A control system for balanced parallel branches of a ship power system and a ship

Abstract

The utility model discloses a control system for a balanced parallel branch of a ship power system, the control system includes a power supply battery cluster, a battery cluster to be switched, a DC bus, a step-down bus, a voltage regulating resistor, a control unit, and a power monitoring unit. The power supply battery cluster and the battery cluster to be switched are connected to the step-down bus through a first switch and a second switch respectively; the power supply battery cluster and the battery cluster to be switched are connected to the DC bus through a third switch and a fourth switch respectively; the DC bus is connected to the step-down bus through a voltage regulating resistor; the power monitoring unit is used to monitor the power of the power supply battery cluster and / or the battery cluster to be switched, and its output end is connected to the control unit, and the output end of the control unit is connected to the first switch, the second switch, the third switch, and the fourth switch respectively, for controlling the opening and closing state of each switch respectively. This scheme avoids the circulation caused by the parallel connection of two battery systems with excessive pressure difference by increasing the resistance to reduce the voltage.

Description

Technical Field

[0001] The utility model relates to the field of ship power systems, and in particular to a control system for balanced parallel branches of a ship power system and a 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. Batteries are generally used as the power source. The batteries are set in different cabins. Considering safety, the ship 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 busbar, 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 it is necessary to avoid circulation. The solution commonly used in the prior art is to add a DC / DC converter, but adding a DCDC converter will reduce the overall efficiency of the power system by about 3-5%, affecting the energy supply of the entire ship, and the increase of the DCDC converter will also greatly increase the cost, making the control system more complicated.

[0003] For example, the patent application number is 202010663989.X, which discloses a method for controlling the constant voltage and current sharing of multiple electric ship chargers in parallel. It discloses that the control coefficient of each charger is obtained by detecting the output voltage, output current and battery voltage of the electric ship energy storage component of several chargers, and then the output voltage command value of the charger is adjusted to make the output current of several chargers tend to the average charging current, thus avoiding the circulation and uneven current between several chargers. Although this patent also solves the circulation problem, it does not solve the circulation in the case of power switching, but solves the circulation between multiple chargers, and is based on controlling the output voltage of the charger, and cannot solve the circulation problem caused by the different voltages of battery clusters in different compartments. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the prior art and to provide a control system and a ship for balancing parallel branches of a ship's power system. The purpose of simple balancing parallel branches is achieved by adding adjustable resistors. By using series resistors, the resistors are first connected in series with a fully charged battery system before switching power, and the voltage of the fully charged battery is reduced to the same as that of the battery system to be replaced. The battery system is then switched, and after the switching is completed, the resistors are disconnected from the circuit to reduce or even avoid the generation of circulating current.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a control system for balanced parallel branches of a ship power system, the control system includes a power supply battery cluster, a battery cluster to be switched, a DC bus, a step-down bus, a voltage regulating resistor, a control unit, and a power monitoring unit. The power supply battery cluster and the battery cluster to be switched are connected to the step-down bus through a first switch and a second switch, respectively; the power supply battery cluster and the battery cluster to be switched are connected to the DC bus through a third switch and a fourth switch, respectively; the DC bus is connected to the step-down bus through a voltage regulating resistor; the power monitoring unit is used to monitor the power of the power supply battery cluster and / or the battery cluster to be switched, and its output end is connected to the control unit, and the output ends of the control unit are respectively connected to the first switch, the second switch, the third switch, and the fourth switch, for respectively controlling the opening and closing states of each switch.

[0006] The voltage regulating resistor is an adjustable resistor, and the adjustable resistor string is controlled by a control unit.

[0007] The adjustable resistor comprises a plurality of resistor strings connected in series in sequence, and an adjustable switch is arranged in parallel at both ends of each resistor string; and the control end of the adjustable switch is connected to the output end of the control unit.

[0008] At least one resistor string among a plurality of resistor strings connected in series in sequence is used as a heating resistor string, and the heating resistor string is arranged on a power supply battery cluster and / or a battery cluster to be switched, and an input end of the control unit is connected to a temperature sensor, and the temperature sensor is used to collect temperature data of the battery cluster; an output end of the control unit is connected to an adjustable switch connected in parallel at both ends of the heating resistor string, and is used to control the closing and opening of the adjustable switches at both ends of the heating resistor string according to the temperature data of the battery cluster.

[0009] 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.

[0010] The first switch, the second switch, the third switch and the fourth switch are all electrically controlled switches.

[0011] The electronically controlled switch includes a relay.

[0012] A ship comprises the control system for balanced parallel branches of the ship power system.

[0013] The advantages of the utility model are: by increasing the resistance to reduce the voltage, the circulation caused by the parallel connection of two battery systems with too large a pressure difference is avoided, thereby optimizing the energy output of the battery; the scheme for reducing the circulating current only needs to add an adjustable resistor and a corresponding electronic switch, which is low-cost, simple and reliable; the heat generated by the adjustable resistor during operation can be recycled to heat the battery, thereby reducing energy waste; the circulating current can be monitored and an alarm can be issued 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 a schematic diagram of electrical connections of the control system of the utility model;

[0016] Figure 2 It is a schematic diagram of an adjustable resistor of the utility model;

[0017] Figure 3 This is the control principle diagram of the utility model.

[0018] The marks in the above figures are: 1, first switch; 2, second switch; 3, third switch; 4, fourth switch. DETAILED DESCRIPTION

[0019] 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.

[0020] This solution uses a series resistor. Before switching power, the resistor is first connected in series with the fully charged battery system. The voltage of the fully charged battery is reduced to the same as the battery system to be replaced through resistor voltage division, and then the battery system is switched. After the switch is completed, the resistor is disconnected from the circuit, thereby achieving the purpose of reducing the circulating current or avoiding the circulating current during switching.

[0021] like Figure 1 , 2 3. A control system for balanced parallel branches of a ship power system, comprising a power supply battery cluster, a battery cluster to be switched, a DC bus, a step-down bus, a voltage regulating resistor, a control unit, and a power monitoring unit. The power supply battery cluster and the battery cluster to be switched are connected to the step-down bus via a first switch and a second switch respectively; the power supply battery cluster and the battery cluster to be switched are connected to the DC bus via a third switch and a fourth switch respectively; the DC bus is connected to the step-down bus via a voltage regulating resistor; the power monitoring unit is used to monitor the power of the power supply battery cluster and / or the battery cluster to be switched, and its output end is connected to the control unit, and the output ends of the control unit are respectively connected to the first switch, the second switch, the third switch, and the fourth switch, so as to control the opening and closing states of each switch respectively.

[0022] The power supply battery cluster refers to the battery cluster in the power supply state, and the battery cluster to be switched refers to the fully charged battery cluster that needs to be switched for power supply; Figure 1When battery cluster A is in the power supply state and the power is low to the set threshold, it is necessary to switch to battery cluster B. Then battery cluster A is the power supply battery cluster, and battery cluster B is the battery cluster to be switched. The first switch, the second switch, the third switch, and the fourth switch are all electronically controlled switches. The electronically controlled switches are controlled by the control unit, that is, the output end of the control unit is connected to the control end of the electronically controlled switch, which is used to control the closing and opening of each electronically controlled switch. The electronically controlled switches include relays, contactors, switch tubes and other electronically controlled switches. The step-down bus and the DC bus are connected through a voltage regulating resistor. Only by setting a suitable voltage regulating resistor can the purpose of avoiding or reducing the circulating current be met during switching. The power monitoring unit is used to detect the power of battery clusters ABC and the like. Only based on the power can it be determined whether it is necessary to switch the power supply. Generally, a voltage sensor is used to collect the voltage at both ends of the battery cluster to characterize the power. When the voltage drops to a certain voltage threshold, it is considered that the battery cluster is low in power and needs to switch to a fully charged battery cluster for power supply. The voltage signal at both ends of the battery cluster can be collected by a voltage transformer or a resistor divider circuit. The control unit is used in this solution to control various switches and other functions. It can reuse the energy management system EMS in the ship power system as a control unit or add a common microcontroller such as STM32 to realize the function. In this embodiment, the main control chip of the EMS system is reused to save costs.

[0023] Its working principle is: when battery cluster A supplies power to the load, the third switch is closed. When it is detected that the power of battery cluster A is lower than the set threshold, it is necessary to switch to battery cluster B for power supply; at this time, the second switch of battery cluster B is closed. At this time, battery cluster B is connected to the DC bus through the voltage regulating resistor. The voltage after voltage reduction is consistent with the voltage of battery cluster A or has only a small difference, so the circulating current is very small or non-existent; at this time, the third switch is disconnected, and then the fourth switch is closed. After the fourth switch is closed, the second switch is disconnected, thereby realizing power switching without circulating current. Switching from battery cluster B to battery cluster C is similar.

[0024] The voltage regulating resistor is an adjustable resistor, which is controlled by the control unit and the resistance value is determined by the control unit. In this way, the resistance value can be adjusted according to the detected voltage of battery cluster A and the voltage of battery cluster B to ensure that the voltages of the two are consistent or close. Figure 2As shown, the adjustable resistor includes a plurality of resistor strings connected in series, and an adjustable switch is arranged in parallel at both ends of each resistor string; the control end of the adjustable switch is connected to the output end of the control unit. The adjustable switch can be an electronic switch such as a relay, a contactor, a switch tube, etc., and its control end is connected to the control unit, and is used to drive and control according to the control signal of the control unit to realize opening and closing, and then adjust the resistance value, because each resistor string is provided with a switch at both ends, when the switch is disconnected, all resistors are connected in series to obtain the total resistance; when the resistance value needs to be reduced, the switches corresponding to the two ends of one or more resistor strings can be closed, so that the switch will short-circuit the resistor string and cut the resistor string out of the series loop, so that the resistance value of the adjustable resistor is removed by the resistance value of the resistor string with the closed adjustable switch, and the resistance value of the remaining resistor string without the closed adjustable switch is added, so that the resistance value of the adjustable resistor can be quickly adjusted.

[0025] Since the resistor consumes electricity in the form of heat during the switching process, resulting in energy waste, in order to reduce energy waste, the resistor heat can be converted and utilized, and in this embodiment, it is used as a heating heat source for the battery cluster; that is, at least one resistor string among multiple resistor strings connected in series is used as a heating resistor string, the number of heating resistor strings is greater than one but less than the number of all battery strings, and the heating resistor string is set on the power supply battery cluster and / or the battery cluster to be switched, and is used to heat the battery cluster through resistor heat; the input end of the control unit is connected to the temperature sensor, and the temperature sensor is used to collect the temperature data of the battery cluster; the output end of the control unit is connected to the adjustable switch connected in parallel at both ends of the heating resistor string, and is used to control the closing and opening of the adjustable switches at both ends of the heating resistor string according to the temperature data of the battery cluster. The heating resistor string can be directly set on the battery cluster or the heating resistor string is set on a metal heat conducting plate, and then the metal heat conducting plate is installed on the battery cluster, and the metal heat conducting plate and the battery cluster are kept in direct contact, so that the heat generated by the heating resistor string can heat the battery cluster. However, heating is not required at all times. Whether heating is required needs to be determined based on the temperature of the battery cluster. The temperature data of the battery cluster can be detected by the temperature sensor, and then whether the battery needs to be heated is determined based on the temperature. If necessary, when switching the battery cluster, the adjustable switches at both ends of the heating resistor string are kept disconnected, so that the heating resistor string is in a working state when switching between two battery clusters, and can generate heat to heat the battery cluster. When it is not needed, the switches at both ends of the heating resistor string are kept closed, so that the heating resistor string can be short-circuited. When the two battery clusters are switched, the heating resistor string is short-circuited and cut out, and will not generate heat. The above-mentioned heating resistor string can reduce energy waste to a certain extent, and energy can be recovered in certain specific cases.

[0026] In a preferred embodiment, the control system of the present solution further includes a circulating current sensor, the output end of which 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.

[0027] 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.

[0028] Through the scheme in this embodiment, the circulation can be reduced or avoided. When the system is running, the third switch of battery cluster A is closed, and other switches are disconnected. The electric energy is directly connected to the busbar through the closed third switch. The power and voltage of the battery cluster are sent to the EMS through the collection module in the cluster. When the power of battery cluster A is exhausted, the EMS will recognize that the voltage has dropped to the cut-off voltage, and send an instruction to the battery system to close the second switch of battery cluster B. At this time, battery cluster B is connected in series with the voltage regulating resistor to the busbar. Through the voltage division of the resistor, the voltage of battery cluster B drops to the same as that of battery cluster A, avoiding the circulation between battery clusters. After battery cluster B provides electric energy to the system, the third switch of battery cluster A is disconnected, and the connection between battery cluster A and the busbar is disconnected. Finally, the fourth switch of battery cluster B is closed, and the second switch of battery cluster B is disconnected to realize the power switching process without interruption of power. The resistance value of the voltage regulating resistor used in this embodiment should be adjustable, and the adjustment range depends on the voltage difference between the two battery systems.

[0029] 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 control system for balanced parallel branches of a ship power system, characterized in that: The control system includes a power supply battery cluster, a battery cluster to be switched, a DC bus, a step-down bus, a voltage regulating resistor, a control unit, and a power monitoring unit. The power supply battery cluster and the battery cluster to be switched are connected to the step-down bus through a first switch and a second switch, respectively; the power supply battery cluster and the battery cluster to be switched are connected to the DC bus through a third switch and a fourth switch, respectively; the DC bus is connected to the step-down bus through a voltage regulating resistor; the power monitoring unit is used to monitor the power of the power supply battery cluster and / or the battery cluster to be switched, and its output end is connected to the control unit, and the output ends of the control unit are respectively connected to the first switch, the second switch, the third switch, and the fourth switch, and are used to control the opening and closing states of each switch, respectively.

2. A control system for balanced parallel branches of a ship power system according to claim 1, characterized in that: The voltage regulating resistor is an adjustable resistor, and the adjustable resistor string is controlled by a control unit.

3. A control system for balanced parallel branches of a ship power system according to claim 1, characterized in that: The voltage regulating resistor comprises a plurality of resistor strings connected in series in sequence, and an adjustable switch is arranged in parallel at both ends of each resistor string; and the control end of the adjustable switch is connected to the output end of the control unit.

4. A control system for balanced parallel branches of a ship power system as claimed in claim 3, characterized in that: At least one resistor string among a plurality of resistor strings connected in series in sequence is used as a heating resistor string, and the heating resistor string is arranged on a power supply battery cluster and / or a battery cluster to be switched, and an input end of the control unit is connected to a temperature sensor, and the temperature sensor is used to collect temperature data of the battery cluster; an output end of the control unit is connected to an adjustable switch connected in parallel at both ends of the heating resistor string, and is used to control the closing and opening of the adjustable switches at both ends of the heating resistor string according to the temperature data of the battery cluster.

5. A control system for balanced parallel branches of a ship 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.

6. A control system for balanced parallel branches of a ship power system according to any one of claims 1 to 4, characterized in that: The first switch, the second switch, the third switch and the fourth switch are all electrically controlled switches.

7. A control system for balanced parallel branches of a ship power system according to claim 6, characterized in that: The electronically controlled switch includes a relay.

8. A ship, characterized in that: The ship comprises a control system for balanced parallel branches of a ship power system as described in any one of claims 1 to 7.

Images