ENERGY EFFICIENCY IN MANUFACTURING MALTA

Department of Industrial Electrical Power Conversion Faculty of Engineering – University of Malta Energy Efficient Electric Motor Systems for the Manufacturing Industry Key Experts: Prof. Ing. C. Spiteri- Staines Co-Supervisors: Dr. Cedric Caruana Researcher: Mr. Peter Spiteri Industrial Partners : Playmobil Toly Products Andrews Feeds

Department of Industrial Electrical Power Conversion, University of Malta Introduction It is estimated that motor driven systems account for around 65% of the electricity consumed by the European industry. 1.5% improvement in the motors’ efficiency implies a reduction of 1% energy consumption in the European industry. The more efficient use of energy in the manufacturing industry has become a key factor for the industrial organisations to maintain a competitive edge.

Department of Industrial Electrical Power Conversion, University of Malta Aims of Project The objective is to facilitate the adoption of energy saving measures on electric motors by the Maltese industry. Carry out an extensive Data gathering exercise on Energy Usage and Patterns of Electrical Motor Systems in various local industries The project will deliver a tool which will allow organisations to evaluate alternative options of reducing their electric motors’ energy consumption. Benefits derived from project: –Knowledge on energy savings mechanisms for manufacturing industry –Additional benefits: reduced heat dissipation and lower maintenance costs.

Department of Industrial Electrical Power Conversion, University of Malta Increasing Efficiency in Motor Systems

Department of Industrial Electrical Power Conversion, University of Malta IE Motor Efficiency Standards The new standard introduces also IE4 (super premium efficiency), a future level above IE3, but IE4 products are not yet commercially available. 6 50Hz Motors

Department of Industrial Electrical Power Conversion, University of Malta Comparing Old & New Efficiency Standards Old Standards EFF1, EFF2 and EFF 3 New Standards : IE1 – Standard Efficiency (comparable to EFF2) IE2 – High Efficiency (comparable to EFF1) IE3 – Premium Efficiency

Department of Industrial Electrical Power Conversion, University of Malta How to minimise losses in Motor Driven Systems Replace Old Motor by HEM Use a Motor Energy Controller (only certain applications as we will see) Use a Variable Speed Drive (inverter) Study carried out by South Carolina Energy Office

Department of Industrial Electrical Power Conversion, University of Malta Check Load Profile of Machine Low Load means Low Efficiency and Low Power Factor Try to use a motor close to its rated power, do not overrate without scope!!!

Department of Industrial Electrical Power Conversion, University of Malta Load Profile of IMMs (w/o accumulator) 10

Department of Industrial Electrical Power Conversion, University of Malta Motor Systems Selected for Study Motor Systems Selected for Study IMM type Motor rating (kW) No. of hrs / yr (ave.) Accum.Colour Clamping Force (kN) K 60/S 3C304002Yes3-colour600 K 60/S 2C224247Yes2-colour600 K /S 2C 30N/AYes2-colour*600 BA No1-colour1500 BA No1-colour2000 Motor application Motor rating (kW) Quantity Mixer301 Conveyer431 Elevator7.511 Cuber55, 75, 908 The study consisted of: Injection Mould Machines and other motor driven systems such as elevators, conveyers, mixers and cubers, at partner premises.

Department of Industrial Electrical Power Conversion, University of Malta Load profile of IMM with Accumulator Base load ≈ 7.5kW (25%) Motor rating = 30kW Average load = 12.2kW (40.7%) Max load = 62.7kW (209%) K 60/S 3C Typical load profile of K 60/S 3C (with accumulator)

Department of Industrial Electrical Power Conversion, University of Malta Load profile of IMM w/o Accumulator Base load ≈ 3.2kW (14.5%) Motor rating = 22kW Average load = 8.1kW (36.8%) BA 1500 Typical load profile of BA 1500 (no accumulator) Max load = 43.9kW (199.5%)

Department of Industrial Electrical Power Conversion, University of Malta Analysis of Injection Mould Machines (Summary) Type Motor rating (kW) Base load (kW) Average load (kW) Max load (kW) Cons. (kWh / hour) Average p.f. K 60/S 3C (25%)12.4 (41.3%)74.2 (247.3%) K 60/S 2C (15.9%)8.1 (36.8%)31.9 (145.0%) K /S 2C 307 (23.3%)10.0 (33.3%)70.3 (234.3%) BA (14.5%)9.9 (45.0%)43.9 (199.5%) ) BA (15.7%)15.9 (53.0%)62.8 (209.3%) ) 14 Table showing the motor ratings, typical base loads, average loads, consumption, power factor and peak maximum of all the types. The values in the brackets are the percentages of the motor ratings ( 1) The IMM motor was power factor corrected )

Department of Industrial Electrical Power Conversion, University of Malta Analysis – K 60/S 3C Motor rating = 30kW 26.3% Mainly due to base load Electric’s motor percentage time vs the power level

Department of Industrial Electrical Power Conversion, University of Malta Analysis – K 60/S 3C 16 Motor rating = 30kW 46.1% Mainly due to base load Energy consumption vs the power level

Department of Industrial Electrical Power Conversion, University of Malta Analysis – BA 1500 Motor rating = 22kW 14.7% 63.7% Mainly due to base load Mainly due to holding pressure Electric’s motor percentage time vs the power level

Department of Industrial Electrical Power Conversion, University of Malta Analysis – BA 1500 Motor rating = 22kW 22% 41% Mainly due to base load Mainly due to holding pressure Energy consumption vs the power level

Department of Industrial Electrical Power Conversion, University of Malta Analysis – Main Mixer Motor at low load = 4.2kW (14%) Motor rating= 30kW Motor on load = 18.5kW (61.7%) Average load = 14.2kW (47.3%) Motor rating = 30kW at low load at high load 13.4% 60.2% at low load at high load 68.1% 8.0% Motor rating = 30kW

Department of Industrial Electrical Power Conversion, University of Malta Analysis – Conveyer Motor rating = 4kW Motor at no load ≈ 1.2kW (30%) Average load = 1.6kW (40%) low load 67.5% high load 32.5% low load 14.1 kWh high load 15.8 kWh

Department of Industrial Electrical Power Conversion, University of Malta Simulated and Experimental determination of Energy Savings Measurements have shown that in many cases, motors are operated for long duration at low load, thus inefficiently. Solutions: –Replace motor with HEM –Lower voltage during low load –Use MEC (effectively lowers voltage) –Use VVVF drive (not always possible) Tests shall be simulated & tested on an experimental set-up

Department of Industrial Electrical Power Conversion, University of Malta Simulation of Low Load with decrease in Voltage Analysis of Motor with constant Low Load: Simulation results with supply voltage reduced from 100% to 45% with a load factor of 25%. The motor rating is 37kW The efficiency is increased by 16.8%. The input power is decreased from 14.2kW to 11.1kW yielding energy savings of 21.8%. If the supply voltage is reduced ONLY during the base load operation, for IMM, the overall potential energy savings become 9.4%. % VoltageP in (kW)P out (kW)Eff (%)rpm rpm change Power factor

Department of Industrial Electrical Power Conversion, University of Malta Analysis of Lower Voltage Concept to Motor Readings MachineLoad factor (%) Base load only energy savings (%) Overall potential energy savings (%) K 60/S 3C K 60/S 2C K /S 2C BA BA MachineLoad factor (%) Low load only energy savings (%) Overall potential energy savings (%) Elevator Cuber Main mixer Conveyer

Department of Industrial Electrical Power Conversion, University of Malta Transient Response of MEC (Lab Rig) One of the main challenges is due to the relatively short times at which the motor operates at the base loads. –occurences of operation at base load are a lot however the timings are very critical. –MEC needs to react rapidly to regulate the supply voltage on the motor according to operation. MEC switched ON

Department of Industrial Electrical Power Conversion, University of Malta Further Work Emulation of Actual Load Profiles on Laboratory Test Rig. Verification of Energy Saving Mechanisms (HEM and MEC) on industrial premises Development of Motor Energy Saving Tool (MEST). –Software tool to guide organisations’ personnel (possibly non-technical) to improve efficiency in motor driven systems

Department of Industrial Electrical Power Conversion Faculty of Engineering – University of Malta Increasing Energy Efficiency during Reliability Testing of Equipment through Grid‐connected Load Units Key Experts: Dr. Maurice Apap Co-Supervisors: Prof. C. Spiteri Staines & Prof. J. Cilia Researchers: Mr. Francarl Galea Industrial Partners : Abertax Delta (Malta)

Department of Industrial Electrical Power Conversion, University of Malta Introduction Manufacturing Cycle Testing of each product must take place before reaching the market and the customer. Testing of certain products leads to high energy consumption. power supply full load burn-in test usually last for a minimum of 24 hours. (can exceed 400,000kWhr yearly.) batteries testing is carried out by cycling.

Department of Industrial Electrical Power Conversion, University of Malta Aims This project is targeted at increasing the efficiency during testing of manufactured electrical equipment: namely, DC Power Supplies and Battery Banks. Currently Electrical Energy consumed during testing is ‘wasted’ (as heat) in Active Loads. The aim of this project is to REDIRECT the Electrical Energy used during testing back to the Electrical Supply. 70% energy saving is predicted.

Department of Industrial Electrical Power Conversion, University of Malta System Description The Regenerative Active Load shall be made up of: DC-DC Converter Design. Grid Connected Inverter. The Regenerative Active Load was designed to operate over a wide input range of Voltages and Currents to support different types of DC Supply Equipment. Input Voltage30 – 300V Max Input Current25A Max Input Power1000W Output Voltage200V Max Output Current<5A Max Output Power<1000W Switching Freq.75kHz DC/DC Converter Specs

Department of Industrial Electrical Power Conversion, University of Malta DC/DC Converter Topology Out of many topologies studied, the isolated Ćuk topology was selected on the following criteria: Low input and output current ripples can ‘step up’ & ‘step down’ the input voltage Bipolar current flowing into the transformer (full utilisation) Saturation of the transformer is not possible Total isolation of input from output Transformer’s turns’ ratio can be used to set duty cycle range.

Department of Industrial Electrical Power Conversion, University of Malta Simulation of Converter V in =30VV in =300V

Department of Industrial Electrical Power Conversion, University of Malta Converter Components Design Magnetic Components Gate Drivers Power Semiconductors Analogue Control Circuit Snubbers Protection Circuit

Department of Industrial Electrical Power Conversion, University of Malta System Testing The built DC-DC converter was tested and the following issues were checked: Components were monitored for overheating Monitoring of voltage overshoots during switching transients (to verify operation within the maximum device ratings). Verification that current and voltage ripples were within design limits Operation over expected RANGE of output voltage and output current for the designed input voltage range Efficiency was measured for various operating conditions

Department of Industrial Electrical Power Conversion, University of Malta Regeneration of Electrical Energy For REDIRECTION of testing energy to the Mains supply: The DC-DC converter was interfaced to a standard off-the- shelf Grid-connected Inverter The DUT was tested for various operating points (input voltage and power) and the energy used was transferred via the DC-DC, into the grid-connected inverter, and back to the mains supply.

Department of Industrial Electrical Power Conversion, University of Malta Results - Measurement of Efficiency 35

Department of Industrial Electrical Power Conversion, University of Malta Results – Burn-In Test (800W, 200V Power Supply) Experimental tests show that 78% less energy was used to burn-in test SM400AR-4 (4.9kWh instead of 20kWh in 24 hours). 36 The overall Active Load system operates at an efficiency of 85%. Efficiencies of the DC- DC converter & grid- inverter were 95% and 89% respectively.

Department of Industrial Electrical Power Conversion, University of Malta Conclusions The results show that: –The Regenerative Active Load unit has the potential of saving electrical energy used in testing in Industry. –The overall efficiency of the Regenerative Active Load unit ranged from 77% to 85% when operating at full power. Device under test (DC Supplies) Power consumed with resistive bank Power consumed with Regenerative Active Load Unit Percentage Savings SM400-AR-4 (200V) 842W195W 76.8% SM70-AR-24 (70V) 928W245W 73.6% SM70-AR-24 (35V) 964W342W 64.5% ER W127W 65.4% Es W64W 63.2% Device under test (Battery Banks) Power consumed with resistive bank at C20 Power consumed with Regenerative Active Load Unit (estimate) Percentage Savings (estimate) 72V 100Ah C20 Battery Bank 360W68W 81%

Department of Industrial Electrical Power Conversion, University of Malta Further Work Input Voltage30V – 600V Max Input Current50A Max Input Power2000W Output Voltage400V To operate system with a wider range of electrical DC supply equipment, modular converters will have to be employed. This shall require that modular converters be connected in parallel or in series depending on the input voltage requirements. Simulation showed successful parallel and series operation. A method of interleaved switching will be applied to obtain a further reduction in the current ripple.

Department of Industrial Electrical Power Conversion, University of Malta Thank you for your attention MALTA