SIST EN 50530:2011

SLOVENSKI STANDARD
SIST EN 50530:2011
01-junij-2011
&HORYLWDXþLQNRYLWRVWIRWRQDSHWRVWQLKUD]VPHUQLNRY
Overall efficiency of photovoltaic inverters
Gesamtwirkungsgrad von Photovoltaik-Wechselrichtern
Rendement global des onduleurs photovoltaïques
Ta slovenski standard je istoveten z: EN 50530:2010
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 50530:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50530:2011

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SIST EN 50530:2011

EUROPEAN STANDARD
EN 50530

NORME EUROPÉENNE
April 2010
EUROPÄISCHE NORM

ICS 27.160


English version


Overall efficiency of grid connected photovoltaic inverters



Efficacité globale des onduleurs Gesamtwirkungsgrad von Photovoltaik-
photovoltaïques raccordés au réseau Wechselrichtern





This European Standard was approved by CENELEC on 2010-04-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50530:2010 E

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SIST EN 50530:2011
EN 50530:2010 – 2 –
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 82, Solar photovoltaic
energy systems. It was submitted to the Unique Acceptance Procedure and approved by CENELEC on
2010-04-01.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented

at national level by publication of an identical

national standard or by endorsement
(dop) 2011-04-01

– latest date by which the national standards conflicting

with the EN have to be withdrawn
(dow) 2013-04-01
__________

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SIST EN 50530:2011
– 3 – EN 50530:2010
Contents
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
3.1 Inverter input (PV generator) . 5
3.2 Inverter output (grid) . 6
3.3 Measured quantities . 6
3.4 Calculated quantities . 7
3.5 Other definitions . 8
4 MPPT efficiency . 8
4.1 General description . 8
4.2 Test set-up . 9
4.3 Static MPPT efficiency . 9
4.4 Dynamic MPPT efficiency .11
4.5 Static power conversion efficiency .12
5 Calculation of the overall efficiency .14
Annex A (normative) Requirements on the measuring apparatus .15
A.1 PV generator simulator .15
A.2 AC power supply .16
Annex B (normative) Test conditions for dynamic MPPT efficiency .17
B.1 Test profiles .17
B.2 Test sequence with ramps 10 % - 50 % P .18
DCn
B.3 Test sequence with ramps 30 % - 100 % P .19
DCn
B.4 Start-up and shut-down test with slow ramps.19
B.5 Total test duration .20
Annex C (normative) Models of current/voltage characteristic of PV generator .21
C.1 1-Diode model .21
C.2 PV generator model for MPPT performance tests .22
Annex D (informative) Inverter efficiency .33
D.1 General / Introduction .33
D.2 Conversion efficiency .33
D.3 MPP-tracking efficiency .33
D.4 Overall efficiency η .34
t
D.5 Consequences .35
Bibliography .36

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SIST EN 50530:2011
EN 50530:2010 – 4 –
Figures
Figure 1 – Exemplary test set-up for MPPT efficiency measurements . 9
Figure B.1 – Test sequence for fluctuations between small and medium irradiation intensities . 17
Figure B.2 – Test sequence for fluctuations between medium and high irradiation intensities . 17
Figure B.3 – Test sequence for the start-up and shut-down test of grid connected inverters . 20
Figure C.1 – Irradiation-dependent U-I- and U-P characteristic of a c-Si PV generator . 25
Figure C.2 – Irradiation-dependent U-I- and U-P characteristic of a thin-film PV generator . 26

Tables
Table 1 – Test specifications for the static MPPT efficiency . 10
Table 2 – Test specification for the conversion efficiency . 13
Table A.1 – General requirements on the simulated I/V characteristic of the PV generator . 15
Table B.1 – Dynamic MPPT-Test 10 % ⇒ 50 % (valid for the evaluation of η ). 18
MPPTdyn
Table B.2 – Dynamic MPPT-Test 30 % ⇒ 100 % (valid for the evaluation of η ). 19
MPPTdyn
Table B.3 . 19
Table C.1 – Technology-dependent parameters . 22
Table C.2 – Technology-dependent parameters . 24
Table C.3 – MPP-values obtained with the cSi PV model . 24
Table C.4 – MPP-values obtained with the TF-PV mode . 27

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SIST EN 50530:2011
– 5 – EN 50530:2010
1 Scope
This European Standard provides a procedure for the measurement of the efficiency of the maximum
power point tracking (MPPT) of inverters, which are used in grid-connected photovoltaic systems. In that
case the inverter energizes a low voltage grid with rated AC voltage and rated frequency. Both the static
and dynamic MPPT efficiency is considered.
Based on the static MPPT efficiency and conversion efficiency the overall inverter efficiency is calculated.
The dynamic MPPT efficiency is indicated separately.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 61683, Photovoltaic systems – Power conditioners – Procedure for measuring efficiency (IEC 61683)
EN 50160, Voltage characteristics of electricity supplied by public distribution networks
EN 50524, Data sheet and name plate for photovoltaic inverters
CLC/TS 61836, Solar photovoltaic energy systems - Terms, definitions and symbols
(IEC/TS 61836:2007)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Inverter input (PV generator)
3.1.1
maximum input voltage (U )
DCmax
allowed maximum voltage at the inverter input
NOTE Exceeding of U may destroy the equipment under test.
DCmax
3.1.2
minimum input voltage (U )
DCmin
minimum input voltage for the inverter to energize the utility grid, independent of mode of operation
3.1.3
rated input voltage (U )
DC,r
input voltage specified by the manufacturer, to which other data sheet information refers
NOTE If this value is not specified by the manufacturer, V = (V + V )/2 shall be used.
dc,r mppmax mppmin
3.1.4
maximum MPP voltage (U )
MPPmax
maximum voltage at which the inverter can convert its rated power under MPPT conditions
NOTE If the specified value of the manufacturer for U is higher than 0,8 × U , the measurement must be performed with
MPPmax DCmax
U = 0,8 × U .
MPPmax DCmax

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SIST EN 50530:2011
EN 50530:2010 – 6 –
3.1.5
minimum MPP voltage (U )
MPPmin
minimum voltage at which the inverter can convert its rated power under MPPT conditions
NOTE The actual minimum MPP voltage may depend on the grid voltage level.
3.1.6
rated input power (P )
DC,r
rated input power of the inverter, which can be converted under continuous operating conditions
NOTE If this value is not specified by the manufacturer, it can be defined as P = P / η , in which η is the conversion
DC,r AC,r conv,r conv,r
efficiency at rated DC voltage.
3.1.7
maximum input current (I )
DC,max
maximum input current of the inverter under continuous operating conditions
NOTE At inverters with several independent inputs, this value may depend on the chosen input configuration.
3.2 Inverter output (grid)
3.2.1
rated grid voltage (U )
AC,r
utility grid voltage to which other data sheet information refers
3.2.2
rated power (P )
AC,r
active power the inverter can deliver in continuous operation
3.3 Measured quantities
3.3.1
PV simulator MPP-Power (P )
MPP, PVS
MPP power provided by the PV simulator
3.3.2
input power (P )
DC
measured input power of the device under test
3.3.3
PV simulator MPP voltage (U )
MPP, PVS
MPP voltage provided by the PV simulator
3.3.4
input voltage (U )
DC
measured input voltage of the device under test
3.3.5
PV simulator MPP current (I )
MPP, PVS
MPP current provided by the PV simulator
3.3.6
input current (I )
DC
measured input current of the device under test
3.3.7
output power (P )
AC
measured AC output power of the device under test

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SIST EN 50530:2011
– 7 – EN 50530:2010
3.3.8
output voltage (U )
AC
measured AC voltage
3.3.9
output current (I )
AC
measured AC output current of the device under test
3.4 Calculated quantities
3.4.1
MPPT efficiency, energetic (η )
MPPT
ratio of the energy drawn by the device under test within a defined measuring period T to the energy
M
provided theoretically by the PV simulator in the maximum power point (MPP):
T
M
p ()td⋅t
DC
∫
0
η= (1)
MPPT T
M
p ()td⋅t
MPP
∫
0
where
p (t) instantaneous value of the power drawn by the device under test;
DC
p (t) instantaneous value of the MPP power provided theoretically by the PV simulator
MPP
3.4.2
conversion efficiency, energetic (η )
conv
ratio of the energy delivered by the device under test at the AC terminal within a defined measuring
period T to the energy accepted by the device under test at the DC terminal:
M
T
M
p ()td⋅t
AC
∫
0
η= (2)
conv
T
M
p ()td⋅t
DC
∫
0
where
p (t) instantaneous value of the delivered power at the AC terminal of the device under test;
AC
p (t) instantaneous value of the accepted power at the DC terminal of the device under test
DC
3.4.3
overall (total) efficiency, energetic (η )
t
ratio of the energy delivered by the device under test at the AC terminals within a defined measuring
period T to the energy provided theoretically by the PV simulator:
M
T
M
p ()td⋅t
AC
∫
0
η= respectively η = η ⋅ η (3)
t conv MPPT
t T
M
p ()td⋅t
MPP
∫
0

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SIST EN 50530:2011
EN 50530:2010 – 8 –
3.5 Other definitions
3.5.1
photovoltaic array simulator
current source emulating the static and dynamic behaviour of a PV array, in particular the current-voltage
characteristic (cf. IEC/TS 61836). The requirements are outlined in Clause A.1
4 MPPT and conversion efficiencies
4.1 General description
The MPPT efficiency describes the accuracy of an inverter to set the maximum power point on the
characteristic curve of a PV generator. The MPPT efficiency is divided into the static and dynamic case.
Both the static as well as the dynamic MPPT efficiencies are determined from the sampled instantaneous
values of voltage and current at the input of the inverter. It indicates which amount of the theoretically
usable PV generator power is actually used by the inverter.
a) Static MPPT efficiency
The static MPPT efficiency is determined by means of measurement as follows:
1
η= UI⋅ ⋅∆T (4)
MPPTstat ∑ DC,,i DC i
PT⋅
i
MPP,PVS M
where
U sampled value of the inverter’s input voltage;
DC,i
I sampled value of the inverter’s input current;
DC,i
T overall measuring period;
M
∆T period between two subsequent sample values.
The static MPPT efficiency describes the accuracy of an inverter to regulate on the maximum power point
on a given static characteristic curve of a PV generator.
NOTE U and I must be sampled at the same time.
DC,i DC,i
b) Dynamic MPPT efficiency
Variations of the irradiation intensity and the resulting transition of the inverter to the new operation point
are not considered with the static MPPT efficiency. For the evaluation of this transient characteristic the
dynamic MPPT efficiency is specified. The dynamic MPPT efficiency is defined as:
1
η= UI⋅ ⋅∆T (5)
MPPTdyn ∑ DC,,i DC i i
PT⋅∆
∑ i
MPP,,PVS j j
j
where
∆T period in which the power P is provided;
j MPP,PVS,j
∆T period in which the power U and I are sampled.
i DC,i DC,i

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SIST EN 50530:2011
– 9 – EN 50530:2010
4.2 Test set-up
The generic test set-up for single phase grid connected inverters is depicted in Figure 1. The diagram can
also be considered as a single phase representation of a test-circuit for multi phase inverters.

Figure 1 – Exemplary test set-up for MPPT efficiency measurements
Key
EUT Equipment under test (inverter);
I DC current meter;
DC
U DC voltage meter;
DC
P DC power meter;
DC
U AC voltage meter;
AC
P AC power meter.
AC
The DC source connected to the PV input of the inverter shall be a PV simulator in accordance to the
specifications in Clause A.1.
The AC supply of the inverter must be in accordance to the specifications in Clause A.2.
NOTE The dc and ac voltages must be measured as close as possible to the inverter terminals.
4.3 Static MPPT efficiency
4.3.1 Test conditions for the static MPPT efficiency
The measurement of the static MPPT efficiency must be performed with test specifications as defined in
Table 1.
For test devices with several independent input terminals, the measurements must be performed for all
input configurations as intended by the manufacturer. Unless otherwise provided by the manufacturer, the
total power must be split equally on the individual input terminals.
NOTE The measurement of the static MPPT should be performed preferably in combination with the conversion efficiency
measurement (see 4.5).

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SIST EN 50530:2011
EN 50530:2010 – 10 –
Table 1 – Test specifications for the static MPPT efficiency
MPP voltage of the Simulated I/U MPP power of the simulated I/U characteristic normalised
d
simulated I/U characteristic to rated DC power , P /P
MPP,PVS DC,r
characteristic (see Annex C)
0,05 0,10 0,20 0,25 0,30 0,50 0,75 1,00
of the PV generator
a,c
U (0,8 · U ) c-Si
MPPmax DCmax
U c-Si
DC,r
U c-Si
MPPmin
a,c b
U (0,7 · U ) TF
MPPmax DCmax
b
U TF
DC,r
b
U TF
MPPmin
a
The value whichever is lower shall be used. The specified MPP voltages ensure that the correct MPPT operation is not affected
by reaching voltage limits.
b
For devices under test, that are not intended for the operation with thin-film technologies, these measuring points can be
omitted.
c
For other cell technologies the value U = n·U must be set accordingly.
MPPmax DCmax
d
 In order to specify the static MPPT efficiency in terms of normalised rated AC power, the procedure in Annex E shall be used

The measurement shall be performed at nominal grid voltage U in order to avoid any impact of the
AC,r
grid voltage level on the measurement results. Deviations must be documented in the measurement
report.
The measurements have to be made at the same reference ambient conditions as conversion efficiency
measurements according to EN 61683.
4.3.2 Measurement procedure
For each of the above specified test conditions a corresponding I/U characteristic has to be defined which
must be emulated by means of the PV simulator.
NOTE 1 The requirements on the accuracy of the defined characteristic are outlined in Annex C.
After commissioning the device under test the stabilization of the MPP tracking must be awaited firstly.
NOTE 2 According to the multitude of various MPPT methods and its parameters a certain waiting period is not defined in this
standard. The stabilization time depends on the individual characteristic of the device under test and must be set accordingly in
each case. It must be documented in the test report. If a stabilisation of the MPPT can’t be observed, due to the behaviour of the
device under test, a latency of at least 5 min is defined.
After the stabilization of the MPP tracking the following parameters have to be logged for a period of
10 min:
– P MPP power provided by the PV simulator;
MPPPVS
– P measured input power of the device under test;
DC
– U MPP voltage provided by the PV simulator;
MPPPVS
– U measured input voltage of the device under test;
DC

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SIST EN 50530:2011
– 11 – EN 50530:2010
– I MPP current provided by the PV simulator;
MPPPVS
– I measured input current of the device under test.
DC
NOTE 3 Both the sampling and recording rate are not specified. However, they must be sufficiently high in order to map the
specific MPP tracking behaviour of the device under test correctly. This covers in particular the fluctuation of the input voltage
appearing at PV inverters with a multiple of the grid frequency.
NOTE 4 P may be calculated from U and I .
DC DC DC
4.3.3 Evaluation – Calculation of static MPPT efficiency
For each test specification according to Table 1 the static MPPT efficiency η is to be calculated based
MPPT
on the recorded data according to the definition. The results are to be documented in the measuring
report.
For each MPP voltage and each simulated I/U characteristic respectively the following particulars are to
be calculated and documented in the measuring report:
– the weighted European MPPT efficiency according to Annex D.1
– as well as the weighted CEC MPPT efficiency (California Energy Commission) according to Annex
D.2.
Furthermore, modifications of the internal setting of the device under test, conspicuous behaviour during
the measurement as well as variations from the defined procedure are to be documented.
4.4 Dynamic MPPT efficiency
4.4.1 Test conditions for the dynamic MPPT efficiency
The measurement of the dynamic MPPT efficiency has to be performed according to the test conditions
as outlined in the tables in Annex B.
NOTE Alternative test procedures are in discussion.
Dynamic MPPT efficiency test must be performed at rated DC voltage. For test devices with several
independent input terminals, the measurements must be performed for all input configurations as
intended by the manufacturer. Unless otherwise provided by the manufacturer, the total power must be
split equally on the individual input terminals.
The measurements have to be made at the same reference ambient conditions as conversion efficiency
measurements according to EN 61683.
4.4.2 Measurement procedure
For each of the test conditions specified in Annex B a corresponding I/V characteristic has to be defined
which must be emulated by means of the PV simulator. A radiation intensity of 1 000 W/m² is related to
the rated DC power P of the device under test. Previous to each test sequence a waiting period (initial
DC, r
set-up time) must be inserted in order to await the stabilization of the device under test. Values measured
during this initial set-up time are not considered for calculation of the dynamic MPPT efficiency according
to 4.4.3.
NOTE 1 The requirements on the accuracy of the defined characteristic are outlined in Annex C.
NOTE 2 According to the multitude of various MPPT methods and its parameters a certain waiting period is not defined in this
standard. The stabilization time depends on the individual characteristic of the device under test and must be set accordingly in
each case. It must be documented in the test report. If a stabilisation of the MPPT can’t be observed, due to the behaviour of the
device under test, a latency of at least 5 min is defined.

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SIST EN 50530:2011
EN 50530:2010 – 12 –
For the evaluation and the determination of the dynamic MPPT efficiency the following parameters are to
be recorded during the measurement:
– P MPP power provided by the PV simulator;
MPPPVS
– P measured input power of the device under test;
DC
– U MPP voltage provided by the PV simulator;
MPPPVS
– U measured input voltage of the device under test;
DC
– I MPP current provided by the PV simulator;
MPPPVS
– I measured input current of the device under test.
DC
NOTE 3 Both the sampling and recording rate are not specified. However, they must be sufficiently high in order to map the
specific MPP tracking behaviour of the device under test correctly. This covers in particular the fluctuation of the input voltage
appearing at PV inverters with a multiple of the grid frequency. U and I must be sampled at exactly the same time.
DC DC
NOTE 4 P may be calculated from U and I .
DC DC DC
4.4.3 Evaluation – Calculation of the dynamic MPPT efficiency
The overall dynamic MPPT efficiency is the mean value of the single dynamic MPPT efficiencies of the
test sequences according to tables B.1 and B.2. It is calculated by:
N
1
η= a⋅η (6)
MPPTdyn,,t ∑ i MPPTdyn i
N
i=1
– η averaged dynamic MPPT efficiency
MPPTdyn,t
– η dynamic MPPT efficiency for each test sequence
MPPTdyn,I
– N number of test sequences
– a weighting factor
i
NOTE Unless other values are defined the weighting factor is assumed to be a =1, i=1.N.
i
For each test sequence according to Annex B the dynamic MPPT efficiency η is to be calculated
MPPT,dyn
based on the recorded data according the definition. The results are to be documented in the measuring
report.
For each test sequence the calculated MPPT efficiency is to be documented tabularly in the measuring
report.
Furthermore, modifications of the internal setting of the device under test, conspicuous behaviour during
the measurement as well as variations from the defined procedure are to be documented.
4.5 Static power conversion efficiency
4.5.1 Test conditions for the static power conversion efficiency
The measurement of the conversion efficiency is specified in EN 61683. The levels of performance
specified in this standard are supplemented with 5 %, 20 %, and 30 %. All levels are normalised to P .
DC,r
NOTE 1 If P is not specified by the manufacturer it shall be calculated according to Definition 3.1.6.
DC,r
The measurement of the conversion efficiency must be performed with test specifications as defined in
Table 2.

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SIST EN 50530:2011
– 13 – EN 50530:2010
For test devices with several independent input terminals, the measurements must be performed for all
input configurations as intended by the manufacturer. Unless otherwise provided by the manufacturer, the
total power must be split equally on the individual input terminals.
NOTE 2 The measurement of the conversion efficiency should be performed preferably in combination with the measurement if
the static MPPT according to 4.3.
Table 2 – Test specification for the conversion efficiency
MPP voltage of the Simulated I/V MPP power of the simulated I/V characteristic normalised
d
simulated I/V characteristic to rated DC power , P /P
MPP,PVS DC, r
characteristic (see Annex C)
0,05 0,10 0,20 0,25 0,30 0,50 0,75 1,00
of the PV generator
a,c
U (0,8 · U ) c-Si
MPPmax DCmax
U c-Si
DC,r
U c-Si
MPPmin
a,c b
U (0,7 · U ) TF
MPPmax DCmax
b
U TF
DC,r
b
U TF
MPPmin
a
The value whichever is lower shall be used. The specified MPP voltages ensure that the correct MPPT operation is not affected
by reaching voltage limits.
b
For devices under test, that are not intended for the operation with thin-film technologies, these measuring points can be
omitted.
c
For other cell technologies the value U = n·U must be set accordingly
MPPmax DCmax
d
 In order to specify the conversion efficiency in terms of normalised rated AC power, the procedure in Annex E shall be used

4.5.2 Measurement procedure
For each of the above specified test conditions a corresponding I/U characteristic has to be defined which
must be emulated by means of the PV simulator.
NOTE 1 The requirements on the accuracy of the defined characteristic are outlined in Annex C.
After commissioning the device under test the stabilization of the MPPP tracking must be awaited firstly.
NOTE 2 According to the multitude of various MPPT methods and its parameters a certain waiting period is not defined in this
standard. The stabilization time depends on the individual characteristic of the device under test and must be set accordingly in
each case. It must be documented in the test report. If a stabilisation of the MPPT can’t be observed, due to the behaviour of the
device under test, a latency of at least 5 min is defined.
After the stabilization of the MPP tracking the following parameters have to be logg
...