WO2015088375A1

WO2015088375A1 - Assembly and method to generate rf high power

Info

Publication number: WO2015088375A1
Application number: PCT/RU2013/001122
Authority: WO
Inventors: Andrey Aleksandrovich KRASNOV
Original assignee: Siemens Research Center Limited Liability Company
Priority date: 2013-12-13
Filing date: 2013-12-13
Publication date: 2015-06-18

Abstract

The present invention relates to an assembly and a method to generate RF high power (1). The assembly (1) comprises at least one electrical power supply (2), at least one RF module (3) and connectors connecting the devices. The connectors comprise at least one docking station (4).

Description

ASSEMBLY AND METHOD TO GENERATE RF HIGH POWER

DESCRIPTION

The present invention relates to an assembly and a method to generate RF high power. The assembly comprises at least one electrical power supply, at least one RF module and connectors connecting the devices.

Radio-Frequency RF and/or microwave power is produced with appropriate generators. RF power generators for high power applications are based on tubes, for example klystrons, inductive output tubes or magnetrons. Disadvantages of high power RF generators known from the state of the art are large dimensions, low reliability and low overall system efficiency. The known tubes require high voltage power supplies, resulting in high system complexity, large dimensions and low efficiency due to losses in the power supply itself.

Using solid state technology, particularly transistor technology, a reliable RF power production with small dimensions and high efficiency is possible. Disadvantage of transistor technology is a low RF power output per transistor chip, in the range of up to 1.5 kW power output at 500 MHz frequency. For comparison, with klystrons as an example for tube technology, up to some Megawatt RF power output is possible.

To generate high amounts of power with transistor based RF generators an aggregation of RF generators is applicable. But, with increasing output power to be generated the system complexity is increased. For example, thousand 1.5 kW transistors are required to produce 1.5 M RF power. An aggregation of transistors in a single power amplifier PA, based for example on push-pull or a balanced kind of topology, can reduce the complexity a bit, but not by a very high extent. PA requires usually DC power and low level of RF to amplify. A number of combining stages is necessary to combine the power, and a cooling system is necessary to keep the temperature of the system and components in an adequate range, to prevent failures. A control system to control the PA operation and the whole system with its components is commonly used. To combine and connect the system components with each other, different cables, transmission lines, wires, busses, hoses, and/or pipes are necessary. With an increasing number of components, the number of connections and complexity increases.

Usually, the design of high power RF generators is respectively adjusted and optimized accordingly to the individual application. It depends on required power level, frequency, pulse width, duty cycles, operation mode like pulse or continues operation, and so on. Different parameters for diverse applications require changes in the system design to fulfill all the requirements. That makes it necessary that every RF generator has an own set of components, specially designed and adjusted to the specific application. The connection and cable architecture has to be adjusted accordingly, specific for every application and RF generator design. For low power RF generators up to a power level of some hundred Watt, simplified and unified designs and components are known from the state of the art, see for example US 20050010206 Al . In the document a PCB (Printed Circuit Board) backplane respectively printed board with at least one PA and at least one control system is described. The PA and control system have modular design. Components are assembled in a standard 19 inch rack. The use of a -backplane simplifies the interconnection of system components since nearly all electrical connections are realized by printed circuit board tracks particularly made of copper laminated to the PCB. Disadvantage of the use of PCB backplanes is the limit of some Kilowatts due to the material. Higher power levels and the associated currents and heat production can cause damage up to irreversible destruction of the device.

In US 20070024362 Al a scalable RF generator is described, with a number of PA modules, a modular power supply system, a power combiner, and a control system. The main considerations within the design are for reliability based on monitoring and different measurements for proper operation. Scalability is described in general, but without details about the mechanical assembling of a system with complex interconnection by cables and wires.

The object of the present invention is to present an assembly and a method to generate RF high power with decreased complexity and increased reliability compared to designs and methods known from the state of the art. A further object is to generate high power RF respectively microwaves with transistor based generators in an easy and cost effective way, particularly in a modular assembly with easy maintenance.

The above objects are achieved by an assembly to generate RF high power according to claim 1 and a -method to generate RF high power with an assembly, particularly with an assembly as described before, according to claim 11.

Advantageous embodiments of the present invention are given in dependent claims. Features of the main claims can be combined with each other and with features of dependent claims, and features of dependent claims can be combined together . The assembly to generate RF high power according to the present invention comprises at least one electrical power supply, at least one RF module and connectors connecting the devices. The connectors comprise at least one docking station .

The use of a docking station to connect devices reduces complexity and increases the reliability compared to assembly designs known from the state of the art. High power RF respectively microwaves can be generated with transistor based generators in an easy and cost effective way. The docking station allows an easy exchange of RF modules, without for example unscrewing connections or other complicated handling. This enables an easy maintenance .

The docking station can be substantially in the shape of a plate, particularly comprising a metal or plastic plate. This enables an easy, cost effective assembly with high mechanical stability, reliability without high consumption of space.

The docking station can comprise at least one plug connector, particularly at least one plug connector to connect to at least one electrical wire and/or at least one plug connector to connect to at least one fluid pipe and/or at least one plug connector to' connect to at least one RF coaxial cable. Plug connectors enable a fast and easy connection and disconnection between components. A fast and easy exchange of RF modules is enabled by plug connectors, without complicated handling steps like for example screwing. The at least one RF module can be directly connected to the docking station, particularly to at least one plug connector of the docking station, and the docking station, particularly at least one plug connector of the docking station, is connected to the devices, particularly at least to one electrical power supply, by at least one electrical wire and/or at least one fluid pipe and/or at least one RF coaxial cable. Directly connected particularly means mechanically connected without parts in-between. Connected in the following is used particularly in the sense of mechanically, electrically, fluidically and/or to transfer HF electrical power.

At least one RF module can be connected removable to at least one docking station in the kind of hot swap, particularly by a screw-free connection. A fast, easy and cost effective exchange of RF modules is enabled, especially in case of maintenance or exchange of spoiled modules, i.e. modules out of order. To at least one docking station a number of 4 to 12 RF modules can be connected, particularly to all docking stations a number of RF modules in the range of 4 to 12 can be connected respectively. At least one power combiner, and/or at least one control unit, and/or at least one capacitor tank, and/or at least one cooling unit can be connected to the at least one docking station. Particularly the connection can be arranged to all docking stations respectively, particularly respectively by at least one electrical wire and/or at least one fluid pipe and/or at least one RF coaxial cable. At least one RF module, particularly 4 to 12 RF modules, and at least one docking station, particularly exactly one docking station, can be comprised by a unit in form of a rack, particularly in form of a 19 inch rack. These racks are commonly used in electronics and allow a standardized form, for an easy, compact and clearly arranged storage and exchange of parts.

The unit in form of a rack can be arranged, particularly 10 to 12 units can be arranged in a cabinet comprised by the assembly, particularly a cabinet for 10 to 12 units. This further increases compactness and enables easy handling and exchange of parts.

The cabinet can comprise at least one unit, particularly 10 to 12 units, with at least one power combiner, and/or at least one unit with control unit, and/or at least one unit with capacitor tank, and/or at least one unit with cooling unit, particularly respectively in form of a 19 inch rack and/or particularly respectively connected electrically and/'or fluidically to every docking station. This arrangement can configure an assembly to generate RF high power with the' before described advantages. A Method according to the present invention to generate RF high power with an assembly, particularly with an assembly as described before, comprises connectors connecting devices with at least one electrical power supply and at least one RF module, in which the devices are interconnected by at least one docking station.

The at least one RF module can be plugged and/or unplugged automatically to/from the at least one docking station by moving the at least one RF module towards/away from the at least one docking station. This enables a fast and easy exchange of modules, particularly if single modules are damaged / not working properly. An exchange of an RF module can be performed in a kind of hot swap, particularly comprising the step of removing an RF module from a docking station by plug out all connections, particularly at the same time simultaneously, and/or of arranging an RF module to a docking station by plug in all connections, particularly at the same time simultaneously .

Connections, particularly all connections can be automatically inactivated/activated during exchange by removing the RF module and/or by arranging the RF module to the docking station, particularly with automatic sealing of fluid connections. This enables an exchange of modules without the risk of electrical damage due to short circuits or leakage of cooling fluid like water.

The method can comprise the steps,

arranging to a cabinet at least one RF module, particularly 4 to 12 modules in particularly a row next to each other, and to at least one docking station, particularly exactly one docking station comprised by a first kind of unit in form of a rack, particularly in form of a 19 inch rack in the cabinet, and

- arranging to the cabinet at least one second kind of unit with an electrical power supply, and/or at least one second kind of unit with a power combiner, and/or at least one second kind of unit for controlling devices, and/or at least one second kind of unit with a capacitor tank, and/or at least one second kind of unit for cooling devices, particularly respectively in form of a 19 inch rack, and electrically connecting via wires and/or fluidically connecting via pipes the at least one docking station of the at least one first kind of unit with at least one second kind of unit, particularly with all units of the second kind. Wires in the following will be used in the sense including coaxial cables if not explicit mentioned.

The advantages in connection with the described method to generate RF high power with an assembly according to the present invention are similar to the previously, in connection with the assembly to generate RF high power described advantages and vice versa. The present invention is further described hereinafter with reference to illustrated embodiments shown in the accompanying drawings, in which:

FIG 1 illustrates a schematic view of an assembly 1 according to the present invention, with electrical 6, 10 and fluidic 8 connections between components 11, 12, 13, 14, 2 and RF modules 3 via a docking station 4, and FIG 2 shows a block diagram of the assembly 1 with connections 5, 6, 7, 8, 9, 10, and FIG 3 shows a schematic view of the use of plug connectors 5, 7, 9 for the connection between modules 3 and docking station 4.

In FIG 1 a schematic view of an assembly 1 to generate RF high power according to the present invention is shown as an example. Six RF modules 3 are connected to a docking station 4 particularly removable in the kind of hot swap. The connection can be screw-free by using plug connectors 5, 7, 9. The docking station 4 is connected to a power combiner 11 by RF coaxial cables 10, to a control unit 12 and to six capacitor tanks 13 by electrical wires 6, and to a cooling unit 14 by fluid pipes 8. Instead of multiple wires, cables and pipes also a single wire, cable or pipe can be used. The number of devices and connectors in FIG 1 is an example, other kinds and numbers can be used depending on the application and electrical and/or thermal parameters .

The components or units 2, 3, 4, 11, 12, 13, 14 can be arranged in a rack respectively, for example a 19 inch rack not shown in FIG 1 for simplicity. Racks 2, 3, 4, 11, 12, 13, 14 can be arranged in a cabinet, also not shown in FIG 1 for simplicity. Such arrangement results in an ordered, easy to handle assembly 1, with components easy to be connected to each other.

The use of a docking station 4 to connect components 2, 4, 11, 12, 13, 14 with RF modules 3, particularly to directly connect in the kind of hot swap, enables an easy and fast exchange of RF modules 3. The arrangement of FIG 1 with six RF modules 3 in parallel accumulated, connected to one docking station 4 is an example. Other arrangements with a higher or lower number of modules 3, and for example accumulated one over the other is possible too. In FIG 1 each RF module 3 shows a shape of a rectangle box. Further possible forms are among others square, rounded or triangular forms. The advantage of a rectangular box is a possibility for a space saving parallel arrangement of modules 3.

Electrical wires 6, RF coaxial cables 10 and fluid pipes among others can be used to connect components 2, 4, 11, 12, 13, 14 with the docking station 4 respectively, and via the docking station 4 for example via plug connectors 5, 7 not shown in FIG 1 for simplicity, to RF modules 3, particularly all RF modules 3 respectively. In use the electrical power supply 2 supplies power to electrical components of the assembly 1. It can be composed of modules, for example four modules like in FIG 1 shown. The AC/DC power supply 2 among others supplies DC voltage to the RF modules 3. It is electrical connected via electrical wires 6 respectively to the docking station 4 and via the docking station 4 to every RF module 3 for example using plug connectors 5.

Low level RF (LLRF) signals from a control unit 12 are amplified by the RF modules 3 and combined in a power combiner 11. A cooling unit 14, for example for water or air cooling, can be used for removal of heat produced in RF modules 3. One or more fluid pipes 8 are used to connect the cooling unit 12 with the docking station 4, and for example to connect via plug connectors for fluids 7 to every RF module 3. Other kinds of cooling arrangements are possible too, for example with the help of indirect cooling via thermal contact between docking station 4 and RF modules 3.

The docking station 4 can be of the shape of a plate, like shown in FIG 1. Other forms are possible too. Materials to form the docking station 4 can comprise among others metals like copper and/or steel, plastic and/or composites. The connection of docking station 4 with wires 6, cables 10 and pipes 8 from components 2, 4, 11, 12, 13, 14 can be arranged on one side. Plug connectors 5, 7, 9 and RF modules 3 can be arranged on the opposite side. Other arrangements are possible too, for example connectors and modules on each side next to each other on different areas of the docking station respectively. For connection SMA, QMA, SMB connector types can be used as LLRF connectors. N and/or 7-16 connector types can be used as high level RF (HLRF) connectors. RG-45, M8 , Ml2, and/or LEMO connector types can be used for control, telemetry and interlock lines. Clamp and/or edge connector types can be used for DC voltage connection. Conical or cylindrical thread, and/or hoses tails can be used to connect water hoses, pipes and/or tubes. Other connectors are possible too, depending among others on the kind of connection and physically requirements.

As plug or quick connectors 5, 7, 9 CombiTac or other connectors with plug-in interface can be used. Water connectors can comprise automatic shut-off. RF modules 3 comprise connectors of opposite sex/type compared with connectors of the docking station 4, ordered for example in a mirror arrangement, to be able to connect both with each other in the kind of hot swap. The connector types and placement can be unified for any kind of RF module 3 to be connected. The connectors can be arranged in a row on the docking station 4, so RF modules 3 can be connected side by side to each other to the docking station 4. The RF modules 3 can consist of power amplifier PA and all auxiliary components to bring it into operation. PA can be realized in any kind of topology, like push-pull, balanced, Doherty, and so on according to the special application. Various auxiliary components as PA drivers, control units, measurement units, DC/DC converters, water-cooling plates or radiators, and so on can be used for different applications. All RF modules 3 in general should comprise plug respectively quick connectors, for easy and fast replacement .

The control unit 14 is used to generate LLRF signals and to control/operate the assembly 1. It allows the user, or a higher level control unit not shown, to control the assembly 1 via for example TCP/IP or RS-485 protocol. Other types of protocols can be used too. The control unit 14 can transmit LLRF signals to RF modules 3 from an internal oscillator or can use external RF sources.

The electrical power supply 2 can be in bulk form or in modular design. A modular design has the advantage that the assembly 1 becomes more scalable. For pulsed mode operation of the assembly 1 capacitor tanks 13 can be connected to a DC bus. Capacitor tanks 13 are used to provide enough power for the pulse to RF modules 3 and to reduce the power supply 2 output power requirements. The number and the capacity of capacitors 13 depend on the requirements of the assembly 1. The use of capacitors is optional.

The cooling unit 14, particularly a water cooling system can comprise two manifolds, input and output, and flow and/or temperature sensors to monitor the water flow. The cooling unit 14 is optional, if no high temperature arises for example in RF modules 3 the assembly does not need to comprise a cooling unit 14. In case of high efficient PA or low overall output RF power, air cooled radiators can be used for heat dissipation from PA. For assemblies 1 with high power RF generation the use of water cooling units can be necessary or advantageous.

The power combiner 11 is used to combine RF power from the RF modules 3 and transmit it to the output of the assembly 1 without losses and reflections. It can be connected to the docking station 4 by RF coaxial cable 10. The docking station 4 and RF modules 3 can comprise a plug connector 9 respectively, to connect for RF power transfer to the power combiner 11. Components of the assembly 1 can be placed in 19 inch racks, with the racks in a cabinet. It is also possible to use any other type of framing system for placement. A number of docking stations 4 can be placed in a row at the back of the cabinet. Components 2, 4, 11, 12, 13, 14 can be connected from the backside of the docking station 4. A number of RF modules 3 can be inserted into the cabinet from the front side and connected to the respective docking station 4 by plug connectors 5, 7, 9. In case of a failure of a RF module 3, the module 3 can be easily replaced.

The system can be used to produce radio frequency (RF) with high power, in the range of a kW to some MW. An easy exchange of RF modules 3 without much handling effort, just in a plug and play way is possible. The system can be easy upgraded and extended. The power supply 2 can be used to provide full power in pulsed mode operation using capacitor tanks 13, which provide extra power during a pulse. The power supply 2 can also be used without capacitor tanks 13, for example with average power without pulses.

In FIG 2 a block diagram of the assembly 1 with connections 5, 6, 7, 8, 9, 10 between components 2, 3, 4, 11, 12, 13, 14, 16, 17 is shown schematically. The RF modules 3, for example three RF modules 3, are respectively connected with plug connectors 5, 7, 9 to the docking station 4. This enables a fast and easy exchange of RF modules 3 from the assembly 1. Plug connectors for electrical power 5, for cooling fluid 7 and RF power 9 transmitted via coaxial cable can be comprised among others.

The docking station 4 is connected via electrical wires 6 and/or RF coaxial cables 10 with the control unit 12. The control unit 12 can comprise an input 16 for an external RF signal.

The cooling unit 14 is connected via a fluid pipe 8 with the docking station 3, to provide the RF modules 3 with cooling fluid like water. Gases like cold air can be used as cooling fluid too, depending on the amount of heat to be removed from components of the assembly 1.

The docking station 4 is connected via electrical wires 6 direct or indirect to a DC output of the electrical power supply 2. For high power pulses capacitor tanks 13 can support the power supply, connected via electrical wires 6 in-between connections. In case of an AC/DC power supply an AC input 17 is comprised.

High RF power from RF modules 3 is respectively transmitted via plug connectors 9 to the docking station 4, which is connected via RF coaxial cables 10 to a power combiner 11. Output high RF power from the assembly 1 is transferred via a RF output 15 to external devices. The high RF power can be used among others for medical devices.

In Fig 3 a schematic view of plug connectors 5, 7, 9 for the connection between modules 3 and docking station 4 is shown in more detail. One or more docking stations 4 comprise plug connectors 5, 7, 9 to connect to RF modules 3. Different kinds of plug connectors for example for electrical power, RF power or fluids can be used, depending on components of the assembly 1. The female/male comppnents are respectively connected by attaching the RF module 3 to the docking station 4. An automatic connection is established and the connection comprises a contact to other respective components 2, 4, 11, 12, 13, 14, which are connected to the docking station 4 by wires 6, pipes 8 and/or coaxial cables 10. The wires 6, pipes 8 and/or coaxial cables 10 can be attached to the docking station 4 for example by screwing, brazing or gluing. The above described embodiments of the present invention can be used on its own or in combination with each other, and combined with embodiments known from the state of the art . The use of one or more docking stations 4 within an assembly to generate RF power 1 simplifies the interconnection of components. The use of unified components is possible and an easy and fast exchange of RF modules 3 is enabled.

The invention is not restricted to the described embodiments. For example other connections and materials can be used, like optical wires, other metals like aluminum, and/or other shapes of components like rounded boxes. Different designs and arrangements like for example adjustable shelves can be used. Connections can be arranged in different zones, and on the same or different sides of the docking station 4. Advantageous is an arrangement with good accessibility of RF modules 3, to be able to exchange single modules 3 easy and fast.

List of Reference Characters

1 Assembly to generate RF high power

2 electrical power supply

3 RF module

4 docking station

5 plug connector to connect an electrical wire

6 electrical wire

7 plug connector to connect to a fluid pipe

8 fluid pipe

9 plug connector to connect to a RF coaxial cable

10 RF coaxial cable

11 power combiner

12 control unit

13 capacitor tank

14 cooling unit

15 RF output

16 External RF In

17 AC In

18 DC Out

Claims

1. Assembly to generate RF high power (1) comprising at least one electrical power supply (2), at least one RF module (3) and connectors connecting the devices,

characterized in that the connectors comprise at least one docking station (4) .

2. Assembly (1) according to claim 1, characterized in that the docking station is substantially in the shape of a plate, particularly comprising a metal or plastic plate.

3. Assembly (1) according to any one of claims 1 or 2, characterized in that the docking station comprises at least one plug connector (5, 7), particularly at least one plug connector (5) to connect to at least one electrical wire (6) and/or at least one plug connector (7) to connect to at least one fluid pipe (8) and/or at least one plug connector (9) to connect to at least one RF coaxial cable (10) .

4. Assembly (1) according to any one of claims 1 to 3, characterized in that the at least one RF module (3) is directly connected to the docking station (4), particularly to at least one plug connector (5, 7) of the docking station, and the docking station (4), particularly at least one plug connector (5, 7) of the docking station, is connected to the devices, particularly at least to one electrical power supply (2), by at least one electrical wire (6) and/or at least one fluid pipe (8) and/or at least one RF coaxial cable (10).

5. Assembly (1) according to any one of claims 1 to 4, characterized in that at least one RF module (3) is connected removable to at least one docking station (4) in the kind of hot swap, particularly by a screw-free connection .

6. Assembly (1) according to any one of claims 1 to 5, characterized in that to the at least one docking station (4) in the range of 4 to 12 RF modules (3) are connected, particularly to all docking stations (4) in the range of 4 to 12 RF modules (3) are connected respectively.

7. Assembly (1) according to any one of claims 1 to 6, characterized in that at least one power combiner (9), and/or at least one control unit (10), and/or at least one capacitor tank (11), and/or at least one cooling unit (12) are connected- to the at least one docking station (4), particularly to all docking stations (4) respectively, particularly respectively by at least one electrical wire (6) and/or at least one fluid pipe (8) and/or at least one RF coaxial cable (10) .

8. Assembly (1) according to any one of claims 1 to 7, characterized in that at least one RF module (3), particularly 4 to 12 RF modules (3), and at least one docking station (4), particularly exactly one docking station (4), are comprised by a unit in form of a rack, particularly in form of a 19 inch rack.

9. Assembly (1) according to claim 8, characterized in that the unit in form of a rack is arranged, particularly 10 to

12 units are arranged in a cabinet comprised by the assembly (1), particularly a cabinet for 10 to 12 units.

10. Assembly (1) according to claim 9, characterized in that the cabinet comprises at least one unit, particularly 10 to 12 units, with at least one power combiner (11), and/or at least one unit with control unit (12), and/or at least one unit with capacitor tank (13), and/or at least one unit with cooling unit (14), particularly respectively in form of a 19 inch rack and/or particularly respectively connected electrically and/or fluidically to every docking station ( 4 ) .

11. Method to generate RF high power with an assembly (1), particularly with an assembly according to any one of claims 1 to 10, with connectors connecting devices comprising at least one electrical power supply (2) and at least one RF module (3),

characterized in that the devices are interconnected by at least one docking station (4) .

12. Method according to claim 11, characterized in that the at least one RF module (3) is plugged and/or unplugged automatically to/from the at least one docking station (4) by. moving the at least one RF module (3) towards/away from the at least one docking station (4) .

13. Method according to any one of claims 11 to 12, characterized in that an exchange of an RF module (3) is performed in a kind of hot swap, particularly comprising the step of removing an RF module (3) from a docking station (4) by plug out all connections, particularly at the same time simultaneously, and/or of arranging an RF module (3) to a docking station (4) by plug in all connections, particularly at the same time simultaneously.

14. Method according to claim 13, characterized in that all connections are automatically inactivated/activated during exchange by removing the RF module (3) and/or by arranging the RF module (3) to the docking station (4), particularly with automatic sealing of fluid connections.

15. Method according to any one of claims 11 to 14, comprising the steps,

arranging to a cabinet at least one RF module (3), particularly 4 to 12 modules (3) in particularly a row next to each other, and to at least one docking station (4), particularly exactly one docking station (4) comprised by a first kind of unit in form of a rack, particularly in form of a 19 inch rack in the cabinet, and

- arranging to the cabinet at least one second kind of unit with an electrical power supply (2), and/or at least one second kind of unit with a power combiner (11), and/or at least one second kind of unit for controlling devices (12), and/or at least one second kind of unit with a capacitor tank (13), and/or at least one second kind of unit for cooling (14) devices, particularly respectively in form of a 19 inch rack, and

electrically connecting via wires and/or fluidically connecting via pipes the at least one docking station (4) of the at least one first kind of unit with at least one second kind of unit, particularly with all units of the second kind.