HEV generator unit

Abstract: The present invention provides an apparatus, system, and method of utilising a home power unit ("HPU") which functions as a battery charger for a hybrid electric vehicle ("HEV") or as a generator, utilising the HEV's electrical power to operate external electrical devices. In its simplest form, the HPU comprises a transformer, inverter means, rectifier means, a control unit, connection means to the HEV and external electrical loads or sources and switching means to change operation between charger and generator function. Alternative embodiments of the present invention utilise the HEV's existing components thereby avoiding component redundancy within the HPU. Specifically, in the first alternative embodiment, the inverter means are utilised within the vehicle, therefore, requiring only filter and transformer to be added to the vehicle. In the second alternative embodiment, the vehicle's DC-to-DC converter is utilised as opposed to implementing a transformer. Therefore, only an inverter and filter are added to the system.

Description: The present invention relates to a home power unit for hybrid electric vehicles ("HEVS") that acts as a generator to operate external electrical devices, such as power tools. The need to reduce fossil fuel consumption and pollutants of automobiles and other vehicles powered by internal combustion engines ("ICES") is well known. Vehicles powered by electric motors have attempted to address these needs. However, electric vehicles have limited range and limited power coupled with the substantial time needed to recharge their batteries. An alternative solution is to combine both an ice and electric traction motor into one vehicle. Such vehicles are typically called hybrid electric vehicles ("HEVS"). See generally, U.S. Pat. No. 5,343,970 (Severinsky). The HEV has been described in a variety of configurations. Many HEV patents disclose systems where an operator is required to select between electric and internal combustion operation. In other, the electric motor drives one set of wheels and the ice drives a different set. Other configurations have developed. A series hybrid electric vehicle ("SHEV") is a vehicle with an engine (most typically an ice) which powers a generator. The generator, in turn, provides electricity for a battery and motor coupled to the drive wheels of the vehicle. There is no mechanical connection between the engine and the drive wheels. A parallel hybrid electrical vehicle ("phev") is a vehicle with an engine (most typically an ice), battery, and electric motor combined to provide torque to power the wheels of the vehicle. A parallel/series hybrid electric vehicle ("PSHEV") has characteristics of both a PHEV and a SHEV. The PSHEV is also known as a torque (or power) splitting powertrain configuration. Here, the torque output of the engine is given in part to the drive wheels and in part to an electrical generator. The electric generator powers a battery and motor that also provide torque output. In this configuration, torque output can come from either source or both simultaneously. In this configuration the vehicle braking system can even deliver torque to drive the generator to produce charge to the battery. As the HEV continues to develop, new challenges are encountered and new uses are developed. One of the main challenges associated with all HEV's is insuring enough battery charge to start and operate the vehicle. All batteries lose charge as a result of use or lapse of time. Generally, the HEV battery is charged by an ice generator in the vehicle; however, during unusual conditions or emergencies, external battery charging may be necessary. A potential use for the HEV is to utilise its battery and generator as a source of electrical power to operate electrical devices such as power tools. This type of vehicle use for auxiliary electrical power is well known for conventional ice vehicles. Specifically, many patents have been issued utilising the components of ices as a power source for electrical devices. For example, U.S. Patent no. 3,824,404 (Leonard Ghere); U.S. Patent 3,953,740 (Charles Seiter, Jr.); U.S. Patent no. 4,074,145 (p. Laffoon, et al.); And U.S. Patent 5,066,866 (William Hallidy), disclose various methods of utilising a vehicle's alternator to generate AC voltage to power electrical devices. However, these patents do not apply to HEV's because the HEV does not require an alternator. The HEV already has a ready source of electrical power within its battery and can generate additional power with an onboard generator. However, the HEV's electrical power, needs to be converted for external use by electrical devices. DE 199 35 873 A describes a hybrid electric vehicle (HEV) operable as a power source to operate external electrical devices. The HEV comprises an engine to drive a generator to create electrical power and inverter/rectifier means to convert electrical sources from AC to DC or DC to AC. Switches alter the electrical power flow from a vehicle traction function to a power supply function and connection means connect the HEV to external electrical devices. The present invention now provides a hybrid electric vehicle (HEV) operable as a power source to operate external electrical devices comprising; an internal combustion engine to drive a generator to create electrical power; a rectifier to convert electrical sources from AC to DC; an AC traction motor; a traction inverter connected to supply the AC traction motor from a DC bus connecting both rectifier and inverter; switching means to alter the electrical power flow from a vehicle traction function to a power supply function; connection means to connect the HEV to external electrical devices; and a transformer connected to supply the said connection means characterised in that; the switching means comprises a contactor that routes AC power from the traction inverter to either the traction motor, or to the transformer in order to supply the said connection means. A system allowing the operation of the HEV as a generator to power external electrical devices can be referred to as a home power unit (HPU). In the hereby presented invention, the HPU is incorporated directly into the components of the HEV. In this manner, redundant components are avoided. In the invention, the HPU inverter means is identified with the traction inverter. The contactor implemented between the traction inverter and the motor switches the power source from the vehicle function (going to the motor) to the HPU function (operating as a generator and proceeding to a filter). The switching devices for the HPU function may comprise a momentary two position switch on the instrument panel, a menu selection from an on-screen display mounted in the instrument panel or a two position switch mounted on the HPU. The invention will now be described further, by way of example, with references to the accompanying drawings, in which: Fig. 1 illustrates the general layout of a hybrid electric vehicle, Fig. 2 illustrates an embodiment of the HPU utilising some of the hybrid electric vehicle's existing components. The present invention provides a unified apparatus, system and method for utilising the power storage and generating capabilities of the vehicle to run external electrical devices. Figure 1 demonstrates one configuration for a parallel/series hybrid electric vehicle ("torque splitting") configuration. The basic makeup of the vehicle includes: an engine 20 connected to a planetary gear 26 through a one way clutch. The planetary gear 26, splits the engine 20 output energy into a series path, from the engine 20 to a generator motor 24, and a parallel path, from the engine 20 to driving wheels 34. The engine speed can be controlled by varying the split to the series path, while maintaining the mechanical connection through the parallel path. The generator motor 24 is connected to a generator brake 45. The generator motor 24 is connected to the battery 28, and is capable of charging the battery 28. The electric motor 30, augments the engine on the parallel path through a second gear set 32. The motor also provides the opportunity to use energy directly from the series path, essentially drawing from the power created by the generator motor 24, thereby reducing the losses associated with converting energy into and out of chemical energy in the battery 28. Many components in this configuration are controlled by vehicle system controller ("VSC") 36. The VSC 36, operate all the vehicle's main components by connecting to each components' controllers. The VSC 36 also contains the powertrain control module ("PCM"). These two "separate" controllers are housed in the same unit. The VSC/PCM 36 is then connected to the engine 20. The VSC 36 is also connected to a battery control unit ("BCU") 38, and a transmission management unit ("TMU") 40 through a communication network. The BCU 38 is then connected to the battery 28. The TMU 40 is connected to a generator controller 42 and a motor controller 44. The generator controller 42 is then connected to the generator motor 24 and the motor controller 44 is connected to the motor 30. The HPU utilises vehicle components to avoid component redundancy. Specifically, this embodiment provides a means for using the HEV as a "generator" without adding a separate HPU unit to the vehicle. Figure 2 illustrates this embodiment. A generator 100 is connected to an engine (typically an ice) to generate electrical power. The generator 100 is connected to a generator inverter 102 which converts the AC source to DC. Both the generator inverter 102 and a high voltage battery 106 are connected to a DC bus 104. The DC bus 104 is also connected to a traction inverter 108. In a normal HEV, the traction inverter 108 then connects to a traction motor 116; however, the present invention, in an attempt to utilise the components previously described would add a contactor 110 between the traction motor 116 and the traction inverter 108. The contactor 110 would then be connected to a filter 112 which is connected to a transformer 114. The transformer 114 could then connect to external loads. The traction inverter 108, which is already part of the HEV, is utilised in place of adding a separate inverter within a HPU. However the traction inverter 108 will require a unique operating strategy to operate with the HPU. The traction inverter 108 coverts the high voltage DC source to AC (300 volt DC to 300 volt AC). This is normally done to run the traction motor 116. The contactor 110 operates as a switch, directing the high voltage AC source to the traction motor 116 or the additional "HPU" components. Specifically, if the generator function of the HPU is selected, the contactor 110 directs the high voltage AC source to the filter 112, where noise is removed. The high voltage AC source is then sent to the transformer 114 which converts the AC source to AC voltage useable by external electrical devices (300 volt AC to 110 volt AC).

Claims: A hybrid electric vehicle (HEV) operable as a power source to operate external electrical devices comprising; an internal combustion engine (20) to drive a generator (100) to create electrical power; a rectifier (102) to convert electrical sources from AC to DC; an AC traction motor (116); a traction inverter (108) connected to supply the AC traction motor (116) from a DC bus (104) connecting both rectifier and inverter; switching means (110) to alter the electrical power flow from a vehicle traction function to a power supply function; connection means to connect the HEV to external electrical devices; and a transformer (114) connected to supply the said connection means; characterised in that ; the switching means (110) comprises a contactor (110) that routes AC power from the traction inverter (108) either to the traction motor (116), or to the transformer (114) in order to supply the said connection means. A vehicle as claimed in claim 1, wherein the inverter/rectifier means (102,108) comprises a generator inverter (102) to convert AC power from the generator (100) to DC power for the DC bus (104). A vehicle as claimed in claim 1 or 2, further comprising filter means (112) to remove signal noise from the supply to the connection means. A vehicle as claimed in claim 1, 2 or 3, wherein the switching means comprises a two position switch. A vehicle as claimed in claim 4, wherein the two position switch is a momentary two position switch on an instrument panel (62). A vehicle as claimed in claim 1, 2 or 3, wherein the switching means comprises a menu selection from an on-screen display mounted on an instrument panel (62). A method of operating the vehicle of any one of the preceding claims as a power source to supply electric power to external electrical devices, comprising the steps of; connecting the connection means to an external electric device; operating the traction inverter (108) to supply AC power; and employing the contactor (110) to route AC power from the traction inverter (108) to the transformer (114).

Inventors: GABRIEL DAVID, GABRIEL, DAVID
Applicants: FORD MOTOR CO, FORD MOTOR COMPANY
Application year: 2001
Main classification: B60L11
IPC codes: H02J7, B60L1, B60L11, B60K6