GB2335553A - Electronic power control and protection - Google Patents

Abstract

A load 11 is supplied from a battery 1 by way of a current detector 10 which may be a resettable fuse and an electronic switch 12 which may be a relay or MOSFET. The detector 10 and switch 12 may provide protection against high and low current, high temperature and low supply voltage. A plurality of load circuits may be controlled and reset in common from a remote panel, for example in a boat or car.

Description

R1598GB2 ELECTRONIC POWER CONTROL OR PROTECTION 2335553 This invention

relates to an electronic power control and/or protection system. In particular, but not exclusively, it relates to a power control and/or protection system for use in an automotive, industrial or mobile environments, amongst many others.

The invention arose in an attempt to provide a power control and protection system for marine use, but has uses extending far beyond these uses.

When power control is required in a boat or automotive application, the source of power is generally a battery or batteries. A plurality of circuits (e.g. lighting, control circuitry, navigational equipment, etc) are supplied with power from the battery and each separate circuit is generally protected by a fuse against overload, overheating, etc.

Existing designs rely on fuses or manually resettable circuit breakers that need to rupture in order to protect the circuit in question. Fuses can be slow to respond and, once ruptured, a spare fuse is required to restore power when the circuit is repaired. Another problem with fuses is that owing to additional electronics being installed, the load on a circuit often tends to creep up. Failure is then often not due to a faulty circuit at all but rather to an overload. With conventional systems, the fuse is replaced and left until the next overload, which tends to happen more fi-equently, and thus the supply of fuses can be exhausted rapidly.

Existing designs are also fitted with manual switches to isolate the circuit, at a central point. The manual nature of existing designs means that switches and fuses must be provided, all of which tend to protrude from a fuse panel for example, and all power cables have to be brought to a central point where the fuse panel is located.

R1598GB2 Existing designs of power control systems are frequently untidy to install and their very nature leaves a lot of exposed connections that can and do corrode in a marine or other mobile environment. Since the fuse box has to be centrally located remote from the battery supply, long cable runs are required which are subject to voltage drops and power loss.

In previous systems, there is absolutely no scope to integrate the power control and protection with other functions. This is because the units are simple and unintelligent and can do no more than protect against current overload.

Additionally, being bulky devices with protruding switches or fuses, existing units tend to be unattractive and to look dated and clumsy, when compared to modem electronic equipment which customers have tended to come to expect to have a sleek and neat appearance.

The present invention arose in an attempt to provide an improved power control and protection system for marine environments, although the invention is applicable beyond the marine field.

According to the present invention there is provided electronic power supply and/or protection apparatus, comprising an input for a power supply, a current detector, an electronic switch and a control means, for protecting and/or controlling power supply to a load.

The apparatus is preferably formed as a single electronic module.

The module may be protocol independent and applicable to both DC and AC loads.

Embodiments of the invention can operate in, inter alia, four configurations: 30 electronic circuit breaker., remotely controlled switch., addressable remotely R1598GB2 controlled switch and an addressable remotely controlled switch with interlock capability. In reality by changing the software any combination is feasible, e.g. a circuit breaker with an interlock capability.

The invention provides an electronic apparatus or module that is protocol independent providing both protection and control capabilities between a power supply and an electricaLlelectronic; device, including electronic circuits. In its protective mode when one of the following events occurs, the current exceeds or falls below pre-set limits; the temperature of a switching element in the module increases above a pre-set limit, or; the power supply voltage falls below a pre-set limit, then the module disconnects the power supply and waits for a reset command. In its control mode the power supply can be connected and disconnected through the application of control signals. Supervisory signals are available that indicate the status of the module. The combination of features and functions can be varied by changing a software program to allow the basic electronic module to be used in several different modes. The basic design can be applied to both DC and AC low voltage applications.

According to the present invention in a further aspect there is provided an electronic power control andlor protection system comprising input means for a power supply and a plurality of power control andlor protection circuits fed by the power supply, wherein each power circuit comprises electronic circuit breaker means arranged to break the circuit in the event of fault or overload conditions, and control panel means, including means for resetting the electronic circuit breaker means.

The system may comprise an electronic switch, for example an electronictype device relay, means for setting the relay off when a fault has occurred, and means for resetting the relay on. The system may comprise a resettable fuse, a latch means or processor means, and an operatoractuated means for resetting the relay on via the latch or processor.

R1598GB2 Preferably, the control panel means is remote from the physical location of the electronic circuit breaker means. This inventive concept is made possible by the fact that the electronic circuit breaker means do not require direct physical manipulation or operation by a user, unlike conventional fuses, circuit breakers etc which must be either replaced or reset at the circuit breaker manually when a fault has occurred at the conventional fuse or circuit breaker location.

Preferably, the control panel means (which may comprise several control panels either located in one position or in several positions and/or be split into a plurality of control panels each controlling one or more functions or circuits) comprises flat panel means. This enables an attractive appearance and also enables easy customisation of the front panels for different uses and environments.

The control panel means may be a virtual control panel. By this is meant that the control panel may be implemented in software for example on a computer screen, the computer being interfaced to the control circuits.

By locating the control panel remotely, only lower power connections are required to wherever the control panel is situated.

The power supply may be a battery supply. The power control circuitry may be located near to the battery supply, which not only allows easier installation, both in terms of cost and time, but also means that several additional control methods can be used such as software control and electronic interlocks to other devices, such as 25 devices for automatic sensing of fire or other conditions.

The use of electronic components allows the power control circuitry and electronic fuses to be totally encapsulated so that none of their physical connections are exposed. Encapsulation enables protection in a harsh marine or automotive 30 environment for example.

R1598GB2 Preferably, the use of electronic components and even of software, enables several additional functions to be used. This may include warning of combinations of alarms that may prove disastrous or of interlocks to prevent misuse.

The use of electronic components in a modular format enables a front panel to be used in the power distribution system that is flat, with no exposed parts such as screw heads, switches, fuses or indicators. This can of course be made visually very pleasing and may be provided with tough labels of plastics material so that change in the artwork only can readily incorporate the requirements of different users. Thus, the requirements of foreign languages and of different presentations for different boat or car builders, for example, can be readily incorporated.

The invention further provides an electronic power control and/or distribution system including any one or more of the novel features or concepts disclosed herein.

is Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows schematically a power distribution circuit., Figure 2 shows part of the distribution circuit and provides more detail of an 20 electronic circuit breaker as applied to a DC system., Figure 3 is a flow chart showing the operation of the circuit., Figure 4 shows an electronic circuit breaker configuration using a microcontroller as applied to a DC system; Figure 5 shows a use of an intelligent power switch; and Figure 6 shows an alternative use of an intelligent power switch.

The drawings illustrate a power distribution system which may, in a nonlimiting example, be for a marine environment such as on a boat. It is intended to distribute low voltage power (for example of up to 24 volts) to a number of separate 30 circuits. The invention may also be used in other embodiments (with different R1598GB2 components as necessary) for the distribution and control of AC circuits.

Referring to Figure 1, in general terms the system comprises a power supply in the form of a battery 1 (or a bank of batteries) which may provide a supply of, typically, 12 to 24 volts, although the invention is applicable to power sources lying outside this range. The output from the battery is supplied through a main isolator switch 2 to a plurality of individual circuits, each protected by an individual circuit breaker means 3a, 3b, 3c, 3d. Circuit breaker 3a forms part of a first individual circuit A, circuit breaker 3b forms part of a second individual circuit B and so on.

Note that although four circuits are shown in the diagram this is by way of example only and more or less individual circuits may be used. The individual circuits are then used for various purposes in the boat, e.g. for instrumentation, various forms of lighting, wipers, bilge pump operation, and so on.

Control is preferably achieved by means of a plurality of respective front panels 4, each of which is used to operate a respective control logic unit 5a, 5b, etc, which act upon the respective circuits A to D and the circuit breakers.

The system can detect a low or open load condition (i.e. low current or circuit disconnected; high component temperature; battery supply disconnected, as well as overcurrent situations). For the latter, for example, when a fault condition exists that results in a defined current being exceeded for a defined period of time in a particular circuit, that individual circuit trips out by virtue of its respective circuit breaker.

Power to the circuit can manually be restored by the use of a reset button for example after a certain period of time during which the fault must be repaired.

Figure 2 illustrates one hardware-based example of electronic circuit breaker 3a in more detail. Referring to the figure, functions which are common to all circuits in the system comprise a voltage display 6, voltage alarm 7, a regulator 8 and a power-on detector 9 and these are functions that may be provided at a control panel or R1598GB2 in the control electronics.

The voltage display 6 comprises a readily available commercial module that measures and displays the voltage of the connected battery 1. A voltage alarm 7 indicates different levels of battery condition.

The regulator 8 powers the electronics in the electronic circuit breaker assembly 3a and provides a voltage of the correct level to power the circuit electronics. If separate control panels and control electronics are used then separate regulators may be required. Power-on detector 9 is arranged to detect when the main isolator switch 2 is closed and to reset all the circuits into the 'off state.

The remaining elements shown in Figure 2 are ones which are provided individually for each circuit.

A resettable fuse 10 is connected to the output of the main isolator switch 2. The resettable fuse is primarily used as a current detector. Other types of current detector may alternatively be used. One example is a Hall Effect current detector. The resettable fuse 10 is a commercial device which sets the current limit for the circuit. These devices can automatically attempt to reset following a defined period. If a load 11 has reduced or a particular fault which caused a trip condition has cleared, then resettable fuse 10 automatically resets during the defined period. If these have not occurred, then the fuse 10 will not reset. Power from the battery is normally fed by the resettable fuse 10 to an electronic switch, which may be a high sided relay 12. In one example, this is a MOSFET high side smart power solid state relay and may in one example be the VN20N relay of STG- Thomson Microelectronics. Many other electronic switches are available and may be used instead, e.g. switches from IOR or Siemens. The electronic switch is used to drive a load 11 which may be, e.g. lighting or other electrical functions of a vehicle or vessel.

The relay is driven by a signal from a latch circuit and the relay can provide R1598GB2 automatic shutdown and alarm signals when the relay either overheats or draws too much current. The solid state nature of the relay enables very fast shutdown and the VN20N relay has on-chip monitoring. The relay is driven by a signal from a latch circuit 13. The alarm signal on the device is fed back on a fault line 14 individually to the latch 3 0 where it is aggregated with reset, off and power on signals (see below). The latch 13 is a simple set/reset latch that operates the enable input 15 of the high sided semi-conductor relay 12 to drive the load or not.

A trip detector 16 detects when the resettable fuse 10 has tripped and provides a signal on the fault line 14 which acts to switch the switch off, by resetting latch 13. After a fault has occurred, and once the resettable fuse has reset, it is necessary to reset the relay, through the latch.

Each individual circuit also includes 'on' and 'off buttons 17 and 18 respectively which, when depressed, switch the high sided relay 12 on or off respectively via the latch 13. The offbutton 18 also serves to reset the latch, and thereby re-enable the relay, following a trip. As it operates electronically, the on/off buttons can be provided in a simple thin film type display and are not analogous with the manual resetting of a conventional circuit breaker. One or more status indicators 19 may also be provided to show the current state of each circuit, that is, whether that circuit is on or off. If no power is applied to any circuit, then of course all the individual status indicators 19 will be off.

Figure 3 is a flowchart schematically illustrating the general operation. Note that an interlock function and addressable circuit breakers are included in this embodiment and these are shown at steps S3 and S9. In effect, in order for power to be enabled to the load, at step 11 the on switch must be pressed whilst the relevant circuit breaker is being addressed.

The above described system uses a combination of discreet analog and digital R1598GB2 components. Figure 4 illustrates an embodiment based upon a microchip controller based software driven module. The embodiment of Figure 4 enables the implementation of a more complex and integrated unit and enables the front control panel to be separated from the actual control unit and the power control electronics.

The control panel can, if desired, be split into a number of panels, each controlling a different electronic circuit or group of circuits. The circuit breakers may then be located remotely from the control panel, typically in or near the battery compartment, which can save on wiring and power distribution as well as causing greatly simplified installation.

The use of software enables the same basic electronics module to be used for several functionally different units. The same software algorithms can be applied to both DC and AC operation. This means, for example, that an electronic circuit breaker can be produced for AC mains operation in both domestic and industrial switch gear.

The embodiment of Figure 4 again uses a resettable fuse 10 (or other current detector) and high sided relay 12 or other electronic switch. Enabling of the relay is, however, achieved by means of a microcontroller 20. This may be a PIC controller using a high speed RISC architecture and is software programmable to provide all the functionality of the control logic modules.

In use, inputs from the trip detector 16, 'on' and 'off buttons 17, 18 and also from the voltage sensor 6, circuit breaker addressed 38, voltage alarms 7 and power on detector 9 are provided through a digital interface 21 to the microcontroller 20.

Under software control, this analyses the information received and operates, via the enable line, the high sided relay 12. The microcontroller 20 can also provide various levels of indication and status by means of indicators 22.

Many other systems, either by hardware/software or a combination of these, R1599GB2 and using analog and/or digital electronics may be used within the scope of the present invention.

Figure 5 shows schematically how a plurality of intelligent power switches P,, P2, P3 can be used in a system. Each of the switches P,, P2 and P3 receives a 12V DC supply and drives a respective load L,, L2, L3. A common switch/mimic panel S/P provides an interface with the power switches. Figure 6 shows a similar arrangement in which the remote switch/mimic panel S/P is remotely located and communicates via a wireless link with a signal interface Si. These systems therefore function as remotely controlled switches. Interlock functions may be provided.

Other types of electronic switches, e.g. diodes, MOSFET, IGBTs, thyristors, etc, may be used instead of the VN20N type relay to cater for other voltages, including AC operation.

R1598GB2

Claims (15)

1. Electronic power control andlor protection apparatus, comprising an input for a power supply, a current detector, an electronic switch and a control means, for protecting and/or controlling power supply to a load.

2. Apparatus as claimed in Claim 1, which is formed as a single electronic module.

3. Apparatus as claimed in Claim 1 or Claim 2, adapted for use with both DC and AC loads.

4. Apparatus as claimed in any preceding claim, adapted to function as an electronic circuit breaker.

5. Apparatus as claimed in any preceding claim, adapted to function as a remotely controlled switch.

6. Apparatus as claimed in any preceding clairn, adapted to function as an 20 addressable device.

7. Apparatus as claimed in any preceding claim, comprising an interlock facility.

8. Apparatus as claimed in any preceding claim, wherein the current detector is a 25 resettable fuse.

9. Apparatus as claimed in any preceding claim, wherein the current detector is a Hall Effect device.

10. Apparatus as claimed in any preceding claim, comprising operator actuated R1598GB2 means for resetting the current detector.

11. Apparatus as claimed in any preceding claim, including a control panel which is remote from the physical location of the electronic power control andlor protection apparatus.

12. Apparatus as claimed in Claim 11, wherein the control panel is virtual.

13. An electronic power control and/or protection system comprising input means for a power supply and a plurality of power control andlor protection circuits fed by the power supply, wherein each power circuit comprises electronic circuit breaker means arranged to break the circuit in the event of fault or overload conditions, and control panel means, including means for resetting the electronic circuit breaker means.

is

14. Apparatus as claimed in Claim 13, comprising respective independent circuit breaker means and control means for each power control andlor protection circuit.

15. Electronic power control and/or distribution apparatus substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.