초록 ▼

An alternator having a sensorless power angle control includes a three phase stator winding and three stator winding outputs connected to a controlled full wave rectifier bridge with a dc output. The controlled full wave rectifier bridge includes upper MOSFET switches and lower MOSFET switches with

An alternator having a sensorless power angle control includes a three phase stator winding and three stator winding outputs connected to a controlled full wave rectifier bridge with a dc output. The controlled full wave rectifier bridge includes upper MOSFET switches and lower MOSFET switches with body diodes. Operation of the alternator results in a three phase back EMF generated in the stator windings and phase voltages across each of the stator windings. The output of the alternator is increased by introducing a phase shift between the back EMF and the phase voltages, resulting in an optimized power angle. In order to provide a reference for the phase of the back EMF, a zero crossing detector is provided which monitors the zero voltage crossings across the body diodes of the lower MOSFET switches. The negative to positive zero voltage crossings across the body diodes of the lower MOSFET devices correspond to the negative to positive zero crossings of the three phase back EMF. With an indication of the zero crossings of the back EMF, the MOSFET switches of the controlled full wave rectifier bridge may be controlled to introduce a desired phase delay in each of the phase voltages. A phase delay between the back EMF and each of the phase voltages results in an optimized power angle and increased alternator output.

대표청구항 ▼

[ What is claimed is:] [1.] An alternator driven by an engine, the alternator comprising:a. three phase stator windings having three stator winding outputs;b. a rotor having a rotor field winding magnetically coupled to said stator windings and driven by the engine to generate a back EMF in said sta

[ What is claimed is:] [1.] An alternator driven by an engine, the alternator comprising:a. three phase stator windings having three stator winding outputs;b. a rotor having a rotor field winding magnetically coupled to said stator windings and driven by the engine to generate a back EMF in said stator windings and electrical current at said three stator winding outputs;c. a rectifier bridge having a dc output comprising a plurality of transistor switches, said plurality transistor switches comprising at least three pairs of connected upper transistor switches and lower transistor switches and each of said plurality of transistor switches including body diodes bridging said transistor switches, wherein each of said three stator winding outputs are electrically connected to said rectifier bridge between a respective pair of said upper transistor switches and said lower transistor switches;d. a zero crossing detector connected to said three stator winding outputs, said zero crossing detector operable to determine the zero voltage crossings across at least one of said body diodes of said transistor switches and generate a signal indicative of said zero voltage crossings, wherein said zero voltage crossings across at least one of said body diodes are representative of zero crossings of said back EMF in said stator windings;e. a microcontroller connected to said zero crossing detector, said microcontroller for receiving said signal indicative of said zero voltage crossings from said zero crossing detector and controlling the operation of said transistor switches in said rectifier bridge to control the phase angle of phase voltages at said three stator winding outputs and introduce a phase shift between said phase voltages and said back EMF.