T 2420/18 31-01-2022

Reasons for the Decision

1. Admissibility of the appeals

Both appeals were filed in due time and form and at least in part sufficiently substantiated. Therefore, both appeals are admissible

2. Main request - Article 123(2) EPC

The opposition division found that claim 1 according to the main request contravenes Article 123 (2) EPC.

In particular, the opposition division found that the application as originally filed provided no disclosure for feature 5a of claim 1 according to the main request.

2.1 Feature group 5 including feature 5a - according to the feature analysis taken over from the opposition division's decision (see point 17.) - reads as follows:

5. a switch (403)

5a. disposed between the power modules and the inverter; and

There is dispute whether claim 1 extends beyond the application as originally filed because according to the original disclosure, the switch is connected between at least one serial string of power modules and the inverter. In claim 1 however, the feature "at least one serial string" has been omitted.

The proprietor argued that the omission of the feature "at least one serial string" was admissible because said feature was not disclosed as being essential for the invention, which could be shown using the essentiality test. The board however agrees with the opponent that on the one hand, the so-called "essentiality test" is not sufficient evidence for proving that an amendment does not contravene Article 123(2) EPC and that on the other hand the omission of "at least one serial string" in claim 1 extends beyond the content of the application as originally filed.

The proprietor essentially argued with respect to paragraphs [0031] to [0034] of the application as filed that the invention was not limited to a serial string of power modules and that the feature "serial string" could be removed from an original claim according to the essentiality test. The board is not convinced by the proprietor's arguments why the criteria of the essentiality test should be fulfilled, or that otherwise Article 123(2) EPC was not infringed.

Regardless of the fact that even a successful essentiality test as such is not sufficient evidence that a feature is originally disclosed, the corresponding arguments of the proprietor also do not convince the board. The fact that a feature was not included in the independent claim of an application does not mean that it is not essential. In particular, as in the present case the interrelated feature, namely the switch, was also not included in the originally filed independent claim 1. The switch is exclusively disclosed in combination with power modules coupled in at least one serial string (see original claim 4). Further, the fact that figure 2 shows two serial strings of power modules which are connected in parallel cannot be interpreted to mean that the serial connection of the power modules is not essential. All power modules according to figure 2 are coupled in serial strings. As pointed out by the opponent, paragraphs [0031] to [0034] of the application as originally filed contain no technical details. They merely state that the disclosure may be applied to alternatives, which are in no way technically specified, such that no conclusions about the technical details of the indicated theoretical alternatives may be derived from those paragraphs. The board further agrees with the opponent, that the sentence in paragraph [0049] that "For simplicity a single string ... is shown..." does not mean that what is shown does not have to be in serial string configuration, but merely that the second serial string shown in other figures is not represented for "simplicity".

As correctly pointed out by the opponent, the whole original specification does not provide a basis for the omission of "serial string" with respect to the claimed switch. The switch is disclosed exclusively with the serial string throughout the description. The originally filed claims provide no basis for the amendment either. The switch is introduced only in originally filed claim 4, being dependent on claim 3 and specifying that "a switch" is disposed "between said serial string and said inverter". Thus, also the original claims do not provide any basis for the omission of the at least one serial string.

Thus, the board agrees with the opponent in that the omission of "at least one serial string" in claim 1 according to the main request represents an inadmissible generalisation.

The board has consequently come to the conclusion that claim 1 according to the main request contravenes Article 123(2) EPC.

3. Auxiliary request 1

Claim 1 according to auxiliary request 1 contains feature group 5 in an identical manner as in claim 1 according to the main request. The above conclusion with respect to claim 1 of the main request therefore applies mutatis mutandis to claim 1 according to auxiliary request 1. Thus, the board has reached the conclusion that claim 1 according to auxiliary request 1 also contravenes Article 123(2) EPC.

4. Auxiliary requests 2 to 5

Auxiliary requests 2 to 5 are new requests presented for the first time during the appeal proceedings. It is not apparent to the board, why it should not have been possible for the proprietor to address the corresponding objections under Article 100(c) EPC raised by the opponent against claim 1 as granted, in relation to the feature group 5, as early as in the notice of opposition, by filing corresponding requests during the first instance proceedings. None of the amendments filed in preparation for the first oral proceedings before the opposition division addressed the opponent's objections regarding the omission of "at least one serial string".

Moreover, although the proprietor has stated that "during the oral hearing ... [they] did not succeed to prepare further suitable auxiliary requests", without indicating why this was the case, they were obviously able to prepare and file auxiliary requests 10, 11 and 12 during the same oral proceedings. The board observes that an amendment addressing the objection of added matter against feature group 5 would have been straightforward.

Finally, the fact that the opposition division gave a positive preliminary opinion with regard to this objection cannot per se justify the late filing of the corresponding amendments, since an opposition division is clearly not bound by the views expressed in preliminary opinions.

It is thus not apparent to the board why the patent proprietor should not also have been able to present requests corresponding to the present auxiliary requests 2 to 5 during the first instance proceedings.

Consequently, the board exercises its discretion under Article 12(4) RPBA 2007 not to admit auxiliary requests 2 to 5 into the proceedings. In addition, since none of the conditions formulated by the opponent regarding their request for remittal is fulfilled, the opponent's request for remittal is moot.

5. Auxiliary request 6

5.1 Broadening of the scope of protection - Article 123(3) EPC

Regarding the opponent's objection under Article 123(3) EPC, the board is not convinced that the deletion of the apparatus claims or the adaptation of the description has led to a broadening of the scope of protection. As argued by the proprietor, there does not exist any overriding requirement that would justify interpreting features of the described and claimed apparatus into the independent method claim.

In particular, the only paragraph of the description dealing with a switch and series connected power modules now explicitly refers to "the claimed method" and thus provides the allegedly missing basis in the description. The opponent's objection is thus moot because in fact the claim according to auxiliary request 6 has a basis in the description.

The further objection of the opponent that the independent method claim according to the granted patent is to be interpreted in the light of the independent apparatus claim and would therefore have been limited by the scope of the apparatus claim contravenes the concept of independent claims in different categories. These are by definition independent. It may be that a party might have interpreted the independent apparatus and method claims in the way the opponent argued. This would however be a purely subjective interpretation. From a legal perspective, such an interpretation would have required a minimal link or reference to the features of the apparatus claim in the method claim. In the present case, the subject-matter of the independent method claim does not contain any such link or reference. The apparatus environment in which the claimed method is defined to be carried out is completely contained in the preamble of the independent method claim. The wording of the independent method claim as such has not been objected to for possible ambiguities or the like, so that an interpretation in the light of the scope of the former apparatus claims or the whole specification does not come into consideration. Thus, the board could not identify any apparatus element in the patent that would have restricted the scope of the granted independent method claim beyond the wording of the independent method claim itself. Therefore, the deletion of the apparatus claims in auxiliary request 6 can not be interpreted as broadening the scope of the remaining independent method claim either.

The board has therefore arrived at the conclusion that the claim according to auxiliary request 6 does not contravene Article 123(3) EPC.

5.2 Inventive step - Article 56 EPC

The subject-matter of the independent method claim according to auxiliary request 6 involves an inventive step over the combination of documents E1 with E3. The board is not convinced by the opponent's arguments in this respect.

On the one hand, the opponent's objections of lack of inventive step rely on the assumption that the method claim of auxiliary request 6 is to be interpreted independently of the description and that consequently method steps 14 to 19 of that claim do not have to be carried out by the parts of the distributed power system as defined in the claim. The opponent seems to assume that since according to their arguments the corresponding method steps can be carried out anywhere, their existence in the prior art may remain unproven. However, the method claim according to auxiliary request 6 does in fact comprise limiting features defining the distributed power system which is to be operated according to the claimed method. Features 14 to 19 are linked by means of definite articles to the corresponding features of the distributed power system defined in the preamble of the claim. Thus, the opponent's assumption is not correct and the board is not convinced by this line of argument.

As argued by the proprietor, the opponent's objection of lack of inventive step combining documents E1 and E3 in fact includes several gaps. For example document E1, besides features 18 and 19, also does not disclose that the operation of the inverter is monitored (feature 14), that at least one electrical parameter of the load is monitored (feature 15), that the production of output power is stopped when said at least one electrical parameter is out of a predetermined specification (features 16 and 16a) and that the switch is activated when production of output power is stopped (feature 17b).

The opponent's related argument that features 14 to 16 were common general knowledge which followed from paragraphs [0002] to [0005] of the specification of the contested patent does not convince the board. These paragraphs describe power grids in general and mention the need for anti-islanding protection. Further it is disclosed therein that islanding may be detected via auxiliary contacts or via active or passive signal monitoring. The distinct combination of features 14 to 16 is however not mentioned in paragraphs [0002] to [0005]. Thus, even if it were established that paragraphs [0002] to [0005] would form part of the common general knowledge of the person skilled in the art, what is disclosed in these paragraphs does not correspond to features 14 to 16.

The board also does not share the opponent's interpretation of the functioning of switch 9 according to document E1 in relation to feature group 17 of claim 1. Figure 1 of E1 is represented below:

FORMULA/TABLE/GRAPHIC

Contrary to the opponent's assertions, the board agrees with the proprietor's interpretation that switch 9 of E1 is not kept closed by a current supplied by the inverter 12 but, as follows directly from paragraph [0041] of E1, by the grid current.

The relevant section of paragraph [0041] of E1 reads: "Sollte jedoch eine Netzunterbrechung vorliegen ... werden die Kontakte in die Öffnungsstellung fallen und die Stromunterbrechung der Stränge 6, 7, 8 verursachen".

As illustrated in Figure 1, the grid 15 is connected at reference 14 from which the power supply of switch 9 branches off. Thus, the disclosure of the disputed paragraph [0041] and the disclosure of figure 1 correspond to each other. The board has no doubt that E1 explicitly discloses that switch 9 is reactive to the grid current and not to the inverter current. Therefore, switch 9 according to E1 cannot correspond to the claimed switch according to features 17, 17a and 17b.

Further, the board could at least not identify where document E3 might disclose that current in the serial string of power modules is sensed in response to activating the switch (feature 18) because, as correctly argued by the proprietor, E3 does not disclose a corresponding switch.

According to E3, a switch is opened after it has been determined that voltage and/or current is not within a predetermined range (see E3, claim 1). Thus according to E3, first the current is sensed and then the switch is opened. According to the claimed method however, first the switch is opened and thereafter the string current is sensed, see in particular claim 1, which explicitly states that the current is sensed "...in response to activating said switch...".

As further argued by the proprietor, even if the circuit 60 according to figure 1 of document E3 were to be inserted between the switch 9 and the inverter 12 according to E1, a sensing of current in the serial string would no longer be possible because after the switch 9 opens, the serial string of power modules would no longer be connected to circuit 60 of E3.

Consequently, the board considers feature 18 not to be disclosed in document E3.

The board is therefore not convinced by the opponent's arguments regarding lack of inventive step of the claim according to auxiliary request 6.

5.3 As none of the opponent's objections against auxiliary request 6 is successful, the board concludes that auxiliary request 6 is allowable.

6. Conclusion

The board has come to the conclusion that the main request and auxiliary request 1 are not allowable, that auxiliary requests 2 to 5 are not admitted into the proceedings, and that auxiliary request 6 is allowable. Consequently, neither the appellant's appeal nor the opponent's appeal is successful.