U.S. patent application number 09/777699 was filed with the patent office on 2001-09-27 for electric power equipment for electric vehicle.
Invention is credited to Egami, Tsuneyuki.
Application Number | 20010024102 09/777699 |
Document ID | / |
Family ID | 18557438 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010024102 |
Kind Code |
A1 |
Egami, Tsuneyuki |
September 27, 2001 |
Electric Power equipment for electric vehicle
Abstract
An electric power equipment for a hybrid electric vehicle
includes a main battery, an auxiliary battery, an inverter for
supplying a prescribed lower-frequency AC power from the main
battery to a motor-generator and DC power to the main battery from
the rotary electric machine and an auxiliary battery charging
circuit. The auxiliary battery charging circuit includes a
frequency filter for passing only AC power of a prescribed higher
frequency that is too high for the motor-generator to be operated,
a rectifier and a controller for controlling the inverter.
Inventors: |
Egami, Tsuneyuki;
(Gamagori-city, JP) |
Correspondence
Address: |
Pillsbury Winthrop LLP
East Tower, Ninth Floor
1100 New York Avenue, N.W.
Washington
DC
20005-3918
US
|
Family ID: |
18557438 |
Appl. No.: |
09/777699 |
Filed: |
February 7, 2001 |
Current U.S.
Class: |
318/801 ;
903/903; 903/904 |
Current CPC
Class: |
Y02T 10/705 20130101;
Y02T 90/40 20130101; Y02T 90/34 20130101; Y10S 903/903 20130101;
Y02T 10/70 20130101; B60K 6/22 20130101; B60L 58/10 20190201; B60L
58/30 20190201; Y10S 903/904 20130101 |
Class at
Publication: |
318/801 |
International
Class: |
H02P 005/34; H02P
007/42 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2000 |
JP |
2000 - 32885 |
Claims
What is claimed is:
1. An electric power equipment for supplying a rotary electric
machine with higher voltage power and electric loads with lower
voltage power, said electric power equipment comprising: a main
battery; an auxiliary battery; an inverter, connected between said
rotary electric machine and said main battery, for supplying said
rotary electric machine a prescribed lower-frequency AC power from
said main battery and said main battery with DC power from said
rotary electric machine; and a main-to-auxiliary battery-power
supply circuit, connected between said rotary electric machine and
said auxiliary battery, for supplying electric power to said
auxiliary battery when the terminal voltage of said auxiliary
battery is lower than a reference voltage; wherein said
main-to-auxiliary power supply circuit comprises: a frequency
filter, connected to said rotary electric machine, for passing only
AC power of a prescribed higher frequency that is too high for said
rotary electric machine to be operated, a rectifier connected
between said frequency filter and said auxiliary DC power source
and a controller for controlling said inverter to provide said AC
power of said higher frequency when the terminal voltage of said
auxiliary battery is lower than a reference voltage.
2. The electric power equipment as claimed in claim 1, wherein said
controller provides inverter control signals to control said
inverter to provide both said lower frequency AC power and said
higher frequency AC power when the terminal voltage of said
auxiliary battery is lower than a reference voltage.
3. The electric power equipment as claimed in claim 1, wherein said
frequency filter comprises a series circuit of a coil and a
capacitor having a resonance frequency.
4. The electric power equipment as claimed in claim 1, wherein said
main-to auxiliary battery power supply circuit further comprises a
voltage transformer having a primary coil connected to said rotary
electric machine and a secondary coil connected to said rectifier,
and said frequency filter comprises a series circuit of said
primary coil and a capacitor.
5. An electric power equipment for supplying a rotary electric
machine with higher voltage power and electric loads with lower
voltage power, said electric power equipment comprising: a main
battery; an auxiliary battery; an inverter, connected between said
rotary electric machine and said main battery, for supplying said
rotary electric machine a prescribed lower-frequency AC power from
said main battery and said main battery with DC power from said
rotary electric machine; and means for charging said auxiliary
battery when the terminal voltage of said auxiliary battery is
lower than a reference voltage, wherein said means including a
frequency filter for passing only AC power of a prescribed
frequency that is too high for said rotary electric machine to be
operated, a rectifier connected between said frequency filter and
said auxiliary DC power source and a controller for controlling
said inverter to provide said AC power of a prescribed frequency
when the terminal voltage of said auxiliary battery is lower than a
reference voltage.
6. An electric power equipment for supplying a rotary electric
machine with higher voltage AC power and electric loads with lower
DC voltage power, said electric power equipment comprising: a main
battery; an auxiliary battery; an inverter for converting DC power
of said main battery to said higher voltage AC power of a first
prescribed frequency from said main battery and converting output
AC power of said rotary electric machine to DC power to charge said
main battery; and means including a frequency filter for passing
only AC power of a second prescribed frequency that is much higher
than said first prescribed frequency, a rectifier connected between
said frequency filter and said auxiliary DC power source and a
controller for controlling said inverter to provide said AC power
of said second prescribed frequency when the terminal voltage of
said auxiliary battery is lower than a reference voltage. from said
main battery and converting output AC power of said rotary electric
machine to DC power to charge said main battery; and means
including a frequency filter for passing only AC power of a second
prescribed frequency that is much higher than said first prescribed
frequency, a rectifier connected between said frequency filter and
said auxiliary DC power source and a controller for controlling
said inverter to provide said AC power of said second prescribed
frequency when the terminal voltage of said auxiliary battery is
lower than a reference voltage.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is based on and claims priority from
Japanese Patent Application 2000-32885 filed Feb. 10, 2000, the
contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an electric power equipment
and, particularly, a dual voltage system for an electric vehicle
that has a high voltage main DC power source and a low voltage
auxiliary DC power source.
[0004] 2. Description of the Related Art
[0005] A dual voltage system of a vehicle that includes a main DC
power source and an auxiliary power source is already known. The
main power source, such as Ni-MH battery, fuel cell or a lead acid
battery is used for driving a hybrid electric vehicle, an electric
vehicle or the like. In order to reduce transmission loss of the
electric power, the voltage of the main DC power source is
generally set as high as possible. On the other hand, the auxiliary
power source is necessary to supply low voltage power to various
vehicle loads.
[0006] A hybrid electric vehicle is equipped with a DC-DC converter
that supplies electric power from the main power source to the
auxiliary power source, which has much smaller capacity than the
main power source, regularly or temporarily in an emergency.
However, such a DC-DC converter complicates a control system of the
dual voltage system.
SUMMARY OF THE INVENTION
[0007] Therefore, a main object of the invention is to provide an
improved and inexpensive dual voltage system that has no DC-DC
converter.
[0008] According to a feature of the invention, an electric power
equipment includes an inverter for supplying a rotary electric
machine a prescribed lower-frequency AC power from a main battery
and for charging the main battery by the rotary electric machine
and a main-to-auxiliary battery-power supply circuit for supplying
electric power to an auxiliary battery when the terminal voltage of
the auxiliary battery is lower than a reference voltage. The
main-to-auxiliary power supply circuit includes a frequency filter
for passing only AC power of a prescribed higher frequency that is
too high for the rotary electric machine to be operated and a
rectifier for converting the AC power to DC power to be charged to
the auxiliary battery.
[0009] Therefore, a DC-DC converter is not necessary for charging
the auxiliary battery.
[0010] Preferably, a controller for the inverter provides both the
lower frequency AC power and higher frequency AC power when the
terminal voltage of the auxiliary battery is lower than a reference
voltage. The frequency filter preferably includes a series circuit
of a coil and a capacitor having a resonance frequency. The main-to
auxiliary battery power supply circuit may further include a
voltage transformer having a primary coil connected to the rotary
electric machine and a secondary coil connected to the
rectifier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other objects, features and characteristics of the present
invention as well as the functions of related parts of the present
invention will become clear from a study of the following detailed
description, the appended claims and the drawings. In the
drawings:
[0012] FIG. 1 is a circuit diagram of an electric power equipment
according to a first embodiment of the invention;
[0013] FIG. 2 is a block diagram of a controller of the electric
power equipment shown in FIG. 1;
[0014] FIG. 3 is a circuit diagram of an electric power equipment
according to a second embodiment of the invention;
[0015] FIG. 4 is a circuit diagram of an electric power equipment
according to a third embodiment of the invention; and
[0016] FIG. 5 is a circuit diagram of a filter-transformer unit of
the electric power equipment shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] An electric power equipment according to a first embodiment
of the invention is described with reference to FIGS. 1, 2 and
5.
[0018] The electric power equipment includes a three-phase
motor-generator 1, a resolver 2, a high voltage main battery 3, an
auxiliary battery 4 and a control circuit unit 5.
[0019] The motor generator 1 is a permanent magnet type synchronous
rotary machine. The motor-generator 1 is linked to an engine
directly or via transmission such as a belt or a gear unit to
supplement engine output torque and to generate AC power. The
resolver detects rotor position of the motor-generator 1. The
terminal voltage of the main battery 3 is 36 V, and the terminal
voltage of the auxiliary battery is 12 V.
[0020] The circuit unit 5 includes AC output terminals U, V and W,
resolver terminals M+, M-, S+, S-, C+ and C-, auxiliary battery
terminals Va+ and Va-, main battery terminals Vm+ and Vm- and
command input terminals Tin and Don. The terminal Tin receives a
torque command signal ST that control the motor-generator 1 from
the outside, and the terminal Don receives a battery-charge command
signal SC from the outside to control charging of the auxiliary
battery 4. When the command signal SC is in a high level H, the
auxiliary battery is charged. On the other hand, when the command
signal SC is in a low level L, the auxiliary battery is not
charged. The circuit unit 5 includes a three-phase inverter 50, a
smoothing capacitor 500, current sensors 513 and 514, a
frequency-filter-and-voltage-transformer unit (hereinafter referred
to as the FTU 520), a rectifier 530 and a controller 540.
[0021] The three-phase inverter 50 is a well-known circuit that
converts high voltage DC power of the main battery 3 into AC power.
The DC power is supplied respectively to a U-phase inverter, a
V-phase inverter and W-phase inverter. The V-phase inverter V is
comprised of series-connected low-side and high-side switching
elements 501 and 502, the U-phase inverter is comprised of
series-connected low-side and high-side switching elements 503 and
504, and the W-phase inverter is comprised of series-connected
low-side and high-side switching elements 505 and 506. Each of the
switching elements 501-506 has one of parallel diodes 507-512 that
is connected so that the polarity thereof is opposite to the
polarity of the switching element.
[0022] The smoothing capacitor 500 is connected in parallel to the
main battery 3 to absorb high frequency noises caused by the
three-phase inverter 50.
[0023] The FTU 520 is comprised of a delta circuit that is formed
of three series circuits of a primary coil and a capacitor and a
common secondary coil, as shown in FIG. 5. The ratio of
transformation of the FTU 520 is set so that the terminal voltage
of the secondary coil is suitable to charge the auxiliary battery
4. The FTU 520 insulates the main battery 3 and its circuit
portions from the auxiliary battery 4 and its circuit portions and
also conducts prescribed high frequency components of electric
power. The resonance frequency fs of the input terminals of the FTU
520 is set a value, for example 50-500 kHz, that is the middle of
the frequency band of the high frequency components to be
conducted. This resonance frequency fs is much higher than the
frequency, for example less than 10 kHz, of the three-phase voltage
signals Vu, Vv and Vw.
[0024] The rectifier 530 is comprised of a single-phase full-wave
bridge circuit, which rectifies the high frequency components of
the electric power supplied from the output terminal of the FTU 520
and supplies the rectified power to the auxiliary battery 4. A
smoothing capacitor (not shown) may be connected across the output
terminals of the rectifier 530, if necessary.
[0025] The controller 540 forms, as motor-generator drive signals,
three-phase PWM-voltage signals Vu', Vv' and Vw', through a
well-known field oriented control, from the torque command signal
ST, sine and cosine signals (rotation angle signals) supplied by
the resolver 2 and current signals supplied from the current
sensors 513 and 514. Each of the PWM-voltage signals Vu', Vv' and
Vw' includes a signal of a low frequency less than 2 kHz that is
pulse-width-modulated by a carrier wave of 10 kHz. If the charge
command signal SC is in the H level, the controller 540 forms PWM
charge signals Vcu', Vcv' and Vcw' from three-phase high frequency
voltage signals Vcu, Vcv and Vcw whose frequency is the same as the
resonance frequency fs, as long as the terminal voltage of the
auxiliary battery 4 is lower than a reference voltage Vref. PWM
charge signals Vcu', Vcv' and Vcw' includes a carrier wave of 100
kHz. The controller 540 also forms three-phase gate control PWM
signals to be applied to the gates of the switching elements
501-506 from the motor-generator drive signals Vu', Vv' and Vw' and
the charge signals Vcu', Vcv' and Vcw'.
[0026] Because the motor generator 1 has a large inductance, the
operation thereof is not affected by such high frequency voltage
signals Vcu, Vcv and Vcw or carrier waves.
[0027] The FTU 520 has a comparatively narrow band for conducting
the signals of the frequencies near the resonance frequency.
Therefore, only the high frequency components of the electric power
that correspond to the charge PMW signals Vcu', Vcv' and Vcw' can
be supplied from the FTU 520 so that the auxiliary battery 4 can be
charged only when the terminal voltage of the auxiliary battery 4
is lower than the reference voltage.
[0028] As shown in FIG. 2, the controller 540 includes a front
low-pass filter 10, a drive-voltage operation unit 20, a
charge-signal operation unit 30 and signal-synthesizing unit 40.
The drive-voltage operation unit 20 provides PWM-voltage signals
Vu', Vv' and Vw' for controlling the motor-generator 1. The
charge-signal operation unit 30 provides the charge signals Vcu',
Vcv' and Vcw', and the signal-synthesizing unit 40 synthesizes
voltage signals Vu', Vv' and Vw' and the charge signals Vcu', Vcv'
and Vcw' to form gate control PMW signals to be applied to the
respective gates of the switching elements 501-506 of the inverter
50.
[0029] The front low-pass filter 10 selects low-frequency
components of the U-phase current Iu and V-phase current Iv, which
are supplied to the low-pass filter 10 via the current sensors 513
and 514. The frequency band for passing the low-frequency
components corresponds to the frequency band (less than 2 kHz) of
the three-phase signal voltage Vu, Vv and Vw.
[0030] The drive-voltage operation unit 20 includes a
three-phase-to-two-phase conversion unit 21, a current command
signal unit 22, a current control unit 23, a
two-phase-to-three-phase conversion unit 24, a PWM unit 25 and a
rotation position detecting unit 26. The drive-voltage operation
unit 20 is comprised of a well-known vector operation circuit that
includes a digital signal processor or a microcomputer that has
software for controlling the motor.
[0031] The three-to-two-phase reduction unit 21 converts the
low-frequency components of U-phase current Iu and V-phase current
Iv to current values Iy and Ix of the static orthogonal coordinates
according to the rotation angle .theta. of the motor-generator 1
that is detected by the rotation position detecting unit 26. The
phase reducton unit 21 further converts the current values Iy and
Ix to current values Id and Iq of the rotational coordinates.
[0032] The current command signal unit 22 converts the torque
command signal to current command values Id' and Iq' of the
rotation coordinates. The current control unit 23 provides motor
input voltages Vd and Vq of the rotational coordinates to be
applied to the motor-generator 1 so that the current values Id and
Iq can near the current command values Id' and Iq'.
[0033] The two-to-three-phase splitting unit 24 converts the
voltage values Vd and Vq of the rotational coordinates to voltage
values Vy and Vx of the static orthogonal coordinates according to
the rotation angle .theta. detected by the rotation position
detecting unit 26 and further converts the voltage values Vy and Vx
to three-phase voltage command values Vu, Vv and Vw.
[0034] The PWM unit 25, which may be comprised of hardware or soft
ware, provides three-phase PWM voltage signals Vu', Vv' and Vw'
having duty ratios that are proportional to the three-phase voltage
command values Vu, Vv and Vw. The PWM voltage signals Vu', Vv' and
Vw' can be formed by providing a saw-tooth wave that has the same
frequency as the carrier wave, which is compared with the command
values Vu, Vv and Vw.
[0035] The rotation position detecting unit 26 forms the rotation
angle .theta. of the motor-generator 1 from the sine and cosine
signals detected by the resolver 2.
[0036] Since the above described inverter that provides phase
current Iu, Iv and Iw and the voltage command signals Vu, Vv and Vw
is well known, a further description thereof is omitted.
[0037] The charge-signal operation unit 30 includes a voltage
regulator 31, a three-phase voltage generation unit 32 and a PWM
unit 33. The charge-signal operation unit 30 operates while the
battery-charge command signal SC is in the high level.
[0038] The voltage regulator 31 compares the terminal voltage Va+
of the auxiliary battery with the reference voltage Vref and
provides a charge signal Vc if the terminal voltage Va+ is lower
than the reference voltage Vref.
[0039] The three-phase voltage generation unit 32 forms the
three-phase high frequency voltage signals Vcu, Vcv and Vcw in
response to the above charge signal Vc.
[0040] The PWM unit 33 forms the three-phase PWM signal Vcu', Vcv'
and Vcw' from the three-phase high frequency voltage signals Vcu,
Vcv and Vcw. The PWM unit 33 is almost the same in structure as the
PWM unit 25 except that the frequency of the carrier wave is 100
kHz and that the output thereof is turned on or off when the level
of the battery-charge command signal SC changes.
[0041] The signal-synthesizing unit 40 includes fast Fourier
transform (FFT) units 401-406, adder units 411-413, inverse Fourier
transform (IFT) units 421-423 and wave-shaping units 431-433.
[0042] The FFT units 401, 402 and 403 are well-known devices that
transform three-phase PWM-voltage signals Vu', Vv' and Vw' to
motor-generator operation signals Fu, Fv and Fw.
[0043] The FFT units 404, 405 and 406 are the same in structure as
the FFT units 401, 402 and 403 that transform the PWM charge
signals Vcu', Vcv' and Vcw' to battery charge condition signals
Fcu, Fcv and Fcw.
[0044] The adder units 411-413 respectively add the motor-generator
operation signals Fu, Fv and Fw to the battery charge condition
signals Fcu, Fcv and Fcw to provide three-phase PWM voltage output
signals. The adder units 411-413 are well-known hardware or
software.
[0045] The IFT units 421-423 inversely transform the output
frequency signals of the adder units 411-423 to time signals.
[0046] The wave-shaping units 431-433 shape the wave forms of the
output signals of the IFT units 421-423 and provide three-phase PWM
voltage signals that are applied to the gates of switching elements
501-506 of the inverter 50. When the three-phase PWM voltage
signals drives the switching elements 501-506, the three-phase
output voltage of the inverter 50 includes the frequency components
of both the three-phase PWM-voltage signals Vu', Vv' and Vw' and
the three-phase PWM charge signals Vcu', Vcv' and Vcw'.
[0047] Thus, the single three-phase inverter 50 can drive the
motor-generator 1 as well as charge the auxiliary battery 4.
[0048] An electric power equipment according to a second embodiment
of the invention is described with reference to FIG. 3. The
electric power equipment includes a switching transistor 101, a
flywheel diode 102, a single-phase voltage transformer 103, a
capacitor 104, a single-phase full-wave rectifier 105, a rotary
electric machine (motor or a generator) 106 and a smoothing
capacitor 107. The transformer 103 and the capacitor 104 form a
frequency-filter-and-voltage-transformer (FTU). The resonance
frequency of the FTU is fs.
[0049] A single-phase PWM voltage signal is formed in the same
manner as described above and applied to the control electrode of
the transistor 101. Accordingly, low-frequency current is supplied
to the rotary electric machine 106, and high frequency current
having the frequency fs is supplied to the auxiliary battery 4
through the FTU that is comprised of the transformer 103 and the
capacitor 104. The low frequency current can be controlled by any
device other than those used in the first to third embodiments.
[0050] An electric power equipment according to a third embodiment
of the invention is described with reference to FIG. 4.
[0051] The electric power equipment includes an H-type bridge
circuit 200, a motor 206, a single-phase voltage transformer 203, a
capacitor 204, a single-phase full-wave rectifier 205 and a
smoothing capacitor 207. The H-type bridge circuit 200 includes
four switching transistors 201 and four flywheel diodes 202.
[0052] When the switching transistors 201 are controlled in the
same manner as described above, low-frequency current is supplied
to the motor 206. At the same time, the high frequency current
having the resonance frequency fs is supplied to the auxiliary
battery 4 through the FTU that is comprised of the transformer 203
and the capacitor 204.
[0053] The foregoing description of the present invention, the
invention has been disclosed with reference to specific embodiments
thereof. It will, however, be evident that various modifications
and changes may be made to the specific embodiments of the present
invention without departing from the broader spirit and scope of
the invention as set forth in the appended claims. Accordingly, the
description of the present invention is to be regarded in an
illustrative, rather than a restrictive, sense.
* * * * *