BSI PD IEC/TS 62578:2015
$215.11
Power electronics systems and equipment. Operation conditions and characteristics of active infeed converter (AIC) applications including design recommendations for their emission values below 150 kHz
Published By | Publication Date | Number of Pages |
BSI | 2015 | 114 |
This Technical Specification IEC TS 62578 describes the operation conditions and typical characteristics of active infeed converters (AIC) of all technologies and topologies which can be connected between the electrical power supply network (lines) a.c. side and a constant current or voltage type d.c. side and which can convert electrical power (active and reactive) in both directions (generative or regenerative).
Applications with active infeed converters are commonly used with the d.c. sides of adjustable speed power drive systems (PDS), uninterruptible power systems (UPS), active filters, photovoltaic systems, wind turbine systems, battery backed power management systems etc. of all voltages and power ratings.
Active infeed converters are generally connected between the electrical power supply network (a.c. side) and a current or voltage d.c. side, with the objective to avoid emitting low frequency harmonics (e.g. less than 1 kHz) by synthesizing a sinusoidal a.c. current. Some of them can additionally compensate the pre-existing harmonic distortion of a given supply side voltage. They are moreover able to control the power factor of a power supply network section by moving the electrical power (active and reactive) in both directions (generative or regenerative), which enables energy saving in the system and stabilizes the power supply voltage or enables coupling of renewable energy sources or electrical energy storage devices to the supply.
A practical and analytical approach for emission values for AICs in power supply networks is given, which is based on the latest results for line impedance values between 2 kHz and 9 kHz and withstand capability of capacitors connected directly to the supply.
This results in design recommendations for emission values below 150 kHz.
The following is excluded from the scope.
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Requirements for the design, development or further functionality of active infeed applications.
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Probability of interactions or influences of the AIC with other equipment caused by parasitic elements in an installation or caused by poor electronic design as well as their mitigations.
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“Overhead line” power supply networks because of lack of information (measurements) of their three phase impedances. This could be the subject for future editions.
PDF Catalog
PDF Pages | PDF Title |
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4 | English CONTENTS |
11 | FOREWORD |
13 | INTRODUCTION |
14 | 1 Scope 2 Normative references |
15 | 3 Terms and definitions |
20 | 4 General system characteristics of PWM active infeed converters connected to the power supply network 4.1 General 4.2 Basic topologies and operating principles 4.2.1 General 4.2.2 Operating principles |
21 | Figures Figure 1 – AIC in VSC topology, basic structure Figure 2 – AIC in CSC topology, basic structure |
22 | 4.2.3 Equivalent circuit of an AIC Figure 3 – Equivalent circuit for the interaction of the power supply network with an AIC |
23 | 4.2.4 Filters 4.2.5 Pulse patterns |
24 | 4.2.6 Control methods 4.2.7 Control of current components 4.2.8 Active power factor correction |
25 | 4.3 AIC rating 4.3.1 General 4.3.2 Converter rating under sinusoidal conditions 4.3.3 Converter rating in case of harmonic currents Figure 4 – Voltage and current vectors of line and converterat fundamental frequency for different load conditions |
26 | 4.3.4 Converter rating under dynamic conditions 5 Electromagnetic compatibility (EMC) considerations for the use of AICs 5.1 General Figure 5 – The basic issues of EMC as tools of economics |
27 | 5.2 Low-frequency phenomena (<150 kHz) 5.2.1 General 5.2.2 Emerging converter topologies and their advantages for the power supply network |
28 | Figure 6 – Typical power supply network current iL(t) and voltage uLN(t) of a phase controlled converter with d.c. output and inductive smoothing Figure 7 – Typical power supply network current iL(t) and voltage uLN(t) of an uncontrolled converter with d.c. output and capacitive smoothing Figure 8 – Typical power supply network current iL(t) and voltage uLN(t) of an AIC realized by a PWM Converter with capacitive smoothing without additional filters |
29 | 5.2.3 Active equalizing of the power supply network Figure 9 – Example of attainable active and reactive power of the AIC (VSC-type) at different line to line voltages in per unit (with 10 % combined transformer and filter inductor short-circuit voltage, X/R ratio = 10/1, d.c. voltage = 6,5 kV) |
30 | Figure 10 – Principle of compensating given harmonics in the power supplysystem by using an AIC and suitable control simultaneously |
31 | Figure 11 – Typical Voltage Distortion in the Line-to-Line and Line-to-Neutral Voltage generated by an AIC without additional filters (u in % and t in degrees) |
32 | Figure 12 – Basic characteristic of the relative voltage distortion (59th harmonic)of one AIC operated at a pulse frequency of 3 kHz versus RSCe with the lineimpedance according to 5.2.4 |
33 | Figure 13 – Basic characteristic of the relative current emission (59th harmonic)of one AIC at a pulse frequency of 3 kHz versus RSCe with the lineimpedance according to 5.2.4 Figure 14 – Single phase electric circuit of the three commonly used differential mode passive line filter topologies for VSC and one example for passive damping |
34 | 5.2.4 Measured power supply network impedances in the range between 2 kHz to 20 kHz Figure 15 – Example of the attenuation of the VSC line to line voltage to the line to line voltage at the IPC with state of the art differential mode passive line filter topologies |
35 | Figure 16 – Connection of the power supply networkimpedance measurement equipment |
36 | Figure 17 – Example of the measured impedance of a low-voltage transformerunder no load condition S = 630 kVA, uk = 6,08 % Figure 18 – Measured variation of the power supply network impedanceover the course of a day at one location |
37 | Figure 19 – Power supply network impedance with partly negative imaginary part Figure 20 – Distribution of power system impedance (measured between phaseand neutral conductor) in low-voltage systems versus frequency |
39 | 5.2.5 Proposal of an appropriate line impedance stabilisation network (LISN) from 2 kHz to 9 kHz Figure 21 – Statistical distribution of positive-sequence impedance versusfrequency in low-voltage power supply networks |
40 | Figure 22 – Equivalent circuit describing the power supply network impedance Figure 23 – Circuit topology for power system simulation |
41 | Figure 24 – Approximated and measured 50 % impedance curve Tables Table 1 – Parameters of line impedance stabilisation network for different power system impedance curves |
42 | Figure 25 – Single phase circuit topology according to IEC 61000-4-7+used for line impedance stabilisation network Table 2 – Parameters of the LISN described in Figure 25 and Figure 26 |
43 | 5.2.6 Effects on industrial equipment in the frequency band 2 kHz to 9 kHz Figure 26 – Three-phase circuit topology for the line impedance stabilisation network Figure 27 – Impedance variation in the 90 % curve of the LISN described in Figure 26 |
45 | Figure 28 – PDS with large d.c. capacitance Figure 29 – PDS with large capacitance and line inductor Figure 30 – PDS with a large d.c. capacitance and inductors in the d.c. link |
46 | 5.3 High-frequency phenomena (> 150 kHz) 5.3.1 General 5.3.2 Mitigation of distortion 5.3.3 Immunity 5.3.4 EMI filters |
47 | 5.4 Audible noise effects 5.5 Leakage currents 5.6 Aspects of system integration and dedicated tests Figure 31 – Basic EMI filter topology Figure 32 – Block diagram of a PDS with high frequency EMI filter system |
48 | 6 Characteristics of a PWM active infeed converter of voltage source type and two level topology 6.1 General 6.2 General function, basic circuit topologies |
49 | Figure 33 – Basic illustration of a topology of a two level PWM voltage source AIC |
50 | Figure 34 – Typical waveforms of voltages uS1N / ULN, 1 and voltage uS12 / ULN, 1 at pulse frequency of 4 kHz Figure 35 – Typical waveforms of the common mode voltage uCM / ULN,1 at pulse frequency of 4 kHz. Power supply frequency is 50Hz |
51 | 6.3 Power control Figure 36 – Waveform of the current iL1 / Iequ at pulse frequency of 4 kHz, relative impedance of uSCV,equ = 6 % Figure 37 – Block diagram of a two level PWM AIC |
52 | 6.4 Dynamic performance 6.5 Desired non-sinusoidal line currents 6.6 Undesired non-sinusoidal line currents |
53 | 6.7 Availability and system aspects Figure 38 – Distortion of the current iL1 of reactance Xequ, pulse frequency: 4 kHz, relative reactance of uSCV,equ = 6 % Figure 39 – Typical voltages uL1N / ULN, 1 and uL12 / ULN, 1at pulse frequency of 4 kHz, relative reactance uSCV, equ = 6 %, RSCe= 100 |
54 | 6.8 Operation in active filter mode 7 Characteristics of a PWM active infeed converter of voltage source type and three level topology 7.1 General function, basic circuit topologies Figure 40 – Basic topology of a three level AIC. For a Power Drive System (PDS) the same topology may be used also on the load side |
55 | 7.2 Power control 7.3 Dynamic performance Figure 41 – Typical curve shape of the phase-to-phase voltageof a three level PWM converter |
56 | 7.4 Undesired non-sinusoidal line currents 7.5 Availability and system aspects Figure 42 – Example of a sudden load change of a 13 MW three level converterwhere the current control achieves a response time within 5 ms |
57 | 8 Characteristics of a PWM Active Infeed Converter of Voltage Source Type and Multi Level Topology 8.1 General function, basic circuit topologies Figure 43 – Typical topology of a flying capacitor (FC) four level AIC using IGBTs |
58 | 8.2 Power control Figure 44 – Typical curve shape of the phase-to-phase voltageof a multi-(four)-level AIC |
59 | 8.3 Dynamic performance 8.4 Power supply network distortion 8.5 Availability and system aspects Figure 45 – Distorting frequencies and amplitudes in the line voltage (measured directly at the bridge terminals in Figure 25 and the line current of a multilevel (four) AIC (transformer with 10 % short-circuit voltage) |
60 | 9 Characteristics of a F3E AIC of the Voltage Source Type 9.1 General function, basic circuit topologies Figure 46 – Topology of a F3E AIC |
61 | 9.2 Power control and line side filter Figure 47 – Line side filter and equivalent circuit forthe F3E-converter behaviour for the power supply network Figure 48 – Current transfer function together with RSCe = 100 and RSCe = 750and a line side filter: G(f) = iL1/ iconv |
62 | Figure 49 – PWM – voltage distortion over power supply network impedancefor F3E-infeed including power supply network side filter |
63 | 9.3 Dynamic performance 9.4 Harmonic current Figure 50 – Input current spectrum of a 75kW-F3E-converter Figure 51 – Harmonic spectrum of the input currentof an F3E-converter with RSCe = 100 |
64 | 10 Characteristics of an AIC of Voltage Source Type in Pulse Chopper Topology 10.1 General 10.2 General function, basic circuit topologies Figure 52 – An illustration of a distortion effect caused by a single phase converter with capacitive load |
65 | 10.3 Desired non-sinusoidal line current 10.4 Undesired non-sinusoidal line current 10.5 Reliability Figure 53 – a.c. to a.c. AIC pulse chopper, basic circuit |
66 | 10.6 Performance 10.7 Availability and system aspects 11 Characteristics of a two level PWM AIC of current source type (CSC) 11.1 General 11.2 General function, basic converter connections |
67 | Figure 54 – Illustration of a converter topology for a current source AIC |
68 | 11.3 Power control Figure 55 – Typical waveforms of currents and voltages of a current source AICwith high switching frequency |
69 | 11.4 Dynamic performance Figure 56 – Typical block diagram of a current source PWM AIC Figure 57 – Current source AIC used as an active filter to compensatethe harmonic currents generated by a nonlinear load |
70 | 11.5 Line current distortion 11.6 Operation in active filter mode 11.7 Availability and system aspects Figure 58 – Step response (reference value and actual value) of current source AIC with low switching frequency [33] |
71 | Annex A (informative) A.1 Control methods for AICs in VSC (Voltage Source Converter) topology A.1.1 General A.1.2 Considerations of control methods |
72 | A.1.3 Short-circuit ride through functionality for decentralized power infeed with AIC A.1.4 Fault ride through mode |
73 | Figure A.1 – Principle sketch for combined voltage- andcurrent-injecting modulation example for phase leg R Table A.1 – Condition state 1: positive current limit reached, transistor T1 is switch-off to reduce the current Table A.2 – Condition state 2: negative current limit reached, transistor T2 is switch-off to reduce the current Table A.3 – Condition state 0: current in phase R within tolerance range, pure voltage injection active (e.g. with PWM) |
74 | A.2 Examples of practical realized AIC applications A.2.1 AIC of current source type (CSC) Figure A.2 – Example for controlled phase current during a voltage dipat the power supply network using hysteresis plus PWM control Figure A.3 – Typical waveforms of electrical power supply network current and voltage for a current source AIC with low switching frequency [33] |
75 | Figure A.4 – Currents and voltages in a (semiconductor) valve device of an AIC and a machine side converter both of the current source with low pulse frequency [33] Figure A.5 – Total harmonic distortion of electricalpower supply network and motor current [33] remains always below 8 %(triangles in straight line) in this application |
76 | A.2.2 Active infeed converter with commutation on the d.c. side (reactive power converter) Figure A.6 – Basic topology of an AIC with commutation on the d.c. side (six pulse variant) |
77 | Figure A.7 – Dynamic performance of a reactive power converter Figure A.8 – Line side current for a twelve pulse Reactive Power Converter in a capacitive and inductive operation mode (uSCV,equ = 15 %) |
78 | A.3 Details concerning two level and multi-level AICs in VSC Topology A.3.1 Properties of active infeed converters (PWM) with different number of levels Figure A.9 – The origin of the current waveform of a RPC by the line voltage (sinusoidal) and the converter voltage (rectangular) Table A.4 – Comparison of different PWM AICs of VSC topology |
79 | A.3.2 Examples of typical waveforms of AICs Figure A.10 – Two level topology with nominal voltage of maximum 1 200 V and timescale of 5 ms/div Figure A.11 – Three level topology with nominal voltage of maximum 2 400 V and timescale of 5 ms/div |
80 | A.3.3 Construction and realization A.4 Basic transfer rules between voltage and current distortion of an AIC Figure A.12 – Four level topology with nominal voltage of maximum 3 300 V and timescale of 5 ms/div |
81 | A.5 Examples of the influence of AICs to the voltage quality Figure A.13 – General influence of significant characteristics to the voltage distortion and current distortion |
82 | A.6 Withstand capability of power capacitors towards distortion in the range of 2 kHz to 9 kHz A.6.1 General Figure A.14 – Measured reduction of voltage distortion when four AICs are connected to the power supply network |
83 | Figure A.15 – Excerpts from a catalogue information of a power capacitor manufacturer; 760 V AC; (rated voltage: 690 V AC) for temperature calculation |
84 | A.6.2 Catalogue information about permissible harmonic load A.6.3 Frequency boundaries for permissible distortion levels Figure A.16 – Reactive power and losses of a power capacitor supplied by a source with constant reference voltage and variable frequency (Rcp = f(h)) |
85 | A.6.4 Frequency spectrum of active infeed converters Figure A.17 – Apparent power and losses of a typical power capacitor at different voltage distortion levels and the critical frequency boundaries (at singular frequency) where the temperature rise reaches substantial values (vertical arrows) |
86 | A.6.5 Conclusion Figure A.18 – Voltage spectrum of an AIC and the impact of a line impedancereduction to the temperature of the capacitor (from 10 K to 0,44 K) andthe composition of the spectrum |
87 | A.7 Impact of additional AIC filter measures in the range of 2 kHz to 9 kHz A.7.1 General |
88 | A.7.2 Example of a PDS constellation (AIC and CSI) Figure A.19 – A wind turbine plant and a mine winder drive connectedon the same power line Figure A.20 – Power supply network configuration for the plantof Figure A.19 with allocated measurement points |
89 | Figure A.21 – Regular current of the CSI (AIC-filter disabled) and amplification of the current in case of resonance caused by the AIC-filter circuit (when AIC filter is enabled) Table A.5 – Voltage distortion on both power lines (II and III) without and with filter circuit (the filter had been designed to achieve 0,2 % distortion level on the MV-power line) |
90 | A.7.3 Conclusion Table A.6 – Current distribution within the network described for specific frequencies and on allocated measurement points as pointed out in Figure A.20 |
91 | A.8 Example of the power supply network impedance measurement A.8.1 General A.8.2 Basic principle of measurement Figure A.22 – Basic principle of impedance measurement |
92 | A.8.3 Harmonic component injection methods for measurement A.8.4 Harmonic current generation by disturbing device A.8.5 References based on current injection by disturbance (Method A) Figure A.23 – Harmonic current generation by disturbing device |
93 | Figure A.24 – Measurement by switching a resistor Figure A.25 – Measurement by a capacitor bank |
94 | A.8.6 References based on sinusoidal single frequency injection (Method B) Figure A.26 – A 6,6 kV power supply network impedance measurement systemfor islanding detection by injecting interharmonics |
96 | Annex B (informative) B.1 Basic considerations for design recommendations of AICs in the range of 2 kHz to 9 kHz B.1.1 Overview B.1.2 General |
97 | B.1.3 Withstand capability of power capacitors connected to the power supply network and recommendation for the compatibility in the frequency range 2 kHz to 9 kHz B.1.4 Basic conditions for setting the capacitor withstand capability curve |
98 | Figure B.1 – Withstand capability level towards harmonic voltages in the power supply network in view of permissible temperature rise within capacitors if the voltage distortion is determined either by one predominating frequency (upper line) or if the distortion is predominantly determined by a harmonic spectrum, caused by several parallel operated AICs (2-Level PWM) (lower line) |
99 | B.1.5 Matching of AIC converters (2-Level PWM) to different power supply network conditions without overloading the power capacitor burden Figure B.2 – Harmonic voltage spectrum of one 2-Level PWM AIC with acceptable temperature increase of a power capacitor not exceeding 10 K |
100 | Figure B.3 – Maximum voltage distortion of a spectrum, caused by several AICs (single phase topologies) Figure B.4 – Maximum voltage distortion of a spectrum, caused by several AICs (three phases topologies) |
101 | B.1.6 Considerations in regard to medium voltage power supply networks Figure B.5 – Spreadsheet of matching single phase AICs (2-level) to different power supply network conditions in order to apply the power capacitor limit curves Figure B.6 – Spreadsheet of matching three phases AICs (2-level) to different power supply network conditions in order to apply the power capacitor limit curves |
102 | B.1.7 AIC filtering considerations B.1.8 AIC appropriate technical and economical amount Figure B.7 – Illustration of the typical power supply network resonance frequency by increasing AIC filtering population, versus the voltage distortion level |
103 | B.1.9 Frequency range from 2 kHz to 9 kHz Figure B.8 – Sketch of the typical size/cost of an AIC applicationversus switching frequency of the AIC Figure B.9 – Illustration of the probability of overload and stress problems for the power supply network and the equipment connected thereto, depending on stipulated distortion levels fixed in miscellaneous assumptions |
104 | B.2 Design recommendations for conducted emission of low voltage AICs in the reasonable context of higher frequencies between 9 kHz and 150 kHz B.2.1 General Table B.1 – AIC design recommendation for a maximum distortion factorin the frequency range from 2 to 9 kHz |
105 | B.2.2 Data collection results Figure B.10 – Results of the data collection versus the maximum values proposedin the IEC TS 62578 for products rated above 75 kVA |
106 | Figure B.11 – Results of the data collection versus the maximum values proposedin the IEC TS 62578 for products rated below 75 kVA Figure B.12 – Results of the data collection versus the maximum values proposedin the IEC TS 62578 for products rated above 75 kVA |
107 | B.2.3 Conclusions Figure B.13 – Recommended maximum emission values for AIC of different categoriesin the range from 9 kHz up to 150 kHz |
108 | Table B.2 – Recommended maximum emission values for AIC of different categories in the range from 9 kHz up to 150 kHz |
109 | Bibliography |