Charging control device

Abstract

The present invention provides a charge control device that suppresses the discharge of a capacitor due to fluctuations in the power output of a generator during its operation. [Solution] In the ship propulsion system 5, the charging control device 7 comprises an AC generator 14, an inverter 15 that rectifies the power generated by the AC generator, a low-voltage battery 25 and a capacitor 16 connected in parallel to the inverter, a capacitor relay 19 that switches between connecting and disconnecting the inverter and the capacitor, and a control unit 21 that controls the capacitor relay 19 to connect the inverter and the capacitor when the output voltage VE of the inverter is greater than the voltage VC of the capacitor during the AC generator's power generation operation, and controls the capacitor relay to disconnect the inverter and the capacitor when the inverter and the capacitor are connected and the capacitor is discharging during the AC generator's power generation operation.

Description

Technical Field

[0001] The present invention relates to a charge control device that controls charging of a capacitor or the like.

Background Art

[0002] As a power source for electric devices such as motors, capacitors such as lithium ion capacitors or electric double layer capacitors may be used, for example.

[0003] The outboard motor in the marine propulsion system described in Japanese Patent Laid-Open No. 2022-49254 (Patent Document 1) includes an engine, a starter motor that starts the engine, an AC (Alternating Current) generator that generates electric power using rotation of the crankshaft of the engine, and a capacitor. In the outboard motor, when the engine is started, the starter motor is driven by electric power supplied from the capacitor. In addition, during operation of the engine, electric power generated by the AC generator is subjected to AC-DC conversion by a rectifier circuit and then supplied to the capacitor, and the capacitor is charged by the electric power.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] In the outboard motor of the marine propulsion system described in the above publication, during operation of the engine, the rectifier circuit connected to the AC generator and the capacitor are connected to each other in order to charge the capacitor.

[0006] The power generated by the AC generator decreases as the engine speed decreases. Similarly, the output voltage of the rectifier circuit, i.e., the voltage applied to the capacitor, decreases as the power generated by the AC generator decreases. While the engine is running, with the rectifier circuit connected to the AC generator and the capacitor connected, when the engine speed decreases, the power generated by the AC generator decreases, and as a result the output voltage of the rectifier circuit decreases, the capacitor may discharge. Such capacitor discharge reduces the charging efficiency of the capacitor while the engine is running. Furthermore, if the capacitor is a lithium-ion capacitor, there is a concern about damage to the capacitor due to over-discharge.

[0007] The present invention has been made in view of the circumstances described above, for example, and the object of the present invention is to provide a charge control device that charges a capacitor using the power generated by a generator, and which can suppress the discharge of the capacitor due to fluctuations in the power generated by the generator during the generator's operation. [Means for solving the problem]

[0008] To solve the above problems, the charging control device of the present invention is characterized by comprising: an AC generator; a rectifier unit that converts the power generated by the AC generator from AC to DC; a first battery connected to the rectifier unit and charged by the power supplied from the rectifier unit; a capacitor connected in parallel with the first battery to the rectifier unit and charged by the power supplied from the rectifier unit; a DC-DC converter that converts the voltage output from the rectifier unit from DC to DC and applies it to the first battery; a first switch that switches between connecting and disconnecting the rectifier unit and the capacitor; and a control unit that, when the output voltage of the rectifier unit is greater than the voltage of the capacitor during the power generation operation of the AC generator, connects the rectifier unit and the capacitor by controlling the first switch, and when the rectifier unit and the capacitor are connected and the capacitor is discharging during the power generation operation of the AC generator, disconnects the rectifier unit and the capacitor by controlling the first switch. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress the discharge of the capacitor due to fluctuations in the power generated by the generator during the generator's operation. [Brief explanation of the drawing]

[0010] [Figure 1] This is an explanatory diagram showing a ship propulsion system including an embodiment of the charging control device of the present invention. [Figure 2] This is a circuit diagram showing a ship propulsion system including an embodiment of the charging control device of the present invention. [Figure 3] This flowchart shows the engine starting process in an embodiment of the present invention. [Figure 4] This flowchart shows the charging control process in an embodiment of the present invention. [Figure 5] This flowchart shows the engine stopping process in an embodiment of the present invention. [Modes for carrying out the invention]

[0011] The charging control device according to an embodiment of the present invention comprises an AC generator, a rectifier unit that converts the power generated by the AC generator from AC to DC, a first battery connected to the rectifier unit and charged by the power supplied from the rectifier unit, a capacitor connected in parallel with the first battery to the rectifier unit and charged by the power supplied from the rectifier unit, a DC-DC converter that converts the voltage output from the rectifier unit from DC to DC and applies it to the first battery, a first switch that switches between connecting and disconnecting the rectifier unit and the capacitor, and a control unit that controls the first switch.

[0012] During the AC generator's operation, when the output voltage of the rectifier is greater than the voltage of the capacitor, the control unit controls the first switch to connect the rectifier and the capacitor. As a result, the capacitor is charged by the power supplied from the rectifier.

[0013] Furthermore, during the AC generator's power generation operation, when the rectifier and capacitor are connected and the capacitor is discharging, the control unit controls the first switch to disconnect the rectifier and capacitor. That is, during the AC generator's power generation operation, when the rectifier and capacitor are connected, the power generated by the AC generator decreases due to a decrease in the rotational speed of the power source driving the AC motor, and as a result the output voltage of the rectifier decreases, the capacitor may discharge. When the capacitor is discharging while the rectifier and capacitor are connected, the control unit controls the first switch to disconnect the rectifier and capacitor. This suppresses the discharge of the capacitor.

[0014] Thus, according to the charging control device of the present embodiment, it is possible to suppress discharge of the capacitor caused by fluctuations in the generated power of the AC generator during the power generation operation of the AC generator. Accordingly, it is possible to suppress a decrease in the charging efficiency of the capacitor due to discharge of the capacitor during the power generation operation of the AC generator, and to improve the charging efficiency of the capacitor. Further, when the capacitor is a lithium ion capacitor, damage to the capacitor due to over-discharge of the capacitor can be prevented. [Examples]

[0015] Hereinafter, a marine vessel propulsion system including an embodiment of the charging control device of the present invention will be described.

[0016] (Marine Vessel Propulsion System) Figure 1 shows a marine vessel propulsion system 5 including an embodiment of the charging control device of the present invention. Figure 2 shows an electric circuit of the marine vessel propulsion system 5.

[0017] In Figure 1, the marine vessel propulsion system 5 is a system that propels the marine vessel 1, and is provided in the marine vessel 1. The marine vessel propulsion system 5 includes an outboard motor 11, a low-voltage battery 25, a high-voltage battery 26, a start switch 28, and a stop switch 29.

[0018] The outboard motor 11 is a device that generates propulsive force for the marine vessel 1. The outboard motor 11 is attached to the transom of the marine vessel 1.

[0019] The low-voltage battery 25 is, for example, a lead-acid battery, and its battery voltage is, for example, 12V. The low-voltage battery 25 is provided in the marine vessel 1. The low-voltage battery 25 is used as a low-voltage power source for devices or equipment provided in the marine vessel 1 or the outboard motor 11. The low-voltage battery 25 is a specific example of the "first battery".

[0020] The high-voltage battery 26 is, for example, a lithium ion battery, and its battery voltage is, for example, 48V. The high-voltage battery 26 is provided in the vessel 1. The high-voltage battery 26 is used as a high-voltage power source for devices or apparatuses provided in the vessel 1. The high-voltage battery 26 is a specific example of the "second battery".

[0021] The start switch 28 is a switch for starting the engine 12 of the outboard motor 11, and is provided in the cockpit 2 of the vessel 1. The vessel operator can start the engine 12 of the outboard motor 11 by pressing the start switch 28.

[0022] The stop switch 29 is a switch for stopping the engine 12 of the outboard motor 11, and is provided in the cockpit 2 of the vessel 1. The vessel operator can stop the engine 12 of the outboard motor 11 by pressing the stop switch 29.

[0023] (Outboard motor) As shown in FIG. 1, the outboard motor 11 includes an engine 12, a propeller 13, an AC generator 14, an inverter 15, a capacitor 16, a DC (Direct Current)-DC converter 18, a capacitor relay 19, a high-voltage battery relay 20, and a control unit 21.

[0024] The engine 12 is an internal combustion engine, and includes a crankshaft provided in a crankcase, a piston provided in a cylinder, an intake valve, an exhaust valve, a valve mechanism and the like provided in a cylinder head. The engine 12 is further provided with a fuel injection device, an electronically controlled throttle device, an ignition device and the like.

[0025] The propeller 13 is rotated by the power of the engine 12 to generate propulsive force for the vessel 1.

[0026] The AC generator 14 is an AC generator that generates electricity when driven by the power of the engine 12. In this embodiment, the AC generator 14 is a three-phase AC generator. The AC generator 14 also has an ISG (Integrated Starter Generator) structure and functions as a starter motor (three-phase motor) to start the engine 12. The rotor of the AC generator 14 is connected to the crankshaft of the engine 12. Note that the AC generator 14 is a specific example of an "AC generator".

[0027] The inverter 15 is a device that controls the AC generator 14 and functions as a three-phase inverter. The inverter 15 also functions as a three-phase rectifier circuit. The inverter 15 converts the DC power supplied from the capacitor 16 to AC to generate three-phase drive current, and supplies this three-phase drive current to the AC generator 14, thereby powering the AC generator 14 (function as a three-phase inverter). This allows the AC generator 14 to operate as a starter motor. Furthermore, the inverter 15 can convert the three-phase AC power generated by the AC generator 14 to DC and output DC power for charging the capacitor 16, the low-voltage battery 25, and the high-voltage battery 26 (function as a three-phase rectifier circuit). Note that the inverter 15 is a specific example of a "rectifier unit".

[0028] Capacitor 16 is a lithium-ion capacitor. Capacitor 16 is configured such that the terminal voltage is approximately 48V when fully charged. Capacitor 16 is used as a power source when driving the AC generator 14 as a starter motor.

[0029] The DC-DC converter 18 has the function of converting the voltage output from the inverter 15, which is operating as a three-phase rectifier circuit, from DC to DC and stepping it down to a voltage (e.g., 12V) suitable for charging the low-voltage battery 25.

[0030] The capacitor relay 19 functions as a switch to toggle the connection and disconnection between the inverter 15 and the capacitor 16. The capacitor relay 19 is a specific example of the "first switch."

[0031] The high-voltage battery relay 20 functions as a switch to connect and disconnect the inverter 15 and the high-voltage battery 26. The high-voltage battery relay 20 is a specific example of a "second switch".

[0032] The control unit 21 includes a CPU (Central Processing Unit), etc. The control unit 21 controls the engine 12 by controlling the fuel injection system, electronic throttle control system, ignition system, etc. The control unit 21 also controls the AC generator 14 by controlling the inverter 15. Furthermore, the control unit 21 controls the capacitor relay 19, high-voltage battery relay 20, DC-DC converter 18, etc. By controlling these devices or equipment, the control unit 21 can control the starting and stopping of the engine 12, as well as the charging of the capacitor 16, low-voltage battery 25, and high-voltage battery 26. Note that the control unit 21 is a specific example of a "control unit".

[0033] (Charging control device) The ship propulsion system 5 includes a charge control device 7 (see Figure 2) according to an embodiment of the present invention. The charge control device 7 controls the charging of the capacitor 16, the low-voltage battery 25, and the high-voltage battery 26. The charge control device 7 according to an embodiment of the present invention is composed of an AC generator 14, an inverter 15, a capacitor 16, a DC-DC converter 18, a capacitor relay 19, a high-voltage battery relay 20, a control unit 21, a low-voltage battery 25, a high-voltage battery 26, and a current sensor 17 and various voltage sensors described later, etc., in the ship propulsion system 5.

[0034] (Electrical configuration in ship propulsion systems) The ship propulsion system 5 has the electrical configuration shown in Figure 2. Specifically, in Figure 2, the AC generator 14 is connected to the output side of the inverter 15 when the inverter 15 is operating as a three-phase inverter (the input side of the inverter 15 when the inverter 15 is operating as a three-phase rectifier circuit).

[0035] Furthermore, when the inverter 15 is operating as a three-phase inverter, three power supply paths a, b, and c are connected in parallel to the input side of the inverter 15 (when the inverter 15 is operating as a three-phase rectifier circuit, it is connected to the output side of the inverter 15). A capacitor 16 is connected to path a, a low-voltage battery 25 is connected to path b, and a high-voltage battery 26 is connected to path c.

[0036] Furthermore, a capacitor relay 19 is connected to path a to switch between the connection and disconnection between the inverter 15 and the capacitor 16. Also, a DC-DC converter 18 is connected to path b to step down the voltage output from the inverter 15, which is operating as a three-phase rectifier circuit. Finally, a high-voltage battery relay 20 is connected to path c to switch between the connection and disconnection between the inverter 15 and the positive terminal of the high-voltage battery 26.

[0037] Furthermore, the control unit 21 is connected to the inverter 15, capacitor relay 19, high-voltage battery relay 20, and DC-DC converter 18 via signal transmission paths. Although not shown in detail, the control unit 21 is also connected to the fuel injection device, electronic throttle control device, and ignition device provided in the engine 12 via signal transmission paths. The control unit 21 can control the above-mentioned devices or equipment by outputting control signals to them via the signal transmission paths.

[0038] Furthermore, the control unit 21 is connected to a start switch 28 and a stop switch 29 via signal transmission paths. When the operator presses the start switch 28, a signal indicating that the start switch 28 has been pressed is output from the start switch 28 to the control unit 21. Based on this signal, the control unit 21 can recognize that the start switch 28 has been pressed. Similarly, the control unit 21 can recognize when the operator presses the stop switch 29.

[0039] Furthermore, the capacitor 16 is equipped with a current sensor 17 that detects the current I flowing into or out of the capacitor 16. For example, when current is flowing into the capacitor 16, that is, when the capacitor 16 is being charged, the value of current I is positive. On the other hand, when current is flowing out of the capacitor 16, that is, when the capacitor 16 is discharging, the value of current I is negative. The control unit 21 is connected to this current sensor 17 via a signal transmission path. The current sensor 17 outputs a detection signal to the control unit 21 indicating the value or polarity of the current I. Based on this detection signal, the control unit 21 can recognize whether or not the capacitor 16 is discharging.

[0040] Although not shown in the diagram, the inverter 15 is equipped with a voltage sensor to detect the output voltage VE of the inverter 15. The capacitor 16 is equipped with a voltage sensor to detect the voltage (terminal voltage) VC of the capacitor 16. The high-voltage battery 26 is equipped with a voltage sensor to detect the voltage (terminal voltage) VHB of the high-voltage battery 26. These voltage sensors are connected to the control unit 21 via a signal transmission path. Based on the detection signals output from these voltage sensors, the control unit 21 can recognize the output voltage VE of the inverter 15, the voltage VC of the capacitor 16, and the voltage VHB of the high-voltage battery 26.

[0041] Although not shown in the diagram, the engine 12 is equipped with a rotation sensor for detecting the rotational speed of the engine 12, and this rotation sensor is connected to the control unit 21 via a signal transmission path. The control unit 21 can recognize the rotational speed of the engine 12 based on the detection signal output from the rotation sensor.

[0042] (Engine starting process) Figure 3 shows the engine starting process by the ship's propulsion system 5. The engine starting process is the process of starting the engine 12 which is currently stopped. The engine starting process will be explained in detail below.

[0043] For example, when starting a voyage, the operator turns on the power to the ship's propulsion system 5. Turning on the power to the ship's propulsion system 5 supplies power from the low-voltage battery 25 to the control unit 21 and the DC-DC converter 18, causing the control unit 21 and the DC-DC converter 18 to start up. However, with only the power to the ship's propulsion system 5 turned on, the engine 12 and inverter 15 are stopped, and the capacitor relay 19 and high-voltage battery relay 20 are turned off. At this time, it is assumed that the capacitor 16 has enough power stored to power the AC generator 14 and start the engine 12. After the control unit 21 starts up, the control unit 21 begins the engine starting process.

[0044] In the engine starting process, the control unit 21 first monitors the state of the start switch 28 (step S1). When the operator presses the start switch 28, the control unit 21 recognizes that the start switch 28 has been pressed based on the detection signal output from the start switch 28 (step S1: YES).

[0045] Next, the control unit 21 turns on the capacitor relay 19 (step S2). This supplies DC power from the capacitor 16 to the inverter 15, making the inverter 15 operational.

[0046] Next, the control unit 21 controls the inverter 15, causing it to operate as a three-phase inverter and start powering the AC generator 14 (step S3). As a result, the crankshaft of the engine 12 starts to rotate using the power of the AC generator 14. At the same time, the control unit 21 controls the electronic throttle device, fuel injection device, ignition device, etc., to start supplying combustion air, injecting fuel, and igniting the fuel-air mixture.

[0047] Next, the control unit 21 determines whether the rotational speed of the engine 12 has reached or exceeded the starting rotational speed within a predetermined first reference time (step S4). The starting rotational speed is a reference value for the rotational speed at which the engine 12 achieves initial combustion, and is set to, for example, 500 [rpm].

[0048] If the engine speed of 12 does not reach or exceed the starting speed within the first reference time (step S4: NO), the process returns to step S1.

[0049] On the other hand, if the rotational speed of the engine 12 reaches or exceeds the starting rotational speed within the first reference time (step S4: YES), the control unit 21 controls the inverter 15 to stop the power supply of the AC generator 14 (step S5). Subsequently, the control unit 21 switches the operation of the inverter 15 to that of a three-phase rectifier circuit. Next, the control unit 21 turns off the capacitor relay 19 (step S6), and then starts the step-down operation of the DC-DC converter 18 (step S7).

[0050] When engine 12 ignites, that is, when engine 12 starts, the rotation of the engine 12's crankshaft rotates the rotor of the AC generator 14, and the AC generator 14 generates electricity. The electricity generated by the AC generator 14 is converted from AC to DC by the inverter 15, which operates as a three-phase rectifier circuit, and output from the inverter 15. At this time, both the capacitor relay 19 and the high-voltage battery relay 20 are off, so the DC power output from the inverter 15 is supplied only to the low-voltage battery 25 via the DC-DC converter 18. In detail, the DC voltage output from the inverter 15 is stepped down by the DC-DC converter 18 and applied to the low-voltage battery 25. This charges the low-voltage battery 25.

[0051] (Charging control processing) Figure 4 shows the charge control process by the charge control device 7 in the ship propulsion system 5. The charge control process controls the charging of the low-voltage battery 25, capacitor 16, and high-voltage battery 26 while the engine 12 is running and the AC generator 14 is generating power. The charge control process starts immediately after the engine start process is completed.

[0052] After the engine 12 starts, the AC generator 14 generates electricity. The amount of electricity generated by the AC generator 14 increases as the rotational speed of the engine 12 increases. The amount of output voltage VE of the inverter 15 also increases as the amount of electricity generated by the AC generator 14 increases. In the charge control process, the control unit 21 first determines whether the state in which the output voltage VE of the inverter 15 is equal to or greater than the voltage VC of the capacitor 16 has continued for a predetermined second reference time (for example, 100 milliseconds) (step S8).

[0053] If the output voltage VE of the inverter 15 does not remain at or above the voltage VC of the capacitor 16 for the second reference time (step S8: NO), both the capacitor relay 19 and the high-voltage battery relay 20 remain in the off state. In this case, the DC power output from the inverter 15 is supplied only to the low-voltage battery 25 via the DC-DC converter 18, thereby charging the low-voltage battery 25.

[0054] On the other hand, if the output voltage VE of the inverter 15 remains at or above the voltage VC of the capacitor 16 for a second reference time (step S8: YES), the control unit 21 turns on the capacitor relay 19 (step S9). This results in the capacitor relay 19 being on and the high-voltage battery relay 20 being off. When the output voltage VE of the inverter 15 is at or above the voltage VC of the capacitor 16, and the capacitor relay 19 is on and the high-voltage battery relay 20 is off, the DC power output from the inverter 15 is supplied to the low-voltage battery 25 and the capacitor 16, respectively, and the low-voltage battery 25 and the capacitor 16 are charged, respectively.

[0055] Next, the control unit 21 determines whether the state in which the output voltage VE of the inverter 15 is equal to or greater than the voltage VHB of the high-voltage battery 26 has continued for a predetermined third reference time (for example, 3 seconds) (step S10).

[0056] If the output voltage VE of the inverter 15 remains at or above the voltage VHB of the high-voltage battery 26 for a third reference time (step S10: YES), the control unit 21 turns on the high-voltage battery relay 20 (step S11). This turns on both the capacitor relay 19 and the high-voltage battery relay 20. When the output voltage VE of the inverter 15 is at or above the voltage VC of the capacitor 16 and at or above the voltage VHB of the high-voltage battery 26, and both the capacitor relay 19 and the high-voltage battery relay 20 are turned on, the DC power output from the inverter 15 is supplied to the low-voltage battery 25, the capacitor 16, and the high-voltage battery 26, respectively, and the low-voltage battery 25, the capacitor 16, and the high-voltage battery 26 are charged, respectively.

[0057] Next, the control unit 21 determines, based on the detection signal output from the current sensor 17, whether or not the discharge state of the capacitor 16 has continued for a predetermined fourth reference time (for example, 3 seconds) (step S12).

[0058] If the capacitor 16 does not remain discharged for the fourth reference time (step S12: NO), the capacitor relay 19 and the high-voltage battery relay 20 are each kept in the ON state.

[0059] On the other hand, when the capacitor relay 19 and the high-voltage battery relay 20 are both ON, the rotational speed of the engine 12 decreases, the power generated by the AC generator 14 decreases, and as a result the output voltage VE of the inverter 15 decreases, the capacitor 16 may discharge. If the capacitor 16 continues to discharge for the fourth reference time (step S12: YES), the control unit 21 turns off the high-voltage battery relay 20 (step S13). By turning off the high-voltage battery relay 20, the discharge rate of the capacitor 16 can be reduced, and the discharge of the capacitor 16 can be suppressed.

[0060] If, after turning off the high-voltage battery relay 20 in step S13, or if, in step S10, the state in which the output voltage VE of the inverter 15 is equal to or greater than the voltage VHB of the high-voltage battery 26 does not continue for a third reference time (step S10: NO), the control unit 21 determines, based on the detection signal output from the current sensor 17, whether or not the state in which the capacitor 16 is discharging has continued for a predetermined fifth reference time (e.g., 100 milliseconds) (step S14).

[0061] If the capacitor 16 does not remain discharged for the fifth reference time (step S14: NO), the process returns to step S10.

[0062] On the other hand, when the capacitor relay 19 is ON and the high-voltage battery relay 20 is OFF, the rotational speed of the engine 12 decreases, the power generated by the AC generator 14 decreases, and as a result the output voltage VE of the inverter 15 decreases, the capacitor 16 may discharge. If the capacitor 16 continues to discharge for the fifth reference time (step S14: YES), the control unit 21 turns off the capacitor relay 19 (step S15). By turning off the capacitor relay 19, the discharge of the capacitor 16 can be stopped. The process then returns to step S8.

[0063] (Engine shutdown process) Figure 5 shows the engine shutdown process performed by the ship's propulsion system 5. The engine shutdown process is the process of stopping the engine 12 that is currently running. The engine shutdown process is performed while the engine 12 is running. Furthermore, the engine shutdown process is performed in parallel or in parallel with the charge control process.

[0064] In the engine shutdown process, the control unit 21 first monitors the state of the stop switch 29 (step S21). When the operator presses the stop switch 29, the control unit 21 recognizes that the stop switch 29 has been pressed based on the detection signal output from the stop switch 29 (step S21: YES). Next, the control unit 21 stops the engine 12 (step S22). Subsequently, the control unit 21 turns off the capacitor relay 19 if it is on, and turns off the high-voltage battery relay 20 if it is on. Furthermore, the control unit 21 stops the DC-DC converter 18 and the inverter 15 (step S23). By turning off the capacitor relay 19 in the engine shutdown process, discharge of the capacitor 16 while the engine 12 is stopped can be prevented. Note that when the engine 12 stops, the charge control process ends.

[0065] As described above, in the embodiment of the present invention in the ship propulsion system 5, the charge control device 7 connects the inverter 15 and the capacitor 16 by controlling the capacitor relay 19 when the output voltage VE of the inverter 15 is greater than the voltage VC of the capacitor 16 during the power generation operation of the AC generator 14. Furthermore, when the inverter 15 and the capacitor 16 are connected and the capacitor 16 is discharging during the power generation operation of the AC generator 14, the charge control device 7 disconnects the inverter 15 and the capacitor 16 by controlling the capacitor relay 19. With these configurations, it is possible to suppress the discharge of the capacitor 16 due to fluctuations in the power generated by the AC generator 14 during the power generation operation of the AC generator 14.

[0066] Furthermore, in this embodiment, the charge control device 7 connects the inverter 15 and the high-voltage battery 26 by controlling the high-voltage battery relay 20 when the output voltage VE of the inverter 15 is greater than the voltage VHB of the high-voltage battery 26 during the power generation operation of the AC generator 14. Also, during the power generation operation of the AC generator 14, when the inverter 15 and the capacitor 16 and the inverter 15 and the high-voltage battery 26 are connected and the capacitor 16 is discharging, the charge control device 7 disconnects the inverter 15 and the high-voltage battery 26 by controlling the high-voltage battery relay 20. These configurations also suppress the discharge of the capacitor 16 due to fluctuations in the power generated by the AC generator 14 during the power generation operation of the AC generator 14.

[0067] Thus, according to the charging control device 7 of this embodiment, the discharge of the capacitor 16 due to fluctuations in the power generated by the AC generator 14 during the AC generator 14's power generation operation can be suppressed, thereby increasing the charging efficiency of the capacitor 16 during the AC generator 14's power generation operation. Furthermore, it is possible to prevent damage to the capacitor 16 (lithium-ion capacitor) due to over-discharge.

[0068] Furthermore, the charge control device 7 in this embodiment is equipped with a current sensor 17 for detecting the discharge of the capacitor 16. This makes it possible to easily and reliably detect the discharge of the capacitor 16 when the capacitor relay 19 is ON. That is, as can be seen in Figure 2, in the electrical circuit of the charge control device 7, when the inverter 15 is operating as a three-phase rectifier circuit, the negative terminal of the inverter 15 is connected to the negative terminal of the capacitor 16, and the positive terminal of the inverter 15 is connected to the positive terminal of the capacitor 16 via the capacitor relay 19. In this circuit configuration, when the capacitor relay 19 is OFF, the output voltage VE of the inverter 15 is detected by the voltage sensor that detects the output voltage VE of the inverter 15, and the voltage VC of the capacitor 16 is detected by the voltage sensor that detects the voltage VC of the capacitor 16, and the difference between the output voltage VE of the inverter 15 and the voltage VC of the capacitor 16 can be detected. However, when the capacitor relay 19 is ON, the voltage detected by the voltage sensor that detects the output voltage VE of the inverter 15 and the voltage detected by the voltage sensor that detects the voltage VC of the capacitor 16 become equal to each other. Therefore, it is difficult to detect whether the capacitor 16 is discharging based on the output voltage VE of the inverter 15 and the voltage VC of the capacitor 16. However, in the charge control device 7 of this embodiment, the discharge of the capacitor 16 is detected by the current sensor 17, so the discharge of the capacitor 16 can be easily and reliably detected when the capacitor relay 19 is ON.

[0069] Furthermore, in the charging control device 7 of this embodiment, the low-voltage battery 25, capacitor 16, and high-voltage battery 26 are charged using electricity generated from the AC generator 14 using the power of the engine 12. If the only energy storage device that is charged using electricity generated from the AC generator 14 using the power of the engine 12 is the low-voltage battery 25, capacitor 16, and high-voltage battery 26, then only a very small portion of the electrical energy generated from the AC generator 14 can be effectively utilized. In contrast, in the charging control device 7 of this embodiment, the energy storage devices that are charged using electricity generated from the AC generator 14 using the power of the engine 12 are the low-voltage battery 25, capacitor 16, and high-voltage battery 26. Therefore, the portion of the electricity generated from the AC generator 14 that can be effectively utilized can be increased, and the utilization efficiency of the electricity generated from the AC generator 14 can be improved. Furthermore, according to the charging control device 7 of this embodiment, the power stored in the low-voltage battery 25 can drive the fuel injection device, electronic throttle control device, ignition device, and control unit 21, the power stored in the capacitor 16 can power the AC generator 14, and the power stored in the high-voltage battery 26 can drive other electrical equipment installed on the ship. For example, if the ship has a cabin and air conditioners, refrigerators, etc. are installed in the cabin, the power stored in the high-voltage battery 26 can drive these air conditioners, refrigerators, etc. Thus, according to the charging control device 7 of this embodiment, the power consumed by numerous devices or equipment installed on the ship can be supplied.

[0070] In the above embodiment, a lithium-ion capacitor was used as an example, but the present invention is not limited to this, and other capacitors such as electric double-layer capacitors can also be used.

[0071] Furthermore, although the above embodiment described the application of the present invention to a ship propulsion system as an example, the present invention can also be applied to, for example, a vehicle propulsion system for driving an automobile.

[0072] Furthermore, the present invention may be modified as appropriate, provided that it does not contradict the gist or idea of ​​the invention as can be read from the claims and the specification as a whole, and a charging control device with such modifications is also included in the technical concept of the present invention. [Explanation of symbols]

[0073] 7. Charging control device 14 AC Generator (Alternating Current Generator) 15. Inverter (rectifier section) 16 Capacitors 17 Current Sensor 18 DC-DC converters 19 Capacitor relay (first switch) 20. High-voltage battery relay (second switch) 21 Control Unit (Control Section) 25 Low-voltage battery (first battery) 26. High-voltage battery (second battery)

Claims

1. AC generator and A rectifier unit that converts the power generated by the aforementioned AC generator from AC to DC, A first battery connected to the rectifier and charged by power supplied from the rectifier, A capacitor connected in parallel with the first battery to the rectifier, and charged by the power supplied from the rectifier, A DC-DC converter that converts the voltage output from the rectifier unit DC-DC and applies it to the first battery, A first switch for switching between connecting and disconnecting the rectifier and the capacitor, A charging control device comprising a control unit that, when the output voltage of the rectifier unit is greater than the voltage of the capacitor during the power generation operation of the AC generator, connects the rectifier unit and the capacitor by controlling the first switch, and when the rectifier unit and the capacitor are connected and the capacitor is discharging during the power generation operation of the AC generator, disconnects the rectifier unit and the capacitor by controlling the first switch.

2. The rectifier is connected in parallel with the first battery and the capacitor, and a second battery is charged by the power supplied from the rectifier. The system includes a second switch for switching between connecting and disconnecting the rectifier unit and the second battery, The charge control device according to claim 1, characterized in that the control unit connects the rectifier unit and the second battery by controlling the second switch when the output voltage of the rectifier unit is greater than the voltage of the second battery during the power generation operation of the AC generator, and disconnects the connection between the rectifier unit and the second battery by controlling the second switch when the connection between the rectifier unit and the capacitor and the connection between the rectifier unit and the second battery are respectively made and the capacitor is discharging during the power generation operation of the AC generator.

3. The charging control device according to claim 1 or 2, further comprising a current sensor for detecting the discharge of the capacitor.

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