1. A system, comprising:
a power supply;
a phase detector coupled to the power supply, said phase detector having
a first phase detector output, said first phase detector output being synchronized to a zero crossing of a motor current; and
a second phase detector output; said second phase detector output being synchronized to a zero crossing of a line voltage of said power supply;
a rectifier; and
a digital microprocessor connected to the first and second phase detector outputs and the rectifier;
said digital microprocessor
sensing a first time at which a phase of the line voltage crosses zero;
sensing a second time at which a phase of the motor current crosses zero;
calculating a difference between the first and second times;
calculating a phase lag of the motor based on said difference; and
calculating a firing time of the rectifier based on said phase lag.
2. The system of claim 1, wherein the phase lag is calculated using the following equation:
\u03b3=(T1\u2212T2)*K
wherein \u03b3 is the phase lag in degrees,
T1 is the time current crosses zero,
T2 is the time voltage crosses zero, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds for the difference between T1 and T2 expressed in milliseconds.
3. The system of claim 2, wherein the firing time of the rectifier is calculated using the following equation:
y=A\u03b3\u2212B
wherein \u03b3 is the firing time, A is the gain, and B is an offset.
4. The system of claim 1, wherein a phase error signal associated with the phase lag is calculated using the following equation:
\u03bb=(\u03b8D\u2212\u03b8FB)*K
wherein \u03bb is the phase error signal,
\u03b8D is a desired phase angle in milliseconds,
\u03b8FB is the second time at which a phase of the motor current is crossing zero minus the first time at which a phase of the motor voltage is crossing zero in milliseconds, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds.
5. The system of claim 1, wherein the firing time of the rectifier is calculated using the following equation:
y=Ax\u2212B
wherein y is the firing time,
A is the gain,
B is an offset, and
x is a measured phase angle of the motor.
6. The system of claim 1, wherein the firing time varies with at least one of the phase lag and a load of the motor.
7. The system of claim 1, wherein the phase detector includes a first phase detector input coupled to a line voltage of the power supply and a second phase detector input coupled to a motor terminal voltage of the motor.
8. A system, comprising:
a power supply;
a phase detector coupled to said power supply, the phase detector having
a first phase detector input coupled to a first non-inverting input of a first operational amplifier via a second voltage divider and a second inverting input of a second operational amplifier via a third voltage divider,
a second phase detector input coupled to the first inverting input of the first operational amplifier via a first voltage divider, and
a phase detector output that includes an output of the first operational amplifier and an output of the second operational amplifier,
wherein the first amplifier output is synchronized to a zero crossing of the motor current and the second amplifier output is synchronized to a zero crossing of the line voltage; and
a digital microprocessor coupled between the phase detector output and a rectifier driver, wherein the digital microprocessor determines a phase lag of the current and voltage of the motor by calculating the time difference between a switching state of the first operational amplifier and a switching state of the second operational amplifier, and calculates, based on the determined phase lag, a firing time for the rectifier driver.
9. The system of claim 8, wherein the rectifier driver fires at least one thyristor coupled between the rectifier driver and the motor terminal voltage of the motor.
10. The system of claim 8, wherein the phase lag is calculated using the following equation:
\u03b3=(T1\u2212T2)*i K
wherein \u03b3 is the phase lag in degrees,
T1 is the time current crosses zero,
T2 is the time voltage crosses zero, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds for the difference between T1 and T2 expressed in milliseconds.
11. The system of claim 10, wherein the firing of the rectifier is calculated using the following equation:
y=A\u03b3\u2212B
wherein \u03b3 is a firing time, A is the gain, and B is an offset.
12. The system of claim 8, wherein the phase lag is calculated using the following equation:
\u03bb=(\u03b8D\u2212\u03b8FB)*K
wherein \u03bb is the phase lag,
\u03b8D is a desired phase angle in milliseconds,
\u03b8FB is the second time at which a phase of the motor current is crossing zero minus the first time at which a voltage phase of the motor is crossing zero in milliseconds, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds.
13. The system of claim 8, wherein the firing of the rectifier is calculated using the following equation:
y=Ax\u2212B
wherein y is a firing time associated with the firing of the rectifier, A is the gain, B is an offset, and x is a measured phase angle of the motor.
14. A method for control of a motor, comprising the steps of:
using a digital microprocessor, sensing a first time at which a phase of the motor voltage is crossing zero;
using a digital microprocessor, sensing a second time at which a phase of the motor current is crossing zero;
using a digital microprocessor, determining the difference in time between the first and second times;
using a digital microprocessor, using the difference in time to calculate a phase lag of the motor; and
using a digital microprocessor, using the phase lag to calculate a firing time of a rectifier.
15. The method of claim 14, further comprising starting a timer in the digital microprocessor upon sensing a first time at which a phase of the motor voltage is crossing zero volts.
16. The method of claim 14, further comprising the step of calculating the phase lag using the following equation:
\u03b3=(T1\u2212T2)*K
wherein \u03b3 is the phase lag in degrees,
T1 is the time current crosses zero,
T2 is the time voltage crosses zero, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds for the difference between T1 and T2 expressed in milliseconds.
17. The method of claim 16, further comprising the step of calculating the firing time of the rectifier using the following equation:
y=A\u03b3\u2212B
wherein \u03b3 is the firing time, A is the gain, and B is an offset.
18. The method of claim 14, further comprising the step of varying the firing time with at least one of the phase lag and a load of the motor.
19. The method of claim 14, wherein the firing time of the rectifier is calculated using the following equation:
y=Ax\u2212B
wherein y is the firing time associated with the firing of the rectifier, A is the gain, B is an offset, and x is a measured phase angle of the motor.
20. The method of claim 14, further comprising the step of calculating a phase lag error associated with the phase lag using the following equation:
\u03bb=(\u03b8D\u2212\u03b8FB)*K
wherein \u03bb is the phase lag,
\u03b8D is a desired phase angle in milliseconds,
\u03b8FB is the second time at which a phase of the motor current is crossing zero minus the first time at which a phase of the motor voltage is crossing zero in milliseconds, and
K is 360 degrees divided by the time of one voltage cycle in milliseconds.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An electrode made of a multilayer material, the multilayer material comprising:
a solid support; and
at least two superposed solid layers which both contain particles of an electrochemically active material and a binder, the first solid layer adhering to the solid support and the second solid layer adhering directly to the first solid layer;
and wherein:
the multilayer material has at least one of the following three properties:
(1) the first solid layer has a thickness, measured using a scanning electron microscope method, constant to at least 95%,
(2) the second solid layer has a thickness, measured using a scanning electron microscope method, constant to at least 95%, and
(3) an average depth of penetration of the second solid layer into the first solid layer is less than 10% of the thickness of the first solid layer; and
wherein the binder present in the first solid layer is of a different nature from the binder present in the second solid layer, and
wherein, at 25\xb0 C:
the binder present in the first layer is a natural rubber or an artificial rubber that is soluble in water with a concentration of greater than 1 gliter and the binder present in the second solid layer is of a PVDF or PTFE type and is soluble in water with a concentration of less than 1 gliter; and
the PVDF or PTFE type binder present in the second layer is soluble in a solvent different from water with a concentration of greater than 1 gliter, and the natural rubber or an artificial rubber binder present in the first solid layer is soluble in the said solvent different from water with a concentration of less than 1 gliter wherein the electrochemically active material of one of the layers is selected from the group consisting of LiFePO4, carbon-coated LiFePO4, FePO4, carbon-coated FePO4, and mixtures thereof; and
the electrochemically active material of the other layer is selected from the group consisting of LiCoO2, LiMn2O4, LiMn13Co13Ni13O2, LiNixCoyAlzO2 (0<x, y, z<1), and mixtures thereof.
2. The electrode as claimed in claim 1, in which the binder present in each solid layer represents between 2% and 55% of the weight of each solid layer.
3. The electrode as claimed in claim 1, in which the first solid layer contains a thickener representing between 5 and 30% of the weight of the solid layer in which it is present.
4. The electrode as claimed in claim 1, which includes a third layer of a solid material of Li3PO4 adhering to the second solid layer.
5. The electrode as claimed in claim 1, in which, the solid support is made of copper, expanded copper, aluminum or nickel, the multilayer material being an anode.
6. The electrode as claimed in claim 1, in which, the solid support is made of aluminum, carbon-coated aluminum, expanded aluminum, expanded carbon-coated aluminum, titanium or platinum, the multilayer material being a cathode.
7. The electrode as claimed in claim 1, further comprising an electronically conductive material of carbon, graphite, carbon fiber, or a mixture of at least two thereof.
8. The electrode as claimed in claim 1, in which at least one of the electrochemically active materials is coated with a layer of a basic material.
9. A process for preparing electrode as claimed in claim 1, said process comprising the steps of:
a) coating, on a solid support, a mixture comprising particles of a first electrochemically active material, a binder for this first electrochemically active material and a solvent in which the binder can be dissolved at a concentration higher than 1 gliter;
b) evaporating the solvent still present in the coating to form a first solid layer;
c) coating, directly on the first solid layer, a mixture comprising particles of a second electrochemically active material, a binder for the second electrochemically active material and a solvent in which the binder can be dissolved at a concentration higher than 1 gliter; and
d) evaporating the solvent present in the second coating to form a second solid layer,
wherein the binder in the first layer is a natural rubber or an artificial rubber, and the binder in the second layer is PVDF or PTFE,
wherein the binder of the first layer cannot be dissolved in the solvent of the second at a concentration higher than 1 gliter, and the binder of the second layer cannot be dissolved in the solvent of the first layer at a concentration higher than 1 gliter.
10. An electrochemical generator comprising at least one anode, at least one cathode and at least one electrolyte, said generator having at least one electrode according to claim 1.
11. The electrochemical generator as claimed in claim 10, in which said at least one electrode forms said at least one cathode, and wherein:
the solid support is made of aluminum, carbon-coated aluminum, expanded aluminum, expanded carbon-coated aluminum, titanium or platinum.
12. The electrode as claimed in claim 1, wherein the binder in the first layer is selected from the group consisting of SBR (Styrene Butadiene Rubber), NBR (butadieneacrylonitrile rubber), HNBR (hydrogenated NBR), and CHR (epichlorohydrin rubber).