Methods for controlling and regulating electrical energy flows

Abstract

Method for controlling and regulating electrical energy flows, in which a target energy requirement of secondary-side consumers is determined, an actual energy supply of primary-side energy suppliers with at least one motor-generator unit (1) and a rechargeable energy storage device (3) is recorded, the primary-side energy suppliers are enabled by an energy manager (6) for target-actual adjustment, and the secondary-side consumers are divided into consumer groups according to their energy requirements, characterized in that, in the case of a target energy requirement, the energy manager (6) sets a singular operation, a mixed operation, and / or a staggered operation depending on the consumer group membership, wherein in singular operation the rechargeable energy storage device (3) is set as the sole energy supplier for a first consumer group,in mixed operation, the rechargeable energy storage device (3) and another energy source are set as energy suppliers for a second consumer group, and in staggered operation, the rechargeable energy storage device (3) and another energy source are set as energy suppliers when the consumers of a third consumer group are switched on at different times, wherein in staggered operation, the other energy source is switched on as energy supplier for one of the consumers of the third consumer group if the charge level of the rechargeable energy storage device (3) is less than a limit value (GW) and a waiting time (t1) has elapsed, after which the consumer must be activated.

Description

[0001] The invention relates to a method for controlling and regulating electrical energy flows, in which a target energy requirement of secondary-side consumers is determined, an actual energy supply of primary-side energy suppliers is recorded and the primary-side energy suppliers are enabled by an energy manager for target-actual adjustment.

[0002] US 2015 / 0 097 437 A1 discloses a microgrid system with multiple motor-generator units and a rechargeable electrical energy storage system. If necessary, the microgrid system can be supplemented with a photovoltaic and wind turbine system. Each motor-generator unit is equipped with a turbo compound system for generating electrical energy from the exhaust gas stream. An energy manager controls the energy flows and activates / deactivates and enables the energy suppliers. A first measure to reduce fuel consumption is to only provide as many motor-generator units as are required to cover secondary load peaks. A second measure is to operate the motor-generator units at a higher load. The excess electrical energy is then diverted by the energy manager to the electrical energy storage system.For example, if a higher load is applied on the consumer side, the energy manager activates another motor-generator unit and releases additional energy from the electrical energy storage system during the ramp-up. This reference assumes a given secondary-side load and considers only the primary-side energy sources. Therefore, there is still potential for optimization with regard to considering secondary-side consumers.

[0003] DE 20 2009 015 027 U1 discloses a device for controlling a vehicle, which has an energy generation device for generating electrical energy, a rechargeable energy storage device, an energy distribution device, and various electrical consumers. Electrical energy generated by the energy generation device and electrical energy stored in the energy storage device can be distributed to the electrical consumers via the energy distribution device. Different priorities are assigned to the electrical consumers, which are taken into account by the control device when distributing the limited electrical energy available to the various consumers. One criterion for assigning priorities is the safety relevance of the respective consumers for the operation of the vehicle.Low priority consumers can be switched off if the available electrical energy is needed to supply higher priority consumers.

[0004] A similar approach to controlling a vehicle is known from DE 198 38 248 A1 A4. The vehicle's electrical consumers are classified into strategy groups, each of which has specific priorities assigned to it. All electrical consumers are monitored, and electrical consumers in lower strategy groups are controlled simultaneously with the higher-level electrical consumers or at a different time interval, based on the evaluation of the switching requirements of higher-level electrical consumers.

[0005] DE 101 04 892 A1 discloses an electrical system for a ship. It includes generators, electrical consumers, such as electric motors, and an on-board power system with switchgear as system components. The electrical system ensures the supply of sufficient electrical power in all operating states of the ship and controls the system components using standard digital modules.

[0006] The invention is based on the object of developing a method for controlling and regulating electrical energy flows with regard to taking secondary-side consumers into account.

[0007] This object is achieved by the features of claim 1. The embodiments are presented in the subclaims.

[0008] The method according to the invention consists in dividing the secondary-side consumers into consumer groups according to their energy requirements. When a target energy requirement is encountered, the energy manager sets a singular, mixed, and / or staggered operation depending on the consumer group membership. In singular operation, the rechargeable energy storage device is set as the sole energy supplier for a first consumer group. The first consumer group therefore includes the devices that permanently require electrical energy. For example, in a marine application, these are the ship and propeller automation. In mixed operation, the rechargeable energy storage device and another energy source, such as a motor-generator unit or wind turbine, are set as energy suppliers for a second consumer group.In staggered operation, the rechargeable energy storage device and another energy source are used as energy suppliers while the loads of a third load group are switched on at different times. In staggered operation, the additional energy source is switched on as the energy supplier for one of the loads in the third load group when the charge level of the rechargeable energy storage device is below a certain threshold and a waiting period has elapsed, after which the load must be activated.

[0009] The central element of the invention is the primary use of the rechargeable energy storage device as the energy source. This further reduces the number of motor-generator units, resulting in a corresponding reduction in fuel consumption. During quieter load periods, the motor-generator unit recharges the rechargeable energy storage device in preparation for higher load periods.

[0010] To prevent the rechargeable energy storage device from becoming deeply discharged, its actual energy supply is compared with a threshold value. In single-mode operation, if the threshold value is exceeded, the rechargeable energy storage device is recharged by the motor-generator unit. In mixed mode, if the threshold value is exceeded, the system switches to another energy source, such as a fuel cell. In staggered mode, if the threshold value is exceeded, the consumers in the third consumer group receive the energy one after the other. The threshold value, in turn, can be variable; for example, based on weather data and a period of good weather, a photovoltaic system can contribute a higher energy supply to recharging the rechargeable energy storage device.

[0011] In an addition, it is planned that the individual performance data of the consumers will be read in when new and their changes over time will be recorded, thus enabling predictive maintenance.

[0012] A further amendment also provides that the further procedure for predictive maintenance will be determined based on the changes over time.

[0013] The energy from all primary energy sources is collected in the rechargeable energy storage unit, so the system regulates itself via the energy balance of the rechargeable energy storage unit. The energy manager, in turn, distributes the collected energy as needed, depending on the consumer group. This results in a harmonious energy balance and high transparency of energy flows. In an existing system, the energy manager can be retrofitted as a software-based solution. In safety-critical systems, the energy manager can also be implemented as a deterministic component, for example, as a programmable logic controller.

[0014] A preferred embodiment is shown in the figures. Fig. 1 a system diagram, Fig. 2 a program flow chart of the main program and Fig. 3A, B, C subroutines

[0015] The Fig. Figure 1 shows a system diagram with primary-side energy suppliers, an energy manager 6, and secondary-side loads. The type of primary-side energy suppliers and the type of secondary-side loads depend on the respective configuration, for example, the arrangement on a ship or a stationary application in a server park. The following description is based on a ship application as an example. The primary-side energy suppliers are a motor-generator unit 1, a wind turbine 2, a rechargeable energy storage device 3, a photovoltaic system 4, and a fuel cell 5. The secondary-side loads are divided into three load groups based on their respective energy requirements. Loads that require a permanent supply of energy are assigned to load group 1.This includes all equipment required for the safe operation of the ship, such as navigation, all emergency lighting, or the control / regulation of the engine-generator units using an electronic engine control unit. Consumers with higher energy requirements are assigned to consumer group 2, such as the entire ship's automation system. Consumer group 3 includes consumers that can be controlled in staggered operation. Staggered operation is characterized by the fact that the individual consumers in consumer group 3 are supplied with energy either sequentially or one after the other with a dead time in between. In a ship application, these are, for example, the fuel and water treatment systems and the heating / ventilation system. The energy flows from the primary energy suppliers to the secondary consumers are controlled / regulated via the energy manager 6.Communication between the individual components takes place via a data bus system, for example, Ethernet, MODBUS, or CAN bus. The figure shows an example of a CAN bus 7. If a consumer sets a target energy requirement on CAN bus 7, the energy manager 6 sets a singular, mixed, and / or staggered operation mode based on the consumer group to which it belongs. For example, in mixed operation, the energy manager 6 transmits an activation value to the electronic engine control unit for starting the motor-generator unit 1 via CAN bus 7, in addition to the rechargeable energy storage device 3.

[0016] The Fig. Figure 2 shows a program flow chart of the main program. At S1, the energy demand E(TARGET) of the secondary consumers is read in and their consumer group membership is determined. At S2, a singular, mixed, and / or staggered operation is set based on the consumer group membership. For an energy demand from consumer group 1 (VGr1), the subroutine UP1 ( Fig. 3A) and in case of an energy request from consumer group 2 (VGr2) into the subroutine UP2 ( Fig. 3B). The two subroutines are described in conjunction with the respective figure. If an energy request comes from consumer group 3 (VGr3), the program flowchart continues at S3. If an energy request is received from all three consumer groups, the corresponding program sections are processed in parallel. A common feature is that the energy requests are primarily taken from the rechargeable energy storage device ( Fig. 1: 3) are fulfilled.

[0017] The following description initially assumes that an energy demand from consumer group 3 is detected by the energy manager. At S3, the charge level E(ACTUAL) of the rechargeable energy storage device is read in and then at S4 a check is made as to whether the charge level E(ACTUAL) is sufficient to meet the energy demand E(TARGET). If this is not the case (query result S4: no), the energy manager switches to another energy source, for example the motor-generator unit, at S8. If the charge level of the rechargeable energy storage device is sufficient, a check is made as to whether staggered operation is possible at S5. If the test result is positive, the system branches to subroutine UP3, which, in conjunction with the Fig. 3C. If, however, staggered operation is not possible, a check is carried out at S6 to determine whether the state of charge E(IST) of the rechargeable energy storage device has temporarily fallen below a limit value GW. If the test result is negative, the consumer in consumer group 3 is supplied with energy at S9 and branched back to point B. If, however, the state of charge of the rechargeable energy storage device is less than the limit value GW, the energy manager switches to another energy source at S7. The query at S6 prevents the state of charge of the rechargeable energy storage device from falling below a limit value GW when the third consumer group VGr3 and, for example, the first consumer group VG1 are supplied with energy in parallel. The program flowchart then ends.

[0018] In the Fig. 3A shows the subroutine UP1. The subroutine UP1 is always run when a target energy requirement E(TARGET) is present from a consumer in the first consumer group VGr1. In a ship application, the consumer group VGr1 includes those devices that are essential for the safe operation of the ship. A characteristic feature is that these devices are completely (100%) supplied from the rechargeable energy storage device. The advantage is that in battery-buffered systems, such as navigation, radio, or radar, emergency batteries can be omitted. Singular operation is set at S1. At S2, the state of charge E(ACTUAL) of the rechargeable energy storage device is recorded and compared with a limit value GW at S3. If the test result is positive, i.e. the state of charge is greater than the limit value GW, the energy is released to the consumer group VGr1 at S5 and the process branches to point C.If, however, the state of charge E(IST) is less than the limit value GW, the energy manager activates the motor-generator unit at S4. The motor-generator unit then supplies the energy to the rechargeable energy storage device. After activation of the motor-generator unit, the system returns to the main program. Fig. 2 to point A.

[0019] In the Fig. 3B shows subroutine UP2. Subroutine UP2 is always run whenever a target energy requirement E(TARGET) is present from a consumer in the second consumer group VGr2. Consumer group 2 includes, for example, ship automation. A characteristic feature is that these devices receive up to 50% of the energy from the rechargeable energy storage device. At S1, mixed operation is set, and then at S2, the charge level E(ACTUAL) of the rechargeable energy storage device is read in. At S3, it is again checked whether the charge level E(ACTUAL) of the rechargeable energy storage device is greater than a limit value GW. If this is the case, the program flow branches to S5. In step S5, the energy manager releases the energy from the rechargeable energy storage device to the consumer group VGr2 and branches to point D.If, however, the state of charge E(IST) is smaller than the limit value GW, the system switches to another energy source at S4 and returns to the main program. Fig. 2 to point A.

[0020] In the Fig. 3C shows subroutine UP3. Subroutine UP3 is always run when a target energy request E(TARGET) from a consumer in consumer group VGr3 is present and staggered operation is possible. Consumer group 3 includes those facilities whose operation is not required immediately after a request, for example the heating / ventilation system, a water treatment plant, and the so-called standby pumps. These facilities receive up to 30% of the energy from the rechargeable energy storage device. A characteristic of staggered operation is that a target energy request is not met immediately, but rather with a time delay, and the requesting consumers are supplied with energy either sequentially or one after the other with a dead time in between. For example, a second consumer is only supplied with energy after the end of the working cycle of a first consumer.

[0021] At S1, staggered operation is set, then at S2 the state of charge E(IST) of the rechargeable energy storage device is read in and compared with a limit value GW at S3. If this is greater than the limit value GW, the program section with steps S8 and S9 is run through. If, however, it was determined at S3 that the state of charge E(IST) of the rechargeable energy storage device is insufficient, a waiting time t1 is queried at S4. The waiting time t1 corresponds to a maximum waiting time, after which the consumer must be activated, for example after five minutes. If this waiting time t1 has expired, query result S4: yes, and if it was determined at S3 that the state of charge E(IST) of the rechargeable energy storage device is less than the limit value GW, then at S5 the system switches to another energy source and at S6 the energy is released to the consumer.If it was determined at S4 that the waiting time t1 has not yet expired (query result S4: no), then a check is made at S7 for consent. Consent means the following: If a consumer determines an immediate need for action based on its own sensors, it can withdraw consent to wait or staggered operation. In this case, the energy manager immediately enables the consumer. If, on the other hand, the consumer determines no immediate need for action, it consents to staggered operation. In addition, query S7 prevents the rechargeable energy storage device from being deeply discharged due to a parallel energy supply. If consent to wait is given (query result S7: yes), the program flowchart branches back to point E. Otherwise, it branches to point F and switches to another energy source at S5.Afterwards, at S6 the energy is released for the consumer and transferred to the main program of the . Fig. 2 returned.

[0022] If it was determined at S3 that the state of charge E(IST) of the rechargeable energy storage device is greater than the limit value GW, a time step t2 is queried at S8 as a waiting time. The time step t2 is used to avoid peak loads, i.e., when several consumers simultaneously set a target energy request. If the time step t2 has expired, the requesting consumer is supplied with energy at S6. However, if the time step t2 is still running (query result S8: no), a check is made at S9 for approval. In terms of content, step S9 corresponds to step S7, so the previous description also applies here. If the wait is approved (query result S9: yes), the program flowchart branches back to point E.

[0023] Otherwise, at S6 the energy is released for the consumer and transferred to the main program of the Fig. 2 returned. Reference symbol 1 motor-generator unit 2 wind turbines 3 rechargeable energy storage 4 photovoltaic system 5 Fuel cell 6 Energy Manager 7 Data bus (CAN)

Claims

[1] Method for controlling and regulating electrical energy flows, in which a target energy requirement of secondary-side consumers is determined, an actual energy supply of primary-side energy suppliers with at least one motor-generator unit (1) and a rechargeable energy storage device (3) is recorded, the primary-side energy suppliers are enabled by an energy manager (6) for target-actual adjustment and the secondary-side consumers are divided into consumer groups according to their energy requirements, characterized bythat, in the case of a target energy requirement, the energy manager (6) sets a singular operation, a mixed operation and / or a staggered operation depending on the consumer group membership, wherein in singular operation the rechargeable energy storage device (3) is set as the sole energy supplier for a first consumer group, in mixed operation the rechargeable energy storage device (3) and a further energy source are set as energy suppliers for a second consumer group, and in staggered operation the rechargeable energy storage device (3) and a further energy source are set as energy suppliers when the consumers of a third consumer group are switched on at a time delay, wherein in staggered operation the further energy source is switched on as the energy supplier for one of the consumers of the third consumer group if the charge state of the rechargeable energy storage device (3) is less than a limit value (GW) and a waiting time (t1) has elapsed,after which the consumer must be activated. [2] Method according to claim 1, characterized by that in singular operation the actual energy supply of the rechargeable energy storage device (3) is compared with a limit value (GW) and if the limit value is undershot the rechargeable energy storage device (3) is recharged by the motor-generator unit (1). [3] Method according to claim 1, characterized by that in mixed operation the actual energy supply of the rechargeable energy storage device (3) is compared with a limit value (GW) and if the limit value is undershot the system switches over to the other energy source. [4] Method according to claim 1, characterized by that in staggered operation the target energy requirement is compared with the actual energy supply of the rechargeable energy storage device (3) and if the limit value is undershot the consumers of the third consumer group are switched on with a time delay and one after the other. [5] Method according to claim 4, characterized by that a second consumer is only activated after the end of the working cycle of a first consumer. [6] Method according to claims 2 to 5, characterized by that the limit value (GW) for the rechargeable energy storage device (3) is set by the energy manager (6) depending on the weather data.

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