GH150 Air Cooled For High Powered AC Drives and Electro-Mechanical Renewable Energy Harvesting
In 1994, Pete Hammond of Robicon introduced a new concept in Medium Voltage Drive technology based on what would be called Cascaded H Bridge (CCH). Siemens would later introduce this as the GH180 product family. This technology would ultimately be copied worldwide as the most widely used and accepted MV Drive topology. 10years later in 2003, Rainer Marquardt of Siemens/ University of Munich would introduce a bridge based version of modular cells for High Voltage DC applications which would be called Modular Multilevel Converter (M2C). Siemens would later introduce this for Large Drive Applications as the GH150 product family. This technology is just beginning to penetrate the Large Drives arena. With the emergence of upstream natural gas production, GH150 is gaining much interest due to its unique features over traditional voltage source bridge and multi-level topologies for high power applications. With the expected boom in electro-mechanical renewable energy within the next 10-20 years (wind and tidal), many consider M2C is well aligned as a key component for bulk energy harvesting and control of power to the AC and upcoming DC grid of the future.
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Components: Recent History and Trend
Existing Tech & Cost Trend
<1960's
Copper and Electrical Steel
Paper Impreg Oil for Var Control
Mercury Arc & Mag Amps
1970's
Copper and Electrical Steel + Super Conducting Magnets
Small E Caps, Oil Insulated Foil/Film Capacitors
Junction Diodes and Thyristors (SCR's)
1980's
Copper and Electrical Steel + Ferrite, Advanced Alloys
1990's
Air Cooled Multilinking Transformers
Present
Copper and Electrical Steel + Ferrite + PFe, Advanced Alloys
Future
Higher Frequency core materials for mainly Isolation & filtering??
Film Capacitors for Energy Storage and Filtering, Large Bipolar Transistors and GTO's Ecaps for Energy and Filtering Segmented Film/Self Healing Capacitors
2nd Gen IGBT's (Optimized for 480vac)
Dry Film for Energy Storage 4th and 5th Generation IGBT's and Filtering and IGCT's (>1700v) High performance/cost dielectric Dry Film, Super Caps, and Batteries?
Wide Band Gap GaN & SIC
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Topologies:
Current Source (initially most popular with commutated SCR’s, then IGCT’s)
Voltage Source (initially with Bipolar transistors now IGBT’s and some IGCT’s)
Matrix (no ride through capability, special applications with IGBT’s)
Most efficient and dense method of storing energy is in an electric field which favors voltage source topology (energy storage proportional to capacitor dielectric permittivity instead of inversely proportional air gap permeability) Confidential © Siemens Industry, Inc. 2019 Page 4
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Optimum Voltage Source Topologies (Bridges): Matrix power conversion with Voltage Sources Initial ideas from Scientists at ORNL? Works well if Vin and Vout significantly different in operating frequency
Minimum Realization is VS Inverter
Alternative Bridge where arms become Voltage sources Rainer Marquardt (Siemens/U of Munich) first to realize 3ph Bridge version with half-bridges
Higher Frequency
GaN
Higher Frequency
Higher Voltage
SiC
Higher Voltage
4th, 5th gen silicon based IGBTâ&#x20AC;&#x2122;s in M2C Inverter
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Massed Produced Cost Comparison (IGBT vrs Power Magnetics)
> 1000:1 Difference in Cost/KVA !! Confidential Š Siemens Industry, Inc. 2019 Page 6
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Current Economics of IGBT’s and Dry Film Capacitors
Wide Band Gap Devices and Higher Voltage Film Capacitors are currently expensive and still limited in operating voltage Utilizing lower voltage ratings in multi-level topologies is a good alternative. As power device voltage ratings increase, voltage levels and cost performance of multilevel topologies utilizing them will also become more efficient and higher performing: •
1700vIGBT/1200v cap = 1pu cost
•
3300vIGBT/2500v cap = 3pu cost
•
6500vIGBT/4000v cap = 5pu cost
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Duality of Siemens GH180 and GH150 Drive Product
GH150: Twice the Switches but <50% of the Step Voltage of GH180
Siemens utilizes 2 multi-level topologies for Drives Applications GH180 (Cascaded H-Bridge), and GH150 (Modular Multilevel Converter) GH180 (Invented by Pete Hammond of Robicon in 1994) is now copied Worldwide GH150 (Invented by Rainer Marquardt of Siemens/University of Munich in 2002) was initially productized by Siemens for T&D as HVDC+ and now GH150
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Arc Flash Immunity and high availability of M2C
• • • •
One of the major features of GH150 (M2C) is its tolerance to faults occurring in the cell section. Unlike GH180 (CCH) topology, there is no electrical interaction between cells from transformer If a cell fails all the cell gates are inhibited so the cells look to the source as a 2pu voltage source A cell bypass feature can therefor be initialized immediately upon the cell’s detection of its own fault
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GH150 Cell as Variable Capacitor
The GH150 cell sections may be thought of as switched (variable) capacitance: •
The more switch is open (h=1) than closed (h=0) C(h) => C
•
The more switch is closed (h=0) than open (h=1) C(h) => ∞
Thus depending on operating frequency (current flowing in cell) and the cell modulated output voltage (function of h), AC voltage ripple voltage can be significant. At low frequency, common mode modulation is used to increase the degree of “closed time” effectively making the “terminal capacitance” look large without effecting the output voltage to the motor thus decreasing this ripple voltage at low frequency
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GH150 Dynamical Model
[1] A. Antonopoulos, L. Angquist, H-P Nee, “On Dynamics and Voltage Control of the Modular Multilevel Converter”, 2009 13th European Conference on Power Electronics and Applications, EPE ’09, IEEE, 2009, 3353-3362
-saN -saP æ æ Vbus × N × d ö k ö R k ç 1 - ×d ×d ×d ÷ ç ÷ 2× L 2× L L 2× L ÷ æç ick ö÷ ç ÷ æç ick+ 1 ö÷ ç saP × ioa × N ç ÷ ç ÷ saP × N k k ç vcp ÷ := k ×d ÷ × ç vcp k ÷ + ç ç ÷ 1 0 ×d k + 1 2× C ç ÷ ç ÷ C ÷ ç vcn ÷ ç ÷ ç vcn k+ 1 ÷ ç ÷ è k ø ç -saN k× ioa k× N ÷ è ø ç saN × N k ×d ÷ ç ÷ ç 0 1 ×d 2× C è ø C è ø
Since saP*Cp+saN*Cn=C, phase impedance is second order (with 2L). Potential operating modes: • Arm Current and Voltage controlled with Large L (GH150) • Static/Open Loop with Small L (Benshaw M2L 3000)
Cell appears as variable capacitors controlled by modulation index Resonances with arm inductance must be controlled or avoided
Modulation generates 2f current in arms •
Filtered and Controlled (GH150)
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24 Cell Proof of Concept (10MVA/4160vac Air Cooled)
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Unloaded Motor Waveforms (Vector Control)
0.5Hz
25Hz
50Hz
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Power Loss Ride Through on 600HP Loaded Dyno
60Hz
~30Hz
GH150 Inverter Control responds to loss of DC link voltage <1/2 cycle
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Full Power Operation (Motor-less Dyno)
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Full Power Operation (Input to Output Power Quality) THDi = 3.7%
THDi = 2.6%
SecKVA/HP = 0.81
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25-33MVA/13.8kv Air Cooled GH150 Current Siemens LDA MV Drives Business ~ 1.5GW/year Projected Siemens-Gamesa Renewable Business in 10yrs ~ 20GW/year
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• • • •
Marc F. Aiello BS/MSEE/PE 43yrs of Power Electronics and Electro-Optical System Design Multiple Patents Authored
• Current Position: Siemens LDA PLM-R&D Principal Engineer
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