Drive systems for a brushless motor employing predefined driving profiles stored in a nonvolatile memory
AssigneeSGS-Thomson Microelectronics S.A.
InventorGiuseppe Maiocchi
Life of this patent
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Abstract
The torque characteristic of an electrically driven brushless motor may be optimized by driving the phase windings of the motor with predefined, digitized and stored current or voltage profiles. Appropriate sequences of digital samples of the predefined driving profile are sequentially read from a nonvolatile memory where they are permanently stored to drive, through a DAC, the relative winding of the motor in synchronism with a signal representative of the rotor position.
Claims21
A method of driving a polyphase brushless motor comprising the steps of:
- defining and storing in a nonvolatile memory a current or voltage profile for each phase winding of the motor by subdividing each profile into a number of sequences equivalent to a number of switching phases of the motor, wherein each sequence comprising N samples, and each sample sequence being stored and read from the memory in the form of digital words of a certain number of bits, so that the sum of the instantaneous values of the profiles is constant;
- and
- forcing a current in conformity with the stored profiles, read from the nonvolatile memory, through the respective phase winding of the motor, in synchronism with a synchronization signal representative of the rotor position, while also converting the sample value read from the non-volatile memory into an analog signal while also controlling the amplitude of the converted analog signal through a speed regulation loop.
A driving system for a polyphase brushless motor of a type comprising a rotor and a plurality of phase windings, the driving system comprising:
- a plurality of output power stages driving as many phase windings of the motor;
- nonvolatile memory means for storing preset driving current profiles for each phase winding;
- a plurality of digital-to-analog or n-bits-to-pulse width modulation (PWM) converters for converting a digital value of each sample of respective stored current profile into a driving analog signal for the relative power stage;
- logic means for synchronizing the conversions with a synchronization logic signal representative of a position of the rotor, and
- a speed regulation loop for controlling the amplitude of a converted analog signal.
Dependencies are inferred from the claim text.