓄電手段の内部抵抗と電動モータの負荷要求電力に基づいて第１蓄電手段及び第２蓄電手段の電流配分を決定するので、微分演算を行うことなく第１蓄電手段及び第２蓄電手段の電流配分を決定することができ、コントローラの負担を軽減することができる。 According to this configuration, the first power storage unit is configured so that the loss of the power supply system device is minimized based on the internal resistances of the first and second power storage units and the required load power of the electric motor during the power running operation of the electric motor. Since the current distribution of the second power storage means is determined, the power supply system apparatus can be used with high efficiency. Therefore, by combining with a technique for improving the amount of recovered regenerative power by the second power storage means during regeneration, it is possible to increase the drive efficiency of the drive unit during both regeneration and power running. Further, since the current distribution of the first power storage means and the second power storage means is determined based on the internal resistances of the first and second power storage means and the load demand power of the electric motor, the first power storage means is performed without performing a differential operation. And the current distribution of the second power storage means can be determined, and the burden on the controller can be reduced.
　また本発明は、前記構成の電動産業車両において、前記コントローラは、前記電動モータの回生動作時に、前記第２蓄電手段にのみ前記電動モータからの回生電力が流れるように、前記ＤＣＤＣコンバータを制御するという構成にした。 According to the present invention, in the electric industrial vehicle having the above-described configuration, the controller controls the DCDC converter so that the regenerative power from the electric motor flows only in the second power storage unit during the regenerative operation of the electric motor. It was configured as follows.
　第２蓄電手段は、短時間大電流での充電特性に優れているので、かかる構成とすることにより、回生電力を効率良く回収することができる。 Since the second power storage means is excellent in charging characteristics with a large current for a short time, by adopting such a configuration, it is possible to efficiently recover regenerative power.
　また本発明は、前記構成の電動産業車両において、前記コントローラは、前記電動モータの回生動作時に、前記第１蓄電手段に流す電流指令値をゼロとし、この電流指令値と前記第１蓄電手段に流れる電流値との偏差がゼロになるように、前記ＤＣＤＣコンバータをフィードバック制御するという構成にした。 According to the present invention, in the electric industrial vehicle having the above-described configuration, the controller sets a current command value to be supplied to the first power storage unit during the regenerative operation of the electric motor to zero, and sets the current command value and the first power storage unit to The DCDC converter is configured to be feedback-controlled so that the deviation from the flowing current value becomes zero.
　かかる構成によると、第１蓄電手段に流す電流指令値に対して第１蓄電手段に流れる電流値を加減算するだけでＤＣＤＣコンバータをフィードバック制御できるので、コントローラの負担を軽減することができる。 According to this configuration, the DCDC converter can be feedback controlled simply by adding or subtracting the current value flowing through the first power storage unit with respect to the current command value flowing through the first power storage unit, so that the burden on the controller can be reduced.
　また本発明は、前記構成の電動産業車両において、前記第１蓄電手段が鉛バッテリであり、前記第２蓄電手段が大容量キャパシタであるという構成にした。 Further, according to the present invention, in the electric industrial vehicle having the above configuration, the first power storage unit is a lead battery, and the second power storage unit is a large capacity capacitor.
　鉛バッテリ及び大容量キャパシタを用いた電動産業車両は、技術的に確立しているので、かかる構成とすることにより、信頼性に優れた電動産業車両を実現できる。 Since the electric industrial vehicle using the lead battery and the large-capacity capacitor has been technically established, an electric industrial vehicle having excellent reliability can be realized by adopting such a configuration.
　本発明によれば、簡便な演算方法により、回生動作時及び力行動作時の双方において高効率駆動が可能な電源システム装置を備えた電動産業車両を提供することができる。 According to the present invention, it is possible to provide an electric industrial vehicle equipped with a power supply system device capable of high-efficiency driving both during regenerative operation and powering operation by a simple calculation method.
一般的なバッテリ式フォークリフトの構成図である。It is a block diagram of a general battery-type forklift. 実施形態に係るバッテリ式フォークリフト用電源システム装置の構成を示すブロック図である。It is a block diagram which shows the structure of the power supply system apparatus for battery-type forklifts which concerns on embodiment. 実施形態に係るバッテリ式フォークリフト用電源システム装置に備えられるＤＣＤＣコンバータ制御部の構成を示すブロック図である。It is a block diagram which shows the structure of the DCDC converter control part with which the power supply system apparatus for battery-type forklifts which concerns on embodiment is equipped. 実施形態に係るバッテリ式フォークリフト用電源システム装置に備えられる要求電力演算部の構成を示すブロック図ある。It is a block diagram which shows the structure of the request | requirement power calculating part with which the battery-type forklift power supply system apparatus which concerns on embodiment is equipped. 実施形態に係るバッテリ式フォークリフト用電源システム装置に備えられる電流分配部の構成を示すブロック図である。It is a block diagram which shows the structure of the electric current distribution part with which the battery-type forklift power supply system apparatus which concerns on embodiment is equipped. 従来例に係るバッテリ式フォークリフト用電源システム装置の構成図である。It is a block diagram of the power supply system apparatus for battery-type forklifts which concerns on a prior art example.
　以下、本発明に係る電動産業車両の実施形態を、バッテリ式フォークリフトを例にとり説明する。 Hereinafter, embodiments of the electric industrial vehicle according to the present invention will be described by taking a battery-type forklift as an example.
　図１に示すように、実施形態に係るバッテリ式フォークリフト１は、走行用電動モータ４により駆動される駆動輪（タイヤ）５と、荷役用電動モータ６により駆動されるポンプ７と、ポンプ７から吐出される圧油にて駆動される油圧シリンダ８と、油圧シリンダ８の伸縮に応じて上昇又は下降するリフト９とを備えている。また、このバッテリ式フォークリフト１には、走行用電動モータ４及び荷役用電動モータ６のエネルギ源として鉛バッテリ２を備えており、鉛バッテリ２に蓄えられた電力は、電源システム装置３により、走行用電動モータ４及び荷役用電動モータ６に対して、それらの各要求パワーに応じた配分で配給される。したがって、実施形態に係るバッテリ式フォークリフト１は、走行用電動モータ４で駆動輪５を回転駆動することによって走行することができ、荷役用電動モータ６でポンプ７を回転駆動し、ポンプ７から吐出される圧油の流れを図示しない方向切換弁などで切り換えて、油圧シリンダ８を伸長又は収縮することによって荷物の上げ下ろしをすることができる。 As shown in FIG. 1, a battery-type forklift 1 according to an embodiment includes a driving wheel (tire) 5 driven by an electric motor 4 for traveling, a pump 7 driven by an electric motor 6 for cargo handling, and a pump 7. A hydraulic cylinder 8 driven by the discharged pressure oil and a lift 9 that rises or falls according to the expansion and contraction of the hydraulic cylinder 8 are provided. The battery-type forklift 1 is provided with a lead battery 2 as an energy source for the electric motor 4 for traveling and the electric motor 6 for cargo handling, and the electric power stored in the lead battery 2 is traveled by the power supply system device 3. The electric motor 4 and the cargo handling electric motor 6 are distributed in accordance with their respective required powers. Therefore, the battery-type forklift 1 according to the embodiment can travel by rotating the drive wheels 5 with the electric motor 4 for traveling, and the pump 7 is rotationally driven with the electric motor 6 for cargo handling and discharged from the pump 7. The flow of the pressurized oil is switched by a direction switching valve (not shown) or the like, and the hydraulic cylinder 8 can be extended or contracted to raise or lower the load.
　電源システム装置３は、図２に示すように、インバータ１０に対して並列に接続された鉛バッテリ２及び大容量キャパシタ１３と、大容量キャパシタ１３に印加される電圧値を調整するＤＣＤＣコンバータ１２と、鉛バッテリ２に流れる電流を検出するカレントセンサ１４と、カレントセンサ１４に流れる電流に応じてＤＣＤＣコンバータ１２を制御すると共に、インバータ１０に指令を与えるコントローラ１１とから構成されている。 As shown in FIG. 2, the power supply system device 3 includes a lead battery 2 and a large capacity capacitor 13 connected in parallel to the inverter 10, and a DCDC converter 12 that adjusts a voltage value applied to the large capacity capacitor 13. The current sensor 14 detects the current flowing through the lead battery 2 and the controller 11 controls the DCDC converter 12 according to the current flowing through the current sensor 14 and gives a command to the inverter 10.
　この電源システム装置は、回生電力が発生した場合に、鉛バッテリ２にはその回生電力を流さず、大容量キャパシタ１３にのみ電力を回収する。その際、コントローラ１１は、図３に示すように、鉛バッテリ２に流れる電流Ｉｂをカレントセンサ１４により検出し、ＤＣＤＣコンバータ１２の制御系にフィードバックさせて、回生電力の回生制御を行う。即ち、コントローラ１１が現在「回生動作」であると判断した場合には、鉛バッテリ２に流す電流指令Ｉｂ＊をゼロとして、カレントセンサ１４の検出値Ｉｂを電流指令Ｉｂ＊にフィードバックする。そして、この電流指令Ｉｂ＊と検出値Ｉｂとの偏差ΔＩｂがゼロとなるように制御器２０で比例積分などの制御演算を行い、大容量キャパシタ１３の目標電圧ＶＣ＊を算出する。さらに、大容量キャパシタ１３の目標電圧ＶＣ＊をＤＣＤＣコンバータ電圧制御系２１に入力して、ＤＣＤＣコンバータ１２による大容量キャパシタ１３の電圧制御を行う。 When the regenerative power is generated, the power supply system apparatus collects the power only in the large capacity capacitor 13 without flowing the regenerative power through the lead battery 2. At that time, as shown in FIG. 3, the controller 11 detects the current Ib flowing through the lead battery 2 by the current sensor 14, feeds it back to the control system of the DCDC converter 12, and performs regenerative power regenerative control. That is, when the controller 11 determines that the current operation is “regenerative operation”, the current command Ib * to be passed through the lead battery 2 is set to zero, and the detection value Ib of the current sensor 14 is fed back to the current command Ib * . Then, the controller 20 performs a control operation such as proportional integration so that the deviation ΔIb between the current command Ib * and the detected value Ib becomes zero, and calculates the target voltage VC * of the large-capacitance capacitor 13. Further, the target voltage VC * of the large-capacity capacitor 13 is input to the DCDC converter voltage control system 21, and the voltage control of the large-capacity capacitor 13 by the DCDC converter 12 is performed.
　以上が、回生モードにおける、大容量キャパシタ１３を併用した電源システム装置３の制御動作例である。このように、鉛バッテリ２に流れる電流がゼロとなるようにＤＣＤＣコンバータ１２を用いて大容量キャパシタ１３の電圧を制御することにより、走行用電動モータ４及び荷役用電動モータ６の回生モードにおいて、回生電力をすべて大容量キャパシタ１３側に回収することが可能となる。これにより、走行用電動モータ４及び荷役用電動モータ６のエネルギ源として、回生電力の受け入れ特性が低い鉛バッテリ２を用いる場合にも、高効率に回生電力の回収が可能となる。 The above is an example of the control operation of the power supply system apparatus 3 using the large-capacitance capacitor 13 in the regeneration mode. Thus, by controlling the voltage of the large-capacity capacitor 13 using the DCDC converter 12 so that the current flowing through the lead battery 2 becomes zero, in the regeneration mode of the electric motor 4 for traveling and the electric motor 6 for cargo handling, All the regenerative power can be collected on the large-capacity capacitor 13 side. As a result, even when the lead battery 2 having low regenerative power acceptance characteristics is used as the energy source of the traveling electric motor 4 and the cargo handling electric motor 6, the regenerative power can be recovered with high efficiency.
　一方、走行用電動モータ４からトルクを発生させて、バッテリ式フォークリフト１を走行したり、荷役用電動モータ６からトルクを発生させてリフト９を昇降する力行動作時には、走行用電動モータ４、荷役用電動モータ６及びインバータ１０が、そのときの動作（作業）に必要な電力をコントローラ１１に要求する。コントローラ１１は、この要求電力に応じて鉛バッテリ２及び大容量キャパシタ１３より電力を取りだす。その際、力行動作においても、前述の回生動作と同様に、高効率で電源システム装置３を制御することが必要である。前述の回生動作では、鉛バッテリ２の回生電力受け入れ特性が低いために、発生する回生電力のすべてを大容量キャパシタ１３で回収するように制御した。これに対して、力行動作では、鉛バッテリ２は大容量キャパシタ１３と同等の放電特性を有するため、鉛バッテリ２と大容量キャパシタ１３を併用して、走行用電動モータ４、荷役用電動モータ６及びインバータ１０からの要求パワーを賄うようにする。このとき、鉛バッテリ２と大容量キャパシタ１３の電力分配は、当然ながら放電時の損失が最小となるように分配することが好ましい。そこで、コントローラ１１は、鉛バッテリ２と大容量キャパシタ１３の各々の内部抵抗を推定し、走行用電動モータ４、荷役用電動モータ６及びインバータ１０の要求パワーを満足するように、鉛バッテリ２と大容量キャパシタ１３の負担電力を決定する。 On the other hand, during the powering operation of generating torque from the traveling electric motor 4 to travel the battery-type forklift 1 or generating torque from the cargo handling electric motor 6 to move the lift 9 up and down, The electric motor 6 and the inverter 10 request the controller 11 for electric power necessary for the operation (work) at that time. The controller 11 takes out power from the lead battery 2 and the large-capacity capacitor 13 in accordance with the required power. At that time, also in the power running operation, it is necessary to control the power supply system device 3 with high efficiency as in the above-described regenerative operation. In the regenerative operation described above, since the regenerative power acceptance characteristic of the lead battery 2 is low, control is performed so that all of the generated regenerative power is recovered by the large-capacitance capacitor 13. On the other hand, in the power running operation, the lead battery 2 has a discharge characteristic equivalent to that of the large-capacitance capacitor 13, and thus, the lead battery 2 and the large-capacitance capacitor 13 are used together to drive the electric motor 4 for traveling and the electric motor 6 for cargo handling. In addition, the required power from the inverter 10 is covered. At this time, it is naturally preferable to distribute the power between the lead battery 2 and the large-capacitance capacitor 13 so that the loss during discharging is minimized. Therefore, the controller 11 estimates the internal resistance of each of the lead battery 2 and the large-capacitance capacitor 13, and satisfies the required power of the electric motor 4 for traveling, the electric motor 6 for cargo handling, and the inverter 10, The burden electric power of the large capacity capacitor 13 is determined.
　図４に、力行動作時における鉛バッテリ２と大容量キャパシタ１３の電力分配を演算する電流分配部３０の構成を示す。この図から明らかなように、本例の電流分配部３０は、要求電力演算部２５と、内部抵抗演算部２６と、電力分配部２７とからなる。なお、この電流分配部３０は、コントローラ１１内に設けられる。 FIG. 4 shows the configuration of the current distribution unit 30 that calculates the power distribution between the lead battery 2 and the large-capacitance capacitor 13 during the power running operation. As is clear from this figure, the current distribution unit 30 of this example includes a required power calculation unit 25, an internal resistance calculation unit 26, and a power distribution unit 27. The current distribution unit 30 is provided in the controller 11.
　要求電力演算部２５は、走行用電動モータ４及び荷役用電動モータ６の回転数及び温度、図示しないアクセルペダルやリフト昇降レバー等から出力されるトルク指令値、並びにインバータ１０の温度を入力し、その時々で必要な電力を演算する。この要求電力演算部２５のより具体的な構成を図５に示す。この図から明らかなように、本例の要求電力演算部２５は、走行用電動モータ４及び荷役用電動モータ６のそれぞれについて、モータ回転数とトルク指令値の乗算に基づいて出力を演算すると共に、走行用電動モータ４及び荷役用電動モータ６のそれぞれについて、そのモータ温度とインバータ１０の温度とから損失演算部３１，３２にて各モータ動作点での損失を演算し、各モータ４，６の出力と損失を合計して、全要求電力を求める。 The required power calculation unit 25 inputs the rotation speed and temperature of the electric motor 4 for traveling and the electric motor 6 for cargo handling, the torque command value output from an unillustrated accelerator pedal, lift lift lever, etc., and the temperature of the inverter 10, Calculate the power required from time to time. A more specific configuration of the required power calculation unit 25 is shown in FIG. As is apparent from this figure, the required power calculation unit 25 of this example calculates the output for each of the traveling electric motor 4 and the cargo handling electric motor 6 based on the multiplication of the motor rotational speed and the torque command value. For each of the electric motor 4 for traveling and the electric motor 6 for cargo handling, the loss at each motor operating point is calculated by the loss calculators 31 and 32 from the motor temperature and the temperature of the inverter 10, and the motors 4, 6 are calculated. Total output and loss are calculated to obtain the total required power.
　内部抵抗演算部２６は、図４に示すように、鉛バッテリ２及び大容量キャパシタ１３の温度を入力して、各蓄電装置についての内部抵抗値を算出する。内部抵抗値演算部２６には、各蓄電装置２，１３に関し、温度に対する内部抵抗特性が記憶されており、この記憶された特性に基づいて内部抵抗値が算出される。 As shown in FIG. 4, the internal resistance calculation unit 26 inputs the temperatures of the lead battery 2 and the large capacity capacitor 13 and calculates the internal resistance value for each power storage device. The internal resistance value calculation unit 26 stores internal resistance characteristics with respect to temperature for each of the power storage devices 2 and 13, and the internal resistance value is calculated based on the stored characteristics.
　図４の電力配分部２７では、要求電力演算部２５にて求められた全要求電力と、内部抵抗演算部２６にて求められた内部抵抗値を用いて、鉛バッテリ２と大容量キャパシタ１３の電力分配を決定する。このときの電力配分方法としては、電源システム装置３の損失が最小になるようにすることが好ましい。一般に、抵抗体に電流を流した際に発生する損失Ｗｌｏｓｓは、電流をＩ、抵抗をＲとすると、数１で表される。 In the power distribution unit 27 of FIG. 4, the lead battery 2 and the large-capacitance capacitor 13 are connected using the total required power obtained by the required power calculation unit 25 and the internal resistance value obtained by the internal resistance calculation unit 26. Determine power distribution. As a power distribution method at this time, it is preferable that the loss of the power supply system apparatus 3 is minimized. In general, a loss W loss that occurs when a current is passed through a resistor is expressed by Equation 1 where I is the current and R is the resistance.
　　　　Ｗｌｏｓｓ＝Ｉ２×Ｒ　　　　　・・・（数１）
　数１から明らかなように、損失Ｗｌｏｓｓは、電流Ｉの２乗及び抵抗値Ｒのそれぞれに比例する。よって損失Ｗｌｏｓｓを最小にするためには、できるだけ抵抗Ｒが小さい蓄電装置の電力分担分を増やすようにする。 W loss = I 2 × R (Equation 1)
As is clear from Equation 1, the loss W loss is proportional to the square of the current I and the resistance value R, respectively. Therefore, in order to minimize the loss W loss , the power share of the power storage device having the smallest resistance R is increased.
　但し、大容量キャパシタ１３の容量は、鉛バッテリの１/１００程度のオーダであり、使用できる電力は限りがある。よって、損失を最小にできる電力配分が可能な条件は、それを賄える程度の電力を大容量キャパシタ１３が蓄えているときであり、大容量キャパシタ１３に蓄えられている電力が減少してきた場合には、残された電力の範囲で可能な限り損失を最小にする電力配分とする。電力配分決定後は、前述の回生動作時と同様に、図３の制御ブロックに基づいてＤＣＤＣコンバータ１２の制御を行う。即ち、鉛バッテリ２に流れる電流Ｉｂをカレントセンサ１４により検出し、ＤＣＤＣコンバータ１２の制御系にフィードバックさせる。このとき、鉛バッテリの電流指令Ｉｂ＊は、電力配分部２７にて算出された鉛バッテリ２の電力配分量に基づいて決定される。例えば、鉛バッテリ２の電力配分量を鉛バッテリ２の電圧値で除した値を電流指令Ｉｂ＊に用いればよい。以上のように、配分された２つの電力のうち、鉛バッテリ２に流れる電流のみを制御することにより、要求電力と鉛バッテリ２の電力の差分を、自動的に大容量キャパシタ１３から負担することができるようになる。 However, the capacity of the large-capacity capacitor 13 is on the order of 1/100 of a lead battery, and the power that can be used is limited. Therefore, the condition for enabling power distribution that can minimize loss is when the large-capacitance capacitor 13 stores enough power to cover it, and when the power stored in the large-capacity capacitor 13 decreases. Is the power distribution that minimizes the loss as much as possible in the remaining power range. After the power distribution is determined, the DCDC converter 12 is controlled based on the control block of FIG. 3 as in the above-described regenerative operation. That is, the current Ib flowing through the lead battery 2 is detected by the current sensor 14 and fed back to the control system of the DCDC converter 12. At this time, the current command Ib * for the lead battery is determined based on the power distribution amount of the lead battery 2 calculated by the power distribution unit 27. For example, a value obtained by dividing the power distribution amount of the lead battery 2 by the voltage value of the lead battery 2 may be used for the current command Ib *. As described above, by controlling only the current flowing in the lead battery 2 out of the two distributed powers, the difference between the required power and the power of the lead battery 2 is automatically borne from the large capacity capacitor 13. Will be able to.
　このように、本例の電動産業車両は、走行用電動モータ４及び荷役用電動モータ６の力行動作時に、鉛バッテリ２及び大容量キャパシタ１３の内部抵抗と各電動モータ２，４の負荷要求電力に基づいて、電源システム装置３の損失が最小となるように、鉛バッテリ２及び大容量キャパシタ１３の電流配分を決定するので、電源システム装置３の高効率な利用が可能になる。よって、回生時における第２蓄電手段による回生電力の回収量を改善する技術と組合わせることにより、回生時と力行時、双方における駆動部の駆動を高効率化することができる。また、微分演算を行うことなく鉛バッテリ２及び大容量キャパシタ１３の電流配分を決定できるので、コントローラの負担を軽減することができる。 As described above, the electric industrial vehicle of this example is configured such that the internal resistance of the lead battery 2 and the large-capacitance capacitor 13 and the required load power of the electric motors 2 and 4 during the power running operation of the traveling electric motor 4 and the cargo handling electric motor 6. Therefore, the current distribution of the lead battery 2 and the large-capacity capacitor 13 is determined so that the loss of the power supply system device 3 is minimized, so that the power supply system device 3 can be used with high efficiency. Therefore, by combining with a technique for improving the amount of recovered regenerative power by the second power storage means during regeneration, it is possible to increase the drive efficiency of the drive unit during both regeneration and power running. In addition, since the current distribution of the lead battery 2 and the large-capacitance capacitor 13 can be determined without performing a differentiation operation, the burden on the controller can be reduced.
　なお、ＤＣＤＣコンバータ１２としては、昇圧型の変換器を用いることもできるし、昇降圧型の変換器を用いることもできる。昇圧型の変換器を用いた場合には、大容量キャパシタ１３の電圧が鉛バッテリ２の電圧以下になったときに、ＤＣＤＣコンバータ１２の上側アーム素子をＯＮに切り換えて、各電動モータ４，６への電力供給を鉛バッテリ２に切り換える。また、ＤＣＤＣコンバータ１２として、昇降圧型の変換器を用いた場合には、各電動モータ４，６の力行動作時において、大容量キャパシタ１３が所定の電圧範囲内で動作するように、ＤＣＤＣコンバータ１２を制御する。 Note that, as the DCDC converter 12, a step-up converter or a step-up / step-down converter can be used. When the step-up converter is used, when the voltage of the large-capacitance capacitor 13 becomes equal to or lower than the voltage of the lead battery 2, the upper arm element of the DCDC converter 12 is switched ON, and the electric motors 4, 6 Is switched to the lead battery 2. Further, when a step-up / step-down converter is used as the DCDC converter 12, the DCDC converter 12 is operated so that the large-capacitance capacitor 13 operates within a predetermined voltage range when the electric motors 4 and 6 are powered. To control.
　また、本実施例では鉛バッテリ２と大容量キャパシタ１３を併用した電源システム装置３を例にとって説明したが、電源システム装置３に備えられる２つの蓄電装置の組合せは、これに限定されるものではなく、短時間大電流での充電特性に劣る第１蓄電手段と、短時間大電流での充電特性に優れた第２蓄電手段との組合せであれば足りる。 In the present embodiment, the power supply system device 3 using the lead battery 2 and the large-capacitance capacitor 13 in combination has been described as an example. However, the combination of the two power storage devices provided in the power supply system device 3 is not limited to this. However, a combination of the first power storage unit that is inferior in charging characteristics at a short time and a large current and the second power storage unit that is excellent in charging characteristics at a short time and a large current is sufficient.
　本発明は、バッテリ式フォークリフト等の電動産業車両に利用することができる。 The present invention can be used for an electric industrial vehicle such as a battery-type forklift.
　１　　バッテリ式フォークリフト
　２　　鉛バッテリ
　３　　電源システム装置
　４　　走行用電動モータ
　６　　荷役用電動モータ
　９　　リフト
　１０　　インバータ
　１１　　コントローラ
　１２　　ＤＣＤＣコンバータ
　１３　　大容量キャパシタ
　２５　　要求電力演算部
　２６　　内部抵抗演算部
　２７　　電力分配部
　３０　　電流分配部
　３１，３２　　損失演算部 DESCRIPTION OF SYMBOLS 1 Battery type forklift 2 Lead battery 3 Power supply system apparatus 4 Electric motor for driving 6 Electric motor for cargo handling 9 Lift 10 Inverter 11 Controller 12 DCDC converter 13 Large capacity capacitor 25 Required power calculation part 26 Internal resistance calculation part 27 Power distribution part 30 Current Distribution unit 31, 32 Loss calculation unit

Claims (4)

  1. 　車両の駆動部を駆動する電動モータと、該電動モータにモータ駆動電力を供給する電源システム装置とを備えた電動産業車両であって、前記電源システム装置が、短時間大電流での充電特性に劣る第１蓄電手段と、短時間大電流での充電特性に優れた第２蓄電手段と、該第２蓄電手段の電圧制御を行うＤＣＤＣコンバータと、前記第１蓄電手段及び前記第２蓄電手段の充放電電力を制御するコントローラとを備えたものからなる電動産業車両において、
    　前記コントローラは、前記電動モータの力行動作時に、前記第１蓄電手段及び前記第２蓄電手段の各内部抵抗と前記電動モータの負荷要求電力に基づいて、前記電源システム装置の損失が最小となるように、前記第１蓄電手段及び前記第２蓄電手段の電流配分を決定することを特徴とする電動産業車両。     An electric industrial vehicle including an electric motor that drives a driving unit of a vehicle and a power supply system device that supplies motor driving power to the electric motor, wherein the power supply system device has a charging characteristic with a large current for a short time. A first power storage unit that is inferior, a second power storage unit that is excellent in charging characteristics with a large current for a short time, a DCDC converter that performs voltage control of the second power storage unit, the first power storage unit, and the second power storage unit In an electric industrial vehicle comprising a controller for controlling charge / discharge power,
    In the power running operation of the electric motor, the controller minimizes the loss of the power supply system device based on the internal resistances of the first power storage unit and the second power storage unit and the required load power of the electric motor. And determining the current distribution between the first power storage means and the second power storage means.
  2. 　前記コントローラは、前記電動モータの回生動作時に、前記第２蓄電手段にのみ前記電動モータからの回生電力が流れるように、前記ＤＣＤＣコンバータを制御することを特徴とする請求項１に記載の電動産業車両。 2. The electric industry according to claim 1, wherein the controller controls the DCDC converter so that regenerative power from the electric motor flows only in the second power storage unit during a regenerative operation of the electric motor. vehicle.
  3. 　前記コントローラは、前記電動モータの回生動作時に、前記第１蓄電手段に流す電流指令値をゼロとし、この電流指令値と前記第１蓄電手段に流れる電流値との偏差がゼロになるように、前記ＤＣＤＣコンバータをフィードバック制御することを特徴とする請求項２に記載の電動産業車両。 The controller sets the current command value that flows to the first power storage means to zero during the regenerative operation of the electric motor, and the deviation between the current command value and the current value that flows to the first power storage means becomes zero. The electric industrial vehicle according to claim 2, wherein the DCDC converter is feedback-controlled.
  4. 　前記第１蓄電手段が鉛バッテリであり、前記第２蓄電手段が大容量キャパシタであることを特徴とする請求項１乃至請求項３のいずれか１項に記載の電動産業車両。 The electric industrial vehicle according to any one of claims 1 to 3, wherein the first power storage means is a lead battery, and the second power storage means is a large-capacity capacitor.
PCT/JP2010/064012 2009-08-26 2010-08-19 Electric industrial vehicle WO2011024707A1 (en)

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