AU2006201767B2

AU2006201767B2 - Method for supplying electric power for actuators, such as relays, contactors and the like, of an electronic controller

Info

Publication number: AU2006201767B2
Application number: AU2006201767A
Authority: AU
Inventors: Luigi Rossi Luciani
Original assignee: Carel SpA
Current assignee: Carel SpA
Priority date: 2005-05-03
Filing date: 2006-04-27
Publication date: 2010-05-20
Anticipated expiration: 2026-04-27
Also published as: ITPD20050123A1; NZ545824A; AU2006201767A1

Description

Pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Method for supplying electric power for actuators, such as relays, contactors and the like, of an electronics controller The following statement is a full description of this invention, including the best method of performing it known to us: I METHOD FOR SUPPLYING ELECTRIC POWER FOR ACTUATORS, SUCH AS RELAYS, CONTACTORS AND THE LIKE, OF AN ELECTRONIC CONTROLLER The present invention relates to an electric power supply method for 5 actuators, such as relays, contactors and the like, of an electronic controller. As it is known, electronic components are supplied with electric power. The electric power required varies depending on the type of component and on the number of components. In the case of electronic microcontrollers, these devices are provided 10 with actuators, such as for example relays, contactors and the like, which are associated with devices to be controlled by means of such microcontrollers. Considering for example relays, these devices are generally supplied by a constant voltage whose value allows both the first excitation of the relay coil (thus allowing the attraction of the relay, with its consequent 15 closure or switching) and the retention of the relay in the closed or switched state. The voltage required to keep the relay energized, however, is lower than the voltage required for initial closing (or switching). The waste of electric power that occurs in using the relay supply 20 voltage at its maximum value is therefore evident. The aim of the present invention is to provide an electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller which allows to reduce the energy consumption of the electronic controller. 25 Within this aim, an object of the present invention is to provide an electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller, which, for an equal amount of electric power available with respect to known methods, allows to increase the number of actuators that can be controlled, distributing the available electric 30 power among them.

2 Another object of the present invention is to provide an electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller which allows to reduce the temperatures inside the controller. 5 Another object of the present invention is to provide an electric power supply method for actuators, such as relays, contactors and the like, which keeps the average voltage across such actuators constant, compensating for increases and decreases of the power supply voltage and thus keeping constant the excitation power and therefore the temperatures inside the 10 actuators. This aim and these and other objects, which will become better apparent hereinafter, are achieved by an electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller, which consists in: 15 - supplying initially to the actuator a closure voltage which is adapted to ensure the closure or switching of such actuator; - subsequently supplying to the actuator a holding voltage, which is lower than said closure voltage and is adapted to ensure that such actuator remains closed or switched. 20 Advantageously, the method supplies such closure voltage to the actuator at programmed time intervals in order to recover any unintended opening or switching of said actuator. Further characteristics and advantages of the invention will become better apparent from the following detailed description of two preferred but 25 not exclusive embodiments thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a functional diagram of an electronic circuit which performs a method according to the invention; Figure 2 is a chart which plots the behavior over time of the voltage 30 supplied to the actuators according to a first embodiment of the method; 3 Figure 3 is a chart which plots the behavior over time of the voltage supplied to the actuators according to a second embodiment of the method. These two preferred embodiments of the method according to the invention, described hereinafter, can be described schematically in a 5 common diagram of an electronic circuit 10 (Figure 1), which comprises a microcontroller 11 connected to one or more actuators 12 (two are shown in the figure and are designated by the reference numerals 12a and 12b), such as for example relays, and a power supply 13 (connected to an external power source 14) for the actuators 12, which is connected to the 10 microcontroller 11. The power supply of the relays is designated schematically by the reference numeral 15, while the control for activation of the relays is designated schematically by the reference numeral 16. The method according to the invention can be summarized in the 15 following steps. First of all, the power supply 13 provides the actuators 12 (for example relays) with a closure voltage (or switching voltage, depending on the applications), which is indeed adapted to ensure the closure (or switching) of the actuators 12 (excitation of the coils of the relays). 20 The power supply 13 then supplies the actuators 12 with a holding voltage (holding the relays in the energized state), which is lower than the closure voltage. Such holding voltage is such as to ensure that the actuators remain closed (or switched in the intended position). 25 Then, at programmed time intervals, such as for example every 60 seconds, the power supply 13 supplies a voltage which is equal to the closure voltage, in order to recover any accidental unintended opening or switching of the actuators 12. Two alternative embodiments of the method thus described are 30 presented hereinafter.

4 In a first embodiment of the invention, a voltage regulator of the switching type, with high efficiency and adjustable output, is associated with the power supply 13 and allows the power supply 13 to supply in a substantially continuous manner, selectively, two different output voltages 5 which can be selected by an external command (provided for example by the microcontroller 11). The command to change the power supply of the actuators 12 is designated schematically by the arrow drawn in broken lines and designated by the reference numeral 17. 10 The closure and holding voltages applied by the power supply 13 are of a continuous and non-pulsed type, and their average value substantially coincides with the application value of the voltage. In practice, the power supply 13 (of the switching type), in a first step, supplies the actuators 12 with a voltage equal to the control voltage 15 (for example, the control voltage is applied for at least 50 ms) and, after the application of the closure voltage, supplies the actuators 12 with a voltage value which is equal to the holding voltage. The holding voltage is lower than the closure voltage and consequently the electric power saving with respect to the case in which the 20 closure voltage is maintained constant is evident. Every 60 seconds, the power supply 13 supplies the actuators 12 with a voltage which is equal to the closure voltage, in order to close (or correctly switch) the actuators 12 if they have opened accidentally. Figure 2 is a chart which plots the behavior over time of the voltage 25 supplied to the actuators 12. The chart illustrates the ramp (designated by the reference letter a) which corresponds to the first application of the closure voltage, the regions of application of the holding voltage (designated by the reference letter b) and the peaks (designated by the reference letter c) which correspond to the 30 application of the closure voltage in order to ensure the constant closure of 5 the actuators. The broken line (designated by the reference letter m) indicates the average value of the applied voltage (which is lower than the applied closure voltage). 5 In a second embodiment of the method, the voltage in input to the actuators 12 is modulated in the PWM (Pulse Width Modulation) mode, with a frequency of the PWM pulses comprised between 1 and 50 kHz. In particular, in this embodiment the microcontroller 11 periodically measures the power supply voltage, which is supplied substantially 10 continuously, upstream of the actuators 12 (the measurement of the supply voltage is indicated in broken lines in Figure 1 by the reference numeral 18; in this embodiment, the arrow 17 of the switching command to the power supply is to be understood as being omitted). Such power supply voltage has a higher value than the closure (or 15 actuation) voltage of the actuators 12. In input to the actuators 12, the power supply voltage is modulated in PWM mode on the basis of the voltage measurement taken upstream of the actuators, so as to obtain a preset average closure voltage for the actuators 12. 20 The power supply voltage is then modulated in PWM mode, again on the basis of the voltage measurement taken upstream of the actuators 12, so as to obtain a preset average holding voltage for the actuator which has a lower value than the average closure voltage. If the power supply voltage varies downstream of the voltage 25 measurement and upstream of the input to the actuators 12, this is compensated by a variation of the amplitude of the voltage pulses modulated in PWM mode in input to such actuators in order to supply the preset average closure or holding voltage. Figure 3 is a chart which plots the behavior over time of the voltage 30 supplied to the actuators.

6 This chart shows a first packet of pulses (designated by the reference letter e), which represents the closure voltage (the associated broken line, designated by the reference sign ml, corresponds to the average closure voltage), then it shows a second packet of pulses (designated by the 5 reference letter f), which represents the holding voltage (the associated broken line, designated by the reference sign m2, represents the average holding voltage). The peak value of these pulses is equal to the measured power supply voltage (Va). 10 A packet of pulses which represents the closure voltage is sent periodically in order to ensure the closure of the actuators. As it has been mentioned, if the power supply voltage varies downstream of the voltage measurement and upstream of the input to the actuators 12, this variation is compensated with a variation of the amplitude 15 of the voltage pulses modulated in PWM mode in input to such actuators, in order to supply the preset average closure or holding voltage; this situation can be seen respectively in the packets g and h, in which a decrease in the power supply voltage (pulses gl and hi) is matched by an increase in the amplitude of the subsequent pulse (pulses g2 and h2) so as to keep constant 20 the value of the average closure or holding voltage. The reference sign m3 designates in broken lines the average voltage applied in total. In a variation of the second embodiment of the described method, instead of modulating in PWM mode the power supply voltage in order to 25 obtain the actuator supply voltage, it is possible to supply directly the power supply voltage to the actuators without modulating it, since its value is higher than the value required for the closure of the actuators. In this manner, it is possible to reduce the calculations of the microcontroller 11; in any case, during the holding step, a PWM-modulated 30 voltage is applied.

7 In practice it has been found that the invention thus described solves the problems noted in known types of method for supplying electric power to actuators, such as relays, contactors and the like, of an electronic controller; in particular, the present invention provides a method which 5 allows to save electric power, since the actuators are not supplied all the time with the maximum control voltage. In this manner, it is possible to use the saved electric power to supply other actuators and therefore other controls. Moreover, energy losses are reduced, since less electric power is 10 used, consequently reducing the excess temperatures inside the microcontrollers. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other 15 technically equivalent elements. In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art. Comprises/comprising and grammatical variations thereof when used in this specification are to be taken to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

1. An electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller, which comprises the steps of: - supplying initially to the actuator a closure voltage which is adapted to 5 ensure the closure or switching of said actuator to an energized state; - subsequently supplying to said actuator a holding voltage, which is lower than said closure voltage and is adapted to ensure that said actuator remains closed or switched in said energized state; and - further supplying said closure voltage to said actuator at programmed 10 time intervals in order to recover any unintentional and unwanted openings or switchings of said actuator to a non-energized state.

2. The method according to claim 1, characterized in that said closure voltage is supplied substantially every 60 seconds.

3. The method according to one or more of the preceding claims, 15 characterized in that said closure and holding voltages are applied continuously and not as pulses, the average values of said closure and holding voltages matching substantially the list application value of the relevant voltage.

4. The method according to claim 3, characterized in that said closure voltage is applied for a time at least equal to 50 ms. 20

5. The method according to one or more of claims 1 to 4, characterized in that said closure voltage and said holding voltage are supplied by a power supply with two different output voltages which can be selected by an external command.

6. The method according to one or more of claims 1 to 2, characterized in that the closure and holding voltages supported to said actuator are modulated in 25 PWM (Pulse Width Modulation) mode. 9

7. The method according to claim 6, characterized in that it comprises the steps of: - periodically measuring a supply voltage, supplied in a substantially continuous manner, upstream of said actuator, said supply voltage being higher 5 in value than the closure voltage of said actuator; - supplying the closure voltage to said actuator; - subsequently modulating in PWM mode said supply voltage on the basis of the voltage measurement taken upstream of said actuator so as to obtain a preset average holding voltage for said actuator which is lower in value than said 10 closure voltage.

8. The method according to claim 7, characterized in that said power supply voltage, in input to said actuator, is modulated in PWM (Pulse Width Modulation) mode on the basis of the voltage measurement taken upstream of said actuator, so as to obtain a preset average closure voltage for said actuator. 15

9. The method according to claim 7, characterized in that said closure voltage is constituted by said supply voltage supplied directly to said actuator.

10. The method according to one of claims 6 to 9, characterized in that a variation of said supply voltage downstream of said voltage measurement and upstream of the input to said actuator is compensated by a variation of the 20 amplitude of the voltage pulses modulated in PWM mode in input to said actuator in order to supply the preset average closure or holding voltage.

11. The method according to one of claims 6-10, characterized in that the frequency of the pulses of the PWM modulation is comprised between 1 and 50 kHz. 25

12. The method according to one of claims 6 to 11, characterized in that the time interval for measuring said supply voltage is chosen substantially between 1 and 10 ms. 10

13. An electronic circuit, characterized in that it performs a method according to one or more of the preceding claims.

14. ' An electric power supply method for actuators, such as relays, contactors and the like, of an electronic controller, according to one or more of the preceding 5 claims, characterized by what is described and illustrated in the accompanying drawings. CAREL S.P.A. WATERMARK PATENT & TRADE MARK ATTORNEYS P26783AU00