Marine charging and discharging device

Abstract

The invention relates to a charging and discharging device for a ship, which integrates reversible energy charging and discharging, and adopts AC / DC high-frequency rectification and DC / DC high-frequency isolation technologies in the charging and discharging process of a storage battery, so that the weight and the size of the device are reduced, and high power factor and low harmonic pollution of a grid side can be realized; the device comprises two independent charging and discharging branches to realize the charging and discharging operation of two groups of marine storage batteries, and under normal conditions, each branch can independently charge or discharge the storage battery of the branch, and can also crossly charge or discharge the storage battery of the other branch; under the condition of heavy load, the two charging and discharging branches can be connected in parallel for operation, and any group of storage batteries can be independently charged or discharged; when a certain branch of the equipment fails or the equipment needs to be charged and discharged strongly, the multiple charging and discharging modes ensure that the equipment can still smoothly perform charging and discharging operation on the two groups of storage batteries, the reliability of the charging and discharging operation of the storage batteries is improved, and uninterrupted power supply of the marine storage batteries is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of charging, and particularly to a marine charging and discharging device. Background Art

[0002] The marine charging and discharging device is mainly used for charging and discharging the marine UPS battery. Inside it, power electronics technology is mainly used to convert the alternating current of the marine main power grid into direct current to charge and discharge the marine battery. The existing marine charging and discharging devices have the following disadvantages:

[0003] 1. Its power conversion usually uses a power frequency transformer for isolation transformation and then AC / DC rectification charging. The device with a power frequency transformer in the main circuit is large in volume and heavy in weight, and it is difficult to meet the requirements of miniaturization and lightweight for marine use;

[0004] 2. When the marine UPS battery is discharged and maintained, the discharging device usually uses the energy consumption method. Through power conversion, it acts on the energy consumption resistor to generate heat and consume it, without being fed back to the power grid, resulting in waste of electric energy;

[0005] 3. The charging and discharging device adopts a single - power - supply design, which is not conducive to capacity expansion. Charging and discharging devices with different capacities require the design of charging and discharging devices with different powers. Summary of the Invention

[0006] In view of the above problems, a marine charging and discharging device is proposed.

[0007] The technical solution of the present invention is as follows: A marine charging and discharging device is connected between an AC380V AC power grid and a battery, and has 1 three - phase AC380V interface and 2 DC220V battery interfaces; inside the device, there are 3 circuit breakers QF1 - QF3, 2 groups of bidirectional power units, 2 groups of contactors, 1 auxiliary power supply, 1 display and control unit, and 2 monitoring units;

[0008] The 3 circuit breakers are used for power distribution protection of AC380V electricity. Circuit breakers QF1 and QF2 are respectively connected between the three - phase AC380V interface and the AC ends of the 2 groups of bidirectional power units, and circuit breaker QF3 is connected between the three - phase AC380V interface and the auxiliary power supply and the fan control circuit;

[0009] The 2 groups of bidirectional power units internally use single or multiple bidirectional power modules in parallel. Each bidirectional power unit realizes bidirectional energy flow, converts AC380V alternating current into DC220V direct current for output to charge the DC220V battery, or discharges the battery DC220V and feeds it back to the AC380V AC power grid;

[0010] One group of contactors KM1 and KM3 in the two groups of contactors are connected in series. The series connection point of the two contactors is connected to a DC220V battery interface, and the other ends of the two contactors far from the series connection point are respectively connected to the DC terminals of the two groups of bidirectional power units; the other group of contactors KM2 and KM4 are connected in series. The series connection point of these two contactors is connected to another DC220V battery interface, and the other ends of the two contactors far from the series connection point are also respectively connected to the DC terminals of the two groups of bidirectional power units; the two groups of contactors are controlled to switch, and are used for various charge and discharge modes such as individual charge and discharge, cross charge and discharge, and parallel charge and discharge.

[0011] The auxiliary power supply combines and converts the AC380V three-phase voltage and the voltage of the battery pack into a stable DC24V output to supply power to two monitoring units, a display and control unit, and the internal fan of the equipment;

[0012] The display and control unit is used to output control signals and centrally transmit them to the two monitoring units through the CAN network. At the same time, it receives communication information from the monitoring units through the CAN network, issues charge and discharge parameters, and displays the current status and fault information of the charge and discharge device;

[0013] The two groups of bidirectional power units are correspondingly connected to two monitoring units. The two monitoring units communicate with each other. Each monitoring unit receives the parameters issued by the display and control unit and start / stop instructions through the CAN, monitors the charge and discharge information of each bidirectional power module and uniformly controls it, and correspondingly controls the contactor to connect to the corresponding battery pack according to one of the individual charge and discharge, cross charge and discharge, and parallel charge and discharge modes selected by the display and control unit.

[0014] Preferably, the bidirectional power module includes two-stage circuits. The front stage is a PWM rectifier circuit for AC / DC conversion, and the rear stage is a DC / DC isolation voltage regulation circuit for electrical isolation and output current regulation or voltage regulation control.

[0015] Preferably, the PWM rectifier circuit is a two-level PWM rectifier circuit or a three-level PWM rectifier circuit with bidirectional flow.

[0016] Preferably, the DC / DC isolation voltage regulation circuit is a bidirectional LLC+BuckBoost conversion circuit, or a bidirectional phase-shifted full-bridge circuit, or a CLLC bidirectional circuit.

[0017] Preferably, the two monitoring units respectively interact with the two groups of bidirectional power units for status and control information through the CAN1 and CAN2 networks.

[0018] Preferably, the two monitoring units interact with the display and control unit for status and control information through the CAN3 network.

[0019] A charging and discharging method for a marine charging and discharging device, where the two groups of contactors in the marine charging and discharging device are controlled and switched by the output of two monitoring units IO, and various charging and discharging modes such as individual charging and discharging, cross charging and discharging, and parallel charging and discharging are carried out. The specific method is as follows:

[0020] 1) When individual charging and discharging is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the contactor KM1. Then, branch A performs charging and discharging operations on the first battery pack; the monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the contactor KM4. Then, branch B performs charging and discharging operations on the second battery pack 2.

[0021] 2) When cross charging and discharging is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the contactor KM2. Then, branch A performs charging and discharging operations on the second battery pack; the monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the contactor KM3. Then, branch B performs charging and discharging operations on the first battery pack.

[0022] 3) When parallel charging and discharging to the first battery pack is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the contactor KM1. The monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the contactor KM3. Then, the bidirectional power modules of branches A and B simultaneously perform parallel charging and discharging operations on the first battery pack.

[0023] 4) When parallel charging and discharging to the second battery pack is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the contactor KM2. The monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the contactor KM4. Then, the bidirectional power modules of branches A and B simultaneously perform parallel charging and discharging operations on the second battery pack.

[0024] The beneficial effects of the present invention are as follows: The marine charging and discharging device of the present invention integrates reversible energy charging and discharging. It can not only charge the battery pack but also invert and grid-connect for discharging. The inversion and grid-connection for discharging eliminate the volume of the energy consumption resistor during the maintenance of marine batteries; during the charging and discharging process of the battery, AC / DC high-frequency rectification and DC / DC high-frequency isolation technologies are adopted to reduce the weight and volume of the device, and high power factor on the grid side and low harmonic pollution can also be achieved; the device contains 2 independent charging and discharging branches to realize the charging and discharging operations for two groups of marine batteries. Under normal circumstances, each branch can independently charge or discharge the batteries of this branch, or cross-charge or discharge the batteries of another branch; under heavy load conditions, the 2 charging and discharging branches can operate in parallel to independently charge or discharge any group of batteries; when a certain branch of the equipment fails or the equipment needs strong charging and discharging, the above-mentioned various charging and discharging modes ensure that the equipment can still smoothly charge and discharge the 2 groups of batteries, improving the reliability of the battery charging and discharging operations and ensuring uninterrupted power supply of marine batteries; the present invention can be extended to multiple independent units to perform charging and discharging operations on multiple groups of battery packs. Brief Description of the Drawings

[0025] Figure 1 is the main circuit diagram of the marine charging and discharging device of the present invention;

[0026] Figure 2 is the internal topology diagram of the bidirectional power module in the device of the present invention. Detailed Embodiment

[0027] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manner and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0028] As Figure 1 shown in the main circuit diagram of the marine charging and discharging device, the device is connected between the AC380V AC power grid and the battery, and has 1 three-phase AC380V interface and 2 DC220V battery interfaces for connecting the battery. The device internally contains 3 circuit breakers QF1-QF3, 2 groups of bidirectional power units, 2 groups of contactors, 1 auxiliary power supply and fan control circuit, 1 display and control unit, and 2 monitoring units.

[0029] The 3 circuit breakers are used for the power distribution protection of AC380V electricity. Among them, 2 circuit breakers QF1 and QF2 provide AC power distribution and protection for 2 groups of bidirectional power units, and the other input circuit breaker QF3 provides AC power distribution and protection for the auxiliary power supply and fan control circuit.

[0030] Inside the two sets of bidirectional power units, single or multiple bidirectional power modules are connected in parallel. Each bidirectional power unit can achieve bidirectional energy flow. Each bidirectional power module adopts AC / DC high-frequency rectification and bidirectional DC / DC high-frequency isolation technologies to convert AC 380V alternating current into DC 220V direct current for charging the DC 220V battery, or discharging the DC 220V of the battery to feed power into the AC 380V alternating current grid.

[0031] One set of contactors KM1 and KM3 are connected in series. The series connection point of the two contactors is connected to one DC 220V battery interface, and the other ends of the two contactors far from the series connection point are respectively connected to the DC terminals of the two sets of bidirectional power units; another set of contactors KM2 and KM4 are connected in series. The series connection point of these two contactors is connected to another DC 220V battery interface, and the other ends of the two contactors far from the series connection point are also respectively connected to the DC terminals of the two sets of bidirectional power units; the two sets of contactors are controlled to switch for various charge and discharge modes such as individual charge and discharge, cross charge and discharge, and parallel charge and discharge.

[0032] The auxiliary power supply combines and converts the three-phase voltage and the voltage of the battery pack into a stable DC 24V output to provide power for two monitoring units, a display and control unit, internal fans of the device, etc.

[0033] The display and control unit is used for power indication, output indication, fault indication, alarm indication, mute button, automatic / manual selection, start / stop selection, charge / discharge selection, charge and discharge branch selection, charge and discharge parameter setting, etc. for the corresponding branch. These signals are centrally transmitted to the two monitoring units through the CAN network. At the same time, it receives the communication information of the monitoring unit through the CAN network, issues charge and discharge parameters, and uses the human-machine interface to display the current state and fault information of the charge and discharge device.

[0034] The two sets of bidirectional power units are correspondingly connected to two monitoring units. The two monitoring units communicate with each other. Each monitoring unit receives the parameters issued by the display and control unit and start / stop instructions through the CAN, monitors the charge and discharge information of each bidirectional power module and controls them uniformly, and controls the contactor to connect the corresponding battery pack. In the present invention, the display and control unit sets the individual charge and discharge, cross charge and discharge, and parallel charge and discharge modes, and then the monitoring unit issues commands to control the corresponding contactors to achieve various power consumption modes of the battery. For example, under normal circumstances, each branch can charge or discharge the battery of this branch alone, or cross-charge the battery of another branch; under heavy load conditions, the two charge and discharge branches can operate in parallel to charge or discharge any one set of batteries alone; when a certain branch of the device fails or the device needs strong charge and discharge, the above-mentioned various charge and discharge modes ensure that the device can still charge and discharge the two sets of batteries smoothly.

[0035] Inside each group of bidirectional power units, multiple bidirectional power modules can operate in parallel. The number of parallel modules ranges from 1 to 8, and more parallel branches can be added depending on the charging power requirements.

[0036] The internal power conversion of the bidirectional power module is mainly divided into two levels. The front stage is a PWM rectifier circuit for AC / DC conversion, and the rear stage is a DC / DC isolation voltage regulation circuit for electrical isolation and output current or voltage regulation control. Due to the requirements of charging and discharging, the topological structures of the two-level circuits must be able to have the function of bidirectional flow. The front-stage AC / DC circuit of this device is not limited to the selected two-level PWM rectifier circuit, and other bidirectional flow topological structures can also be used, such as three-level PWM rectifier circuits, etc.; the rear-stage DC / DC circuit is not limited to the selected LLC+BuckBoost conversion circuit, and other bidirectional flow isolation voltage regulation topologies can also be used, such as bidirectional phase-shifted full-bridge circuits, CLLC bidirectional circuits, etc. As Figure 2 shown in the internal topology diagram of the bidirectional power module.

[0037] The two groups of contactors mentioned above are controlled and switched by the IO outputs of two monitoring units, and are used for various charging and discharging modes such as individual charging and discharging, cross charging and discharging, and parallel charging and discharging:

[0038] 1) When individual charging and discharging is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the KM1 contactor. Then, branch A performs charging and discharging operations on battery pack 1; the monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the KM4 contactor. Then, branch B performs charging and discharging operations on battery pack 2;

[0039] 2) When cross charging and discharging is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the KM2 contactor. Then, branch A performs charging and discharging operations on battery pack 2; the monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the KM3 contactor. Then, branch B performs charging and discharging operations on battery pack 1;

[0040] 3) When parallel charging and discharging to battery pack 1 is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the KM1 contactor. The monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the KM3 contactor. Then, the bidirectional power modules of branches A and B simultaneously perform parallel charging and discharging operations on battery pack 1;

[0041] 4) When the parallel charge and discharge of the battery pack 2 is selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the contactor KM2. The monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the contactor KM4. Then, the bidirectional power modules of branches A and B perform parallel charge and discharge operations on the battery pack 2 simultaneously.

[0042] The auxiliary power supply takes the three-phase voltage and the voltages of two battery packs as the comprehensive input, and after being converted by three sets of auxiliary power supplies respectively and merged, it outputs a stable DC24V to provide DC24V power for the monitoring unit, the display and control unit, the internal fan of the equipment, etc.

[0043] The display and control unit uses a human-machine interface to display the current parameters, status and fault information of the charge and discharge device, including power indication, output indication, fault indication, alarm indication, mute button, automatic / manual selection, start / stop selection, charge / discharge selection, charge and discharge branch selection, charge and discharge parameter setting, etc. for two branches. The display and control unit transmits the operation parameter setting and start / stop signals to the two monitoring units through the CAN3 network, and the two monitoring units then start the bidirectional power modules and the corresponding branch contactors of their respective branches respectively. At the same time, the display and control unit also receives the status and fault information uploaded by the monitoring unit through the CAN3 network.

[0044] The two monitoring units are used for the interaction of status and control information between the monitoring units of branches A and B and the display and control unit through the CAN3 network. They receive the operation parameter setting and start / stop signals sent by the display and control unit, and at the same time, they also send the status and fault information uploaded by the bidirectional power module and themselves through the CAN3 network. Due to the limited control IO ports of the display and control unit, the monitoring units of branches A and B are mainly used for forwarding control information and status information, and for the expansion and use of control IO and other interfaces.

[0045] The two monitoring units communicate downward through the CAN1 and CAN2 networks respectively. The CAN1 communication is used for the interaction of status and control information between the monitoring unit of branch A and the bidirectional power unit of branch A; the CAN2 communication is used for the interaction of status and control information between the monitoring unit of branch B and the bidirectional power unit of branch B.

[0046] The above embodiments only represent the specific implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A marine charging and discharging device, characterized in that: It is connected between the AC380V AC grid and the battery, and has one 3-phase AC380V interface and two DC220V battery interfaces. The device contains three circuit breakers QF1~QF3, two sets of bidirectional power units, two sets of contactors, one auxiliary power supply, one display and control unit and two monitoring units. The three circuit breakers are used for AC380V power distribution protection. Circuit breakers QF1 and QF2 are respectively connected between the three-phase AC380V interface and the AC ends of two sets of bidirectional power units, and circuit breaker QF3 is connected between the three-phase AC380V interface and the auxiliary power supply and fan control circuit; The two groups of bidirectional power units use a single or multiple bidirectional power modules in parallel, and each bidirectional power unit realizes a bidirectional flow of energy, converting AC380V alternating current into DC220V direct current output to charge the DC220V battery, or discharging the DC220V battery to feed the AC380V alternating current grid; Among the two groups of contactors, one group of contactors KM1 and KM3 are connected in series, and the series connection point of the two contactors is connected to a DC220V battery interface, and the other ends of the two contactors away from the series connection point are respectively connected to the DC ends of two groups of bidirectional power units; another group of contactors KM2 and KM4 are connected in series, and the series connection point of the two contactors is connected to another DC220V battery interface, and the other ends of the two contactors away from the series connection point are also respectively connected to the DC ends of two groups of bidirectional power units; the two groups of contactors are used for various charging and discharging modes such as individual charging and discharging, cross charging and discharging, and parallel charging and discharging through control switching. The auxiliary power supply combines the AC380V three-phase voltage and the voltage of the battery pack into a stable DC24V output to power the two monitoring units, the display and control unit, and the internal fan of the equipment; The display and control unit is used to output control signals and transmit them to the two monitoring units through the CAN network, and at the same time receive communication information from the monitoring units through the CAN network, send charging and discharging parameters, and display the current status and fault information of the charging and discharging device; The two groups of bidirectional power units are connected to two monitoring units correspondingly, and the two monitoring units communicate with each other. Each monitoring unit receives parameters and start and stop instructions sent by the display and control unit through CAN, monitors the charging and discharging information of each bidirectional power module and controls it uniformly, and controls the contactor to connect the corresponding battery group according to one of the respective charging and discharging, cross charging and discharging, and parallel charging and discharging modes selected by the display and control unit.

2. The marine charging and discharging device according to claim 1, characterized in that: The bidirectional power module includes two-stage circuits, the front stage is a PWM rectifier circuit for AC / DC conversion, and the rear stage is a DC / DC isolation voltage regulation circuit for electrical isolation and output current or voltage regulation control.

3. The marine charging and discharging device according to claim 2, characterized in that: The PWM rectification circuit is a two-level PWM rectification circuit or a three-level PWM rectification circuit with bidirectional flow.

4. The marine charging and discharging device according to claim 2, characterized in that: The DC / DC isolation voltage regulation circuit is a bidirectional LLC+BuckBoost conversion circuit, or a bidirectional phase-shifted full-bridge circuit, or a CLLC bidirectional circuit.

5. The marine charging and discharging device according to any one of claims 1 to 4, characterized in that: The two monitoring units exchange status and control information with two groups of bidirectional power units via CAN1 and CAN2 networks respectively.

6. The marine charging and discharging device according to claim 5, characterized in that: The two monitoring units exchange status and control information with the display and control unit via the CAN3 network.

7. A charging and discharging method for a marine charging and discharging device, characterized in that: The two groups of contactors in the marine charging and discharging device described in claim 5 are switched by the IO output control of the two monitoring units to perform charging and discharging in various charging and discharging modes such as individual charging and discharging, cross charging and discharging, and parallel charging and discharging. The specific method is as follows: 1) When charging and discharging are selected, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network, and closes the KM1 contactor, and then branch A performs charging and discharging operations on the first battery pack; the monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network, and closes the KM4 contactor, and then branch B performs charging and discharging operations on the second battery pack 2; 2) When cross-charging and discharging is selected, the A branch monitoring unit sends a start command to the A branch bidirectional power module through the CAN1 network, and closes the KM2 contactor, and then the A branch performs charging and discharging operations on the second battery pack; the B branch monitoring unit sends a start command to the B branch bidirectional power module through the CAN2 network, and closes the KM3 contactor, and then the B branch performs charging and discharging operations on the first battery pack; 3) When the first battery pack is selected for parallel charging and discharging, the A branch monitoring unit sends a start command to the A branch bidirectional power module through the CAN1 network and attracts the KM1 contactor, and the B branch monitoring unit sends a start command to the B branch bidirectional power module through the CAN2 network and attracts the KM3 contactor, and then the bidirectional power modules of the A and B branches simultaneously perform parallel charging and discharging operations on the first battery pack; 4) When it is selected to charge and discharge the second battery pack in parallel, the monitoring unit of branch A sends a start command to the bidirectional power module of branch A through the CAN1 network and closes the KM2 contactor. The monitoring unit of branch B sends a start command to the bidirectional power module of branch B through the CAN2 network and closes the KM4 contactor. After that, the bidirectional power modules of branches A and B simultaneously charge and discharge the second battery pack in parallel.

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