A power switching control system for a marine power system and an electric ship

Abstract

The utility model discloses a power switching control system and an electric ship of a marine power system, including a DC bus, a boost bus, and a super capacitor; a power supply battery cluster is respectively connected to the boost bus and the DC bus through a first switch system; a battery cluster to be switched is respectively connected to the boost bus and the DC bus through a second switch system, and the boost bus is connected to the DC bus through a super capacitor; the DC bus is used to provide DC power to the load; the power monitoring unit is used to monitor the power of the power supply battery cluster and the battery cluster to be switched respectively, and its output end is connected to an energy control unit; the output end of the energy control unit is respectively connected to the first switch system and the second switch system, and the power supply of the power supply battery cluster and the battery cluster to be switched is controlled based on the first switch system and the second switch system. Whether to connect the power supply of the power supply battery cluster and the battery cluster to be switched to the boost bus and the DC bus. This solution avoids the generation of large circulating currents during switching, thereby improving the safety of the ship's power system.

Description

Technical Field

[0001] The utility model relates to the field of ship electrical systems, and in particular to a power switching control system of a ship power system and an electric ship. Background Art

[0002] With the development of new energy technologies, electric ships and ship electrification have gradually matured. The ship power system provides power for the electrical loads on the ship, and batteries are generally used as the power source. For example, an electric ship propulsion system and an electric ship with patent application number 201920269899.5 disclose a scheme for driving a ship by using a yokeless segmented armature axial flux permanent magnet motor, which is driven by electricity.

[0003] Generally, in order to meet the stability and endurance of the ship, multiple battery clusters are set up, and the battery clusters are set in different cabins. Considering safety, the marine power system is usually a segmented architecture. During the navigation of the ship, at least one power switch will be performed to switch the power from one cabin to another. Each cabin corresponds to a battery cluster, and the battery clusters between different cabins are isolated from each other. During the switching process, in order to ensure that the entire ship does not lose power, it is necessary to first connect the two cabins in parallel to the bus, and then cut off the branch with less power. In the short parallel connection, the two cabins have a large voltage difference due to different charge states, resulting in serious circulation problems. Circulation problems can cause safety hazards in the circuit system and even electrical problems such as shortened battery life, so circulation needs to be avoided. The traditional solution to ship circulation is to add diodes, but the stability of diodes is poor and does not meet the requirements of long ship life. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and to provide a power switching control system for a marine power system and an electric ship, which can avoid the generation of large circulating currents during switching by improving the power switching system of the ship.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a power switching control system for a marine power system, the control system includes a power supply battery cluster and a battery cluster to be switched, a power monitoring unit, and an energy control unit, and the control system also includes a DC bus, a boost bus, and a supercapacitor; the power supply battery cluster is connected to the boost bus and the DC bus respectively through a first switch system; the battery cluster to be switched is connected to the boost bus and the DC bus respectively through a second switch system, and the boost bus is connected to the DC bus through a supercapacitor; the DC bus is used to provide DC power to the load; the power monitoring unit is used to monitor the power of the power supply battery cluster and the battery cluster to be switched respectively, and its output end is connected to the energy control unit; the output end of the energy control unit is connected to the first switch system and the second switch system respectively, and based on the first switch system and the second switch system, the power supply of the power supply battery cluster and the battery cluster to be switched is controlled whether to be connected to the boost bus and the DC bus.

[0006] The first switch system and the second switch system each include a boost bus switch and a DC bus switch.

[0007] The boost bus switch and the DC bus switch are both electrically controlled switches.

[0008] The electronically controlled switch is a relay.

[0009] The control system also includes a power replenishment system, which is connected to the supercapacitor through a power replenishment switch and is used to charge the supercapacitor to keep the power of the supercapacitor stable; the output end of the energy control unit is connected to the power replenishment switch and is used to control the closing and opening of the power replenishment switch.

[0010] The control system further comprises a supplementary power monitoring unit, which is connected to the energy control unit, and the energy control unit drives and controls the action of the supplementary power switch according to the monitored power of the supplementary power monitoring unit.

[0011] The control system further comprises a circulation sensor, an output end of which is connected to an energy control unit, and an output end of which is connected to an alarm.

[0012] An electric ship adopts the power switching control system of the marine power system.

[0013] The advantages of the utility model are: simple and reliable structure, stable system, and by improving the ship's power switching system, it is possible to avoid the generation of large circulating currents during switching, thereby improving the safety of the ship's power system and avoiding electrical failures caused by circulating currents; the system is simple to control, low in cost, stable and reliable, and can monitor the circulating current and issue an alarm in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0015] Figure 1 This is the electrical schematic diagram of the control system of the utility model;

[0016] Figure 2 This is a control principle diagram of the control system of the utility model.

[0017] The reference numerals in the figure are: 1. Boost bus switch of the first switch system; 2. DC bus switch of the first switch system; 3. Boost bus switch of the second switch system; 4. DC bus switch of the second switch system; 5. Supplementary power switch. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0019] The main reason for the circulation when the ship's power system is switched is that in order to ensure that the power system is not disconnected, the low-power battery cluster and the full-power battery cluster will be connected in parallel. Due to the existence of the voltage difference, the circulation between the two is caused. Therefore, the main purpose of this solution is to increase the power of the low-power battery cluster to the same or close to the voltage of the full-power battery cluster by adding a boost bus and a supercapacitor, thereby reducing the generation of circulation or reducing the circulation.

[0020] like Figure 1 , 2 As shown, a power switching control system for a marine power system, the control system includes a power supply battery cluster and a battery cluster to be switched, as well as a power monitoring unit, an energy control unit, a DC bus, a boost bus, and a supercapacitor;

[0021] The power supply battery cluster is connected to the boost bus and the DC bus respectively through the first switch system; the battery cluster to be switched is connected to the boost bus and the DC bus respectively through the second switch system, and the boost bus is connected to the DC bus through a supercapacitor; the DC bus is used to provide DC power to the load; the power monitoring unit is used to monitor the power of the power supply battery cluster and the battery cluster to be switched respectively, and its output end is connected to the energy control unit; the output end of the energy control unit is connected to the first switch system and the second switch system respectively, and based on the first switch system and the second switch system, it controls whether the power supply of the power supply battery cluster and the battery cluster to be switched is connected to the boost bus and the DC bus.

[0022] like Figure 1As shown, the first switch system and the second switch system each include a boost bus switch and a DC bus switch. Battery clusters A, B, C... one of which is a power supply battery cluster, and the others are switching battery clusters. Battery cluster A is a power supply battery cluster, and B is a battery cluster to be switched, then A switches to B; when B is a power supply battery cluster, battery cluster C is a battery cluster to be switched, then B switches to C. Taking A and B as an example, battery cluster A is connected to the boost bus through the boost bus switch of the first switch system, and battery cluster A is connected to the DC bus through the DC bus switch of the first switch system; battery cluster B is connected to the boost bus through the boost bus switch of the second switch system, and battery cluster B is connected to the DC bus through the DC bus switch of the second switch system; battery cluster C is connected to the boost bus through the boost bus switch of the third switch system, and battery cluster C is connected to the DC bus through the DC bus switch of the third switch system, and so on.

[0023] The DC bus is used to supply power to the load, that is, the load is connected to the DC bus to obtain power. A supercapacitor is connected in series between the boost bus and the DC bus, and the DC bus and the boost bus are connected through the supercapacitor. The supercapacitor has a certain amount of power, and the voltage of the supercapacitor and the low-power battery cluster A are added to approximately equal to or equal to the power of the battery cluster B, so that no circulating current or a small circulating current is generated when switching from battery cluster A to battery cluster B.

[0024] In this application, the boost bus switch and the DC bus switch are both electronically controlled switches, which are controlled by the energy control system. The electronically controlled switches can be switches such as relays and contactors, which are driven and controlled by the energy control unit. The power monitoring unit is used to monitor the power of batteries such as battery cluster ABC. The voltage sensor can be used to collect the terminal voltage to perform power conversion judgment. Its output end is connected to the power control unit, which can be implemented by a voltage sensor. The power control unit needs to switch to battery cluster B for power supply after the power of the monitored battery cluster A is lower than a certain value. At this time, the energy control unit controls the boost bus switch and the DC bus switch in the battery clusters A and B to avoid the switching of circulating current or reduce the switching of circulating current. In this application, the energy control unit mainly realizes the control of boost bus switches and DC bus switches such as relays. Therefore, the energy management system EMS that comes with the ship can be used as a control unit to realize the drive control function of the energy control unit or a new processor can be used to realize it. The processor is developed and implemented with the STM32 series single-chip microcomputer, which has the advantages of low cost and reliable control.

[0025] Its working principle is: when it is determined through power detection that the power of battery cluster A is lower than a certain value, it is necessary to switch the power supply battery cluster from A to B. At this time, when A is supplying power, the boost bus switch of the first switch system is disconnected and the DC bus switch is closed; the switches in the second switch system of battery cluster B are all disconnected; when switching is required, the energy control unit first controls the boost bus switch of the first switch system to close and the DC bus to disconnect, and then controls the DC bus switch of the second switch system of battery cluster B to close and the boost bus switch to disconnect; after the DC bus switch of the second switch system of battery cluster B is closed, the boost bus switch in battery cluster A is disconnected, thereby reducing the circulating current by means of capacitor boosting. When the system is running, the DC bus switch of battery cluster A is in a closed state, and the voltage of battery cluster A will be sent to the energy management system EMS system through the voltage acquisition device of the battery pack. As the battery continues to discharge, the EMS will identify whether the battery has reached a low power state through the battery voltage. When the battery charge reaches the critical value for replacement, the EMS will send a command to the boost bus switch connected to battery cluster A to close it, and the supercapacitor will be connected in series with battery cluster A through the boost bus and then connected to the DC bus. After the boost bus switch is closed, the DC bus switch is disconnected. At this time, the voltage of the battery cluster A in the depleted state connected in series with the supercapacitor is equivalent to that of the fully charged battery cluster B. Then the DC bus switch of battery cluster B is closed. At this time, although battery cluster A and battery cluster B are connected in parallel, the voltage difference between the two is not large, so a large circulating current can be avoided. After battery cluster B is connected to the bus, the boost bus switch of battery cluster A is disconnected to complete the power switching process.

[0026] In a preferred embodiment of the present application, the control system also includes a power replenishment system, which is connected to the supercapacitor through a power replenishment switch, and is used to charge the supercapacitor to keep the power of the supercapacitor stable; the output end of the energy control unit is connected to the power replenishment switch, which is used to control the closing and opening of the power replenishment switch. Since the voltage between the supercapacitor and the low-voltage battery cluster after series connection is the sum of the two, the supercapacitor needs to always meet a certain power. Under this power, the sum of the voltage of the supercapacitor and the voltage of the low-power battery cluster is the same or close to the voltage of the fully charged battery cluster to be switched, so that the circulation can be reduced. Therefore, in order to ensure that the power of the supercapacitor is always in a stable state and avoid consumption, a power replenishment system is set, and then the power replenishment is performed through the power replenishment system and the power replenishment switch; wherein the power replenishment system can be a special charging power supply or other power supply, which is connected to the two ends of the supercapacitor through the power replenishment switch, so as to charge the supercapacitor and ensure the stability of the power of the supercapacitor. The supercapacitor used is composed of multiple supercapacitor monomers in series, and the number of series connections depends on the voltage of the battery system. The capacity of the supercapacitor needs to be calculated in combination with the power consumption of the entire ship and the duration of battery replacement. When the voltage of the supercapacitor is insufficient due to low power, it can be recharged by a fully charged battery during idle time when the battery is not being replaced.

[0027] When controlling the supercapacitor recharging switch, the recharging monitoring unit can be set to collect the voltage across the supercapacitor according to the power of the supercapacitor or the voltage across the two ends. The recharging monitoring unit is connected to the energy control unit, and the energy control unit drives the action of the recharging switch according to the monitored power of the recharging monitoring unit. When the sum of the voltage of the supercapacitor and the voltage of the low-power battery cluster is the same or close to the voltage of the fully-powered battery cluster to be switched, the voltage across the supercapacitor is detected as a voltage threshold. When the real-time detected supercapacitor voltage value is less than the threshold, the recharging switch is controlled to close, thereby charging the supercapacitor, wherein the recharging switch is an electrically controlled switch, such as a relay, a DC contactor, etc.

[0028] In a preferred embodiment of the present application, the control system further includes a circulating current sensor, the output end of the circulating current sensor is connected to the energy control unit, and the output end of the energy control unit is connected to the alarm. The circulating current sensor is arranged on the boost bus or the DC bus, and is used to collect circulating current signals. A voltage transformer or a current transformer can be used to collect circulating current voltage or current parameters. Based on the collected circulating current parameters during the switching process, it is determined whether the circulating current is abnormal and an alarm signal is issued in time, thereby improving the monitoring function of the circulating current.

[0029] This embodiment also provides an electric ship, which adopts the power switching control system of the marine power system in the above embodiment. Since the ship adopts the power switching control system in this embodiment, the occurrence of circulating current during the switching process can be reduced or avoided.

[0030] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A power switching control system for a marine power system, the control system comprising a power supply battery cluster, a battery cluster to be switched, a power monitoring unit, and an energy control unit, characterized in that: The control system also includes a DC bus, a boost bus, and a supercapacitor; the power supply battery cluster is connected to the boost bus and the DC bus respectively through a first switch system; the battery cluster to be switched is connected to the boost bus and the DC bus respectively through a second switch system, and the boost bus is connected to the DC bus through a supercapacitor; the DC bus is used to provide DC power to the load; the power monitoring unit is used to monitor the power of the power supply battery cluster and the battery cluster to be switched respectively, and its output end is connected to the energy control unit; the output end of the energy control unit is connected to the first switch system and the second switch system respectively, and based on the first switch system and the second switch system, the power supply of the power supply battery cluster and the battery cluster to be switched is controlled to be connected to the boost bus and the DC bus.

2. A power switching control system for a marine power system as claimed in claim 1, characterized in that: The first switch system and the second switch system each include a boost bus switch and a DC bus switch.

3. A power switching control system for a marine power system according to claim 2, characterized in that: The boost bus switch and the DC bus switch are both electrically controlled switches.

4. A power switching control system for a marine power system according to claim 3, characterized in that: The electronically controlled switch is a relay.

5. A power switching control system for a marine power system according to any one of claims 1 to 4, characterized in that: The control system also includes a power replenishment system, which is connected to the supercapacitor through a power replenishment switch and is used to charge the supercapacitor to keep the power of the supercapacitor stable; the output end of the energy control unit is connected to the power replenishment switch and is used to control the closing and opening of the power replenishment switch.

6. A power switching control system for a marine power system according to claim 4, characterized in that: The control system further comprises a supplementary power monitoring unit, which is connected to the energy control unit, and the energy control unit drives and controls the action of the supplementary power switch according to the monitored power of the supplementary power monitoring unit.

7. A power switching control system for a marine power system according to any one of claims 1 to 4, characterized in that: The control system further comprises a circulation sensor, an output end of which is connected to an energy control unit, and an output end of which is connected to an alarm.

8. An electric ship, characterized in that: The electric ship adopts the power switching control system of the marine power system as described in any one of claims 1-7.

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