Watercraft propulsion system, watercraft, and power system

Abstract

A watercraft propulsion system includes an engine, a propeller to be driven by the engine, a generator to be driven by the engine, a rectifier regulator connected to the generator, and a charging controller configured or programmed to control charging of a battery with power generated by the rectifier regulator such that an inductive voltage of the generator approaches one half an inter-terminal voltage of the battery.

What is claimed is: 
     
         1 . A watercraft propulsion system comprising:
 an engine;   a propeller to be driven by the engine;   a generator to be driven by the engine;   a rectifier regulator connected to the generator; and   a charging controller configured or programmed to control charging of a battery with power generated by the rectifier regulator such that an inductive voltage of the generator approaches one half an inter-terminal voltage of the battery.   
     
     
         2 . The watercraft propulsion system according to  claim 1 , wherein
 the battery includes a first battery having a first inter-terminal voltage, and a second battery having a second inter-terminal voltage that is higher than the first inter-terminal voltage;   the watercraft propulsion system further comprises an engine rotation speed sensor to detect a rotation speed of the engine; and   the charging controller includes a switch to connect the rectifier regulator to either one of the first battery and the second battery, and a controller configured or programmed to control the switch according to the engine rotation speed detected by the engine rotation speed sensor.   
     
     
         3 . The watercraft propulsion system according to  claim 2 , further comprising a first power line through which the switch is connected to the first battery, and a second power line through which the switch is connected to the second battery; wherein
 the charging controller further includes a boost converter connected between the first power line and the second power line and, when the switch connects the rectifier regulator to the first battery, the controller is configured or programmed to activate or deactivate the boost converter depending on a residual capacity of the first battery.   
     
     
         4 . The watercraft propulsion system according to  claim 2 , further comprising a first power line through which the switch is connected to the first battery, and a second power line through which the switch is connected to the second battery; wherein
 the charging controller further includes a buck converter connected between the first power line and the second power line and, when the switch connects the rectifier regulator to the second battery, the controller is configured or programmed to activate the buck converter.   
     
     
         5 . The watercraft propulsion system according to  claim 1 , further comprising an engine rotation speed sensor to detect a rotation speed of the engine; wherein
 the charging controller includes a capacitor connected between terminals of the rectifier regulator, a buck converter to reduce an inter-terminal voltage of the capacitor and output a voltage-reduced power to the battery, and a controller configured or programmed to regulate the output power of the buck converter according to the engine rotation speed detected by the engine rotation speed sensor.   
     
     
         6 . The watercraft propulsion system according to  claim 1 , wherein
 the battery includes a first battery having a first inter-terminal voltage, and a second battery having a second inter-terminal voltage that is higher than the first inter-terminal voltage;   the watercraft propulsion system further comprises an engine rotation speed sensor to detect a rotation speed of the engine; and   the charging controller includes a capacitor connected between terminals of the rectifier regulator, a first buck converter to reduce an inter-terminal voltage of the capacitor and output a voltage-reduced power to the first battery, a second buck converter to reduce the inter-terminal voltage of the capacitor and output a voltage-reduced power to the second battery, and a controller configured or programmed to regulate the output power of the first buck converter according to the engine rotation speed detected by the engine rotation speed sensor, and to regulate the output power of the second buck converter according to an actual output power of the first buck converter and the engine rotation speed detected by the engine rotation speed sensor.   
     
     
         7 . The watercraft propulsion system according to  claim 1 , wherein the water propulsion system includes an outboard motor. 
     
     
         8 . A watercraft comprising:
 a hull;   a battery provided on the hull; and   the watercraft propulsion system according to  claim 1  provided on the hull.   
     
     
         9 . The watercraft according to  claim 8 , further comprising an electrical load provided on the hull and connected to the battery. 
     
     
         10 . A power system comprising:
 an engine;   a generator to be driven by the engine;   a rectifier regulator connected to the generator;   a battery to be charged with power generated by the rectifier regulator; and   a charging controller configured or programmed to control the charging of the battery with the power generated by the rectifier regulator such that an inductive voltage of the generator approaches one half an inter-terminal voltage of the battery.   
     
     
         11 . The power system according to  claim 10 , wherein
 the battery includes a first battery having a first inter-terminal voltage, and a second battery having a second inter-terminal voltage that is higher than the first inter-terminal voltage;   the power system further comprises an engine rotation speed sensor to detect a rotation speed of the engine; and   the charging controller includes a switch to connect the rectifier regulator to either one of the first battery and the second battery, and a controller configured or programmed to control the switch according to the engine rotation speed detected by the engine rotation speed sensor.   
     
     
         12 . The power system according to  claim 11 , further comprising a first power line through which the switch is connected to the first battery, and a second power line through which the switch is connected to the second battery; wherein
 the charging controller further includes a boost converter connected between the first power line and the second power line and, when the switch connects the rectifier regulator to the first battery, the controller is configured or programmed to activate or deactivate the boost converter depending on a residual capacity of the first battery.   
     
     
         13 . The power system according to  claim 11 , further comprising a first power line through which the switch is connected to the first battery, and a second power line through which the switch is connected to the second battery; wherein
 the charging controller further includes a buck converter connected between the first power line and the second power line and, when the switch connects the rectifier regulator to the second battery, the controller is configured or programmed to activate the buck converter.   
     
     
         14 . The power system according to  claim 10 , further comprising an engine rotation speed sensor to detect a rotation speed of the engine; wherein
 the charging controller includes a capacitor connected between terminals of the rectifier regulator, a buck converter to reduce an inter-terminal voltage of the capacitor and output a voltage-reduced power to the battery, and a controller configured or programmed to regulate the output power of the buck converter according to the engine rotation speed detected by the engine rotation speed sensor.   
     
     
         15 . The power system according to  claim 10 , wherein
 the battery includes a first battery having a first inter-terminal voltage, and a second battery having a second inter-terminal voltage that is higher than the first inter-terminal voltage;   the power system further comprises an engine rotation speed sensor to detect a rotation speed of the engine; and   the charging controller includes a capacitor connected between terminals of the rectifier regulator, a first buck converter to reduce an inter-terminal voltage of the capacitor and output a voltage-reduced power to the first battery, a second buck converter to reduce the inter-terminal voltage of the capacitor and output a voltage-reduced power to the second battery, and a controller configured or programmed to regulate the output power of the first buck converter according to the engine rotation speed detected by the engine rotation speed sensor, and to regulate the output power of the second buck converter according to an actual output power of the first buck converter and the engine rotation speed detected by the engine rotation speed sensor.