GB2538058A

GB2538058A - A variable speed drive module

Info

Publication number: GB2538058A
Application number: GB1507229.1A
Authority: GB
Inventors: Jones Glyn; Phillips Steve
Original assignee: INVERTEK DRIVES Ltd
Current assignee: INVERTEK DRIVES Ltd
Priority date: 2015-04-28
Filing date: 2015-04-28
Publication date: 2016-11-09
Anticipated expiration: 2035-04-28
Also published as: GB201507229D0; DE102016107904A1; FR3035754A1; FR3035754B1; GB2538058A8; GB2538058B8; GB2538058B

Abstract

A variable speed drive module comprising a power supply input 3 (fig 1) to be connected to a source of power. The module comprises a switching arrangement 4 which is controllable to modulate power input via the power supply input and to output variable frequency drive signals to a motor output 5 (fig 1). The module comprises a first control connector 7 (fig 1) which is coupled to the switching arrangement 4 and is configured to connect removably to a second control connector 8 provided on a control arrangement 9, to receive control signals from the control arrangement. The switching arrangement 4 is incapable of outputting variable frequency drive signals to the motor output 5 if the control connectors are disconnected from one another, thus disabling the device. The variable speed drive module may further comprise a control arrangement comprising a second control connector and an attachment arrangement to allow it to releasably attached. The control module may comprise a processor, a communications module communicating signals between the processor and the second control connector and a memory for storing instructions to be executed by the processor.

Description

Title: A Variable Speed Drive Module

Description of Invention

The present invention relates to a variable speed drive module.

A variable or adjustable speed drive is typically configured to control the speed of an electric motor, such as a motor that is used in a pump, fan, elevator or conveyor. A variable speed drive is usually configured to control the motor so that any changes in the speed of rotation of the motor occur smoothly.

A variable speed drive comprises a switching arrangement which modulates a power input to provide a variable frequency power signal that is suitable for driving a motor. For instance, a variable speed drive may incorporate an AC-AC converter which converts an AC line input into an AC inverter output that is suitable for driving an AC motor. The variable speed drive controls the speed of the motor by adjusting the frequency and voltage of the AC output signal that drives the motor.

A conventional variable speed drive comprises a control unit which is configured to control the switching arrangement to output the variable frequency drive signals that are required to drive a motor. The control unit usually communicates with a user interface which may be operated by a user to set control parameters that are used by the control unit. The control unit may also incorporate an input/output port to be connected to a communications bus to enable a user to program the control unit by sending instructions to the control unit via the communications bus.

There is an increasing demand for variable speed drives which is mainly due to the high efficiency at which a variable speed drive operates. This provides a variable speed drive with a significant environmental benefit over conventional, less efficient motor drive arrangements. It is therefore desirable to use variable speed drives wherever possible. However, variable speed drives are not currently available for use in all low cost applications due to the relative complexity of the circuitry. Consequently, there are low-cost applications that could benefit from the improved efficiency and environmental benefits of variable speed drives but which currently do not make use of the technology.

There is a need for a variable speed drive that is suitable for use in all applications, including those applications that require a low set up cost.

The present invention seeks to provide an improved variable speed drive module.

According to one aspect of the present invention, there is provided a variable speed drive module comprising: a power supply input to be connected to a source of power; a switching arrangement which is controllable to modulate power input via the power supply input and to output variable frequency drive signals to a motor output; and a first control connector which is coupled to the switching arrangement and configured to connect removably to a second control connector provided on a control arrangement, to receive control signals from the control arrangement and to communicate the control signals to the switching arrangement to control the switching arrangement, wherein the switching arrangement is incapable of outputting variable frequency drive signals if the control connectors are disconnected from one another.

In one embodiment, the variable speed drive module further comprises: a control arrangement which incorporates a control module, the control module comprising: the second control connector which is configured to connect removably to the first control connector; and an attachment arrangement which is configured to attach the control module releasably to the variable speed drive module when the control connectors are connected to one another.

Preferably, the attachment arrangement is configured to enable tool-free attachment of the control module to the variable speed drive module and tool-free separation of the control module from the variable speed drive module.

In another embodiment, the variable speed drive module further comprises: a control arrangement which incorporates: a control module; an elongate cable; and the second control connector which is configured to connect removably to the first control connector, one end of the cable carrying the second control connector and the other end of the cable being connected to the control module so that the control module can be positioned remotely from the switching arrangement with control signals being communicated along the cable.

Preferably, the control module comprises: a processor; a communication module which is configured to communicate control signals between the processor and the second control connector; and a memory storing instructions which, when executed by the processor, cause the processor to output control signals to the communication module, so that the communication module can communicate the control signals to the variable speed drive module via the control connectors.

Conveniently, the control module is configured to be re-programmed by overwriting at least some of the instructions stored in the memory with customised instructions.

Advantageously, the control module comprises at least one hardware 30 component which is configured to be customised according to user requirements.

Preferably, the variable speed drive module and the control module each comprise respective self-contained housings.

Conveniently, the housings are electrically isolated from one another.

According to another aspect of the present invention, there is provided a variable speed drive arrangement comprising a first variable speed drive module and a second variable speed drive module, each variable speed drive module being in accordance with any one of claims 1 to 9 as defined hereinafter, wherein the first variable speed drive module has a higher output power rating than the second variable speed drive module, and wherein the variable speed drive arrangement further comprises at least one control module according to any one of claims 2 to 9 as defined hereinafter which is configured to attach releasably to either one of the first and second variable speed drive modules.

According to another aspect of the present invention, there is provided a variable speed drive arrangement comprising first and second control modules according to any one of claims 2 to 9 as defined hereinafter, wherein the first and second control modules are configured differently from one another, and wherein control modules are each configured to attach releasably to a variable speed drive module according to any one of claims 1 to 9 as defined hereinafter.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view of a variable speed drive module of one embodiment of the invention, Figure 2 is a schematic diagram of components of the variable speed drive module of figure 1, Figure 3 is a diagrammatic perspective view of the variable speed drive module of figure 1 and a control module which is not yet connected to the variable speed drive module, Figure 4 is a schematic diagram of components of the control module of figure 3, and Figure 5 is a diagrammatic view of the variable speed drive module of figure 1, with a control module releasably connected to the variable speed drive module.

Referring initially to figures 1 and 2 of the accompanying drawings, a variable speed drive module of an embodiment of the invention comprises a modular power block 1 which incorporates a housing 2. In this embodiment, the housing 2 is a self-contained housing which encases components of the power block 1. The housing 2 is provided with ventilation apertures but it is to be appreciated that in other embodiments the housing 2 is a watertight or substantially watertight housing that does not incorporate vent apertures.

In a preferred embodiment, the power block 1 is configured to be mounted to a heatsink module (not shown) to dissipate heat from the power block 1.

The housing 2 houses components of the power block 1 including a power input 3 and a switching arrangement 4. The power input 3 is configured to be connected to a source of power 5, such as an AC mains power supply. In other embodiments, the power input 3 is configured to be connected to a different power source, such as a three-phase or DC power supply. The power input 3 is preferably in the form of a releasable connector.

The power block 1 further comprises a motor output 5 which is configured to be connected to a motor 6. The motor output 5 is preferably in the form of a releasable connector. In use, the switching arrangement 4 outputs a modulated power signal to the motor output 5 so that a motor 6 connected to the motor output 5 may be powered by the modulated signal.

In embodiments of the invention, the power block 1 is configured to power a motor selected from a group of motor types including induction machines, permanent magnet, synchronous machines, brushless DC machines and synchronous reluctance machines.

The power block 1 further comprises a first control connector 7 which is coupled to the switching arrangement 4. The first control connector 7 on the power block 1 is configured to connect removably to a second control connector 8 which is provided on a control arrangement. In this embodiment, the control arrangement is in the form of a control module 9, as shown in figures 3 and 4.

The control module 9 comprises a housing 10. In this embodiment, the housing 10 is a self-contained housing that contains components of the control module 9 and the housing 10 incorporates vent apertures 11. However, in other embodiments, the housing 10 is a watertight or substantially watertight housing that does not incorporate vent apertures. In embodiments of the invention, the housing 10 of the control module 9 is a separate housing from the housing 2 of the power block 1. The two discrete housings 2, 10 are configured to be provided separately from one another, with each housing 2, 10 containing respectively the components of the power block 1 and the control module 9. The housings 2, 10 are preferably independent and electrically isolated from one another.

In this embodiment, a releasable attachment element 12 protrudes from the control module housing 10 to releasably attach to a corresponding attachment formation 13 on the power block housing 2. When the control connectors 7, 8 are connected together and the housings 2, 10 of the control module 9 and the power block 1 are adjacent one another, the releasable attachment element 12 engages with the attachment formation 13 to provide an interference fit attachment (or other type of releasable attachment) to releasably attach the control module 9 to the power block 1. A user may, at a later time, disengage the attachment element 12 from the attachment formation 13 in order to separate the control module 9 from the power block 1.

The attachment arrangement 12, 13 is configured to enable tool-free attachment of the control module 9 to the power block 1 and tool-free separation of the control module 9 from the power block 1. The attachment is tool-free in the sense that no tools, such as a soldering iron or cutter are required to release the attachment element 12 from the attachment formation 13.

In a further embodiment, an elongate cable is provided with one end of the cable carrying or configured to carry the second control connector 8 and the other end of the cable being connected or releasably connected to the control module. This embodiment allows the control module 9 to be positioned remotely from the switching arrangement 4 and the power block 1, with control signals being communicated along the cable.

The control module 9 comprises components which are contained within the housing 10. The components include a processor 14 and a communication module 15 which is configured to communicate data between the processor 14 and the second control connector 8. The control module 9 further comprises a memory 15 which is configured to store instructions which, when executed by the processor 14, cause the processor 14 to output control signals to the communication module 16.

In other embodiments, the control module 9 is configured to be reprogrammed by a user overwriting at least some of the instructions stored in the memory 15 with customised instructions. In further embodiments the control module 9 comprises at least one hardware component which is configured to be customised according to user requirements.

The communication module 16 is configured to communicate the control signals via the control connectors 7, 8 to control the switching arrangement 4 within the power block 1.

When the switching arrangement 4 in the power block 1 is controlled by control signals from the control arrangement, the switching arrangement 4 outputs variable frequency drive signals to the motor output 5. These variable frequency drive signals may then drive a motor 6 connected to the motor output 5.

The power block 1 is only capable of outputting variable frequency drive signals via the motor output 5 if the required control signals are provided to the power block 1. Consequently, if the control module 9 is separated from the power block 1, so that the control connectors 7, 8 are disconnected from one another, the power block 1 is incapable of outputting variable frequency drive signals via the motor output 5.

Referring now to figure 5 of the accompanying drawings, the control module 6 of this embodiment further comprises a communication port 17 which is configured to connect to an external control unit which may be used to configure and program the control module 9. In this embodiment, the control module 9 further comprises user-configurable digital or analogue input and output controls 18 which are configured to be operated by a user to configure the control module 9. In this embodiment, the control module 9 also comprises a relay connection 19. It is, however, to be appreciated that in other embodiments of the invention, at least one or more of the communication port 17, the user-configurable input and output controls 18 and the relay connection 19 may be omitted.

An embodiment of the invention is a modular system that is only configured to function as a variable speed drive which outputs variable frequency drive signals when a control arrangement is connected to the first control connector 7 on the power block 1. The control arrangement is, however, configured to be separated from the power block 1. A standard power block can thus be used with multiple different motor types, with the control modules being selected and configured appropriately for each motor type. For instance, the same standard power block may be used with either a permanent magnet motor or a synchronous reluctance motor, with an appropriate control module being selected and configured for use with the power block to control each motor type.

It is therefore only the control module, and not the power block, that needs to be customised and programmed according to the motor type. The benefit of this arrangement is that the cost of producing the standard power block is reduced significantly since the standard power block can be manufactured in large volumes. This avoids the need to redesign and manufacture different power blocks for different motor types or applications. The reduction in the manufacturing cost enables a variable speed drive to be used in lower cost applications. Therefore, lower cost applications can also benefit from the high efficiency and low environmental impact provided by a variable speed drive.

Conversely, the configuration of embodiments of the invention also enables the same control arrangement to be used with different standard power blocks. For instance, the same control arrangement or control module may be used with different sizes of power block that provide different power outputs.

Whilst certain embodiments of the invention are applicable to low cost applications, it is to be appreciated that embodiments of the invention are equally applicable to any application that can incorporate a variable speed drive, even applications that are not necessarily low cost.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS: 1 A variable speed drive module comprising: a power supply input to be connected to a source of power; a switching arrangement which is controllable to modulate power input via the power supply input and to output variable frequency drive signals to a motor output; and a first control connector which is coupled to the switching arrangement and configured to connect removably to a second control connector provided on a control arrangement, to receive control signals from the control arrangement and to communicate the control signals to the switching arrangement to control the switching arrangement, wherein the switching arrangement is incapable of outputting variable frequency drive signals if the control connectors are disconnected from one another.
2. The variable speed drive module of claim 1, further comprising: a control arrangement which incorporates a control module, the control module comprising: the second control connector which is configured to connect removably to the first control connector; and an attachment arrangement which is configured to attach the control module releasably to the variable speed drive module when the control connectors are connected to one another.
3. The variable speed drive module of claim 2, wherein the attachment arrangement is configured to enable tool-free attachment of the control module to the variable speed drive module and tool-free separation of the control module from the variable speed drive module.
4. The variable speed drive module of claim 1, further comprising: a control arrangement which incorporates: a control module; an elongate cable; and the second control connector which is configured to connect removably to the first control connector, one end of the cable carrying the second control connector and the other end of the cable being connected to the control module so that the control module can be positioned remotely from the switching arrangement with control signals being communicated along the cable.
5. The variable speed drive module of any one of claims 2 to 4, wherein the control module comprises: a processor; a communication module which is configured to communicate control signals between the processor and the second control connector; and a memory storing instructions which, when executed by the processor, cause the processor to output control signals to the communication module, so that the communication module can communicate the control signals to the variable speed drive module via the control connectors.
6. The variable speed drive module of any one of claims 2 to 5, wherein the control module is configured to be re-programmed by overwriting at least some of the instructions stored in the memory with customised instructions.
7. The variable speed drive module of any one of claims 2 to 6, wherein the control module comprises at least one hardware component which is configured to be customised according to user requirements.
8. The variable speed drive module of any one of claims 2 to 7, wherein the variable speed drive module and the control module each comprise respective self-contained housings.
9. The variable speed drive module of claim 8, wherein the housings are electrically isolated from one another.
10. A variable speed drive arrangement comprising a first variable speed drive module and a second variable speed drive module, each variable speed drive module being in accordance with any one of claims 1 to 9, wherein the first variable speed drive module has a higher output power rating than the second variable speed drive module, and wherein the variable speed drive arrangement further comprises at least one control module according to any one of claims 2 to 9 which is configured to attach releasably to either one of the first and second variable speed drive modules.
11. A variable speed drive arrangement comprising first and second control modules according to any one of claims 2 to 9, wherein the first and second control modules are configured differently from one another, and wherein control modules are each configured to attach releasably to a variable speed drive module according to any one of claims 1 to 9.
12. A variable speed drive module substantially as hereinbefore described 20 with reference to and as shown in figures 1 to 5 of the accompanying drawings.
13. Any novel feature or combination of features disclosed herein.