SYSTEM FOR THE ENERGY MANAGEMENT OF BATTERY-POWERED FLOOR CONVEYORS

Description

[0001] The present invention relates to a system for energy management of battery-powered industrial trucks, which includes an energy control unit.

[0002] The present invention relates to optimizing energy use and thereby reducing costs in the operation of battery-powered industrial trucks. Particularly with the increasing use of renewable energies, the current price of electricity can fluctuate considerably, even throughout the day. Furthermore, electrical supply networks are increasingly reliant on intelligent consumers to ensure grid stability and quality.

[0003] From DE 10 2012 212 878 A1, an energy supply system with a solar energy generation device and an energy storage device is known, wherein the charging and discharging of the energy storage device is controlled in accordance with a predetermined charging-discharging plan.

[0004] From WO 2011 / 092821 A1 a method has become known in which the amount of energy called up from a power grid is determined depending on the electricity costs, the required amount of energy, the locally generated energy and the state of charge of an energy storage device.

[0005] From US 10,011,183 B2 a method for charging an electrically powered vehicle has become known in which the vehicle is charged from a local energy source, depending on the expected operation of the electrically powered industrial truck.

[0006] German patent application DE 10 2017 128 590 A1 discloses a method for coordinating the charging processes of the batteries of several industrial trucks, wherein a central control unit wirelessly receives operating data from the batteries and monitors the occupancy status of several chargers. Depending on the operating data of the batteries and the occupancy of the chargers, the central control unit wirelessly transmits a charging authorization to industrial trucks not connected to the chargers. This wirelessly exchanged operating data also includes the current charge states of the batteries of the industrial trucks.

[0007] When using battery-powered industrial trucks, it is known to connect them to a warehouse management system (WMS) via a control system. It is also known that automated guided vehicles (AGVs) automatically travel to a charging station for recharging when their electrical battery is depleted.

[0008] The invention is based on the objective of providing an energy management system for battery-powered industrial trucks that integrates existing systems and simultaneously optimizes the charging and use of the industrial trucks.

[0009] According to the invention, the problem is solved by an energy management system with the features of claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0010] The energy management system according to the invention has the features of claim 1. The system is designed and suitable for coordinating the energy withdrawal from the electrical supply network for a large number of battery-powered industrial trucks. For this purpose, an energy control unit is provided, which receives data on the current state of charge of the batteries of several industrial trucks, data on the anticipated demand for industrial trucks, and data on the occupancy of charging stations. This data thus relates to the electrical energy currently stored in the industrial trucks, the expected energy demand of the industrial trucks, and the availability of the charging stations. The energy control unit is designed to determine, based on this data, when a particular industrial truck needs to be charged and can also determine when it can be deployed to meet the anticipated demand for industrial trucks.The energy management system according to the invention goes significantly beyond simple charging management, which determines a charging time based on the battery's state of charge. The system also takes into account the anticipated demand for industrial trucks and, consequently, when the trucks are expected to be used. This coordination of the charging and deployment times is based on the availability of chargers for the trucks. The energy management system thus provides an efficient means of deploying and coordinating a fleet of industrial trucks.

[0011] The system according to the invention comprises a control system for the industrial trucks, which is configured to generate and send travel orders to individual industrial trucks. A travel order includes, for example, an approach route to a goods item to be picked up, the picking up of the goods, and a transport route along which the picked-up goods are to be transported to their destination. Preferably, the control system is configured to receive a loading command for an industrial truck from the control unit and forward it to the corresponding industrial truck. This forwarding can take into account a travel order to be implemented automatically. In a preferred embodiment, the loading system can also receive a loading command for an industrial truck from the control unit and forward this loading command to the corresponding industrial truck.The received charging command causes the industrial truck, particularly an autonomously driving and steering truck, to approach an assigned charging station and initiate a charging process. According to the invention, the control system is designed to receive data from a warehouse management system and evaluate this data to determine the anticipated demand for industrial trucks. In this way, the control system can access current data and does not have to rely on empirical or estimated data.

[0012] Preferably, the battery-powered industrial trucks for the energy management system have at least one automated guided vehicle (AGV). Automated guided vehicles receive a driving command and execute it automatically. The energy system according to the invention can be used particularly advantageously with automated guided vehicles. For example, the number of orders to be processed and their deadlines are known from a warehouse management system (WMS). Therefore, the coordinating energy control unit can very reliably access the anticipated demand for industrial trucks. However, the energy system also offers advantages for manually operated industrial trucks if the users adhere to and implement the transmitted charging instructions. These instructions can be displayed to the users visually and / or audibly on the industrial truck.

[0013] Furthermore, the energy control unit is preferably designed to receive parameters for the current state of a power grid and to control the charging and / or discharging process of at least one of the batteries to support the power grid. A key aspect of this enhanced design is that the energy control unit monitors the current state of the power grid and controls the charging and / or discharging process of the industrial trucks accordingly. The current state of the power grid, which may, for example, necessitate intervention via battery control, can include over- and under-frequencies or over- and undervoltages of the electrical supply network. Changes in the power factor can also, to a limited extent, contribute to grid support.In particular, the fact that this grid-supporting function uses the anticipated demand for industrial trucks makes it clear that the grid-supported function does not necessarily lead to a restriction in the use of industrial trucks. While the short-term injection of electrical power from the batteries connected to the charger reduces their charge level, it does not yet mean that the anticipated demand for industrial trucks cannot be met.

[0014] In a preferred advanced configuration, the control unit is designed to select between at least two different electrical supply networks for powering the chargers and to choose between the different networks based on the current price of electricity. This configuration of the control unit serves to reduce costs. The at least two electrical supply networks could, for example, be the public electricity grid and a private grid, such as one powered by a photovoltaic system. The control unit is then able to compare the costs of these two networks with regard to the current prices and switch accordingly. Similarly, the control unit can also be configured to feed electrical power from the connected batteries into the electrical supply network.As already mentioned, this is preferably done from the perspective of grid stabilization. However, it is also possible to do so from a cost perspective, for example, if the price paid for fed-in electrical power is particularly high. Here, too, the operational capability of the industrial trucks should not be restricted, but rather, at most, additional energy that is not expected to be needed for the industrial trucks should be fed into the grid.

[0015] The anticipated demand can refer to the projected energy consumption of the industrial trucks or the projected number of industrial trucks required. Information from logistics companies can also be considered for this purpose. In this case, the warehouse management system is configured to receive data from a logistics company regarding goods to be stored and retrieved, and to provide this data to the control system for determining the projected demand. This ensures, for example, that when a truck arrives with goods to be stored, a sufficient number of loaded industrial trucks are available. Similarly, it is also known, for example, that if a truck to be loaded has a fixed departure time, the loading process must be completed on time, requiring increased use of industrial trucks.By incorporating this data, the logistics company can seamlessly manage the flow of goods into and out of the warehouse. Ideally, the data received by the warehouse management system from the logistics company includes one or more of the following: size, weight, etc., of goods being stored or retrieved; arrival and collection times; quantity; any delays in delivery or collection; a time window for delivery or collection; and any special transport requirements. This information assists the energy management system and warehouse management in planning the demand and anticipated deployment of material handling equipment.

[0016] The energy management system according to the invention is explained in more detail below in a block diagram.

[0017] At the center is the energy management system 10, which acts as an energy control unit and has four modules for the charging process. Module 12 deals with production-optimized charging, module 14 with active load management, module 18 with market-price-optimized charging, and module 16 with reverse charging or feeding power back into the electrical grid.

[0018] The module for production-optimized loading 12 works with the following information: State of charge of the batteries in the AGVs 44 and their remaining operating time, expected demand for AGVs calculated by a warehouse management system 46 and state of charge of batteries 44 connected to chargers 42 and their remaining operating time.

[0019] From these parameters, module 12 provides a charging strategy for the individual industrial trucks and determines when which battery of the industrial truck should be charged.

[0020] Module 14 for active load management attempts to stabilize the power drawn from the electrical grid as much as possible throughout the day. This is intended to prevent excessive loads from being drawn from the grid, for example, during shift changes or other times. Module 14 ensures that power consumption is as consistent as possible.

[0021] The market-price-oriented module 18 takes into account information from energy trading 20 when determining the charging time. Energy trading 20 accesses information from electricity supply companies (ESCs) 22, grid operators 24, and other energy producers 26. Based on this information, module 20 determines current prices for providing electrical power and, if necessary, also for feeding electrical power into the grid. This information is exchanged with the energy management system 10 via an interface 28 and can be considered by module 18 for market-price-optimized charging. As a result of module 18 for market-price-optimized charging, it may be advantageous, for example, if the electricity price is low, to fully charge the existing batteries and also charge any local buffer storage.This charging process occurs independently of actual logistical needs. The market-price-optimized charging module 18 can also, if the electricity price is high, empty local buffer storage, utilize any photovoltaic systems, and otherwise restrict battery charging to the absolute minimum necessary. In this case, the market-price-optimized charging module 18 can also switch to other energy sources. The inverse charging module 16, or feed-in to the grid, also uses the data received via the interface and makes assessments as to whether electrical energy stored in the system can be fed back into the electrical grid to generate additional revenue.

[0022] The energy management system is connected to local energy generators or storage units 30. These can be buffer storage units (accumulators), such as those located near charging stations or centrally within the warehouse. The buffer storage units can store electrical energy and release it as needed, storing electrical energy from the electrical grid or from a local energy generator 30 and supplying it to the generator or to the industrial trucks. A photovoltaic system 34, for example, supports the energy management system and allows for the provision of additional electrical power.

[0023] The four modules 12, 14, 16, and 18 of the energy management system are coordinated with each other. Priority is given to production-optimized charging (module 12) to ensure the availability of forklifts in the warehouse and thus the production flow. Second priority is given to market-price-optimized charging (module 18) and grid feed-in (module 16), followed by active load management (module 14), which avoids power surges and thus cost spikes in electricity procurement. Should active load management (module 14) intervene because power surges in the internal power grid infrastructure must be avoided, it takes precedence over market-price-optimized charging and reverse charging. This results from the technical necessity for the energy management system to prevent power and voltage spikes.The energy management system is particularly effective when the industrial trucks operate with lithium-ion batteries, as these also allow partial charging and intermediate charging and can therefore be used flexibly.

[0024] The energy management system 10 communicates with an AGV control system 40 and the chargers 42 via interfaces 36 and 38. A further component of the AGV control system 40 is a direct logical data exchange with the chargers 42 and the AGVs 44 with their respective batteries. The AGV control system 40 controls the AGVs operating autonomously in the warehouse. It handles the route planning for the individual AGVs and executes the transport orders from the warehouse management system 46 by having the individual AGVs transport the goods. Alternatively, it can also be provided that the AGV control system merely transmits and monitors the transport and charging orders to the AGVs, specifying the start and destination locations, while the route planning is carried out autonomously by each AGV. In the context of this invention, the focus is on providing information to the energy management system 10 and implementing charging recommendations for the AGVs.

[0025] Interface 38 is used to control the chargers from the energy management system 10. Interface 36 handles general communication between the energy management system 10 and the AGV control system 40. The charge status of the batteries in the AGVs 44 is queried via interface 48, as is the remaining battery runtime. This information is then forwarded to the energy management system 10 via interface 36. Interface 50 allows the AGV control system 40 to exchange information with the chargers. The chargers 42 report to the AGV control system 40 which batteries are available in the AGVs and their remaining charging time. The AGV control system can switch chargers via interface 50, just as the energy management system can switch them directly via interface 38. The information required for the charging process can be transmitted from the battery to the charger via interface 52.

[0026] The warehouse management system (WMS) 46 obtains information from one or more logistics companies 56 via an interface 54. The exchange via the interface 54 can be bidirectional, allowing the warehouse management system 46 to provide the logistics company 56 with information on loading and unloading operations in the warehouse, just as the logistics company 56 can send information on the delivery or collection of goods to the warehouse management system 46. The logistics company 56 determines the estimated time of arrival of deliveries, using information on its own trucks 58 and those of external freight forwarders 60. The logistics company 56 can also access publicly available data, such as weather data 62 and traffic information 64, to account for potential delivery delays.

[0027] The warehouse management system 46 is also connected to the production system 66 and receives information from it about the need for goods for production or information about produced goods if they are intermediate products to be stored.

[0028] The warehouse management system 46 also stores the locations of the goods in the warehouse, as well as the available storage locations. Available storage locations for delivered goods are assigned via the warehouse management system. This means that the AGV control system 40 is informed of the storage location for a specific item via interface 68. The AGV control system selects a suitable AGV for the transport order and then transmits this location as the destination to the AGV transporting the goods, possibly also determining the route to be taken. Similarly, when goods are retrieved, the warehouse management system 46 transmits the destination storage location (e.g., a shelf compartment) and the destination location of the goods to the AGV control system 40 via interface 68.The AGV control system then assigns a transport order via interface 48 to an AGV that is particularly suitable for the transport order because it is currently or will soon be available and is, for example, nearby or has a sufficiently charged battery for the transport order. If necessary, the AGV control system 40 also creates the route to be traveled by the AGV and transmits it via interface 48.

[0029] In principle, the warehouse management system 46 can also transmit desired delivery and collection times for specific deliveries to the logistics companies 56 via interface 54. This ensures a smooth process for the storage and retrieval of goods and also optimizes the cost-effective charging of the AGV batteries. The information from the warehouse management system 46 is made available via interface 68.

[0030] The charging processes for the AGV fleet are planned by the energy management system 10. For this purpose, the energy management system 10 receives information about the current state of charge of the AGVs 44 and the future energy requirements of the AGV fleet from the AGV control system 40 via interface 36 and / or from the charging units 42 via interface 38. This energy requirement is based on the transport orders from the warehouse management system 46. Using module 12, the energy management system 10 plans the charging processes for the AGVs 44 to ensure warehouse operation. Modules 14-18 also take into account further requirements, such as market prices, voltage peaks, and the stabilization of energy consumption from the grid. Based on this optimized charging strategy, the energy management system 10 generates specific charging orders, i.e., charging times and durations.The desired battery charge levels for each AGV 44 are determined and transmitted to the AGV control system 40 via interface 36. Depending on whether an AGV 44 is to be charged or energy is to be drawn from it for feed-in to the grid, a corresponding order must be transmitted to the appropriate charger 42. This can be done directly via interface 38 from the energy management system 10, from the AGV control system via interface 50, or by the AGV 44 itself via interface 52. The AGV control system plans the charging orders received from the energy management system 10 by transmitting to the AGVs 44 the chargers 42 to be visited, the charging durations, and, if applicable, the routes to be traveled. If necessary, the charging duration can also be transmitted directly to the chargers 42 via interface 50. Reference symbol list

[0031] 10 Energy management system 12 Module for production-optimized charging 14 Module for active load management 16 Module for reverse charging or feeding power back into the electrical grid 18 Module for market-price-optimized charging 20 Energy trading module 22 Electrical grid 24 Grid operator 26 Other energy producers 28 Interface 30 Local energy generation 32 Storage 34 Photovoltaic system 36 Interface 38 Interface 40 AGV control system 42 Chargers 44 AGVs 46 Warehouse management system 48 Interface 50 Interface 52 Interface 54 Interface 56 Logistics company 58 Own trucks 60 Third-party trucks from external freight forwarders 62 Weather data 64 Traffic information 68 Interface

Claims

1. An energy management system for battery-powered industrial trucks (44), having an energy control unit (10) to which - data on the current state of charge of the batteries of multiple industrial trucks are applied, - data on an expected energy demand of the industrial trucks are applied, and - data on the occupancy of charging devices are applied, wherein the energy control unit (10) is designed to ascertain when an industrial truck is being charged at an available charging device (42) and when it is being used from the applied data (36, 38), wherein a guidance system (40) for the industrial trucks is designed to generate driving tasks for individual industrial trucks and to send said driving tasks thereto and to receive data from a warehouse management system (46) and to evaluate said data when determining the expected energy demand of the industrial trucks.

2. The system according to claim 1, characterized in that the industrial trucks comprise at least one autonomously guided vehicle (AGV), which receive a driving task and implement same automatically.

3. The system according to one of claims 1 or 2, characterized in that the guidance system (40) is designed to receive a charging command for an industrial truck from the energy control unit and to forward said charging command to the corresponding industrial truck.

4. The system according to one of claims 1 to 3, characterized in that the energy control unit is designed to receive characteristic variables for a current state of a power grid and to control a charging and / or discharging process of at least one of the batteries in order to support the power grid.

5. The system according to one of claims 1 to 4, characterized in that the energy control unit is designed to select between at least two different electrical supply grids (30, 20) for supplying the charging devices and to select between the electrical supply grids according to a current purchase price for electrical power.

6. The system according to one of claims 1 to 5, characterized in that the energy control unit is designed to actuate charging devices in such a way that electrical power is fed into the electrical supply grid from a connected battery.

7. The system according to claim 6, characterized in that the energy control unit is designed to feed into the supply grid depending on a current purchase price for electrical power.

8. The system according to claim 1, characterized in that the warehouse management system is designed to receive from a logistics company (56) data relating to goods to be put into and removed from storage and to forward said data to the guidance system (40) in order to ascertain the likely demand.

9. The system according to claim 8, characterized in that the data from the logistics company (56) received by the warehouse management system contain one or more of the following items of information: information about a good to be put into or else removed from storage, information about an arrival or else pickup time of the good, information about the quantity of the good, information about any delays in delivering or else picking up the good, information about a time slot for delivering or else picking up the good, and information about special transport requirements for the good.

10. The system according to claim 8 or 9, characterized in that the warehouse management system sends messages to the logistics company or companies (56) which contain one or more of the following items of information: information about a good to be put into or else removed from storage, information about an arrival or else pickup time of the good, information about the quantity of the good, information about a time slot for delivering or else picking up the good, and information about special transport requirements for the good.