Source: https://patents.justia.com/patent/20090102292
Timestamp: 2019-10-14 13:25:55
Document Index: 206034849

Matched Legal Cases: ['§15', 'art 15', '§15', 'art 2', '§2', '§2', '§2', '§1', 'art 167']

US Patent Application for Biological Effects of Magnetic Power Transfer Patent Application (Application #20090102292 issued April 23, 2009) - Justia Patents Search
Justia Patents Electromagnet Or Highly Inductive SystemsUS Patent Application for Biological Effects of Magnetic Power Transfer Patent Application (Application #20090102292)
Sep 18, 2008 - NIGEL POWER, LLC
Wireless power transfer based on limits from multiple different agencies.
Latest NIGEL POWER, LLC Patents:
It is desirable to transfer electrical energy from a source to a destination without the use of wires to guide the electromagnetic fields. A difficulty of previous attempts has delivered low efficiency together with an inadequate amount of delivered power.
The present application describes transfer of energy from a power source to a power destination via electromagnetic field coupling.
The FCC is the governing body for wireless communications in the USA. The applicable regulatory standard is FCC CFR Title 47. The FCC also specifies radiative emission limits for E-fields in §15.209. These limits are shown in Table I and the equivalent H-field limits are shown in Table 2.
TABLE I Frequency Field Strength Measurement Distance (MHz) (microvolts/meter) (meters)
0.009-0.490 2400/F(kHz) 300 0.490-1.705 24000/F(kHz) 30 1.705-30.0 30 30 30-88 100** 3 88-216 150** 3 216-960 200** 3 Above 960 500 3 **Except as provided in paragraph (g), fundamental emissions from intentional radiators operating under this Section shall not be located in the frequency bands 54-72 MHz, 76-88 MHz, 174-216 MHz or 470-806 MHz. However, operation within these frequency bands is permitted under other sections of this Part, e.g., Sections 15.231 and 15.241.
Error! No text of specified style in document. FCC Title 47 Part 15 H-filed radiated emission limits
Frequency (MHz) H-Field Strength (μA/m) Measurement Distance (m)
0.009-0.490 6.366/f(kHz) 300 0.490-1.705 63.66/f(kHz) 30 1.705-30.0 0.0796 30 13.553-13.567 42.04 30
In order to compare the EN 300330 regulatory limits to the FCC regulatory limits, the FCC limits can be extrapolated to measurements made at 10 m. The FCC states in §15.31 that for frequencies below 30 MHz, an extrapolation factor of 40 dB/decade should be used. The table 3 shows the extrapolated values for the two frequencies of interest. These levels can be used for comparison purposes.
TABLE 3 Frequency (MHz) H-Field Strength (dBμA/m) @10 m
0.130 32.8 13.56 51.6
Frequency range (MHz) H-field strength limit (Hf) dBμA/m at 10 m 0.009 ≦ f < 0.315 30 0.009 ≦ f < 0.03 72 or according to note 1 0.03 ≦ f < 0.05975 72 at 0.03 MHz descending 3 dB/oct 0.06025 ≦ f < 0.07 or according to note 1 0.119 ≦ f < 0.135 0.05975 ≦ f < 0.06025 42 0.07 ≦ f < 0.119 0.135 ≦ f < 0.140 0.140 ≦ f < 0.1485 37.7 0.1485 ≦ f < 30 −5 (see note 4) 0.315 ≦ f < 0.600 −5 3.155 ≦ f < 3.400 13.5 7.400 ≦ f < 8.800 9 10.2 ≦ f < 11.00 9 6.765 ≦ f ≦ 6.795 42 (see note 3) 13.553 ≦ f ≦ 13.567 26.957 ≦ f ≦ 27.283 13.553 ≦ f ≦ 13.567 60 (see notes 2 and 3) note 1: For the frequency ranges 9 to 70 kHz and 119 to 135 kHz, the following additional restrictions apply to limits above 42 dBμA/m. for loop coil antennas with an area ≧0.16 m2 table 4 applies directly; for loop coil antennas with an area between 0.05 m2 and 0.16 m2 table 4 applies with a correction factor. The limit is: table value + 10 × log (area/0.16 m2); for loop coil antennas with an area <0.05 m2 the limit is 10 dB below table 4. note 2: For RFID and EAS applications only. note 3: Spectrum mask limit, see annex G. note 4: For further information see annex H.
TABLE 5 Frequency Total H-field strength density at 10 m in a range H-field strength 10 kHz resolution bandwidth MHz at 10 m dBμA/m dBμA/m
0.1485 to 30.0 −5 (note 1) −15 (note 2) note 1: Without transmitter modulation. note 2: With transmitter modulation.
EN 50366: “Household and similar electrical appliances—Electromagnetic fields—Methods for evaluation and measurement” (CLC TC 61, produced in a joint group with CLC TC 106X)
EN 50392: “Generic standard to demonstrate the compliance of electronic and electrical apparatus with the basic restrictions related to human exposure to electromagnetic fields (0 Hz-300 GHz)”
Basic restrictions: “restrictions on exposure to time-varying electric, magnetic and electromagnetic fields that are based directly on established health effects” quantities used for measurement: current density, specific energy absorption rate and power density.
Reference levels: “provided for practical exposure assessment purposes to determine whether the basic restrictions are likely to be exceeded” quantities used for measurement: electric field strength, magnetic field strength, magnetic flux density, power density and currents flowing through the limbs.
Temperature rises of more than 1-2° C. can have adverse health effects such as heat exhaustion and heat stroke.
A 1° C. body temperature increase can result from approximately 30 minutes exposure to an EMF producing a whole-body SAR of 4 W/kg.
Pulsed (modulated) radiation tends to produce a higher adverse biological response compared to CW radiation. An example of this is the “microwave hearing” phenomenon where people with normal hearing can perceive pulse-modulated fields with frequencies between 200 MHz-6.5 GHz.
ICNIRP Basic Restrictions (up to 10 GHz) Table 4. Basic restrictions for time varying electric and magnetic fields for frequencies up to 10 GHz.a
Current density for Whole-body Localized SAR Exposure head and trunk average SAR (head and trunk) Localized SAR characteristics Frequency range (mA m−2) (rms) (W kg−1) (W kg−1) (limbs) (W kg−1) Occupational up to 1 Hz 40 — — — exposure 1-4 Hz 40/f — — — 4 Hz-1 kHz 10 — — — 1-100 kHz f/100 — — — 100 kHz-10 MHz f/100 0.4 10 20 10 MHz-10 GHz — 0.4 10 20 General public up to 1 Hz 8 — — — exposure 1-4 Hz 8/f — — — 4 Hz-1 kHz 2 — — — 1-100 kHz f/500 — — — 100 kHz-10 MHz f/500 0.08 2 4 10 MHz-10 GHz — 0.08 2 4 aNote: 1. f is the frequency in hertz. 2. Because of electrical inhomogeneity of the body, current densities should be averaged over a cross-section of 1 cm2 perpendicular to the current direction. 3. For frequencies up to 100 kHz, peak current density values can be obtained by multiplying the rms value by √2 (~1.414). For pulses of duration tp the equivalent frequency to apply in the basic restrictions should be calculated as f = 1/(2tp). 4. For frequencies up to 100 kHz and for pulsed magnetic fields, the maximum current density associated with the pulses can be calculated from the rise/fall times and the maximum rate of change of magnetic flux density. The induced current density can then be compared with the appropriate basic restriction. 5. All SAR values are to be averaged over any 6-min period. 6. Localized SAR averaging mass is any 10 g of contiguous tissue, the maximum SAR so obtained should be the value used for the estimation of exposure. 7. For pulses of duration tp the equivalent frequency to apply in the basic restrictions should be calculated as f = 1/(2tp). Additionally, for pulsed exposures in the frequency range 0.3 to 10 GHz and for localized exposure of the head in order to limit or avoid auditory effects caused by thermoelastic expansion, an additional basic restriction is recommended. This is that the SA should not exceed 10 mJ kg−1 for workers and 2 mJ kg−1 for the general public, averaged over 10 g tissue.
ICNIRP Basic Restrictions (10-300 GHz) Table 5. Basic restrictions for power density for frequencies between 10 and 300 GHz.a
Exposure characteristics Power density (W m−2) Occupational exposure 50 General public 10 aNote: 1. Power densities are to be averaged over any 20 cm2 of exposed area and any 68/f1.05 -min period (where f is in GHz) to compensate for progressively shorter penetration depth as the frequency increases. 2. Spatial maximum power densities, averaged over 1 cm2, should not exceed 20 times the values above.
ICNIRP Reference Levels - Occupational Exposure Table 6. Reference levels for occupational exposure to time-varying electric and magnetic fields (unperturbed rms values).a
E-field strength H-field strength B-field Equivalent plane wave Frequency range (V m−1) (A m−1) (μT) power density Seq (W m−2)
up to 1 Hz — 1.63 × 105 2 × 105 — 1-8 Hz 20,000 1.63 × 105/f2 2 × 105/f2 — 8-25 Hz 20,000 2 × 104/f 2.5 × 104/f — 0.025-0.82 kHz 500/f 20/f 25/f — 0.82-65 kHz 610 24.4 30.7 — 0.065-1 MHz 610 1.6/f 2.0/f — 1-10 MHz 610/f 1.6/f 2.0/f — 10-400 MHz 61 0.16 0.2 10 400-2,000 MHz 3f1/2 0.008f1/2 0.01f1/2 f/40 2-300 GHz 137 0.36 0.45 50 aNote: 1f as indicated in the frequency range column. 2Provided that basic restrictions are met and adverse indirect effects can be excluded, field strength values can be exceeded. 3For frequencies between 100 kHz and 10 GHz, Seq, E2, H2, and B2 are to be averaged over any 6-min period. 4For peak values at frequencies up to 100 kHz see Table 4, note 3. 5For peak values at frequencies exceeding 100 kHz see FIGS. 1 and 2. Between 100 kHz and 10 MHz, peak values for the field strengths are obtained by interpolation from the 1.5-fold peak at 100 kHz to the 32-fold peak at 10 MHz For frequencies exceeding 10 MHz it is suggested that the peak equivalent plane wave power density, as averaged over the pulse width, does not exceed 1,000 times the Seq restrictions, or that the field strength does not exceed 32 times the field strength exposure levels given in the table. 6For frequencies exceeding 10 GHz, Seq, E2, H2, and B2 are to be averaged over any 68/f1.05-min period (f in GHz) 7No E-field value is provided for frequencies <1 Hz, which are effectively static electric fields. Electric shock from low impedance sources is prevented by established electrical safety procedures for such equipment.
ICNIRP Reference Levels - General Public Exposure Table 7. Reference levels for general public exposure to time-varying electric and magnetic fields (unperturbed rms values).a
up to 1 Hz — 3.2 × 104 4 × 104 — 1-8 Hz 10,000 3.2 × 104/f2 4 × 104/f2 — 8-25 Hz 10,000 4,000/f 5,000/f — 0.025-0.8 kHz 250/f 4/f 5/f — 0.8-3 kHz 250/f 5 6.25 — 3-150 kHz 87 5 6.25 — 0.15-1 MHz 87 0.73/f 0.92/f — 1-10 MHz 87/f1/2 0.73/f 0.92/f — 10-400 MHz 28 0.073 0.092 2 400-2,000 MHz 1.375f1/2 0.0037f1/2 0.0046f1/2 f/200 2-300 GHz 61 0.16 0.20 10 aNote: 1f as indicated in the frequency range column. 2Provided that basic restrictions are met and adverse indirect effects can be excluded, field strength values can be exceeded. 3For frequencies between 100 kHz and 10 GHz, Seq, E2, H2, and B2 are to be averaged over any 6-min period. 4For peak values at frequencies up to 100 kHz see Table 4, note 3. 5For peak values at frequencies exceeding 100 kHz see FIGS. 1 and 2. Between 100 kHz and 10 MHz, peak values for the field strengths are obtained by interpolation from the 1.5-fold peak at 100 kHz to the 32-fold peak at 10 MHz For frequencies exceeding 10 MHz it is suggested that the peak equivalent plane wave power density, as averaged over the pulse width, does not exceed 1,000 times the Seq restrictions, or that the field strength does not exceed 32 times the field strength exposure levels given in the table. 6For frequencies exceeding 10 GHz, Seq, E2, H2, and B2 are to be averaged over any 68/f1.05-min period (f in GHz) 7No E-field value is provided for frequencies <1 Hz, which are effectively static electric fields, perception of surface electric charges will not occur at field strengths less than 25 kVm−1. Spark discharges causing stress or annoyance should be avoided.
In addition to regulatory limits, the FCC also specifies maximum exposure levels based on adverse health effects in CFR Title 47. These health limits are specified based on different categories of devices which are specified in Part 2 of Title 47 (§2.1091 and §2.1093):
In §2.1093, it is specified that for modular or desktop transmitters, the potential conditions of use of a device may not allow easy classification of that device as either mobile or portable. In such cases, applicants are responsible for determining minimum distances for compliance for the intended use and installation of the device based on evaluation of either SAR, field strength or power density, whichever is most appropriate.
The exposure limits are the same for mobile devices and general/fixed transmitters are given in §1.1310 and are shown in Table 2-8. The only difference is that the time-averaging procedures may not be used in determining field strength for mobile devices. This means that the averaging time in the table below does not apply to mobile devices.
FCC Exposure Limits LIMITS FOR MAXIMUM PERMISSIBLE EXPOSURE (MPE)
Electric field Magnetic field Power Averaging Frequency range strength strength density time (MHz) (V/m) (A/m) (mW/cm2) (minutes)
0.3-3.0 614 1.63 *(100) 6 3.0-30 1842/f 4.89/f *(900/f2) 6 30-300 61.4 0.163 1.0 6 300-1500 f/300 6 1500-100,000 5 6
0.3-1.34 614 1.63 *(100) 30 1.34-30 824/f 2.19/f *(180/f2) 30 30-300 27.5 0.073 0.2 30 300-1500 f/1500 30 1500-100,000 1.0 30 f = frequency in MHz *= Plane-wave equivalent power density NOTE 1 TO TABLE 1: Occupational/controlled limits apply in situations in which persons are exposed as a consequence of their employment provided those persons are fully aware of the potential for exposure and can exercise control over their exposure. Limits for occupational/controlled exposure also apply in situations when an individual is transient through a location where occupational/controlled limits apply provided he or she is made aware of the potential for exposure. NOTE 2 TO TABLE 1: General population/uncontrolled exposures apply in situations in which the general public may be exposed, or in which persons that are exposed as a consequence of their employment may not be fully aware of the potential for exposure or can not exercise control over their exposure.
Occupational/Controlled SAR: 0.4 W/kg as averaged exposure: apply when over the whole body persons are exposed as a and spatial peak SAR consequence of their not exceeding 8 W/kg as employment provided they averaged over any are aware of the exposure 1 g of tissue General population/Uncontrolled SAR: 0.08 W/kg as averaged exposure: apply over the whole body when the general and spatial peak SAR public is exposed not exceeding 1.6 W/kg as averaged over any 1 g of tissue
Persons in controlled Action levela environments Exposed tissue fe (Hz) Es (rms) (V/m) E0 (rms) (V/m)
Brain 20 5.89 × 10−3 1.77 × 10−2 Heart 167 0.943 0.943 Extremities 3350 2.10 2.10 Other tissues 3350 0.701 2.10 aWithin this frequency range the term “action level” is equivalent to the term “general public” in IEEE Std C95.6-2002.
Persons in controlled Action levela environments SARb (W/kg) SARc (W/kg)
Whole-body Whole-Body 0.08 0.4 exposure Average (WBA) Localized Localized 2c 10c exposure (peak spatial- average) Localized extremitiesd 4c 20c Exposure and pinnae aBR for the general public when an RF safety program is unavailable. bSAR is averaged over the appropriate averaging times as shown in Table 8 and Table 9. cAveraged over any 10 g of tissue (defined as a tissue volume in the shape of a cube).* dThe extremities are the arms and legs distal from the elbows and knees, respectively. *The volume of the cube is approximately 10 cm3.
MPE for exposure to head and torso for frequencies between 3 kHz and 5 MHz
Persons in controlled Frequency Action levela environments
range Brms Brms (kHz) (mT) Hrms (A/m) (mT) Hrms (A/m) 3.0-3.35 0.687/f 547/f 2.06/f 1640/f 3.35-5000 0.205 163 0.615 490 NOTE f is expressed in kHz. aWithin this frequency range the term “action level” is equivalent to the term “general public” in IEEE Std C95.6-2002.
range Brms Brms (kHz) (mT) Hrms (A/m) (mT) Hrms (A/m) 3.0-3.35 3.79/f 3016/f 3.79/f 3016/f 3.35-5000 1.13 900 1.13 900 NOTE f is expressed in kHz. aWithin this frequency range the term “action level” is equivalent to the term “general public” in IEEE Std C95.6-2002.
RMS electric RMS magnetic field RMS power density (S) Averaging time Frequency range field strength (E)a strength (H)a E-field, H-field |E|2, |H|2 or S (MHz) (V/m) (A/m) (W/m2) (min)
0.1-1.0 1842 16.3/fM (9000, 100 000/fM2)b 6 1.0-30 1842/fM 16.3/fM (9000/fM2, 100 000/fM2) 6 30-100 61.4 16.3/fM (10, 100 000/fM2) 6 100-300 61.4 0.163 10 6 300-3000 — — fM/30 6 3000-30 000 — — 100 19.63/fG1.079 30 000-300 000 — — 100 2.524/fG0.476 NOTE fM is the frequency in MHz, fG is the frequency in GHz. aFor exposures that are uniform over the dimensions of the body, such as certain far-field plane-wave exposures, the exposure field strengths and power densities are compared with the MPEs in the Table. For non-uniform exposures, the mean values of the exposure fields, as obtained by spatially averaging the squares of the field strengths or averaging the power densities over an area equivalent to the vertical cross section of the human body (projected area), or a smaller area depending on the frequency (see NOTES to Table 8 and Table 9 below), are compared with the MPEs in the Table. bThese plane-wave equivalent power density values are commonly used as a convenient comparison with MPEs at higher frequencies and are displayed on some instruments in use.
RMS electric RMS magnetic field RMS power density (S) Averaging timeb Frequency range field strength (E)a strength (H)a E-field, H-field |E|2, |H|2 or S (MHz) (V/m) (A/m) (W/m2) (min)
0.1-1.34 614 16.3/fM (1000, 100 000/fM2)c 6 6 1.34-3 823.8/fM 16.3/fM (1800/fM2, 100 000/fM2) fM2/0.3 6 3-30 823.8/fM 16.3/fM (1800/fM2, 100 000/fM2) 30 6 30-100 27.5 158.3/fM1.658 (2, 9 400 000/fM3.336) 30 0.0636fM1.337 100-400 27.5 0.0729 2 30 30
400-2000 — — fM/200 30 2000-5000 — — 10 30 5000-30 000 — — 10 150/fG 30 000-100 000 — — 10 25.24/fG0.476 100 000-300 000 — — (90fG − 7000)/200 5048/[(9fG − 700)fG0.476] NOTE fM is the frequency in MHz. fG is the frequency in GHz. aFor exposures that are uniform over the dimensions of the body, such as certain far-field plane-wave exposures, the exposure field strengths and power densities are compared with the MPEs in the Table. For non-uniform exposures, the mean values of the exposure fields, as obtained by spatially averaging the squares of the field strengths or averaging the power densities over an area equivalent to the vertical cross section of the human body (projected area) or a smaller area depending on the frequency (see NOTES to Table 8 and Table 9 below), are compared with the MPEs in the Table. bThe left column is the averaging time for |E|2, the right column is the averaging time for |H|2. For frequencies greater than 400 MHz, the averaging time is for power density S cThese plane-wave equivalent power density values are commonly used as a convenient comparison with MPEs at higher frequencies and are displayed on some instruments in use.
Power Electric Magnetic Density (S)† Averaging Time Frequency Range (*) Field (E) Field (H) E field, H field (Tavg in min.) (MHz) (V/m) (A/m) (W/m2) (E.H.S)
0.003-0.1 614 163 (103, 107)** 6 0.1-3.0 614 16.3/f (103, 105/f2** 6 3-30 1842/f 16.3/f (9000/f2, 105/f2)** 6 30-100 61.4 16.3/f (10, 105/f2)** 6 100-300 61.4 0.163 10** 6 300-3000 f/30 6 3000-15000 100 6 15000-300000 100 616000/f1.2
Ministry of Internal Affairs and Communications (MIC), Japan has also set certain limits.
Exposure E-Field H-Field Category Frequency Strength (kV/m) Strength (A/m) Occupational 10 kHz-30 kHz 0.614 163 30 kHz-3 MHz 0.614 4.9/f 3 MHz-30 MHz 1.842/f 4.9/f General public 10 kHz-30 kHz 0.275 72.8 30 kHz-3 MHz 0.275 2.18/f 3 MHz-30 MHz 0.824/f 2.18/f
SAR Limit Condition (W/kg)
The SAR averaged over the whole body mass 0.4 The local SAR for head, neck and trunk, averaged 8 over any one gram (g) of tissue The SAR in the limbs, as averaged over 20 10 g of tissue
SAR Condition Limit (W/kg)
The SAR averaged over the whole body mass 0.08 The local SAR for head, neck and trunk, averaged 1.6 over any one gram (g) of tissue The SAR in the limbs, as averaged 4 over 10 g of tissue
2 3 1 Electric Field Magnetic Field 4 5 Frequency Strength: rms Strength: rms Power Density Averaging Time (MHz) (V/m) (A/m) (W/m2) (min) 0.003-1 600 4.9 6 1-10 600/f 4.9/f 6 10-30 60 4.9/f 6 30-300 60 0.163 10* 6 300-1 500 3.54f0.5 0.0094f0.5 f/30 6 1 500-15 000 137 0.364 60 6 15 000-150 000 137 0.364 60 616 000/f1.2 150 000-300 000 0.354f0.5 9.4 × 10−4f0.5 3.33 × 10−4f 616 000/f1.2 *Power density limit is applicable at frequencies greater than 100 MHz. Notes: 1. Frequency, f, is in MHz. 2. A power density of 10 W/m2 in equivalent to 1 mW/cm2. 3. A magnetic field strength of 1 A/m corresponds to 1.257 microtexla (μT) or 12.57 milligram (mG).
2 3 1 Electric Field Magnetic Field 4 5 Frequency Strength: rms Strength: rms Power Density Averaging Time (MHz) (V/m) (A/m) (W/m2) (min)
0.003-1 280 2.19 6 1-10 280/f 2.19/f 6 10-30 28 2.19/f 6 30-300 28 0.073 2* 6 300-1 500 1.565f0.5 0.0042f0.5 f/150 6 1 500-15 000 61.4 0.163 10 6 15 000-150 000 61.4 0.163 10 616 000/f1.2 150 000-300 000 0.158f0.5 4.21 × 10−4f0.5 6.67 × 10−5f 616 000/f1.2 *Power density limit is applicable at frequencies greater than 100 MHz. Notes: 1. Frequency, f, is in MHz. 2. A power density of 10 W/m2 in equivalent to 1 mW/cm2. 3. A magnetic field strength of 1 A/m corresponds to 1.257 microtexla (μT) or 12.57 milligram (mG).
For vicinity power transmission to small portable devices present frequency regulations for ‘short range devices’ may allow power transfer up to a few hundreds of mW over distances <0.5 m.
Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish˜more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art. For example, other sizes, materials and connections can be used. Other embodiments may use similar principles of the embodiments and are equally applicable to primarily electrostatic and/or electrodynamic field coupling as well. In general, an electric field can be used in place of the magnetic field, as the primary coupling mechanism. Also, other values and other standards can be considered in forming the right values for transmission and reception.
forming a wireless power transfer system which uses magnetically resonant elements, and which has values which are set to comply with standards set by organizations corresponding to more than one national standard.
2. A method as in claim 1, wherein said standards organizations include a USA regulatory agency, and at least one other regulatory agency.
a transmitter which creates a power field at a level that complies with a first level set by a first standards organization associated with a first country, and also with a second level set by a second standards organization associated with a second country different than the first country.
9. A system as in claim 8, wherein said transmitter is also compliant with a third standard set by a third standards organization set forth by a third country.
Publication number: 20090102292
Patent Grant number: 8614526
Applicant: NIGEL POWER, LLC (San Diego, CA)
Inventors: Nigel P. Cook (El Cajon, CA), Stephen Dominiak (Fribourg), Hanspeter Widmen (Wohlenschwill)
Application Number: 12/233,441