Abstract: An AC generating system having a power source, a controller, and an energy storage subsystem including a rotatable flywheel connected to an electrical machine which is operable to convert flywheel rotation into electrical energy and vice versa, the energy storage subsystem to transfers energy from or to the generating to maintain a target state of charge of the flywheel. The controller is arranged to monitor the AC frequency of the output power from the power source and to feed in power or extract power from the energy storage subsystem into the generating system to counteract relatively short term frequency errors due to changes in demanded load on the AC generating system. Or the power source and energy storage subsystem may be interconnected via a DC bus, and wherein the controller is arranged to monitor the DC power or voltage on the bus against a target power.

Abstract: A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

Abstract: The invention relates to an energy storage and recovery system (ERS) coupleable to a prime mover and to an energy storage flywheel. The ERS has a hydrostatic arrangement with a first pumping element and a second pumping element. The pumping elements have a respective fluid displacement and a fluid coupling arrangement for the transfer of fluid power between the first and second pumping elements. The ERS also includes a differential device comprising at least three inputs, wherein a first driveshaft of the first pumping element is coupled to a prime mover in use, a first input of the a differential device is coupled to said prime mover in use, a second input of the differential device is coupled to a second driveshaft of the second pumping element, and the third input of the differential device is coupled to a flywheel in use.

Abstract: An energy storage and transmission system (ESRS) (69) comprises a transmission (9, 11) and an energy storage device such as a flywheel (1). While energy is being transferred between the energy storage device (1) and an energy source/sink (7), the transmission ratio of the transmission (9, 11) will usually be changing constantly. In order to manage the torque applied by the energy transfer device (1) or the power transferred, a controller (100) responds to discrepancy between the torque or power supplied and the torque or power demanded.

Abstract: The invention relates to an energy storage and recovery system (ERS) coupleable to a prime mover and to an energy storage flywheel. The ERS has a hydrostatic arrangement with a first pumping element and a second pumping element. The pumping elements have a respective fluid displacement and a fluid coupling arrangement for the transfer of fluid power between the first and second pumping elements. The ERS also includes a differential device comprising at least three inputs, wherein a first driveshaft of the first pumping element is coupled to a prime mover in use, a first input of the a differential device is coupled to said prime mover in use, a second input of the differential device is coupled to a second driveshaft of the second pumping element, and the third input of the differential device is coupled to a flywheel in use.

Abstract: A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

Abstract: A transmission for an energy storage and recovery system is disclosed. A variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

Abstract: An energy storage and transmission system (ESRS) (69) comprises a transmission (9, 11) and an energy storage device such as a flywheel (1). While energy is being transferred between the energy storage device (1) and an energy source/sink (7), the transmission ratio of the transmission (9, 11) will usually be changing constantly. In order to manage the torque applied by the energy transfer device (1) or the power transferred, a controller (100) responds to discrepancy between the torque or power supplied and the torque or power demanded.

Abstract: A transmission for an energy storage and recovery system is disclosed. A variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.