WO2009147551A1

WO2009147551A1 - Scalable power supply system for providing electrical power for a computer tomography device

Info

Publication number: WO2009147551A1
Application number: PCT/IB2009/052033
Authority: WO
Inventors: Max C. Urban; Peter-Christian E. H. H.-J. Leymann; Christoph Loef
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninklijke Philips Electronics N. V.
Priority date: 2008-06-02
Filing date: 2009-05-15
Publication date: 2009-12-10

Abstract

The invention provides a power supply device for providing electrical energy for a computer tomography gantry, wherein the device comprises a first power supply module (121) for supplying electrical energy, a unit for reversibly connecting a second power supply module (104, 105) for supplying electrical energy, wherein a power supply module (121, 104, 105) out of the group consisting of the first and the second power supply module comprises a mains unit 101 for rectifying an AC input voltage into an DC voltage, and an inverter 103 for switching the DC voltage. Further, the invention provides a power supply module for supplying electrical energy for a computer tomography gantry, comprising a mains unit (101) for rectifying an AC input voltage into a DC voltage, an inverter (103) for switching the DC voltage, a unit for reversibly connecting to a power supply device according to one of the preceding claims. Furthermore, the invention provides a computer tomography device comprising a power supply device according to the invention.

Description

Scalable power supply system for providing electrical power for a computer tomography device

FIELD OF THE INVENTION

The present invention relates to a power supply system for providing electrical power for a computer tomography (CT) device. The invention also relates to components of such a power supply system such as a power supply device or a power supply module to be used in such power supply device. Finally, the invention furthermore relates to a computer tomography device comprising the inventive power supply device.

BACKGROUND OF THE INVENTION

In a computer tomography device, electrical energy is usually transferred from a stationary part of a gantry connected to a power supply device to a rotary part of the gantry in order to supply power to consumer devices such as an X-ray tube or an X- ray detector mounted on the rotary part. Therein, the requirements with respect to the amount of power to be supplied by a power source and to be transferred to the rotary part of the gantry may significantly vary depending on a specific application. For example, high quality applications such as cardiac computer tomography may require high power supply of up to 15OkW whereas simple applications may require e.g. only 6OkW. The power may be transferred from the stationary part to the rotary part using slip rings or, preferably, using a rotary power transformer which transfers energy contactlessly using magnetical inductance.

The power supply device usually comprises a high voltage generator. Typically, high voltage generators are realized as series resonant converters. Each generator consists of a mains unit for rectifying AC input. The rectified DC voltage is shaped in a DC/DC converter or preconditioner that generates a controlled constant output voltage. The output voltage is fed to an inverter/converter which switches the output power according to the required electrical power of a computer tomography gantry.

Former systems need components for generating an output power which exactly fit to the required power of the consumers of the gantry such as the X-ray tube. In case of a change of the required power of the consumers at the gantry, extensive reconstructions or structural changes both to the power supply device and to the power transfer device may be necessary.

SUMMARY OF THE INVENTION

There may be a need to provide improved devices which enable the possibility to adjust the supply of electrical energy to the requirements of a computer tomography gantry device. According to a first aspect, the invention provides a power supply device for providing electrical energy for a computer tomography gantry, wherein the device comprises a first power supply module for supplying electrical energy, a unit for reversibly connecting a second power supply module for supplying electrical energy, wherein a power supply module out of the group consisting of the first and the second power supply module comprises a mains unit for rectifying an AC input voltage into a DC voltage, an inverter for switching the DC voltage.

According to a second aspect, the invention provides also a power supply module for supplying electrical energy for a computer tomography gantry, the power supply module comprising a mains unit for rectifying an AC input voltage into a DC voltage, an inverter for switching the DC voltage, and a unit for reversibly connecting to a power supply device according to the above first aspect.

According to a third aspect, the invention provides a computer tomography gantry comprising a power supply device and/or a power supply module according to the above first or second aspect. It may be seen as a gist of the present invention according to the above first, second and third aspect to provide a scaleable power supply for a computer tomography gantry. The advantages can be summarized as providing the possibilities of a quick and simple upgrading of the power supply of the gantry, e.g. in case the customer wishes to add additional features to his existing gantry thereby increasing its power requirements. It is proposed to install all the necessary interfaces for further power supply modules. The interfaces comprise interfaces of the cooling system, interfaces of the data transfer, interfaces for the supply of the power supply modules by the 3 phase AC input and the interface of supplying the current resulting of the power supply modules to the power transformer. According to the invention the interfaces are adapted to connect the additional power supply modules within a limited period of time.

Therefore, the connections to connect the power supply modules to the gantry must be prepared, especially with the use of connection assemblies. It is also an aspect of the invention to render the possibility to disconnect the power supply modules in a limited period of time. This would lead to the advantage, that damaged power supply modules can be repaired without stopping the use of the gantry, because of the fact, that the power supply module can be repaired without connection to the gantry. As a result thereof the power supply modules should have a reversibly connectivity with respect to the power supply device.

The present invention renders the possibility to connect as many power supply modules as necessary. Therefore, the customer has the opportunity to buy at first a low-cost gantry and to upgrade the gantry according to increasing needs of the customer. Therefore, the customer can distribute necessary investments along the timeline. It is no more necessary to pay a high price at once for ensuring the satisfaction of increasing needs for a time period. According to an exemplary embodiment, it is provided a power supply device, wherein a module out of the group consisting of the first and the second module further comprises a DC-DC converter for providing a DC voltage such that the DC voltage is constant controlled.

The mains unit supplies a DC voltage. In order to keep away fluctuations of the 3 phase AC input in could be necessary to install a DC-DC converter between the mains unit and the inverter. This would result in a safe operation mode without impact of the fluctuations of the mains supply.

According to an exemplary embodiment it is provided a power supply device, wherein the device comprises a cooling system for cooling the first and the second power supply module, a control signal system for controlling the first and the second power supply module.

In other words the power supply device enables the possibility to connect further power supply modules to all the systems, which are necessary for controlling a power supply module (control signal system) and which are necessary to prevent damage from the further power supply modules (cooling system).

According to the present invention it is provided a power supply device, wherein the cooling system comprises a heat exchanger system.

Usually, the cooling system of the present power supply device is a closed loop. This leads to the fact, that a constant cooling can be provided. Further, the heated cooling medium can be used for heating e.g. facilities. This aspect can be achieved with the help of a heat exchanger.

According to an exemplary embodiment it is provided a power supply device, wherein the device is adapted to connect the first and the second module with the cooling system and the control signal system. According to an exemplary embodiment it is provided a power supply device, wherein the unit for connecting a second power supply module comprises a connector out of the group consisting of a male connector and a female connector.

The inventive concept provides the possibility to adjust the supply of electrical power according to the requirements of the computer tomography gantry. Due to this fact upgrading of a computer tomography gantry, which conventionally results in time-consuming reconstructions, is no longer a problem. Therefore, the present invention enhances the availability of the computer tomography gantry. Especially, the feature of having switches to simply connect the required power supply modules may accelerate the work of adjustment. According to another exemplary embodiment it is provided a power supply device, wherein the device comprises a current compensation choke for compensating the currents of the first power supply module and the second power supply module. The arrangement of a current compensating choke leads to an equal work load of the several power supply modules. Due to this fact an overall protection of the power supply modules is guaranteed. Further, the cooling system does not have to cool heat peaks. This leads to smaller requirements for the cooling system. As an effect resulting thereof the size of the cooling system can be reduced, which results in smaller production costs and smaller dimensions of the coolings system.

According to an exemplary embodiment it is provided a power supply device, wherein the device is adapted to couple the current of the first power supply module and the current of the second power supply module. According to another exemplary embodiment it is provided a power supply module, wherein the unit for reversibly connecting is a connector out of the group consisting of a male connector and a female connector.

The power supply module according to the inventive concept can be used in several systems by simply adding the power supply module to the cooling system and the corresponding controlling circuits. No additional control signals have to be generated, if an additional power supply module is added. Each power supply module can use the same control signals. Thus, a new power supply module can be added without changing the control algorithm.

According to an exemplary embodiment it is provided a power supply module, wherein the power supply module is adapted to be connected to the cooling system and the control signal system.

It should be noted that the above features may also be combined, possibly even if described with respect to different subject matters. The combination of the above features may also lead to synergetic effects, even if not explicitly described in detail. These and other aspects of the present invention will become apparent from and elucidated with reference to the embodiments described hereinafter, to which the invention is not limited.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described in the following with reference to the following drawings.

Fig. 1 shows a block diagram of a power-scaled computer tomography system architecture serving as a power supply device according to an embodiment of the present invention;

Fig. 2 shows a single power supply module according to a further embodiment of the present invention; Fig. 3 shows a computer tomography gantry according to a further embodiment of the present invention.

All figures are only schematically and not to scale.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 shows a power supply device according to an embodiment of the present invention. It is provided a modular power-scalable concept for a high power X- ray generator for computer tomography and/or cardio-vascular systems using a 3-level- resonant control system. Deviating from standard X-ray generators, the generator according to the inventive concept is scaled along a power chain with concern to mains units 101, preconditioners 102 and converters/inverters 103. Each basis power supply module 121 contains a mains unit 101, a preconditioner unit 102 and a converter/inverter unit 103 for a defined output power. An addition of those field- replaceable power supply modules 121, 104, 105 leads to the required output power without additional effort. The output power can be fed either to a high voltage stage or a rotary transformer system.

In the described power-scalable system, power supply modules 121, 104, 105, 125 with a defined output power are used in combination to have the needed output power. This renders the possibility of scalability of electrical power. Each power supply module 121, 104, 105, 125 can be seen as a uniform black box producing the required output power and being a complete enclosed power chain with defined uniform interfaces. If two or more power supply modules 121, 104, 105, 125 are switched together, they act like one bigger power supply module. The power supply modules 121, 104, 105, 125 are field upgradeable / field replaceable even if the system has been used at the customer side. If a customer needs to have more output power (for using larger tubes) power supply modules 121, 104, 105, 125 can be added. A power-scalable X-ray generator topology can easily be used in different X-ray generator systems by changing heat exchanger and external circuits depending on the intended use. Fig. 1 shows a part of a computer tomography gantry. It is depicted four power supply modules 121, 104, 105, 125, wherein an additional number of power supply modules can be connected. The power supply module 121, power supply module 104 and the power supply module 105 are supplied by a three phase AC input voltage, wherein the AC input voltage is for example in the range from 380 to 480 V. Every power supply module 121, 104, 105, 125 is able to supply a power of 40 kW, for example. Every power supply module 121, 104, 105 comprises a plurality of parts 101, 102 and 103, 123. The part 101 is an AC/DC converter, which converts the AC input voltage into a DC voltage. The part 102 is a preconditioner, which smoothens the DC voltage of the part 101. The part 103 is a converter/inverter, which switches the DC voltage of the preconditioner 102. The switched DC voltage is supplied to the transformer 109. The currents produced from the power supply modules 121, 104, 105 will be balanced by a current compensating choke 119. The different currents will be coupled in a unit 120 and transferred to the transformer 109. The resulting currents of the transformer will be balanced by a current compensating choke 124 and supplied to the high voltage unit of the computer tomography gantry, HVU. The HVU controls the power supply modules 121, 104, 105 with control signals 122, which is processed in the power supply module control unit 123 and corresponding control units of the power supply modules 104 and 105. There is also an auxiliary power supply module 125 which comprises corresponding parts to the power supply modules 121, 104, 105. This auxiliary power supply module 125 is supplied by the three phase AC input voltage 115. The current produced by the auxiliary power supply module 125 is supplied to the transformer 113.

For cooling the power supply modules 121, 104, 105 there is a cooling unit 117 with a cold side 118 and a hot side 116.

A scalable Architecture block consists of a power chain from input power (380-480V, 3phase) to (controlled) output i.e. to a rotary transformer. The output current of all power supply modules is compensated with a current compensating choke 119. In spite of a plurality of power supply modules 121, 104, 105 for supplying the computer tomography system only one current is present at the point 120. If more current (power) is needed at the tube (computer tomography gantry), further power supply modules 104, 105 can be added. In order to divide the power equally between the plurality of equally modules 121, 104, 105 a current balancing choke 119 is arranged before the point 120. Each power supply module 121, 104, 105, 125 has one control unit to control the mains unit, the preconditioner unit and the converter/inverter unit. The most left hand power supply modulel21 is shown "with open cover", power supply modules 104 and 105 are "closed". The control signals 122 (fast control data and slow control data) to the control units 123 are the same for every control unit, it does not matter how many power supply modules are involved. Based on the concept of the current compensation the control signals are automatically scaled. Every equal module has one water cooling input and one water cooling output and a serial cool-pipeline that cools the mains unit 101, the preconditioner 102 and converter/inverter 103. Critical components of the power supply modules 121, 104, 105, 125 will be cooled first (see cold side 118 and hot side 116 of the cooling system). All equal modules 121, 104, 105, 125 can be connected to a heat exchanger in a parallel (or serial) way. Each computer tomography system needs an additional auxiliary power supply 125 to power electronics, anode drives and peripheral components. The auxiliary power supply 125 has to be connected to the 3 -phase input 115 separately to guarantee a 100% operation availability. Nevertheless it is recommended to use the same power supply module concept for the auxiliary power as mentioned above. Moreover the same cooling circuit can be used.

The input voltage is typically a 3 -phase input voltage with a range from 380 to 480V and a frequency of 50 to 60Hz. The output power is a switched (controlled) DC voltage and being fed to a high voltage transformer and eventually a cascade for multiplying the voltages. The frequency and the resonant current is the same at each output of every power supply module 121, 104, 105. Therefore, the several power supply modules can be easily connected together. Every power supply module 121, 104, 105 copes usually with 4OkW.

Therefore, a total of 12OkW is available. Converter components operate with high frequency MosFET transistors (range from 80-30OkHz) in a small frequency band (20- 4OkHz). The required 400V input is generated by a full-bridge IGBT Preconditioner unit 102. The preconditioner 102 is powered by a state of the art mains unit 101 that rectifies the 3-phase input voltage.

Figure 2 depicts the interfaces of a single power supply module 201. Fig. 2 shows a power supply module 201, which is supplied by an input power 202 (three phase AC input voltage, for example 380 to 480 V). The output power of the power supply module 201 is transferred to the transformer 206. The power supply module 201 is controlled by a fast control data line 208 and a slow control data 207. The power supply module 201 is cooled by the cooling pipeline 204. The heat is extracted by the cooling pipeline 205.

The innovative concept can be applied with a computer tomography gantry with a contactless inductive rotary transformer. Fig. 3 shows an exemplary embodiment of a computer tomography gantry (91) arrangement. The gantry (91) comprises a stationary part (92) connected to a high frequency power source (98) and a rotary part (93) adapted to rotate relative to the stationary part (92). An X-ray source (94) and an X-ray detector (95) are attached to the rotary part (93) at opposing locations such as to be rotatable around a patient positioned on a table 97. The X-ray detector (95) and the X-ray source (94) are connected to a control and analysing unit (99) adapted to control same and to evaluate the detection results of the X-ray detector (95).

It should be noted that the term 'comprising' does not exclude other elements or steps and the 'a' or 'an' does not exclude a plurality. Also elements described in association with the different embodiments may be combined. It should be noted that the reference signs in the claims shall not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

101 Mains unit;

102 Preconditioner unit; 103 Converter/inverter unit;

104 power supply module 2;

105 power supply module 3;

106 Auxiliary mains unit 106;

107 Auxiliary preconditioner unit 107; 108 Auxiliary converter/inverter 108;

109 Transformer;

110 HVU, high vo ltage unit;

111 Tube;

112 Block diagram; 113 Auxiliary transformer;

114 Three phase AC input;

115 Three phase AC input;

116 Hot side;

117 Cooling unit; 118 Cold side;

119 Current compensating choke;

120 Joining point A;

121 power supply module 1 ;

122 control signals; 123 module control unit;

124 current compensating choke;

125 Auxiliary power supply module;

201 power supply module;

202 input power; 203 interfaces of a power supply module;

204 cooling in; 205 cooling out;

206 output power;

207 slow control data;

208 fast control data;

91 computer tomography gantry;

92 stationary part;

93 rotary part;

94 X-ray source;

95 X-ray detector;

97 table;

98 high frequency power source;

99 control and analysing unit;

Claims

CLAIMS:

1. A power supply device for providing electrical energy for a computer tomography gantry, wherein the device comprises

- a first power supply module (121) for supplying electrical energy, - a unit for reversibly connecting a second power supply module (104,

105) for supplying electrical energy, wherein a power supply module (121, 104, 105) out of the group consisting of the first and the second power supply module comprises

- a mains unit (101) for rectifying an AC input voltage into a DC voltage, and

- an inverter (103) for switching the DC voltage.

2. The power supply device according to claim 1, wherein a module out of the group consisting of the first and the second power supply module (121, 104, 105) further comprises

- a preconditioner (102) for providing a DC voltage such that the DC voltage is constant controlled.

3. The power supply device according to one of the preceding claims, wherein the device comprises

- a cooling system for cooling the first and the second power supply module,

- a control signal system for controlling the first and the second power supply module.

4. The power supply device according to claim 3, wherein the cooling system comprises

- a heat exchanger system.

5. The power supply device according to claim 3, wherein the device is adapted to connect the first and the second power supply module with a cooling system and the control signal system.

6. The power supply device according to one of the preceding claims, wherein the unit for connecting a second power supply module (104, 105) comprises a connector out of the group consisting of a male connector and a female connector.

7. The power supply device according to one of the preceding claims, wherein the device comprises

- a current compensation choke (119) for compensating the currents of the first power supply module (121) and the second power supply module (104, 105).

8. The power supply device according to one of the preceding claims, wherein the device is adapted to couple the current of the first power supply module (121) and the current of the second power supply module (104, 105).

9. A power supply module for supplying electrical energy for a computer tomography gantry, wherein the power supply module comprises

- a mains unit (101) for rectifying an AC input voltage into a DC voltage,

- an inverter (103) for switching the DC voltage,

- a unit for reversibly connecting to a power supply device according to one of the preceding claims.

10. The power supply module according to claim 9, wherein the unit for reversibly connecting is a connector out of the group consisting of a male connector and a female connector.

11. The power supply module according to one of the claim 9 or 10, wherein the power supply module is adapted to be connected to the cooling system and the control signal system.

12. A computer tomography device comprising a power supply device according to one of the claims 1 to 8 and/or a power supply module according to one of the claims 9 to 11.