Magnetic actuator, valve arrangement and method
A magnetic actuator having an actuator element, a coil for actuating the actuator element, and a circuit for energizing the coil, the circuit having a supply voltage input to which a supply voltage for energizing the coil is applicable, and the circuit being configured to provide a clocked energization of the coil in a holding current reduction phase and to adapt a duty cycle of the clocked energization as a function of the supply voltage.
1. A magnetic actuator having an actuator element, a coil for actuating the actuator element, and a circuit for energizing the coil, the circuit having a supply voltage input to which a supply voltage is applicable for energizing the coil, and the circuit being configured to provide, during a holding current reduction phase, a clocked energization of the coil,
wherein the circuit comprises a voltage divider connected in parallel to the supply voltage input and configured to provide an intermediate voltage, and wherein the circuit is configured to adjust, during the holding current reduction phase, the duty cycle based on the intermediate voltage, and
wherein the voltage divider comprises a first diode.
2. The magnetic actuator according to claim 1 , wherein the circuit is configured, when the supply voltage changes, to reduce or prevent, via the adjustment of the duty cycle, a change in a time average value of a current flowing through the coil.
3. The magnetic actuator according to claim 1 , wherein the circuit is configured to increase the duty cycle in response to the supply voltage decreasing and/or to decrease the duty cycle in response to the supply voltage increasing.
4. The magnetic actuator according to claim 1 , wherein the circuit comprises a clock signal generation section for generating a clock signal used to clock the energization of the coil to provide the clocked energization.
5. The magnetic actuator according to claim 4 , wherein the circuit comprises a switch via which the coil is electrically connectable to the supply voltage input for energizing the coil, and the circuit is configured to control the switch on the basis of the clock signal in order to provide the clocked energization of the coil.
6. The magnetic actuator according to claim 5 , wherein the switch is a first transistor.
7. The magnetic actuator according to claim 4 , wherein the clock signal generation section comprises a comparator which provides the clock signal at its comparator output.
8. The magnetic actuator according to claim 7 , wherein the clock signal generation section comprises a positive feedback path for the comparator.
9. The magnetic actuator according to claim 7 , wherein the clock signal generation section defines a hysteresis for the comparator.
10. The magnetic actuator according to claim 1 , further comprising a timing element defining an attraction phase, wherein the circuit is configured to provide in the attraction phase a non-clocked attraction energization of the coil, in order to move the actuator element into an attracted position, and after the end of the attraction phase to provide the clocked energization of the coil in order to hold the actuator element in the attracted position.
11. The magnetic actuator according to claim 10 , wherein the circuit comprises a clock signal generation section for generating a clock signal used to clock the energization of the coil to provide the clocked energization, wherein the circuit has a first circuit branch connected in parallel to the supply voltage input, wherein the first circuit branch comprises a first diode and the timing element, and the clock signal generation section is connected to the supply voltage input via the first diode.
12. A valve arrangement comprising a magnetic actuator having an actuator element, a coil for actuating the actuator element, and a circuit for energizing the coil, the circuit having a supply voltage input to which a supply voltage is applicable for energizing the coil, and the circuit being configured to provide, during a holding current reduction phase, a clocked energization of the coil and to adapt a duty cycle of the clocked energization as a function of the supply voltage, wherein the actuator element is designed as a valve member or serves to actuate a valve member of the valve arrangement, and
wherein the magnetic actuator further comprises a timing element defining an attraction phase, wherein the circuit is configured to provide during the attraction phase a non-clocked attraction energization of the coil, in order to move the actuator element into an attracted position, and after the end of the attraction phase to provide the clocked energization of the coil in order to hold the actuator element in the attracted position, and
wherein the circuit comprises a clock signal generation section for generating a clock signal used to clock the energization of the coil to provide the clocked energization, wherein the circuit has a first circuit branch connected in parallel to the supply voltage input, wherein the first circuit branch comprises a first diode and the timing element, and the clock signal generation section is connected to the supply voltage input via the first diode.
13. The magnetic actuator according to claim 12 , wherein the circuit comprises a voltage divider connected in parallel to the supply voltage input and configured to provide an intermediate voltage, and wherein the circuit is configured to adjust, in the holding current reduction phase, the duty cycle based on the intermediate voltage.
14. The magnetic actuator according to claim 13 , wherein the voltage divider comprises a first diode.
15. The valve arrangement according to claim 12 , comprising a carrier section and a plurality of valve modules disposed side-by-side on the carrier section, wherein the circuit is disposed in a valve module or in the carrier section.
16. A method of operating a magnetic actuator having an actuator element, a coil for actuating the actuator element, and a circuit for energizing the coil, the circuit having a supply voltage input, wherein the circuit comprises a voltage divider connected in parallel to the supply voltage input, wherein the voltage divider comprises a first diode, the method comprising the steps of:
applying, to the supply voltage input, a supply voltage for energizing the coil;
the voltage divider providing an intermediate voltage;
during a holding current reduction phase, providing a clocked energization of the coil by means of the circuit; and
during the holding current reduction phase, the circuit adjusting a duty cycle of the clocked current circuit based on the intermediate voltage.