Power generating apparatus of renewable energy type

Abstract

A power generating apparatus includes a rotating shaft, a hydraulic pump driven by the rotating shaft, a hydraulic motor driven by pressurized oil supplied from the hydraulic pump, and a generator coupled to the hydraulic motor. Each of the hydraulic pump and motor includes working chambers each defined by a cylinder and a piston, a high pressure manifold and a low pressure manifold. Each of the high and low pressure manifolds includes branch channels connected to the working chambers and a merging channel connected to a high or low pressure oil line. The branch channels are equipped with high or low pressures valves, joined together and merged into the merging channel.

1 . A power generating apparatus of renewable energy type which generates power from a renewable energy source, comprising:
 a rotating shaft driven by the renewable energy source;   a hydraulic pump driven by the rotating shaft;   a hydraulic motor which is driven by pressurized oil supplied from the hydraulic pump;   a generator coupled to the hydraulic motor;   a high pressure oil line through which a discharge side of the hydraulic pump is in fluid communication with an intake side of the hydraulic motor; and   a low pressure oil line through which an intake side of the hydraulic pump is in fluid communication with a discharge side of the hydraulic motor,   wherein each of the hydraulic pump and the hydraulic motor comprises:   a plurality of working chambers each of which is surrounded by a cylinder and a piston reciprocating within the cylinder;   a high pressure manifold including first branch channels each connected to the working chambers and a first merging channel connected to the high pressure oil line, the first branch channels joining together and merging into the first merging channel;   a low pressure manifold including second branch channels each connected to the working chambers and a second merging channel connected to the low pressure oil line, the second branch channels joining together and merging into the second merging channel;   a plurality of high pressure valves which are respectively provided in the first branch channels of the high pressure manifold to open and close the first branch channels;   a plurality of low pressure valves which are respectively provided in the second branch channels of the low pressure manifold to open and close the second branch channels; and   a casing which accommodates the working chambers, the high pressure manifold, the low pressure manifold, the high pressure valves and low pressure valves.   
     
     
         2 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein at least one of the hydraulic pump and the hydraulic motor comprises a cylinder block accommodated in the casing, the cylinders being provided inside the cylinder block, and   wherein the first branch channels and the second branch channels of the at least one of the hydraulic pump and the hydraulic motor are arranged inside the cylinder block.   
     
     
         3 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the first merging channel of the high pressure manifold of at least one of the hydraulic pump and the hydraulic motor is provided inside an endplate that forms an end face in a direction of a rotation central axis of the at least one of the hydraulic pump and the hydraulic motor.   
     
     
         4 . The power generating apparatus of renewable energy type according to  claim 2 ,
 wherein a plurality of cylinder arrays are arranged inside the cylinder block in a circumferential direction of the at least one of the hydraulic pump and the hydraulic motor, each of the cylinder arrays being constituted of the cylinders aligned in a direction of a rotation central axis of the at least one of the hydraulic pump and the hydraulic motor,   wherein a high pressure communication channel is provided inside the cylinder block between adjacent two of the cylinder arrays, and   wherein the first branch channels connected to the working chambers of the cylinders belonging to one or the adjacent two of the cylinder arrays are in fluid communication with the first merging channel via the high pressure communication channel.   
     
     
         5 . The power generating apparatus of renewable energy type according to  claim 2 ,
 wherein in the at least one of the hydraulic pump and the hydraulic motor, an annular space between the casing and the cylinder block forms the second merging channel of the low pressure manifold.   
     
     
         6 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the high pressure manifold of the hydraulic pump is directly connected to the high pressure manifold of the hydraulic motor through the high pressure oil line without any intervening valves that restrict oil flow in the high pressure oil line, and   wherein the low pressure manifold of the hydraulic pump is directly connected to the low pressure manifold of the hydraulic motor through the low pressure oil line without any intervening valves that restrict oil flow in the low pressure oil line.   
     
     
         7 . The power generating apparatus of renewable energy type according to  claim 1 , further comprising:
 a bypass passage which connects the high pressure oil line and the low pressure oil line to bypass the hydraulic motor; and   a high pressure relief valve which is provided in the bypass passage.   
     
     
         8 . The power generating apparatus of renewable energy type according to  claim 1 , further comprising:
 at least one accumulator valve; and   at least one accumulator which is connected to the high pressure oil line through the at least one accumulator valve respectively,   wherein the at least one accumulator valve opens and closes to switch between a state where the at least one accumulator is in fluid communication with the high pressure oil line and a state where the at least one accumulator is isolated from the high pressure oil line.   
     
     
         9 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the high pressure valves of the hydraulic pump open to allow hydraulic oil to flow from the working chambers of the hydraulic pump to the high pressure oil line through the high pressure manifold when pressure in the working chambers exceeds pressure in the high pressure oil line.   
     
     
         10 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the low pressure valves of the hydraulic pump open to allow hydraulic oil to flow from the low pressure oil line to the working chambers of the hydraulic pump through the low pressure manifold when pressure in the working chambers falls below the pressure in the low pressure oil line.   
     
     
         11 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein at least one of the high and low pressure valves of the hydraulic pump and the hydraulic motor is a pressure-operated check valve which is openable to allow hydraulic oil to flow in one direction due to pressure difference across the at least one of the high and low pressure valves.   
     
     
         12 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the at least one of the high and low pressure valves of the hydraulic pump and the hydraulic motor is an electronically controlled valve, and   wherein the power generating apparatus of renewable energy type further comprises a controller which controls opening and closing of the electronically controlled valve in phased relation to cycles of movement of the piston to adjust net volume of hydraulic oil displaced by the working chambers on each of the cycles.   
     
     
         13 . The power generating apparatus of renewable energy type according to  claim 12 ,
 wherein the controller changes number of the working chambers in idle state to adjust the net volume of the hydraulic oil displaced by the working chambers on each of the cycles, the low pressure valves of the working chambers in the idle state being kept open for a full cycle of the movement of the piston.   
     
     
         14 . The power generating apparatus of renewable energy type according to  claim 12 ,
 wherein the controller changes closure timing of at least one group of the low pressure valves and the high pressure valves in each cycle of the movement of the piston to adjust the net volume of the hydraulic oil displaced by the working chambers on each of the cycles, the closure timing being changed commonly for all valves belonging to the at least one group of the low pressure valves and the high pressure valves.   
     
     
         15 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the at least one of the high and low pressure valves of the hydraulic pump and the hydraulic motor is an electronically controlled valve, the electronically controlled valve being a face-sealing poppet valve which is not openable against a prescribed pressure.   
     
     
         16 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the at least one of the high and low pressure valves of the hydraulic pump and the hydraulic motor is an electronically controlled valve, and   wherein the power generating apparatus of renewable energy type further comprises a controller which controls opening and closing of the electronically controlled valve to counter fluctuations in torque and flow arising from asymmetric flow of hydraulic oil out of the working chamber during each cycle of movement of the piston.   
     
     
         17 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein each of the low pressure valves of the hydraulic pump is a normally open solenoid closed valve which opens passively when pressure in the working chamber is less than pressure in the low pressure oil line.   
     
     
         18 . The power generating apparatus of renewable energy type according to  claim 1 , further comprising:
 a pressure sensor which measures pressure of hydraulic oil in the high pressure oil line, and   a temperature sensor which is provided in one of the high pressure oil line and the low pressure oil line to measure temperature of hydraulic oil in the one of the high pressure oil line and the low pressure oil line.   
     
     
         19 . The power generating apparatus of renewable energy type according to  claim 1 ,
 wherein the power generating apparatus is a wind turbine generator which generates power from wind as the renewable energy source.