Not Applicable
Not Applicable
Not Applicable
Power converters are well known devices that are generally used to convert power from one set of power, voltage and current parameters from a power source into a second set of voltage and current parameters for use by a load. Most often, power converters are used to convert a standard AC supply voltage into a lower DC voltage or an AC voltage of fixed or variable frequency for use by DC motors, AC motors, or connection to the power grid. Most conventional power converters are designed for a particular product having a particular set of power requirements and, thus, cannot usually be used for multiple applications having different topologies and power requirements. For example, in high power applications, the switches used in the power converter (such as insulated gate bipolar transistors (IGBTs)) must be carefully sized to handle the highest anticipated load requirements. Power switches such as IGBTs are expensive and have been tightly integrated into the core power converter, thereby reducing flexibility and gains available in high volume cost reductions via reuse of the core structure and reduction in reengineering development times. As a result of this tight integration, new power converter configurations are continuously being designed for each new application. Designing a new power converter is a process that requires substantial time and effort by skilled individuals. Furthermore, supporting a large number of different power converters requires stocking a large number of different parts and assemblies and reduces economies of scale.
A particular type of power converter product in common use today is a motor drive. A family of motor drive product is typically designed to cover a range of power levels, but this family of motor drives is made up of several different products designed to optimize the cost of the hardware (electronic components and packaging) for a relatively narrow power range and specific drive application. For example, a typical motor drive may integrate one or more of the following: an AC to DC converter (simple diode, or regenerative converters (boost or buck)), a DC bus regulator, an inverter, magnetics, filters, relays, control logic, sensors, and input/output communications or interfaces, into a single package for a narrow power range. The end uses for such motor drive assemblies include (but are not limited to) elevators, material handling devices, cranes and hoists, alternative energy sources such as windmills and fuel cells, and general industrial applications. However, the applications of a motor drive are limited to the conversion of power from an AC or DC supply for use by particular AC or DC motor having a defined set of power, voltage and current parameters.
In some conventional motor drive applications, multiple inverters are used in a system configuration to handle multiple drives in an application. Such a system typically has a converter in the front end to create a DC supply bus for distributing power to the multiple inverters. In conventional designs, the converter is designed to a specific topology (regenerative or non-regenerative) to provide a specific amount of power having a specified set of parameters and, therefore, must be redesigned for each application.
Another limitation in the design of conventional motor drives is heat management. A typical motor drive might include a fan, heat sink, heat exchanger, or cold plate as a complete heat management system. In conventional power supply designs, the physical location and implementation of these thermal management components often interferes or limits flexibility in providing connections to the onboard magnetics or limits the ability the switch to different cooling schemes such as liquid cooling and heatpipes. In addition, conventional motor drives will stack or combine multiple IGBT switches such that heat from the lower IGBTs is transferred to the switches at the top of the stack.
Therefore, what is needed is a modular power converter assembly that can be easily and inexpensively adapted for a wide variety of products having a wide variety of power requirements and thermal management systems.
One embodiment of the present invention is directed toward a modular power converter assembly for providing power to a power consuming device. The modular power converter includes a core power conversion module for receiving power from a power source and converting the source power from a first set of power characteristics to a second set of power characteristics. The core power conversion module has input connectors, a set of power conversion switches and associated electronics, bus capacitors, and output connectors. The core power conversion module also includes a thermal management system. The core power conversion module is designed such that it can be connected in parallel with one or more additional core power conversion modules such that the power output of the core power conversion modules is combined. The bus capacitance of the core power conversion module is preferably approximately equally distributed along the output. An application specific module is adapted to be removably coupled to the output connector of the core power conversion module. The application specific module contains power components and application specific components designed to interface the core power conversion module to a particular power consuming application. The application specific module may contain a filter, a contactor, a relay and a current sensor.
Another embodiment of the present invention is directed toward a power converter for receiving supplied electrical power having a first set of parameters and converting the supplied electrical power into load electrical power having a second set of parameters. The power converter includes a power conversion module adapted to receive one of a plurality of application specific modules. The power conversion module has at least one power conversion switch and the application specific module has at least one power component. The power conversion component is preferably mounted on a sub-panel assembly of the modular power converter. The core power module has an AC or DC bus and is adapted to be connected in parallel with a second core power module such that the bus of the core power module is connected in parallel with a bus of the second core power module. The core power module also preferably includes the thermal management system for the core power conversion assembly. The power conversion module can be configured to allow for bi-directional power flow. The application specific module may contain at least one of the following power components such as a filter, a contactor, a relay or a current sensor.
Yet another embodiment of the present invention is directed toward a modular power converter system adapted to provide varying amounts of power having different power characteristics. The power converter includes a core power converter module having at least one power converter switch for receiving power from an AC or DC power source and converting the source power to a DC or AC voltage. The converted voltage is coupled to a bus. The core module has an output connector adapted to receive at least one of a plurality of application specific modules such that the bus voltage is coupled to the application specific module. In addition, the core module is configured to be connected in parallel with a second core module such that the bus of the core module is electrically coupled to a bus of the second core module. The core module further includes an option board coupling for receiving one of a plurality of option boards. At least one power converter switch is mounted on an option board of the core module. The modular power converter is configured to allow for bi-directional power flow. The application specific power inverter modules may contain at least one of the following power components such as a filter, a contactor, a relay and a current sensor.
Yet another embodiment of the present invention is directed toward a modular power converter design. The design includes mechanical packaging means that are modular and scalable. This modularity and scalability allows for a variety of power topologies to be quickly implemented by selection of the appropriate thermal and or power semiconductor combination, which makes up the power conversion module. This flexibility in design provides power conversion that is modular and scalable for a variety of topologies and applications. Modular and flexible thermal management means allow the cooling scheme to be changed to air or liquid or heat pipes. Modular hardware logic is provided that can be configured to handle various applications and customer requirements. Control software is provided that is modular and flexible to support the application and power modularity. The design can be used with an AC motor, DC motor, grid connected loads, grid independent loads, bidirectional wind generator drives, and any other application with a DC input/output or AC input/output and handle conversion from any AC or DC source to any AC or DC load.
The present invention is directed toward a modular power converter having a power conversion module that can be quickly and easily configured to support a wide range of power levels and circuit topologies. The applications of the power conversion modules include, but are not limited to, inverters, boost or buck converters, converters, regenerative inverters, and bus regulators. Some of the end applications include, but are not limited to, elevators, alternative energy applications such as windmills, fuel cells, material handling, cranes and hoists, and a wide range of other industrial applications.
In accordance with the present invention, an easily adaptable power converter is implemented by creating an extremely flexible and modular power conversion assembly. The modularity of the assembly is designed to allow the use of the same or very similar hardware assemblies to produce multiple power levels and/or multiple topological configurations by simply reconfiguring the associated input and output electronics, the control logic configuration, the size of the semiconductor switch used, and the input and output switch gear for multiple power conversion applications.
A typical power converter, such as a motor drive, has a converter, a thermal management system, an inverter, magnetics, filters, relays, control logic, current sensors and input and output interface electronics. Preferred embodiments of the present invention separate these components by placing components of the converter and thermal system on a core module. The application specific components, such as magnetics, filters, current sensors, relays, etc., are located on a separate application specific module. By using the same basic power conversion module for a wide range of power sizes and applications, the power conversion modules can be produced with economies of scale that will allow for significant cost advantages. In addition, the modules are designed to be connected in parallel to accommodate multiple power level outputs and power flow including bidirectional.
Referring now to
The core modules 102 and 104 preferably contain the thermal system 110, gate drive and power supply components for the power conversion switches, optional power interface electronics, control electronics and configurable input/output interface electronics, all mounted within a housing 112. The control electronics are programmable so that they can be varied for individual applications. The application specific interface modules 106 and 108 include application specific components such as AC/DC contactors, current sensors, electromagnetic interference filters, etc. As shown in
The electrical and mechanical designs of the thermal system, gate drive if IGBTs or a driving circuit for other power semiconductor switches and power supply components, optional power interface electronics, control electronics, input/output interface electronics, AC/DC contactors, current sensors, electromagnetic interference filters, etc., are conventional and well understood by those of skill in the art and are not shown in detail. The present invention is directed to the novel modular arrangement and architecture of these functional components within the power supply assembly.
Typically, the magnetics, filters, etc., which are application and power dependent, are combined with the basic power conversion switches (IGBTs for example) and with the thermal system. By separating the application specific components from the non-application specific components, the basic power conversion module can be reused with the required application specific components. Thus, the core modules can be built on a separate high volume, highly efficient line and married with the application specific power level components at a separate manufacturing location. The input and output power semiconductor switches, such as the IGBTs, are mounted on a flexible thermal system assembly including a heatsink (air or liquid) for easy configuration and flexibility. When modifications to the power semiconductor switches of the core modules 102 and 104 are required, they can be accomplished by simply replacing the power semiconductor switches mounted on a flexible thermal assembly (air or liquid). However, the same IGBT or equivalent power semiconductor switch may often be used in the core power conversion module for multiple applications or topologies simply by altering the application specific sub-panels and re-programming of the control software and installing the proper hardware logic module.
Referring now to FIGS. 2(a-c), an embodiment of a core power module 200 is shown. The core power module 200 (102, 104 on
A vent 210 is provided on the core power module 200 that allows the thermal system 210 to dissipate heat. The thermal system, which includes components such as a fan, heat sink, heat exchanger and/or liquid cooled plate, is oriented such that the interface 208 to the magnetics is not impeded. This makes it easy to connect to and configure the magnetics. As will be appreciated by those skilled in the art of power converter electronics, the thermal management function of the power module 200 can be implemented in accordance with either an air or liquid cooled approach.
As shown in
Referring now to FIGS. 3(a) and 3(b), sample application specific modules 302 and 304 are shown. The application specific modules 302 and 304 contain application specific components such as magnetic transformers and inductors 306 (sometimes collectively referred to herein as “magnetics”), contactors 308, filters 310, relays, current sensors, etc. The application specific module housing 312 is designed to mate with the core module enclosure 202. In addition, contacts (not shown in
A fundamental approach of the present design is to separate the typical drive inverter and converter design functions of a power converter into separate assemblies. Referring now to
Referring now to
The application specific module 504 includes interface electronics 516 for mating with the interface electronics 514 of the core module 502 and receiving the output of the core module 502. The application specific module 504 shown in
Various power converter arrangements constructed in accordance with embodiments of the present invention are shown in
The preferred embodiments of the present invention can handle bi-directional power flow for applications in fields such as general industrial, elevators, cranes and hoists, material handling and alternative energy. For example, in elevator applications, the design can be configured to allow for a full four quadrant or fully line regenerative power converter for both AC and DC motors. The input or output power can be an AC or DC voltage. Because the topologies can be easily reconfigured, the type of power that is sourced is flexible. In an elevator end use application, the power source is the AC line; however, if one reconfigures the system to a simple output inverter, the input can be a DC source from a photovoltaic panel.
The modular power converter of the present invention is an improvement over the prior art in that it allows the same basic core assemblies to be used to generate multiple power levels, allows for paralleling of the conversion modules at the DC bus level, and provides for flexible controls and input/output interfacing. In addition, the present invention provides for easy AC and DC control and bidirectional power flow control. The power conversion elements are contained within a configurable or expandable enclosure that accommodates a wide range of applications. The product resources required in terms of time and cost for a wide range of applications is dramatically reduced because the time to develop the product is limited to the selection of the non-power conversion elements and the selection of the proper option boards. In conventional motor drive designs, the objective was to optimize the complete power conversion cost at a particular size, power and limited application focus. The present invention optimizes the cost and size of power conversion but separates out the integration of the application and power specific elements.
Thus, although there have been described particular embodiments of the present invention of a new and useful Modular Power Converter Assembly, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.