• Kanagawa Institute of Technology

Itako Lab.

  • At Itako Lab. we are engaged in research on new controls for new energy systems—primarily solar photovoltaic
    and fuel cell power generation systems.
    We also perform electronic analysis of the tone of classical guitars and other musical instruments.


  • Kazutaka Itako
  • Professor,Dr.Eng.
  • Fields of specialization
  •  • Power Electronics Control
  •  • Musical acoustic engineering

  •    Visiting scientist, Technical University of Braunschuweig (Germany)

Academic society affiliations
  • The Institute of Electrical Engineers of Japan
  • The Institute of Electrical Installation Engineers of Japan
  • Japan Solar Energy Society
  • Society of Instrument and Control Engineers
  • Society of Advanced Science
  • Acoustical Society of Japan
  • IEEE
  •  Memberships

  • FY2014: 20th ICEE Best Paper Award
  • FY2013: 61st Electrical Science and Engineering Promotion Award (formerly OHM Technology Award),
      from The Promotion Foundation for Electrical Science and Engineering
  • FY2010: 21st Paper Encouragement Award, from The Institute of Electrical Installation Engineers of Japan
  •   Among many others

Major articles(Journal)

Relating to new energy
  •   “Proposal for Active PV Array to Improve System Efficiency During Partial Shading”
       IEEE ACCESS,Vol.9,pp.143426~143433(2021)

      “Monitoring and Suppression of Typical Hot-Spot Phenomenon Resulting from Low-Resistance Defects in PV string”,
       IEEE Journal of Photovoltaics,Vol.8,Issue:6,pp.1809~1817(2018)

Musical acoustics
  •   “Investigation of a new evaluation method (Consonant interval factor) based on music theory for guitar timbre”
      Journal of Advanced Science,Vol.34, 34108-1-34108-7(2022)

  •   “Investigation of a New evaluation method (Octave factor) for Guitar tones using FFT analysis”
      Journal of Advanced Science, Vol. 33, 33101-1~33101-5(2021)

Patents awarded
  • Japan: 8 patents in solar photovoltaic and fuel cell power generation
  • America: 2 patents in solar photovoltaic power generation
  • India: 1 patent in solar photovoltaic and fuel cell power generation
  • China: 1 patent in solar photovoltaic power generation
  •   Numerous patents pending

External funding

Public funds
  •    Grants-in-Aid for Scientific Research(JSPS), Grants from Kanagawa Prefecture, Japan Science and Technology Agency (JST),
       and other entities

Private enterprise
  • Extensive research performed jointly with or commissioned by large, medium-size, and small enterprises,
     and under research grants
  • Domestic and overseas consulting

Public service record
  • Member, Challenges Research Evaluation Section Committee, Executive Council,
     Kanagawa Institute of Industrial Science and Technology
  • Visiting scientist, Kanagawa Institute of Industrial Science and Technology

Main lectures
  • “High-efficiency control methods for solar photovoltaic and fuel cell power generation systems“
      Era Reform Council, July 3, 2018 (First Members’ Office Building of the House of Representatives)
  • “Research on maximum efficiency point detection (MEPD) of fuel cells”
      10th Energy Creation, Collection, and Conservation Forum, KANAGAWA Industry Accompanied
      by Environment network Sagamihara Incubation Center Ltd. (SIC), March 8, 2016 (Kanagawa)
  • “Introduction to power conditioner for solar photovoltaic system—Achievement of high-efficiency solar photovoltaic system”
      Japan Research Institute for New Systems of Society, July 21, 2014 (Tokyo)
  • “Development of high-efficiency power conditioner for grid-connected solar photovoltaic system” (lecture)
      JST recommended seeds, New Technology Presentation Meeting
      Japan Science and Technology Agency sponsorship, March 4, 2013 (Tokyo)
  • “Energy creation and solar photovoltaic power generation” (Keynote lecture) KSP, Inc., February 3, 2012 (Yokohama)
  • “New MPPT control for solar photovoltaic systems”
      The Institute of Electrical Engineers of Japan sponsorship, December 5, 2011 (Keio University)
  •   Among many others

Research content

Research on New MPPT Control in Solar Photovoltaic Power Generation
  • The operating point of a solar cell varies with the insolation intensity, temperature, load,
    and other conditions, and control that enables operation at the most efficient point,
    known as MPPT control, is therefore necessary.
    In our laboratory, we perform research on a new MPPT control method
    to eliminate the shortcomings of existing MPPT control.
    If a shadow falls on a solar cell array of a solar photovoltaic system or its panels face
    in different directions, the output characteristics relative to the solar cell voltage exhibit multiple peaks.
    The MPPT algorithm of the existing P&O method poses the problem of low peak point selection
    and a consequent sharp reduction in output.

    To eliminate this problem, we have developed a new scanning technique
    that has enabled a new MPPT control method.
    This new method can quickly read the I-V characteristics of the solar cell for effective determination
    and tracking of the maximum power point.

    A power conditioning system (PCS) using this scanning principle in a household solar photovoltaic system is marketed
    by Hitachi Appliances, Inc. under the Hitachi brand.

    Dragonwake Technology Co. Ltd. has also begun to market an MPPT controller for a battery charger
    that applies this scanning technique.
    With this controller, the multiple peaks of output power caused by partial shadowing or differing directions of solar cells
    are scanned, the highest peak is detected and operation proceeds at that operating point,
    substantially increasing the power output over that obtained by the conventional P&O method.

Research on Diagnosis Method of Hot Spots in Solar Cells
  • A hot spot is one cause of solar cell module malfunction.
    It involves a defect in a cell that causes a high partial or entire cell temperature
    in the event of a prolonged cell shadowing, which may cause
    cell surface resin deformation or breakage and thus pose a risk of fire.

    In our laboratory, we have applied the physical principles involved
    in the related crystal defect (low-resistance defect) to develop
    a new self-reverse current (SRC) test method for simple diagnosis of hot spots
    by module.

    This method can be used to identify a defective panel before it is incorporated.
    It is simpler to perform than the existing method, which uses an infrared camera.
    The figure below shows defect detection in cells 21 and 23, on the monitor of the test instrument developed at our laboratory.

Research on System for Real-time Detection and Prevention of Hot Spots in Solar Photovoltaic Systems
  • In our laboratory, we have developed a new system for real-time detection and prevention of hot spots on panels.

    This system, which involves scanning by an internal power conditioning system (PCS),
    represents a new method for detecting solar cell abnormalities from periodically measured I-V characteristics.
    The system calculates the conductance of the low-resistance defect from string I-V characteristics
    to detect the occurrence of a hot spot and simultaneously prevent heat generation while obtaining maximum output
    by transferring the PCS operating point to a position where heat generation does not occur.

    In the figure below, the thermographs on the left and right show the images obtained with the conventionl system
    and the new system, respectively.
    As can be seen, a hot spot occurs and the temperature rises to 115°C with the conventional system,
    but the temperature remains at the usual 32°C with the new system.

Research on Active PV Arrays
  • To control the maximum power point tracking (MPPT)
    using power conditioning systems (PCSs),
    the algorithm known as the P&O method can usually be used,
    but if two or more peaks in the power output characteristic relative to
    the solar cell voltage occur in the event of partial shadowing,
    combined use, or differing directions of the panels,
    the lower peak may be selected with a consequent sharp decline
    in output.

    Inter-string mismatching may also occur
    if the optimum operating conditions differ between strings due to
    partial shadowing or other impediments, thus making it impossible to
    obtain operation at the maximum power point with MPPT control
    by PCS.

    To solve this problem, we propose an active PV array
    which connects a unit to each panel on the input side of the existing PCS in the emplaced PV system.

    This allows us to obtain that can perform aggregation of power, which is the sum of the maximum power of all panels
    at the arbitrarily set voltage point of the array.
    With this system, it is possible to select with certainty the maximum power point despite partial shadowing or other impediments,
    and thereby sharply increase the power generation efficiency even with a PCS using a conventional P&O method.

Research on High-efficiency Control of Fuel Cells
  • A fuel cell is a power generation system that uses hydrogen as the energy source,
    with heat and water as the only waste products of the power generation.
    The hydrogen can be obtained, moreover, by electrolysis of water powered
    by solar cells.
    It is accordingly a clean method of power generation.

    In our laboratory, we have developed a maximum efficiency point detection (MEPD)
    method using the scanning technique that we developed for
    solar photovoltaic systems, and applied it to fuel cells to reduce
    hydrogen consumption and enable efficient operation of fuel cells.

Research on Power Electronics Control
  • In any electrical instrument, power control is obtained by semiconductor switching with
    power electronics control.
    For semiconductor switching, the voltage, current, or another parameter is read
    and feed back to cause generation of a PWM signal, generally using a microcomputer.

    In our laboratory, we are engaged in research on control technologies
    in a comprehensive range with various conversion circuits using microcomputers.

Research on Electronic Analysis of the Tone of Musical Instruments
  • Among classical guitars, for example, cheap instruments clearly
    differ in tone from traditional high-quality ones.

    In our laboratory, we perform electronic analysis of the tone
    of musical instruments, for effective use of cheap materials
    to produceinstruments that approach high-quality
    instruments in tone.

Transport access

  • 1030 Shimo-ogino Atsugi Kanagawa 243-0292 Japan


  • Kanagawa Institute of Technology, Itako Lab.
    Project research support section

    itakolab_kait@yahoo.co.jp(to Itako Lab.)