Control method and circuit for a direct current motor for an infusion unit of a machine for preparing coffee beverages
AssigneeDe'Longhi Appliances S.R.L. Con Unico Socio
InventorsPaolo Evangelisti, Alberto Acciari, Davide Bonotto
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Abstract
Embodiments described here concern a method to control a direct current motor powered by an alternating supply voltage, which provides to detect the instant of the zero-crossing of the supply voltage and to selectively activate a switch device to power the motor by the positive half-waves of the supply voltage in order to make it rotate in one sense, and by the negative half-waves in order to make it rotate in the opposite sense. The disclosure also concerns a control circuit for the motor.
Claims12
A machine (70) for preparing coffee beverages comprising an infusion unit (71) provided with an infusion chamber (73), a direct current motor (50) connected to said infusion unit (71) and with a control circuit (10) for said motor (50), wherein said control circuit (10) comprises:
- a power supply circuit (14) which connects said motor (50) to an electric power supply grid (60) configured to supply an alternating supply voltage (Vin);
- a detection device (12) for detecting the instant of the zero-crossing of said supply voltage (Vin) of the electricity grid;
- a switch device (11) connected between said electric power supply grid (60) and said motor (50), which can be selectively activated to allow or prevent the passage of an electric current between said electric power supply grid (60) and said motor (50);
- and a control and command unit (13) configured to selectively activate said switch device (11) to power the motor (50) by means of the positive half-waves (Vin1) of said supply voltage (Vin) to rotate it in one sense, and by means of the negative half-waves (Vin2) to rotate it in the opposite sense, wherein said control and command unit (13) is configured to receive a detection signal (Sz) of said instant of the zero-crossing of said supply voltage (Vin) and supply an activation command signal (ST1, ST2) for said switch device (11) with a delay time (Td1, Td2) with respect to said crossing instant detected, so that said switch device (11) enters into conduction when the value of the current (Im) applied to the motor (50) is near zero.
A method to move a mobile infusion unit (71) of a machine (70) for preparing coffee beverages provided with an infusion chamber (73), according to a predefined trajectory, from at least one initial position to at least one position for closing the chamber (73) and at least one position for discharging the exhausted coffee powder (80), wherein the infusion unit (71) comprises a direct current motor (50) powered by an alternating supply voltage (Vin), wherein said method provides to detect the instant of the zero-crossing of the supply voltage (Vin) and to selectively activate a switch device (11) to power the motor (50) by means of the positive half-waves (Vin1) of the supply voltage (Vin) in order to make it rotate in one sense between said initial position and at least said closing position, and by means of the negative half-waves (Vin2) in order to make it rotate in the opposite sense from said closing position at least toward said discharging position, wherein said method provides to activate said switch device (11) with a determinate delay time (Td1, Td2) with respect to said instant of the zero-crossing of said supply voltage (Vin) so that said switch device (11) enters into conduction at the moment in which the value of the current (Im) that powers the motor (50) is near zero.
Dependencies are inferred from the claim text.