Washing appliance and control method thereof

An appliance comprising

• a drain pump capable of operating in a full-flow drainage mode, the drain pump having an impeller and a motor supplied with an alternating supply voltage that drives the impeller, the motor comprising a stator,
• a controller adapted to apply and monitor a stator voltage to the motor according to the frequency of the alternating supply voltage and to control the frequency of the alternating supply voltage among a plurality of predetermined frequencies when the drain pump is operated in the full drainage mode,
• a storage medium associated with the controller that stores for each predetermined frequency a maximum stator voltage value, a minimum stator voltage value and a pre-set optimal stator voltage value;
• and
• the controller storing computer implemented instructions that when executed (a) determines an initial stator voltage value when an alternating supply voltage is first supplied to motor when the drain pump is operated in the full-flow drainage mode, the alternating supply voltage corresponding to one of the plurality of predetermined frequencies, (b) compares the initial stator voltage value with the corresponding pre-set optimal stator voltage value for the predetermined frequency, (c) monitors the stator voltage value applied to the motor to determine if the monitored stator voltage value is between the maximum stator voltage value and the minimum stator voltage value, (d) upon determining that the monitored stator voltage value is between the maximum stator voltage value and the minimum stator voltage value, compares the monitored stator voltage value with the optimal stator voltage value, and (e) adjusts the frequency of the alternating supply voltage among the plurality of predetermined frequencies to cause the monitored stator voltage value to more closely match the optimal stator voltage value.

A method of controlling a motor of a drain pump of an appliance, the motor configured to operate at a plurality of predetermined frequencies between minimum and maximum alternating supply voltage frequencies, the motor configured to operate at each predetermined frequency at a corresponding pre-set optimal motor current value, the method comprising:

• determining an initial motor current value of the motor when an alternating supply voltage is first supplied to the motor when the drain pump is operated in a full-flow drainage mode, the alternating supply voltage corresponding to one of the plurality of predetermined frequencies,
• comparing the initial motor current value with the corresponding pre-set optimal motor current value for the predetermined frequency,
• upon determining that the initial motor current value is different from the pre-set optimum motor current value, determining a multiplication factor whose value derived by a ratio of the pre-set optimum motor current value and the initial motor current value,
• determining a modified optimal motor current value for each of the predetermined frequencies by multiplying each pre-set optimal stator voltage value by the multiplication factor, or maintaining the optimal motor current value for each of the predetermined frequencies if the initial motor current coincides with the pre-set optimum motor current value,
• monitoring the motor current value applied to the motor to determine if the monitored motor current value is between a maximum motor current value and a minimum motor current value,
• upon determining that the monitored motor current value is between the maximum motor current value and the minimum motor current value comparing the monitored motor current value with the modified or maintained optimal motor current value, and
• adjusting the frequency of the alternating supply voltage among the plurality of predetermined frequencies to cause the monitored motor current value to more closely match the modified or maintained optimal motor current value.

A method of controlling a motor of a drain pump of an appliance, the motor configured to operate at a plurality of predetermined frequencies between minimum and maximum alternating supply voltage frequencies, the motor configured to operate at each predetermined frequency at a corresponding pre-set optimal stator voltage value, the method comprising:

• determining an initial stator voltage value when an alternating supply voltage is first supplied to the motor when the drain pump is operated in a full-flow drainage mode, the alternating supply voltage corresponding to one of the plurality of predetermined frequencies,
• comparing the initial stator voltage value with the corresponding pre-set optimal stator voltage value for the predetermined frequency,
• monitoring the stator voltage value applied to the motor to determine if the monitored stator voltage value is between a maximum stator voltage value and a minimum stator voltage value,
• upon determining that the monitored stator voltage value is between the maximum stator voltage value and the minimum stator voltage value comparing the monitored stator voltage value with the optimal stator voltage value, and
• adjusting the frequency of the alternating supply voltage among the plurality of predetermined frequencies to cause the monitored stator voltage value to more closely match the optimal stator voltage value.