Electric power system for supplying electric energy to a vessel

Abstract

A power system for supplying electric power from shore-side to a vessel is presented. The power system includes one or more shore-side converters (101-112) for receiving electric power from a shore-side alternating voltage network (137) and for producing one or more direct voltages. Each shore-side converter can be a controllable converter for controlling the produced direct voltage to be suitable for the vessel in accordance with a control signal received from the vessel, or the vessel may include a direct voltage converter for converting the direct voltage received from the shore-side to be suitable for the vessel. The vessel can be an electric vessel which includes a chargeable battery (132) for supplying electric power to the propulsion system (135) of the vessel.

Claims

1. An electric power system for supplying one or more direct voltages from shore-side to a vessel, the electric power system comprising: one or more controllable converters configured to receive the electric power from a shore-side alternating voltage network and to produce the one or more direct voltages; at least one transformer configured to connect the one or more controllable converters to the shore-side alternating voltage network, the at least one transformer comprising a primary winding for being connected to the shore-side alternating voltage network, and a plurality of secondary windings each being connected to a corresponding one of the controllable converters, electric connectors configured to connect an electric circuitry of the vessel; one or more direct voltage links configured to transfer the one or more direct voltages from the one or more controllable converters to the electric connectors; and a control system configured to receive a control signal from the vessel and to directly control the one or more controllable converters in accordance with the received control signal to control the one or more direct voltages to be transferred from the electric connectors to the electric circuitry of the vessel.

2. The electric power system according to claim 1, wherein the electric power system further comprises one or more capacitive energy storages connected to direct voltage terminals of the one or more controllable converters.

3. The electric power system according to claim 2, wherein each of the one or more capacitive energy storages comprises one or more electric double layer capacitors.

4. The electric power system according to claim 1, wherein each of the one or more direct voltage links comprises one or more over-current protectors.

5. The electric power system according to claim 4, wherein at least one of the over-current protectors is a fuse.

6. The electric power system according to claim 1, wherein the electric power system further comprises one or more supply breakers configured to break supply of the electric power from the shore-side alternating voltage network to one or more of the controllable converters.

7. The electric power system according to claim 1, wherein the control system comprises a communication protocol processor configured to control the reception of the control signal in accordance with one or more digital data transfer protocols.

8. The electric power system according to claim 7, wherein the one or more digital data transfer protocols comprises at least one of the following: Internet Protocol, Ethernet protocol, Asynchronous Transfer Mode protocol, and MultiProtocol Label Switching.

9. The electric power system according to claim 1, wherein the control system comprises a radio receiver configured to receive the control signal from the vessel.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Exemplifying and non-limiting embodiments of the invention and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic illustration of an electric power system according to an exemplifying and non-limiting embodiment of the invention and a vessel according to an exemplifying and non-limiting embodiment of the invention, and

(3) FIG. 2 shows a schematic illustration of a vessel according to an exemplifying and non-limiting embodiment of the invention.

DESCRIPTION OF THE EXEMPLIFYING EMBODIMENTS

(4) The specific examples provided in the description given below should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

(5) FIG. 1 shows a schematic illustration of an electric power system according to an exemplifying and non-limiting embodiment of the invention. Furthermore, FIG. 1 shows a schematic illustration of a vessel 126 according to an exemplifying and non-limiting embodiment of the invention. The vessel 126 can be for example a ship, a boat, or a ferry. The electric power system is located on the shore-side and the electric power system is arranged to supply electric power to the vessel 126. The electric power system comprises controllable converters 101, 102, 103, 104, 109, 110, 111, and 112. The controllable converters 101, 102, 103, and 104 are arranged to receive electric energy from a shore-side alternating voltage network 137 and to produce direct voltage V.sub.DC1. Correspondingly, the controllable converters 109, 110, 111, and 112 are arranged to receive electric energy from the shore-side alternating voltage network 137 and to produce direct voltage V.sub.DC2. The electric power system comprises electric connectors for connecting to an electric circuitry of the vessel 126. In FIG. 1, one of the electric connectors of the electric power system is denoted with a reference 105. The electric power system comprises direct voltage links 106 and 107 for transferring the direct voltages V.sub.DC1 and V.sub.DC2 from the controllable converters 101-104 and 109-112 to the above-mentioned electric connectors. The direct voltage links 106 and 107 may comprise for example bendable cables. The electric power system comprises a control system 108 for receiving a control signal from the vessel 126 and for controlling the controllable converters 101-104 and 109-112 in accordance with the received control signal so as to control the direct voltages V.sub.DC1 and V.sub.DC2 to be suitable for the vessel 126. In the exemplifying case illustrated in FIG. 1, there are two groups of controllable converters so that each group comprises four controllable converters. It is however clear to a skilled person that many different system architectures are possible, e.g. there can be only one group or more than two groups and each group may comprise one or more converter devices. A group having a single member is understood here as a special case of a group. Furthermore it is possible that different groups have different number of converter devices. In each case, the system architecture may depend on several factors such as e.g. the charge power need, the shore-side alternating voltage network, factors related to cost efficiency, etc.

(6) The vessel 126 comprises electric connectors for receiving the above-mentioned direct voltages V.sub.DC1 and V.sub.DC2 from the above-mentioned direct voltage links 106 and 107. In FIG. 1, one of the electric connectors of the vessel 126 is denoted with a reference 127. The vessel 126 comprises a transmitter 128 for transmitting, to the above-mentioned electric power system, the above-mentioned control signal so as to enable the electric power system to control the direct voltages V.sub.DC1 and V.sub.DC2 to be suitable for the vessel 126. In this exemplifying case, the vessel 126 is an electric vessel that comprises a chargeable battery system 132 for receiving charging energy from the electric connectors of the vessel and for supplying electric power to a propulsion system 135 of the vessel. The vessel 126 comprises a control system 131 for determining the above-mentioned control signal in accordance with e.g. the state of charge of the chargeable battery system 132 and/or in accordance with other information such as e.g. one or more predetermined control parameters. A control parameter may indicate for example a reference value for direct voltage V.sub.DC of a direct voltage link 138 of the vessel 126. In the exemplifying case illustrated in FIG. 1, the vessel comprises a direct voltage converter 133 between the direct voltage link 138 and the chargeable battery system 132. The direct voltage converter 133 is advantageously controllable so that the direct voltage V.sub.DC of the direct voltage link 138 can be kept substantially constant even if the voltage of the chargeable battery system 132 were changing. Furthermore, the vessel 126 may comprise an inverter 136 for converting the direct voltage V.sub.DC of the direct voltage link 138 into one or more alternating voltages suitable for an alternating voltage system 134 of the vessel.

(7) In the exemplifying case illustrated in FIG. 1, the above-mentioned control signal is transferred from the vessel 126 to the electric power system on the shore-side with the aid of a radio link. In this exemplifying case, the transmitter 128 of the vessel 126 comprises a radio transmitter and the control system 108 on the shore-side comprises a radio receiver. It is, however, also possible that the control signal is transferred from the vessel 126 to the electric power system on the shore-side with the aid of an electric signal cable or an optical fiber. The control signal can be an analog signal, and the control system 108 can be configured to be responsive to the level, frequency, phase, and/or other properties of the control signal. It is also possible that the control signal is a digital signal. In exemplifying cases where the control signal is a digital signal, the transmitter 128 of the vessel comprises a modulator and the receiver of the control system 108 comprises a corresponding demodulator so as to enable the transfer of the digital control signal from the vessel 126 to the electric power system on the shore-side.

(8) In an electric power system according to an exemplifying and non-limiting embodiment of the invention, the control system 108 comprises a communication protocol processor 125 for controlling the reception of the control signal in accordance with one or more digital data transfer protocols. Correspondingly, the transmitter 128 of the vessel 126 comprises a communication protocol processor 129 for controlling the transmission of the control signal in accordance with the one or more digital data transfer protocols. The one or more digital data transfer protocols may comprise for example the Internet Protocol IP, Ethernet protocol, the Asynchronous Transfer Mode ATM protocol, and/or the MultiProtocol Label Switching MPLS.

(9) The exemplifying electric power system illustrated in FIG. 1 comprises capacitive energy-storages 113 and 114. The capacitive energy-storage 113 is connected to the direct voltage terminals of the controllable converters 101-104, and the capacitive energy-storage 114 is connected to the direct voltage terminals of the controllable converters 109-112. Each of the capacitive energy storages 113 and 114 may comprise for example one or more electric double layer capacitors EDLC which can be called also super capacitors.

(10) In the exemplifying electric power system illustrated in FIG. 1, the direct voltage link 106 comprises an over-current protector 115 and the direct voltage link 107 comprises an over-current protector 116. Each over-current protector can be for example a fuse or an over-current protector relay or another protector circuit breaker.

(11) The exemplifying electric power system illustrated in FIG. 1 comprises a transformer 117 for connecting the controllable converters 101-104 to the shore-side alternating voltage network 137, and another transformer 118 for connecting the controllable converters 109-112 to the shore-side alternating voltage network 137. Each of the transformers comprises a three-phase primary winding for being connected to the shore-side alternating voltage network 137 and four three-phase secondary windings each being connected to a respective one of the controllable converters. In FIG. 1, the three-phase primary winding of the transformer 117 is denoted with a reference 119 and two of the three-phase secondary windings of the transformer 117 are denoted with references 120 and 121.

(12) The exemplifying electric power system illustrated in FIG. 1 comprises supply breakers 122, 123, and 124 for interrupting the electric power supply from the shore-side alternating voltage network 137 to the controllable converters 101-104 and/or to the controllable converters 109-112. The supply breakers can be controlled e.g. by the control system 108 so that the electric power supply from the shore-side alternating voltage network 137 to the controllable converters 101-104 and/or 109-112 is interrupted in response to a fault situation in the controllable converters 101-104 and/or 109-112.

(13) FIG. 2 shows a schematic illustration of a vessel 226 according to an exemplifying and non-limiting embodiment of the invention. The vessel 226 comprises electric connectors for receiving direct voltages V.sub.DC1 and V.sub.DC2 from a shore-side electric power system. In FIG. 2, one of the electric connectors is denoted with a reference 227. The vessel 226 comprises controllable direct voltage converters 239 and 240, and a control system 231 for controlling the direct voltage converters 239 and 240 so that the received direct voltages V.sub.DC1 and V.sub.DC2 are converted to be suitable for the vessel 226. Each of the direct voltage converters 239 and 240 can be for example a buck and/or boost converter. Usually, a buck and/or boost converter can be arranged to support a broad input voltage range more cost effectively than is a case with a controllable rectifier for converting alternating voltage into controllable direct voltage.

(14) The vessel 226 is an electric vessel that comprises a chargeable battery system 232 for receiving charging energy from the electric connectors of the vessel and for supplying electric power to a propulsion system 235 of the vessel. The control system 231 can be configured to control the direct voltage converters 239 and 240 in accordance with e.g. the state of charge of the chargeable battery system 232 and/or in accordance with other information such as e.g. one or more predetermined control parameters. A control parameter may indicate for example a reference value for direct voltage V.sub.DC of a direct voltage link 238 of the vessel 226. In the exemplifying case illustrated in FIG. 2, the vessel comprises a direct voltage converter 233 between the direct voltage link 238 and the chargeable battery system 232. The direct voltage converter 233 is advantageously controllable so that the direct voltage V.sub.DC of the direct voltage link 238 can be kept substantially constant even if the voltage of the chargeable battery system 232 were changing.

(15) Each of the above-mentioned control systems 131, 108, and 231 can be implemented with one or more processor circuits each of which can be a programmable processor circuit provided with appropriate software, a dedicated hardware processor such as for example an application specific integrated circuit ASIC, or a configurable hardware processor such as for example a field programmable gate array FPGA. Furthermore, each of the above-mentioned control systems may comprise one or more memory circuits such as e.g. a Random Access Memory RAM circuit.

(16) The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.