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

Claim 2

A circuit for controlling the energization of an electrical load from an AC source comprising: a pair of DC lines; means for rectifying the AC output of the source to apply a DC voltage across said DC lines in the form of a full wave rectified sinusoidal signal; means connected between said DC lines and the load 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 load for modulating the width of the pulses; means responsive to current in said DC lines for modifying the externally derived signal to maintain the amplitude of the DC line current below a predetermined level; means for detecting zero crossovers of the full wave rectified sinusoidal signal; and means responsive to said detecting means for applying the pulses only during a predetermined time 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, respectively; whereby the load presents a high power factor to the AC source.

Claim 3

The circuit in accordance with claim 1 wherein the phase angle spacing is generally about 30°.

Claim 4

The circuit in accordance with claim 1 wherein said chopping means comprises a switching transistor having its base connected to the output of said pulse width modulating means; and filter means connected between said transistor and the load; whereby current flow in said DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

Claim 5

The circuit in accordance with claim 3 further comprising means responsive to the load current for modifying the externally derived signal to maintain the amplitude of the load current below a predetermined limit.

Claim 6

The circuit in accordance with claim 4 wherein the load is a DC motor, and further comprising: means responsive to the energization of the motor for deriving a feedback signal; means for comparing the feedback signal with the modified externally derived signal to provide an error signal; and means for energizing the pulse width modulation means with the error signal.

Claim 7

The circuit in accordance with claim 5 wherein the feedback signal is derived from the effective voltage applied to the DC motor which has a rotatable assembly and a stationary assembly with a plurality of winding stages, and further comprising means responsive to the angular position of the rotatable assembly for deriving commutation signals; and electronic commutating means responsive to the commutation signals for applying the effective voltage to the winding stages in sequence.

Claim 8

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.

Claim 9

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.

Claim 10

The circuit as set forth in claim 7 wherein the phase angle spacing is generally about 30°.

Claim 11

The circuit as set forth in claim 7 wherein the chopping means comprises a switching transistor having its base connected to the output of the pulse width modulating means; and filter means connected between said transistor and the electronically commutated DC motor; whereby current flow in said DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

Claim 12

The circuit as set forth in claim 9 further comprising means responsive to the load current of the electronically commutated motor for modifying the externally derived signal to maintain the amplitude of the load current below a predetermined limit.

Claim 13

The circuit as set forth in claim 10 further comprising: means responsive to the energization of the motor for deriving a feedback signal; means for comparing the feedback signal with the modified externally derived signal to provide an error signal; and means for energizing the pulse width modulating means with the error signal.

Claim 16

A method as set forth in claim 12 wherein the phase angle spacing is generally about 30°.

Claim 17

A method as set forth in claim 12 comprising the additional step of filtering the full wave rectified sinusoidal signal, whereby current flow in the DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

Claim 18

A method as set forth in claim 14 comprising the additional step of modifying the externally derived signal in response to the load current to maintain the amplitude of the load current below a predetermined limit.

Claim 21

A method as set forth in claim 16 wherein the phase angle spacing is generally about 30°.

Claim 22

A method as set forth in claim 16 comprising the additional step of filtering the full wave rectified sinusoidal signal, whereby current flow in the DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

Claim 23

A method as set forth in claim 18 comprising the additional step of modifying the externally derived signal in response to the DC motor load current to maintain the amplitude of the load current below a predetermined limit.

Claim 24

A method as set forth in claim 19 comprising the additional steps of: deriving a feedback signal in response to the energization of the motor; and comparing the feedback signal with the modified externally derived signal to provide an error signal, the modulation of the width of the pulses being responsive to the error signal.

Claim 25

A method as set forth in claim 20 comprising the additional steps of deriving commutation signals in response to the angular position of the rotatable assembly and applying the effective voltage to the winding stages in sequence, the feedback signal being derived from the effective voltage applied to the DC motor.