Laundering apparatus, method of operating a laundry machine, control system for an electronically commutated motor, method of operating an electronically commutated motor, and circuit

A circuit for controlling the energization of an electronically commutated DC motor from an AC source, said DC motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the circuit comprising:

• a pair of DC lines;
• means for rectifying the AC output of the source to apply a DC voltage across the DC lines in the form of a full wave rectified sinusoidal signal;
• means connected between the DC lines and the electronically commutated DC motor for chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;
• means responsive to an externally derived signal representative of the desired energization of the electronically commutated DC motor for modulating the width of the pulses;
• means responsive to current in the DC lines for modifying the externally derived signal to maintain the amplitude of the DC line current below a predetermined level;
• and
• means connected to the pulse width modulating means for applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal, respectively;
• whereby the electronically commutated DC motor presents a high power factor to the AC souce.

A method of controlling the energization of an electrical load from an AC source comprising the steps of:

• rectifying the AC output of the source to apply a DC voltage across a pair of DC lines in the form of a full wave rectified sinusoidal signal;
• chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;
• modulating the width of the pulses in response to an externally derived signal representative of the desired energization of the load;
• modifying the externally derived signal in response to the current in the DC lines to maintain the amplitude of the DC line current below a predetermined level;
• and
• applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal;
• whereby the load presents a high power factor to the AC source.

A method of controlling the energization of an electronically commutated DC motor from an AC source, said DC motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• rectifying the AC output of the source to apply a DC voltage across a pair of DC lines in the form of a full wave rectified sinusoidal signal;
• chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;
• modulating the width of the pulses in response to an externally derived signal representative of the desired energization of the electronically commutated DC motor;
• modifying the externally derived signal in response to the current in the DC lines to maintain the amplitude of the DC line current below a predetermined level;
• and
• applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the time intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal;
• whereby the electronically commutated DC motor presents a high power factor to the AC source.