Control System for an Electrical Apparatus and Method of Using the Same

Abstract

A control system is disclosed which comprises a first control module generally integrated into a controlling device (e.g. a thermostat), and a second control module generally integrated into an electrical apparatus (e.g. a heating apparatus) under the control of the controlling device. The second control module is responsive to command signals remotely transmitted thereto by the first control module over the power lines which power the electrical apparatus. In response to the signals, the second control module can selectively turn on, or off, or modulate, some or all of the electrical components (e.g. heating elements, fans) of the electrical apparatus.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application claims the benefits of priority of commonly assigned U.S. Provisional Patent Application No. 61/417,346, entitled “Control System for an Electrical Apparatus and Method of Using the Same”, and filed at the United States Patent and Trademark Office on Nov. 26, 2010; the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to the field of electrical apparatuses and more particularly to control systems and methods for controlling electrical apparatuses.

BACKGROUND OF THE INVENTION

Several control systems for controlling electrical apparatuses and more particularly electrical heating apparatuses have been proposed throughout the years.

These control systems are however generally complex and/or need additional communication wires for linking a controlling device to the electrical apparatus.

Other control systems transmit modulated control signals over the power lines which power the electrical apparatus. However, in such systems, the modulated control signals are transmitted at high frequencies and the systems need additional circuitries (e.g. modulators, transceivers, filters, etc) to modulate, transmit and extract the high-frequency control signals. These additional circuitries are complex and can be expensive.

Hence, despite ongoing developments in the field, there is still a need for a control system for an electrical apparatus which is simpler and which can be used with different types of electrical apparatuses.

SUMMARY OF THE INVENTION

The shortcomings of prior art control systems are generally mitigated by a control system which transmits control signals to the electrical apparatus directly over the power lines which power the electrical apparatus.

In accordance with the principles of the present invention, the control system generally comprises a first control module typically integrated into a controlling device, and a second control module typically integrated into the electrical apparatus which is remotely under the control of the controlling device. Still in accordance with the principles of the present invention, the first control module is typically a transmitting control module and is adapted to send command signals to the second control module directly over the power lines which carry the power to the electrical apparatus. To do so, the first control module selectively switches on and off, for predetermined amounts of time, the voltage (and current) carried over the power lines. Depending on the command signals transmitted by the first control module, the second control module, which is typically a receiving control module, selectively turns on, or off, or modulate, one or more electrical components of the electrical apparatus.

A control system in accordance with the principles of the present invention does not need additional wires for communication since the command signals are sent directly over the power lines which carry the power.

In addition, a control system in accordance with the principles of the present invention can be configured such as to avoid the creation of unwanted harmonics on the power lines.

Other and further aspects and advantages of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. The features of the present invention which are believed to be novel are set forth with particularity in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which:

FIG. 1 is a schematic diagram of an embodiment of the connection between a thermostat and an electrical heating apparatus incorporating a control system in accordance with the principles of the present invention.

FIG. 2 is a graph of the voltage versus the time showing an embodiment of command signals when the heating apparatus is initially turned off.

FIG. 3 is a graph of the voltage versus the time showing an embodiment of command signals when the heating apparatus is already turned on.

FIG. 2A is a graph of the voltage versus the time showing another embodiment of command signals when the heating apparatus is initially turned off.

FIG. 3A is a graph of the voltage versus the time showing another embodiment of command signals when the heating apparatus is initially turned on.

FIG. 4 is a schematic diagram of an embodiment of the first control module in accordance with the principles of the present invention.

FIG. 5 is a schematic diagram of another embodiment of the first control module in accordance with the principles of the present invention.

FIG. 6 is a schematic diagram of another embodiment of the connection between a thermostat and a heating apparatus incorporating a control system in accordance with the principles of the present invention.

FIG. 7 is a schematic diagram of an embodiment of the second control module in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A novel control system and a novel method for controlling an electrical apparatus will be described hereinafter. Although the invention is described in terms of specific illustrative embodiments, it is to be understood that the embodiments described herein are by way of example only and that the scope of the invention is not intended to be limited thereby.

Referring first to FIG. 1, an embodiment of a control system in accordance with the principles of the present invention is illustrated. In FIG. 1, the control system 10 is used, for example purposes only, with a thermostat 200 (i.e. a controlling device) and an electrical heating apparatus 400 (i.e. an electrical apparatus). Understandably, a control system in accordance with the principles of the present invention could be used with other electrical apparatuses which are controlled by a controlling device. Non-limitative examples of electrical apparatuses are: heating systems, ventilation systems, air conditioning systems, lighting systems, etc.

The control system 10 comprises a first (or transmitting) control module 100 typically integrated into the thermostat 200, and a second (or receiving) control module 300 typically integrated into the heating apparatus 400.

In the present embodiment, the thermostat 200 is configured to monitor the ambient temperature of the room where it is installed and is configured to turn on, or off, or modulate, the heating apparatus 400 depending on the ambient temperature and the desired temperature set by the user, and possibly depending on other settings such as, but not limited to, timers and heating periods.

The heating apparatus 400 typically comprises at least one heating element and can comprise at least one fan. It is to be understood that the heating apparatus 400 can be embodied as a conventional baseboard heater, a fan heater, a convection heater, etc. In the non-limitative embodiment of FIG. 1, the heating apparatus 400 comprises two heating elements and one fan.

In accordance with the principles of the present invention, the first control module 100 is adapted (e.g. programmed, designed, etc.) to send command signals to the second control module 300 over the power line 500 which carries the power (i.e. voltage and current) from the thermostat 200 to the heating apparatus 400. Hence, no other or additional communication wires are necessary.

In accordance with the principles of the present invention, the command signals are transmitted by selectively switching on and off the voltage carried over the power line 500 for predetermined amounts of time. Depending on the command signals transmitted by the first control module 100, the second control module 300, which is configured to monitor the voltage on the power line 500, selectively turns on, or off, or modulate, one or more heating elements, and selectively turns on, or off, or modulate, one or more fans, based on the transmitted command signals.

In a first example of the present embodiment, the heating apparatus 400 is either a baseboard heater or a fan heater which comprises a first heating element 410, a second heating element 420 and a fan 430 (see FIG. 1).

In the present embodiment, if no heating is required as determined by the thermostat 200, the first control module 100 simply turns off the power which consequently turns off the heating apparatus 400. Understandably, in other embodiments, when no heating is required as determined by the thermostat 200, the first control module 100 could send command signals to turn off the heating elements 410 and 420 while maintaining the power on the power line 500.

If heating is required, as determined by the thermostat 200, the first control module 100 turns on the power for a first period of time T_s which is a synchronization period (e.g. 500 ms). Then, the first control module 100 turns off the power for a second period of time T_c, which is a control period. The duration of the control period determines the amount of heating which is required. Then, the first control module 100 again turns on the power for as long as heating is required and as determined by the thermostat 200.

The second control module 300, which is connected to the first control module 100 via the power line 500 (see FIG. 1), monitors the voltage over the power line 500 such as to detect the synchronization period T_s and the control period T_c.

At this point, it is to be understood that the synchronization period T_s also serves as a powering period. Indeed, in order for the second control module 300 to function during the control period T_c, a period during which no power is transmitted over the power line 500, the second control module 300 uses the power transmitted during the synchronization period T_s to accumulate energy using known accumulators such as, but not limited to, capacitor(s) (not shown). This accumulated energy will then be used during the control period T_c to power the second control module 300.

Upon detecting the synchronization period T_s, the second control module 300 will monitor the duration of the control period T_c such as to act accordingly.

In the present example, if T_c is equal to 62.5 ms, then low heating is required and the second control module 300 turns on only the first heating element 410 and drives the fan 430 at low speed. If T_c is equal to 125 ms, then medium heating is required and the second control module 300 turns on the first heating element 410 and cyclically turns on the second heating element 420 according to a 33% cycle (i.e. the second heating element 420 only heats 33% of the time). The second control module 300 also drives the fan 430 at medium speed. Finally, if T_c is equal to 0 ms, then full heating is required and the second control module 300 turns on both heating elements 410 and 420 and drives the fan 430 at high speed.

This first temporal sequence is illustrated in the graph of FIG. 2.

If the heating apparatus 400 is already operating and thus is already receiving power over the power line 500, the first control module 100 can still send command signals to the second control module 300 to change the current heating mode. To do so, the first control module 100 temporarily turns off the power for a third period of time T_d (e.g. 62.5 ms) which is a delay period before sending the synchronization period T_s and the control period T_c.

This second temporal sequence is illustrated in the graph of FIG. 3.

In other embodiments, the synchronization period T_s and/or the control period T_c and/or the delay period T_d could include a sequence of pulses instead of being completely either on or off during the full period. Such a sequence of pulses could be used to make one or more of the periods more detectable by the second control module 300. Examples of a sequence of pulses in the synchronization period T_s are shown in FIGS. 2A and 3A.

Understandably, the first control module 100 can send command signals to the second control module 300 to make the heating apparatus 400 heat more or less, as required by the thermostat 200.

In a second example of the present embodiment, the heating apparatus 400 is a convector heater and comprises a first heating element 410, a second heating element 420 and a fan 430 (see FIG. 1).

In a similar fashion, in this second example, if no heating is required, the first control module 100 typically simply turns off the power to turn off the heating apparatus 400.

In this second example, the functioning is generally the same. The only differences generally lie in the delays of T_c, in the speeds of the fan 430 and in the selection and cycling of the heating elements 410 and 420.

Hence, in this second example, if T_c is equal to 187.5 ms, then very low heating is required and the second control module 300 only turns on the first heating element 410; the fan 430 is not driven. If T_c is equal to 250 ms, then low heating is required and the second control module 300 turns on the first heating element 410, cyclically turns on the second heating element 420 according to a 23% cycle (i.e. the second heating element 420 only heats 23% of the time), and drives the fan 430 at low speed. If T_c is equal to 125 ms, as in the first example, then medium heating is required and the second control module 300 turns on the first heating element 410, cyclically turns on the second heating element 420 according to a 33% cycle (i.e. the second heating element 420 only heats 33% of the time), and drives the fan 430 at medium speed. Finally, if T_c is equal to 0 ms, as in the first example, then full heating is required and the second control module 300 turns on both heating elements 410 and 420 and drives the fan 430 at high speed.

It is to be noted that in the present embodiment, the second control module 300 is the same in both examples. In that sense, it is worth noting that in both examples, a T_c equal to 125 ms generates an identical response by the second control module 300.

In that sense, in the present embodiment, the second control module 300 is preferably, though not necessarily, capable of being used with different types of heating apparatuses 400 without modifications.

At this point, it is important to note that the delays of the control period T_c are preferably, though not necessarily, chosen such that the temporary switching at off of the power during the control period T_c does not affect the electrical components (e.g. heating elements, fans, lights, etc.) of the electrical apparatus in a manner which would be obviously perceptible by the user.

Indeed, if the delay of the control period T_c is too long, then the user might notice sudden and/or punctual changes (e.g. noises, flickering lights, etc) during the control periods T_c, changes which might be considered annoying.

Still, it is to be understood that a control system in accordance with the principles of the present invention will still work with more or less long delays, as long as the second control module 300 has enough stored energy to function properly during the control periods T_c.

As the skilled addressee will understand, in typical applications, the power (i.e. voltage and current) transmitted over the power line 500 is transmitted by voltage in alternative current (V_ac). However, it is to be understood that a control system in accordance with the principles of the present invention can also function when the power is transmitted by voltage in direct current (V_dc).

Still, when the power transmitted over the power line 500 is effectively transmitted by voltage in alternative current (V_ac), the switching at off of the power (by the first control module 100) is preferably effected at zero crossings of the typically sinusoidal signal in order to avoid the creation of unwanted harmonics on the power line 500.

Still, it is to be understood that a control system in accordance with the principles of the present invention will still function even if the commutation of the power is not effected at zero crossings. Such random commutation could however generate unwanted harmonics on the power lines 500.

In alternate embodiments, such as the one in FIG. 6, the first heating element 410A of the heating apparatus 400 could be independent from the second control module 300 such that the second control module 300 would not have control over the first heating element 410A. In such embodiments, the first heating element 410A would remain under the direct control of the thermostat 200.

An embodiment such as the one in FIG. 6 could be used, for example, to assure at least minimal heating when heating is required as determined by the thermostat 200.

In accordance with the principles of the present invention, should the thermostat 200 fail to comprise a first control module 100 (e.g. a conventional bimetal thermostat), the second control module 300 would still work, although in a limited fashion. Indeed, if the thermostat 200 only turns on and off the power as heating is required, then turning on the power for the first 500 ms would indicate to the second control module 300 to be ready for a control period T_c. As the control period T_c would be equal to 0 ms, the second control module 300 would turn on both heating elements and drive the fan at high speed as a normal bimetal thermostat would operate.

In addition, if the heating apparatus 400 does not comprise a fan, then the second control module 300 will only operate on the heating elements on which it has control.

The skilled addressee will readily understand that the examples given above are not limitative. Indeed, the first and second control modules 100 and 300 could be programmed or designed to modulate more, or less, than two heating elements, and/or to drive more, or less, than one fan, and/or to control additional electrical components (e.g. lights, air-conditioning unit, etc.). In addition, the values of the cycling of the heating element(s) could be different from the 23% and 33% given above. These values could possibly be programmable on the first control module 100, on the second control module 300, or on both. Also, the number of heating modes is not limited to three (i.e. low, medium and high) as in the first example, or four (i.e. very low, low, medium and high) as in the second example. In fact, the number of heating modes should be chosen as required.

Referring now to FIGS. 4 and 5, schematic diagrams of two embodiments of the first control module 100 are illustrated. The two embodiments are relatively similar except for small differences which will be noted as the description proceeds.

The first control module 100 generally comprises a processor or processing unit 110 (e.g. a microprocessor, a microcontroller) which can be independent or integral with the processing unit of the thermostat 200. In the present embodiment, the processor 110 is integral with the processor of the thermostat 200.

The processor 110 is in communication with a user interface 210 of the thermostat 200 for receiving input data (e.g. temperature settings, timer, etc.) therefrom and for transmitting output data thereto (e.g. current temperature, current settings, etc.). The user interface 210 typically comprises one or more buttons and a display screen (not shown).

The processing unit 110 is also in communication with a temperature sensor 220 for receiving temperature data therefrom.

The processing unit 110 is further operably connected to one (FIG. 4) or more (FIG. 5) electrically actuated switches 120 (e.g. relays, bilateral triode thyristors (aka triacs), etc.) which selectively allow the passage of the power over the power line 500.

The processor 110 is also connected to a power supply 230, the power supply 230 being connected, in the embodiment of FIG. 4, to the power lines 500 via a current transformer 240. In the embodiment of FIG. 5, the power supply 230 is directly connected to the power line 500.

In accordance with the principles of the present invention, the processing unit 110 is programmed, designed, or configured to run instructions, to selectively actuate the switch(es) 120 for predetermined amounts of time such as to allow or block the passage of power over the power line 500.

As the skilled addressee will understand, as the switch(es) 120 is(are) selectively actuated for predetermined amounts of time, the power on the power line 500 is selectively turned on and off. As indicated above, the amounts of time during which the power is turned on or off will be monitored by the second control module 300 to control the heating apparatus 400.

Referring now to FIG. 7, a schematic diagram of an embodiment of the second control module 300 is illustrated.

In the present embodiment, the second control module 300 comprises a power supply unit 310, a processing unit 320, a first heating element controlling unit 330A, a second heating element controlling unit 330B, and a fan controlling unit 340.

The power supply unit 310 is directly connected to the power line 500 which is connected to the first control module 100 located in the controlling device 200. The power supply unit 310 is responsible for powering the other units via the power received over the power line 500. In that sense, the power supply unit 310 typically comprises transformer(s) and/or converter(s) for converting the typically alternating current received over the power line 500 into typically lower voltage direct current.

The power supply unit 310 is also configured to detect the presence and absence of voltage (or current) on the power line 500 in order to detect the transmission of command signals over the power line 500. In that sense, the power supply unit 310 is also configured to transmit synchronization signals to the processing unit 320 when the voltage (and the current) on the power line 500 is selectively turned on and off.

The processing unit 320, which can be a processor, a microcontroller, a programmable microelectronic circuit, etc., is at the heart of the second control module 300.

In that sense, the processing unit 320 is connected to the power supply unit 310, for receiving the synchronization signals therefrom, and to the heating element controlling units 330A and 330B and the fan controlling unit 340 for transmitting command signals thereto.

The processing unit 320 is therefore programmed, configured to run instructions, designed, etc., to process the synchronization signals transmitted by the power supply unit 310 in order to decode the actual command transmitted by the first control module 100. Once properly decoded, the processing unit 320 is responsible for transmitting the proper command signals to the heating element controlling units 330A and 330B, and/or to the fan controlling unit 340.

In the present embodiment, the processing unit 320 comprises three outputs for the operation of the fan 430, one output for the operation of the heating element 410, and one output for the operation of the heating element 420 (see the embodiment of FIG. 1). In other embodiment, the processing unit 320 could have additional outputs for additional heating elements and/or for other electrical components (e.g. lights).

The heating element controlling units 330A and 330B are operatively connected to the processing unit 320 in order to receive the command signals therefrom, and are also connected to the power line 500.

In the present embodiment, the controlling units 330A and 330B are configured to output voltage (and current), typically equal to the voltage (and current) transmitted over the power line 500, when they receives a trigger signal from the processing unit 320. Hence, the controlling unit 330 typically comprises a relay, or any other electrically actuated switch, which allows the passage of the voltage (and current) when the trigger signal is active.

Hence, if, as mentioned above, the command signals transmitted to the second control module 300 imply that the heating element 410 is to operate at 100% and that the heating element 420 is to operate 33% of the time, then the processing unit 320, upon processing these command signals, will continuously activate the trigger signal of the heating element controlling unit 330A and will activate the trigger signal of the heating element controlling unit 330B only 33% of the time. However, to prevent rapid switching of the heating element 420, the cycling of the trigger signal could be as long as a few minutes (e.g. the trigger signal is active for 3 minutes in a cycle of 9 minutes).

Understandably, in the present embodiment, the heating element controlling units 330A and 330B are under the control of the processing unit 320 as they only respond to the presence of the trigger signals.

As for the heating element controlling units 330A and 330B, the fan control unit 340 is operatively connected to the processing unit 320 in order to receive the command signals therefrom, and is also connected to the power line 500. In the present embodiment, the fan control unit 340 typically comprises a series of transformers and relays which are selectively activated depending on the instructions received and processed by the processing unit 320. The transformers are necessary to lower the voltage according to the possible operating speeds of the fan 430. In the present embodiment, the fan 430 can be operated at three speeds, i.e. low, medium and high (or full) speed. Hence, in the present embodiment, the fan control unit 340 comprises three outputs having low, medium and high voltages respectively and in accordance with the operating speeds of the fan 430. The exact voltages depend on the operating parameters of the fan 430 and on desired low, medium and high speeds of the fan 430.

The output corresponding to the desired operating speed of the fan 430 is selected by a selecting signal transmitted by the processing unit 320 upon the decoding of the command signals sent by the first control module 100.

In the present embodiment, the selecting signal is used to activate the relay corresponding to the output of the selected operating speed.

As for the heating element control unit 330, the fan control unit 340 is directly under the control of the processing unit 320 as it outputs voltage only in the presence of a selecting signal.

Understandably, in other embodiments, the configuration of the second control module 300 and of the different units 310, 320, 330 and 340 could be different based, for instance, on different operating parameters, on different configurations of electrical components to be operated, etc. In still other embodiments, all the units could be integrated into a multifunctional single unit.

The skilled addressee will understand that a control system in accordance with the principles of the present invention does not need additional wires to transmit command signals from the first control module to the second control module. Furthermore, if the commutation of the power is effected as indicated in the preceding description, unwanted harmonic signals could be avoided on the power line.

While illustrative and presently preferred embodiments of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.

Claims

1) A control module for remotely controlling an electrical apparatus connected to a power line, the control module comprising:

a) an electrically actuatable electric switching unit, the switching unit being configured to be connected to the power line to selectively allow and block the passage of electric current over the power line;

b) a processing unit operatively connected to the switching unit, the processing unit being configured to selectively actuate the switching unit for predetermined amounts of time to selectively allow and block the passage of current over the power line for the predetermined amounts of time, the predetermined amounts of time being determinative of instructions transmitted to the electrical apparatus over the power line.

2) A control module as claimed in claim 1, wherein the switching unit comprises at least one relay.

3) A control module as claimed in claim 1, wherein the switching unit comprises at least one bilateral triode thyristor.

4) A control module as claimed in claim 1, wherein the control module is a transmitting control module.

5) A control module for controlling an electrical apparatus comprising at least one electrical component, the electrical apparatus being connected to a power line, the control module comprising:

a) a power supply unit configured to be connected to the power line and configured to output first signals based on the monitoring of predetermined amounts of time during which electrical current is present and absent on the power line;

b) a processing unit connected to the power supply unit, configured to extract instructions from the first signals, and configured to output at least second signals based on the extracted instructions;

c) at least one electrical component controlling unit connected to the processing unit and operatively connected to the at least one electrical component of the electrical apparatus, the at least one electrical component controlling unit being configured to receive the at least second signals and to control an operation of the at least one electrical component as a function of the at least second signals.

6) A control module as claimed in claim 5, wherein the power supply unit and the processing unit are unitary.

7) A control module as claimed in claim 5, wherein the power supply unit, the processing unit and the at least one electrical component controlling unit are unitary.

8) A control module as claimed in claim 5, wherein the control module comprises several electrical component controlling units.

9) A control module as claimed in claim 5, wherein the control module is a receiving control module.

10) A control system for controlling an electrical apparatus comprising at least one electrical component, the electrical apparatus being connected to a power line, the control system comprising:

a) a transmitting control module configured to be connected to the power line to selectively allow and block the passage of electric current over the power line for predetermined amounts of time, the predetermined amounts of time being determinative of instructions transmitted to the electrical apparatus over the power line;

b) a receiving control module configured to be connected to the power line to detect the predetermined amounts of time during which the current is present and absent in order to extract the instructions transmitted by the transmitting control module, the receiving control module being configured to control an operation of the at least one electrical component as a function of the extracted instructions.

11) A control system as claimed in claim 10, wherein the transmitting control module comprises:

a) an electrically actuatable electric switching unit, the switching unit being configured to be connected to the power line to selectively allow and block the passage of electric current over the power line;

b) a processing unit operatively connected to the switching unit, the processing unit being configured to selectively actuate the switching unit for the predetermined amounts of time to selectively allow and block the passage of current over the power line for the predetermined amounts of time.

12) A control system as claimed in claim 11, wherein the switching unit comprises at least one relay.

13) A control system as claimed in claim 11, wherein the switching unit comprises at least one bilateral triode thyristor.

14) A control system as claimed in claim 10, wherein the receiving control module comprises:

a) a power supply unit configured to be connected to the power line and configured to output first signals based on the detection of the predetermined amounts of time during which the current is present and absent;

b) a processing unit connected to the power supply unit, configured to extract the instructions from the first signals, and configured to output at least second signals based on the extracted instructions;

c) at least one electrical component controlling unit connected to the processing unit and operatively connected to the at least one electrical component of the electrical apparatus, the at least one electrical component controlling unit being configured to receive the at least second signals and to control the operation of the at least one electrical component as a function of the at least second signals.

15) A control system as claimed in claim 14, wherein the power supply unit and the processing unit are unitary.

16) A control system as claimed in claim 14, wherein the power supply unit, the processing unit and the at least one electrical component controlling unit are unitary.

17) A control system as claimed in claim 14, wherein the receiving control module comprises several electrical component controlling units.

18) A method for remotely controlling an electrical apparatus connected to a power line, the electrical apparatus comprising at least one electrical component, the method comprising:

a) at a first location, selectively allowing and blocking the passage of current over the power line for predetermined amounts of time, the predetermined amounts of time being determinative of instructions transmitted over the power line;

b) at a second location, monitoring the predetermined amounts of time during which the current is selectively allowed or blocked;

c) as a function of the monitored predetermined amounts of time, operating the at least one electrical component according to the transmitted instructions.