ES2431244A1 - Power adaptation system (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Power adaptation systems. The system described here allows a power adequacy to be made for anaerobic or independent air power generation plants (known by its acronym in english aip) from fuel cells, mounted on vehicles and charged with providing power to it from of energy extracted from fuel cells without the need for any intermediate transformation step, so that the use of transformers is not necessary. For this, a system is used that includes a lifting part responsible for raising the voltage from the fuel cell output conditions to a constant voltage of the internal bus, a part of power adequacy in charge of converting the power and a bus intermediate (dc link) intermediate between the lifting part and the power matching part. (Machine-translation by Google Translate, not legally binding)

Description

OBJECT OF THE INVENTION

The present invention is framed in the field of a system of adaptation of the power generated by an anaerobic power generation plant known by its acronym in English AIP (Air Indenpendent Plant), AIP plant that operates from fuel cells.

The object of the invention consists of a system for adapting power from an autonomous power generation plant from fuel cells, a power that will be responsible for providing energy to a vehicle. Said adapted power can be used for the vehicle's own systems as well as for use as an alternative, auxiliary or complementary energy source for the vehicle itself.

BACKGROUND OF THE INVENTION

Among the existing technologies for propulsion of marine or naval vehicles such as submarines are conventional systems that use diesel engines for propulsion and systems based on nuclear technologies and anaerobic (or anaerobic systems depending on the terminology to be used).

Submarines with diesel technology have a lower autonomy than other technologies and also have the disadvantage that they are less discreet than other technologies because they need to use snorkeling.

Within the anaerobic systems are the Al P (Air independent plant by its abbreviations in English of Air Indenpendent Plant) systems. There are different AIP systems, one of them is the AIP system based on fuel cell. Some of the advantages of these fuel cell based systems are:

Fuel cells represent a real alternative as a means of producing silent, safe, reliable and high-performance electricity. Getting powers of up to 500 kW is relatively simple with the right technology. They can be fed with different fuels, simply choosing the right reformer

In AIP plants based on fuel cells, the fuel used is transformed into electrical energy in the fuel cell by a chemical reaction that occurs in its cells.

Since at the exit of the fuel cells it is necessary to adapt the energy to the voltage conditions of the submarine's power bus, a push-pull configuration is required as a typical means of adaptation, which requires an intermediate transformer, which means lower efficiency, difficulty of transformer integration due to its weight and volume, superior cost and maintenance complexity. Due to the high powers used with low voltage jump between the input and output, it is more interesting to use a different type of topology than the push-pull, because the push-pull has a series of drawbacks such as: lower efficiency, difficulty of transformer integration due to its volume and weight, difficulty of finding transformers that work at high frequencies of high power, superior cost and maintenance complexity. Therefore, a high performance energy adaptation system is sought that does not require an intermediate alternating transformation.

The Korean patent application KR2011 000631 OA details a power conditioning system for a multi-level converter comprising: a lifting part (boas! Converter), an intermediate OC-link and an adaptation part responsible for converting the power of the OC -intermediate link to the exit. However, this document makes use of a transformation and the power conditioning stage is not a stage OC-OC direct current-direct current, but oC-AC direct current-alternating current, also presenting a transformer at the output of the inverter of In this document, an embodiment is collected by means of a push-pull converter that requires a transformer. Something similar occurs in the solution collected by document KR100799446 B1 where a power adaptation system for a fuel cell is disclosed that has a conditioning system that has an inverter, a transformer and a final rectifier, that is, it has an intermediate transformation in alternating current.

Document W02005036684 A2 describes a power conditioning system for a fuel cell that allows connection to an alternating network. The system comprises at least one bidirectional DC / AC inverter and an intermediate continuous bus between the cell and the inverter.

Also in document ES2270392 T3 of HOWALDTSWERKE-DEUTSCHE WERFT GMBH details an OC-OC converter connected between a battery and a fuel cell in which the OC-OC converter that has an intermediate alternating transformation

DESCRIPTION OF THE INVENTION

The system object of the invention has application in the supply of energy to vehicles that have a power bus, such as maritime vehicles from which submarines that can use auxiliary energy obtained from batteries have been determined as a possible destination of the invention of fuel, since these are a real alternative, as a means of producing energy for quiet, safe, reliable and high-performance propulsion.

Among the possible uses of the power once appropriate, it is worth mentioning the use of the power adapted to power a means of propulsion, auxiliary or complementary to a vehicle. From the energy generated in an AIP plant (Air Independent Plant) from one or more fuel cells, a power matching system is used, which is capable of adapting the energy of a fuel cell system to A continuous power bus. With this they manage to overcome the inconveniences mentioned in the previous section. The power adaptation system adapted to an AIP plant for a vehicle object of the invention, is capable of adapting the electrical energy of a power generation module, such as the aforementioned AIP plant, based on fuel cell to a power bus in continuous but in this case without the need for an intermediate step to alternating current, that is, without the need for transformers.

Being able to perform the power adaptation between the fuel cell and the power bus without the need to implement a DC / AC / DC converter with an intermediate alternating transformer, the use of intermediate transformer is avoided, which allows the efficiency of the equipment It is higher, allowing to work with high powers with low voltage jumps between the input and output. The voltage range for which the system is prepared to work at the input is 100 Vdc as a minimum value and 700 Vdc as a maximum value and at the output this value varies between 100 and 700 Vdc. The absence of a transformer minimizes the number of components of the equipment so that its reliability increases and its size decreases, a very important characteristic given the environment in which the system is operational, preferably a submarine; This also has a direct impact on the control of operating temperature and the vibrations and harmonics that are generated, important in work environments such as the interior of a marine vehicle such as a submarine.

Another notable advantage is that related to the eventual maintenance of a transformer inside a submarine, which is necessary in other solutions and is not a simple task due to the limited space that normally exists for maintenance tasks, the system described here avoid this maintenance task since it does not use intermediate transformer. Since the AIP plant comprises at least one fuel cell in charge of generating power, and at least one power output, the power adaptation or adaptation system comprises a number of inputs equal to a number of fuel cell outputs; The power adaptation system described here comprises at least one output and as many branches as inputs from the output of the fuel cells count, where each branch is divided into three blocks: - A lifting part responsible for raising the voltage from the conditions of output of the fuel cell to a constant internal bus voltage. This part is formed by two elevators switched in antiparallel. -A part of power adaptation responsible for converting the power from the intermediate bus (OC Link) to the output of the vehicle's power bus, this part comprises a bridge H on each branch with modulations offset by 120º. -A intermediate bus (OC Link) intermediate which is the link between the lifting part and the power adaptation part. This bus is responsible for storing energy and establishing a constant voltage serving as a means of decoupling electrical parameters, being a high capacity capacitor.

The system described here has a configuration that allows at least two modes of operation since it is bidirectional, not only can the power be supplied to the vehicle, but it is capable of extracting current from the vehicle's power bus and injecting it into the system's intermediate storage which can be of the condenser type or an element that acts as such. This is that in one mode of operation the system is responsible for absorbing current from the fuel cell and pouring it into the bus of the vehicle but thanks to the aforementioned bidirectionality it is possible to extract current from the vehicle's power bus and inject it into an intermediate storage , or extra, which can be defined by an electrical component capable of storing energy that can be subsequently dumped; In this sense, the possibility of having an element designed to increase the storage capacity is available in the intermediate bus (OC Link).

Both in one mode of operation and in another, during the first phase of the start-up, a preload circuit is used (parallel to the main circuit) through which current flows from the vehicle's power bus to the intermediate bus in order to achieve The OC Link intermediate bus a voltage corresponding to that of the vehicle's power bus. Once the system reaches this preset voltage, it can operate with a main circuit both in the direction of pouring power to the vehicle's power bus (obtained from the fuel cell system) and absorbing power from it (disconnected from the fuel cell system ).

The decision to pour power to the bus or absorb it from the vehicle's power bus is made by means of indications to the system control. The current that is extracted from the power bus of the vehicle to the intermediate storage included in the Bus itself a series of Hall-type sensors to monitor those parameters related to the current and LEM-type sensors for those parameters related to voltage. Also, and in combination with these sensors, a series of voltage monitoring relays are available to detect voltage failure and at least one motorized circuit breaker at input (100-500 A) and output (800-3000 A); which is isolated from the ground and incorporates a minimum voltage coil and the motor for its mechanism.

So that the load of springs of the motors of the switches occurs progressively without prejudice to the power supplies, timed relays are installed that act on the motor. Likewise, the preload circuit, in addition to incorporating a double diode to prevent the flow of current in the reverse direction, incorporates a resistance of less than 150 Ohms to limit the absorbed current of the power bus and the contact that closes the preload circuit is controlled from the control of the system object of the invention.

The system described herein may comprise a series of safety measures such as earth protections for both indirect contacts and electrical service (in the case of EMI filters that have a ground connection in the housing and a weak ground connection of the electrical circuit), voltage arresters, coils, leak cards, chassis, discharge resistance with protective earth connection or leak cards which are located in the input branches. There are also automatic switches at the power supply input of the power adaptation system described here, for protection of said lines and one or more resistance (of a value less than 100 W) of discharge that are installed to produce a controlled discharge of the voltage with which the intermediate bus (OC Link) buses are charged before a stop. In order to absorb possible voltage peaks that may occur, a series of voltage arresters (or surge protectors) are included in a system configuration.

Finally and stop the correct functioning of the system, it has a water cooling subsystem that has been designed taking into account that the dissipated thermal power of the equipment is maximized in the cooling circuit, so that the thermal losses that are minimized are minimized. dissipate to the environment of the vehicle, such as a submarine with a very specific environment. The cooling circuit is formed by a water circuit that is divided into parallel branches, which together with needle valves at the entrance of each branch achieves a distribution as uniform as possible between the coils and the water sinks of the semiconductors and is controlled by NTC and PTC temperature probes at various points; It is possible to additionally include a flowmeter to check that the water flow level is correct. The cooling subsystem is complemented by a ventilation circuit formed by two air circuits that prevent possible condensation at both the entrance and the exit, maintaining the specified IP degree of the equipment. To control the operation of the fans, and thus avoid possible condensation, it is planned to install an operating hygrostat in such a way that the fans operate based on the determined humidity data, that is to say when there is a certain humidity level that is above of a predetermined humidity threshold value.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- Shows a view of a general schematic diagram of the system object of the invention.

Figure 2.- Shows a view of a general schematic diagram of the intermediate branch of the system object of the invention.

Figure 3.- Shows a view of a schematic diagram of the input branch of the system object of the invention.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the figures, a preferred embodiment of the system object of this invention is described below.

As presented in Figure 1, where a general circuit scheme of the system described here can be seen, in this exemplary embodiment a power adaptation system adapted to an AIP plant with a fuel cell for a submarine is implemented, the The system is capable of adapting the electrical energy of a system of at least one fuel cell to a continuous power bus, without the need for an intermediate passage to alternating current, with high efficiency. For this, the system acts as an OC / OC converter consisting of multiple inputs and one output and can have as many inputs as connections to fuel cell outputs are needed.

As shown in Figure 2, where a lifting part of the system can be seen, it is seen that it comprises at least two elevators switching in antiparallel, so that its PWM modulation is 180 ° out of phase. With this it is possible to minimize the dimensions of the components since the current flowing through each of the branches of the elevators is half, and in addition, the curling is reduced.

The intermediate bus of the Intermediate Bus (OC Link) equipment is responsible for storing energy and establishing a constant voltage to have an electrical parameter decoupling stage between the lifting part and the power matching part. This Intermediate Bus (OC Link) is a high capacity capacitor, which allows it to function as an energy storage bus when the system operates bidirectionally, absorbing energy from the Submarine's power bus. If there is a need to store more power of the intermediate bus capacity (OC Link), there is the possibility of connecting some elements that act as energy storage such as batteries, capacitors or supercapacitors so as to increase their storage capacity.

The power adaptation stage is formed by a bridge H on each branch thus minimizing the curling of the current at the output. The bridges H of each branch have PWM modulations that are outdated, this offset corresponds to a division of the possible angles between the number of branches, that is 360 / n where n is the number of branches, in this preferred embodiment being two branches The H bridges of each branch have PWM modulations that are 120º out of phase. This stage of adequacy of power at startups functions as a lifting topology so that an intermediate bus is charged by absorbing current from the submarine's power bus.

In the power output a coil is located that allows besides filtering the output current, that it is possible for the bridge H together with the coil to function as an elevator.

As seen in Figure 3 in a possible embodiment of the system, this comprises at least one first EMI type filter located at each input, EMI filter intended to dampen high frequency harmonics, also additionally comprises at least a second EMI type filter located at the power output intended to dampen high frequency harmonics. The EM I filters dampen the high frequency electromagnetic emissions and the output capacitor dampens the low frequency, also said EMI filters comprise a weak connection to the electrical ground to prevent recirculation from forming on the ground.

In an alternative embodiment of the system described herein, it is equipped with at least one output capacitor located at the power output intended to dampen harmonics at low frequencies, for this embodiment the output capacitor preferably has a capacity of 100 and 300 microF.

Given the nature of the system described here, it is planned to use it in different applications such as its use to adapt the power of an anaerobic power generation plant to a power bus of a vehicle, such as a maritime vehicle and more specifically a submarine

Claims (13)

1. Power adaptation system of an anaerobic generation plant of energy, plant comprising: at least one fuel cell in charge of generating power, and at least one power output and a number of inputs equal to a number of fuel cell outputs, power matching system characterized in that it comprises : at least one elevator block, which comprises an even number of at least two elevators, where the elevator block is responsible for raising the voltage from the conditions of the fuel cell to a constant voltage of an internal bus, at least one Intermediate bus (OC Link), connected next to the lifting block, which comprises at least one high capacity capacitor, and, where the intermediate bus (OC Link) is responsible for storing energy and establishing a constant voltage serving as a means of decoupling electrical parameters, and at least one power adaptation block, connected next to the intermediate bus (OC Link), which comprises at least one branch that at its It also includes an H bridge with modulations, where the power adaptation block is responsible for converting power from the intermediate bus (OC Link) to a power bus.

2.

System according to claim 1 characterized in that the bridge H comprises outdated modulations at an angle equal to 360 ° / n where n is the number of branches.

3.

System according to claim 1 or 2 characterized in that the elevators are switched in antiparallel.

Four.

System according to claim 1 characterized in that the intermediate bus (OC Link) additionally comprises at least one element intended to increase the storage capacity.

5.

System according to any one of the preceding claims characterized in that it additionally comprises at least a first EM type filter located at each input, EM I filter intended to dampen high frequency harmonics

6.

System according to any one of the preceding claims characterized in that it additionally comprises at least a second EMI type filter located in the power output, EM I filter intended to dampen high frequency harmonics.

7.

System according to any one of the preceding claims characterized in that it additionally comprises at least one output capacitor located at the power output intended to dampen harmonics at low frequencies.

8.

System according to claim 1 characterized in that it comprises a parallel circuit, wherein said parallel circuit is a preload circuit that allows the intermediate bus (OC Link) to be raised to a voltage equal to that of the power bus and is intended to carry a current that it is extracted from the vehicle's power bus to the intermediate storage included in the Intermediate Bus (OC Link).

9.

System according to claim 5 or 6, characterized in that the EMI filter comprises a weak connection to electrical ground to prevent recirculation from forming on the ground

10.

Use of the system described in any one of claims 1 to 9 to adapt the power of an anaerobic power generation plant to a power bus of a vehicle.

eleven.

Use according to claim 10 wherein the vehicle is a maritime vehicle.

12.

Use according to claim 11 wherein the vehicle is a submarine.

        SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 201330648 SPAIN Date of submission of the application: 03.05.2013 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: H02M3 / 02 (2006.01) RELEVANT DOCUMENTS

Category

56 Documents cited Claims Affected

X

EP 2407339 A1 (VALEO SYS CONTROLE MOTEUR SAS) 18.01.2012, column 1, line 5 - column 5, line 30; figure 8. 1-12

X

ALIREZA NAMI and FIRUZ ZARE: "Renewable Energies"; Chapter 15: "Multilevel converters in renewable energy systems"; Queensland University of Technology, School of Engineering Systems; Book edited by T J Hammons, ISBN 978-953-7619-52-7, Published: 01.12.2009; DOI: 10.5772 / 7365. 1-12

X

US 2012262437 A1 (KELLER THOMAS et al.) 18.10.2012, summary; figure 3.

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims □ for claims no:

Date of realization of the report 08.11.2013

Examiner B. Pérez García Page 1/5

REPORT OF THE STATE OF THE TECHNIQUE Application number: 201330648 Minimum documentation sought (classification system followed by classification symbols) H02M Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC, WPI, INSPEC State of the Art Report Page 2/5  WRITTEN OPINION Application number: 201330648 Date of Completion of Written Opinion: 08.11.2013 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-12 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-12 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/5  WRITTEN OPINION Application number: 201330648 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

EP 2407339 A1 (VALEO SYS CONTROLE MOTEUR SAS) 18.01.2012

D02

ALIREZA NAMI and FIRUZ ZARE: "Renewable Energies"; Chapter 15: "Multilevel converters in renewable energy systems" 01.12.2009

D03

US 2012262437 A1 (KELLER THOMAS et al.) 18.10.2012

2. Statement motivated according to articles 29.6 and 29.7 of the Regulation of execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement D01 is considered the state of the art document closest to the object of the request. Following the wording of the first claim, D01 describes a power matching system for generating Energy; plant comprising:

-

at least one fuel cell (reference 1 in D01; column 2, line 53) responsible for generating power,

-

at least one power output and a number of inputs equal to a number of fuel cell outputs,

-

a power matching system characterized in that it comprises:

or at least one lifting block (boost circuit 11; column 1, lines 49-54)), responsible for raising the voltage from the fuel cell output conditions to a constant internal bus voltage;

or at least one intermediate bus connected next to the elevator block (boost 11 output), comprising at least one high capacity capacitor (supercapacitor 27; column 4, lines 31-32) and where the intermediate bus is responsible for storing energy and establish a constant voltage serving as a means of decoupling electrical parameters;

or at least one power adaptation block (inverter 3) connected next to the intermediate bus comprising at least one branch which in turn has an H bridge with modulations (see figure 8), where the power block is responsible for convert power from the intermediate bus to a power bus.

Both documents have great similarities and use common general knowledge electronic circuits (boost / boost converter and H-bridge) to adapt the voltage at a constant level and adapt the energy without using an AC transformer. There are two differences between D01 and the first claim. The first, relative to the application and the second regarding the boost circuit. Regarding the first difference, the first claim explicitly cites that the circuit is intended for an anaerobic plant while in D01, the circuit serves to drive a mechanical equipment. Although it is not exactly the same application, the circuit described in D01 is suitable for application in an anaerobic plant and therefore, this detail does not provide inventive activity to said claim. The second difference refers to the lifting block; in D01 this is composed of an even number of elevators, at least two. The technical effect that is pursued with this design is to minimize the size of the components (since the current flowing through them is distributed by the branches in parallel). The objective technical problem then is how to make less current flow through the components. The solution proposed in the application is obvious to a person skilled in the art, since by placing circuits in parallel the current is distributed between them (Kirchoff Current Law). In summary, the first claim does not meet the requirement of inventive activity, according to Art. 8 of the Spanish Patent Law. The second claim indicates that the bridge H comprises offset modulations at an angle equal to 360 ° / n, where n is the number of branches. The third claim adds that the elevators are switched in antiparallel. D01 details (column 6, lines 52-56) that the bridge connection elements are controlled with pulse width modulation (PWM), whose work cycles will be calculated to obtain the desired current in the motor and in the capacitor. In addition, although it is not indicated, it is obvious that the rule defined in claim 2 is met, since in D01 a three-legged H bridge is provided to feed a three-phase motor, whose phases - like any three-phase system - are 120º out of phase ( 360º / 3 = 120º). Regarding the third claim and following the same reasoning applied for the first, putting two circuits instead of one and switched in antiparallel with the aim of distributing the current also has no inventive activity. In addition, the rule that the PWM modulation is out of phase 360 / n (in this case as the number of lifting circuits or branches is 2, the offset is 180º) is fulfilled so that it works correctly and curling is reduced as much as possible. That is, claims 2 and 3 have no inventive activity. State of the Art Report Page 4/5  WRITTEN OPINION Application number: 201330648 Claim number 4 specifies that the intermediate bus additionally comprises an element intended to increase storage capacity. This effect is achieved by placing another capacitor in parallel or a capacitor of greater capacity. An unexpected technical effect is not obtained and is a common technique. It does not involve inventive activity. Claims 5 and 6 add the use of EMI filters to the input and output of the circuit to dampen high frequency harmonics. Claim 9 further clarifies that these filters are grounded to avoid ground recirculation. This type of filters, well known in the market, are always used for this purpose. It is about adding a component, of common general knowledge, to the circuit to avoid unwanted harmonics. No inventive activity. The seventh claim places an output capacitor to dampen harmonics at low frequencies. A capacitor at low frequencies, has a high impedance and therefore, allows to eliminate / decrease / dampen said low frequencies. It does not involve technical effort. Claim 8 presents a parallel circuit for preload, which allows the intermediate bus voltage to be raised to a voltage equal to that of the power bus and is intended to carry current that is drawn from the power bus to the intermediate bus storage. This claim indicates the existence of a parallel preload circuit, although it does not appear in the drawings and its design or location is not clear. The description on the other hand, specifies that the objective is to be able to pour power to the intermediate bus or absorb it from the vehicle's power bus by means of two control loops (this is not claimed). However, these two control loops are given by the control of the elevator circuit and the H-bridge, which is "controlled" by activating the respective transistors (both in the application and in D01). Does not meet the requirement of inventive activity. Claims 10-12 relating to use are interpreted considering that the circuit is suitable for use in anaerobic plants, and as discussed in the reasoning of the first claim, D01 is suitable for use in them. In summary, the application submitted does not meet the requirement of inventive activity for an expert in the field (Art. 8 of the Spanish Patent Law) in light of the disclosure made in D01. State of the Art Report Page 5/5