JP3205755B2 - Power regeneration method of motor in battery power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of regenerating electric power of an electric motor using a battery power supply, and more particularly to a method of regenerating electric power in a drive system of a permanent magnet field type electric motor using a battery as a power supply used in an electric vehicle or the like. It is suitable for use in

[0002]

2. Description of the Related Art As is well known, as a base power source of an inverter for driving a permanent magnet field type electric motor, there are quite many known three-phase type electric power regeneration methods, but they are effective for battery type electric vehicles. There are few things.

[0003] The problem with the battery type is that the base power source does not change with time unlike the three-phase type, so that it is necessary to boost the battery voltage to a value higher than the battery voltage in order to regenerate and charge the power. Moreover, the battery type is disadvantageous economically in view of the means, labor, cost, and the like, and the actual situation is that power regeneration is not performed in a positive direction.

At the present time, there are very few electric vehicles in which a permanent magnet field brushless DC motor by an inverter is directly mounted in a tire wheel and driven by direct drive, and effective means of a power regeneration method is also known. Absent. By the way, when charging as a battery-powered vehicle, the main points to be noted are prevention of overcharging and prevention of sudden braking.

[0005] With respect to these cautions at the time of charging, several techniques have been conventionally proposed. For example,
For example, Japanese Patent Application Laid-Open No. Sho 60-207475 proposes a technique for preventing the overcharging of the vehicle, and Japanese Patent Application Laid-Open No. 60-207475 discloses a technique for preventing sudden braking. 207475 proposes. However, conventionally proposed techniques are individual methods as seen in the above-described methods, and in reality, there have been few proposals for techniques that enable these problems at once.

[0006]

For example, in the case of an electric vehicle driven by a battery, many studies have been made in the direction of improving the traveling distance per charge to the level of a gasoline vehicle. These methods include designing and manufacturing a motor drive system that is as efficient as possible, reducing the weight of the vehicle body, designing and manufacturing a vehicle shape with low running resistance, and tires with low frictional resistance. To develop a battery that is smaller and lighter, and has a higher current density.

That is, in an electric vehicle using a battery as a driving source, there is a wide variety of technologies required to improve the traveling distance per charge to the level of a gasoline vehicle. the above~
Various technologies have been studied at present, and some of them have been implemented little by little, and their effectiveness has come to be known.

However, a method of extending the traveling distance per charge by improving the power regeneration method has not yet been sufficiently studied. This is because it is necessary to modify the current drive system as described above in order to extend the traveling distance per charge by improving the power regeneration method.
Also, there are quite a number of technical issues that need to be resolved.

[0009] Therefore, from the viewpoint of the examination of means for satisfying these problems and the needs, the extension of the traveling distance per charge by improving the electric power regeneration method has not been modified, and other methods will be examined. The current situation is that technical considerations have been added to this mainstream, and the improvement of the power regeneration method has been postponed.

In view of the above problems, the present invention makes it possible to stabilize the charging current and to prevent abrupt charging, and furthermore, to make the battery in a braking state without a sense of discomfort when stopping. An object of the present invention is to provide a power regeneration method for a motor in a battery power supply capable of performing charging.

[0011]

According to the present invention, there is provided a power regeneration method applied to an electric motor which operates by using a battery as a power source and generates an induced electromotive force at the time of braking. The full-wave rectified and smoothed voltage of the induced electromotive force stored in the smoothing capacitor is previously adjusted so that the choke coil, the chopping transistor, and the braking current due to the induced electromotive force fall within the rating of the chopping transistor. By determining a resistance value, boosting the voltage by a charging current sensitivity adjusting resistor connected in series to the chopping transistor, and controlling the duty ratio between the on state and the off state of the chopping transistor, the braking current is reduced. Is adjusted so that the charging current value is within the allowable range, and the above chopping transistor and Characterized in that so as to recover the braking current attenuated by supplying a current to fine the charging current sensitivity adjustment resistor.

In the electric power regeneration method according to the present invention having the above-described configuration, in order to perform electric power regeneration in the motor power generation mode, the motor line current (charge current) detection sensor 32 is used.
As soon as the power generation mode timing is detected, the battery voltage 35 is confirmed, and the full-wave rectified and smoothed voltage of the induced electromotive force stored in the smoothing capacitor 8 is converted to the choke coil 7, the chopping transistor 30, and the charging current sensitivity. The duty ratio between the ON state and the OFF state of the chopping transistor 30 is controlled so that the boosting current is boosted by the adjustment resistor 31 and the braking current I0, which is the braking current, becomes an allowable range. This is performed by the appropriate current control block 33.

Thereafter, the brake current I0 is controlled so as to be substantially constant, and the resistance value of the resistor 31 connected in series with the chopping transistor 30 is adjusted so that the brake current falls within an allowable range. In this way, power regeneration is performed while preventing overcharge in battery charging and stabilizing the brake current.

Further, a power regeneration apparatus and method for an inverter-driven motor in a battery power supply according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram in which a power regenerative device (dotted line) of the present invention is added to a general configuration of a device that drives a permanent magnet field type electric motor driven based on a battery power supply by an inverter.

That is, in order to achieve the above-mentioned object, the power regeneration device for an inverter-driven motor using a battery power supply according to the present invention, as shown in FIG. Is added. In the apparatus of FIG. 1, in the accelerator on state, that is, in the state where the applied voltage is supplied to the motor, the operation is not performed by turning off the chopping transistor 30. It is configured to work. That is, first,
Operation state, but the state after the accelerator is off and the power generation mode is detected. Also, this is a case where the brake is off on a downhill and the power generation mode is detected, or the like.

In these states, the charging current is kept constant /
The accelerator signal 5 and the output signal of the line / charge current detection sensor 32 are input to the appropriate current control block 33. Then, the transition from the operating state to the charging state is determined based on the value of the line current and the direction thereof in the power generation mode, and then the chopping transistor 30 provided in the power regeneration device 36 indicated by the dotted line block is provided. Is first turned on with a clock pulse having a predetermined basic frequency.

The voltage generated in this manner is smoothed after full-wave rectification by the diode in the inverter section. in this case,
An impulse-like high voltage is generated by the smoothing capacitor 8 and the choke coil 7. The current I1 flowing at this time
Is from left to right as shown by the dotted line in FIG.

Next, when the chopping transistor 30 is turned off, the brake current I0 flows toward I2 so as to continue flowing under the influence of the choke coil 7.
If this state is shown in FIG. 2, it will be downwardly rightward from upper left to lower right. The current flowing in this section, that is, the current I2 flowing when the chopping transistor 30 is off is the charging current.

[0019]

According to the present invention, the full-wave rectified and smoothed voltage of the induced electromotive force stored in the smoothing capacitor is converted to a choke coil, a chopping transistor, and a braking current by the induced electromotive force is converted to the chopping transistor. The resistance value is determined in advance so as to be within the rating, and boosted by a charging current sensitivity adjustment resistor connected in series to the chopping transistor, and the duty ratio between the on state and the off state of the chopping transistor is determined. By controlling, it is possible to generate a voltage higher than the voltage value of the battery based on the induced electromotive force only by adding and controlling simple elements and functions to the electric motor in the conventional battery power supply, and the power generation mode The energy at the time can be effectively collected and stored in the battery well.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a power regeneration apparatus and method for an inverter-driven motor in a battery power supply according to the present invention; As shown in FIG. 1, the power regeneration device for an inverter-driven motor in a battery power supply according to the present invention includes a circuit in which a charging current sensitivity adjustment resistor 31 and a chopping transistor 30 are connected in series with a flywheel diode 6 in series. In addition to the connection, a power generation mode determination block 34 and a charging current stabilization / appropriate current generation block 33 are newly provided, so that the power regeneration device 3
6 to perform power regeneration.

Next, the configuration of the entire motor driving device provided with such a power regeneration device 36 will be described. In FIG. 1, reference numeral 24 denotes an entire motor, 22 denotes a motor main body, and 23 denotes a switching sensor and an encoder unit. Reference numeral 21 denotes a U-phase raw current detection sensor,
The signals output from these three locations are input to the motor power factor improving advance angle control board 25. This block is provided to control the advance angle of the applied voltage so that the phase of the induced electromotive force and the phase current of each phase are almost always the same.

Reference numerals 9 to 14 denote inverter transistors, and reference numerals 15 to 20 denote reflux diodes.
The switching signals of the U, V, and W phases whose advance angles are controlled are supplied from the switching / power control unit 26 to the transistors 9 to 14, respectively. Then 29
Is a block for determining whether the accelerator signal 5 is on or off. When the accelerator signal 5 is off, the switching signal output of the switching / power control unit 26 is stopped.

In the configuration of such a motor driving device, first, an outline of an operation in a normal operation mode is shown in FIG.
Will be described. During the operation of the motor drive device, the driver determines the accelerator opening according to the speed. This opening information is given to the pulse duty ratio determination block 4. The pulse duty ratio determination block 4 includes a power supply voltage control D
It has the function of determining the pulse duty ratio of the transistor 3 provided for performing C chopping.

In addition to the pulse duty ratio determination block 4, the accelerator opening information is used as a power generation mode determination block 34, a charging current stabilization / appropriate current control block 33.
And an accelerator on / off determination block 29.

Each block operates according to the input accelerator opening information. In the accelerator on state, the pulse duty ratio determining block 4 corresponding to the accelerator opening and the accelerator on / off determining block 29 output signals. . In this case, the pulse duty ratio determination block 4
A chopping signal having a frequency of about KHz is output, and the on-time time width within one cycle of the chopping signal is adjusted in proportion to the accelerator opening of the accelerator opening information 5 to be inputted, thereby driving the chopping transistor 3. Control the state.

As a result, the chopping transistor 3 is energized only during one cycle of the chopping signal supplied from the pulse duty ratio determination block 4. Then, the current is supplied to the smoothing capacitor 8 via the choke coil 7 so that the smoothing capacitor 8 is charged.

Next, the pulse duty ratio determination block 4
When the chopping pulse signal output from is turned off, the choke coil 7 acts so as to continuously supply a current. This current flows in a closed loop of the capacitor 8 → the flywheel diode 6 → the choke coil 7 → the capacitor 8. As described above, the charging current changes depending on the length of the on-time of the chopping signal output from the pulse duty ratio determination block 4, so that the terminal voltage of the smoothing capacitor 8 is finally controlled to a predetermined value. .

When the terminal voltage of the smoothing capacitor 8 is Y
The voltage applied from the inverter connected to each winding terminal of the connected motor 22 becomes a line voltage.
Rotates according to the load. In such an operating state, if the accelerator opening is reduced to zero by some condition or operation, a so-called power generation mode is set. This power generation mode state will be described with reference to FIG. 1. First, when the accelerator opening becomes zero, the chopping pulse (output of the pulse duty ratio determination block 4) of the high frequency power supply voltage control DC chopper is turned on during one cycle. The duty ratio becomes zero.
As a result, the chopping signal output from the pulse duty ratio determination block 4 becomes zero, and the chopping transistor 3 is turned off.

At this time, the voltage supplied to the inverter becomes the voltage of the smoothing capacitor 8, and the motor 22 is rotated until the voltage becomes zero. However, the electric charge stored in the smoothing capacitor 8 is eventually lost. It is completely discharged. However, even after the electric charge stored in the smoothing capacitor 8 becomes zero, if the motor 22 continues to rotate with the inertia up to this point, the power generation mode starts at this point, and the inverter unit of FIG. Upper transistors 9, 11, 13 and lower transistors 10, 1
2 and 14 are turned off.

At the same time as the motor driving device enters the power generation mode, only the induced electromotive force is applied to the three-phase Y-connected motor winding, and the return diodes 15 to 20 of the inverter section are connected to the full bridge. Acts as full-wave rectification. This full-wave rectified output voltage is smoothed by the smoothing capacitor 8 to average the pulsating flow.

On the other hand, the charging current stabilization / appropriate current control block 33 determines whether the accelerator opening is zero and the Hall element type current detection sensor (CT) 32 detects the line current and then performs an averaging process to determine the power generation mode. At 34, the current value and direction are monitored, and a change from the operating state to the power generation state is determined.

After this judgment, the chopping transistor 30 for boosting the generated voltage is immediately changed from several hundred Hz to 1 Hz.
Chopping is performed with a pulse of about KHz. When the chopping pulse is in the ON state, the line current flows through the coil 7 to the resistor 31 and the transistor 30. At this time, the terminal voltage of the smoothing capacitor 8 is boosted by the coil 7.

FIG. 2 is a diagram showing the charging current and the timing thereof according to the present invention. The step-like waveform indicates ON / OFF of the chopping transistor 30. The upper side is ON, the current flows in the direction I1, and the lower side is ON. The side is off and represents the charging current I2. In the power regeneration device 36 of the present invention, the ratio of the on-time to the off-time of the chopping pulse of the chopping transistor 30 is such that the highest regeneration rate is 75% for the on-time and 25% for the off-time. FIG.

The reference value of the charging current range can be set by adjusting the regenerative current sensitivity adjusting resistor 31 connected in series to the chopping transistor 30. The size of the resistor 31 is preferably as small as possible, but may be determined in consideration of the current capacity of the chopping transistor 30 and an appropriate range of the charging current.

By repeating the above operation, power regeneration during the power generation mode can be effectively performed.
In addition, the average value of the brake current I0 at this time is constantly obtained, and the charge current stabilization / appropriate current control block 33 controls the simple P value so that this value is kept as constant as possible.
By configuring the I control system, it has become possible to stabilize the charge current, prevent sudden charging, and create a braking state without a sense of incongruity when stopping.

[0036]

As described above, according to the present invention, since it is only necessary to add and control a circuit block having a simple structure, the electric power can be reduced without largely modifying the structure of the motor in the battery power supply conventionally used. A regenerative method can be realized. As a result, it is possible to provide a device that can be configured at low cost and that can effectively perform power regeneration, and can greatly improve the operating distance per charge. Therefore, the present invention is extremely effective for various devices that operate on a battery power source, and can greatly contribute to, for example, greatly extending the mileage per charge of an electric vehicle to realize a higher degree of practical use. Further, the present invention can be applied to, for example, elevators and lift cars.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a general configuration of a device that drives a permanent magnet field type electric motor that operates based on a battery power supply with an inverter.

FIG. 2 is an explanatory diagram showing a charging current and its timing.

FIG. 3 is a characteristic diagram showing a ratio between an on-time and an off-time of a chopping pulse for driving a chopping transistor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery 2 Charging diode 3 DC chopping transistor for power supply voltage control 4 Pulse duty ratio decision block according to accelerator opening 5 Accelerator opening signal 6 Flywheel diode 7 Choke coil 8 Smoothing capacitor 9-14 Three-phase full bridge Inverter transistor 15-20 Feedback diode for three-phase full-bridge inverter 21 U-phase current detection sensor 22 Motor body 23 Sensor / encoder 24 Entire motor 25 Advance angle control board for motor power factor improvement 26 Switching / power control unit 27 Charging current Detection sensor 28 Charge current monitoring meter 29 Accelerator ON / OFF determination block 30 Chopping transistor 31 Charge current sensitivity adjustment resistor 32 Line / charge current detection sensor 33 Constant charge current / Appropriate current reduction control block 34 generating mode decision block 35 the power supply voltage signal 36 power regenerating device

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Teruo Tsuji 1-28-13 Hinosato, Munakata-shi, Fukuoka (72) Inventor Asahiko Niimura 3-2-1 Sensui-cho, Tobata-ku, Kitakyushu-shi, Fukuoka (56) Reference Reference JP-A-61-18378 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 3/18 101 B60L 15/28

Claims (1)

(57) [Claims] 1. A power regeneration method applied to an electric motor that operates using a battery as a power source and generates an induced electromotive force during braking, wherein the induced electromotive force is rectified and stored in a smoothing capacitor when the induced electromotive force is AC. The full-wave rectified and smoothed voltage of the induced electromotive force is determined by a choke coil, a chopping transistor, and a resistance value previously determined so that a braking current due to the induced electromotive force is within the rating of the chopping transistor. The boosting current is increased by a charging current sensitivity adjusting resistor connected in series to the chopping transistor, and the duty ratio between the on state and the off state of the chopping transistor is controlled so that the charging current value is within an allowable range. And the chopping transistor and the charging current sensitivity. Power regeneration method of the electric motor in a battery power source, characterized in that so as to recover the braking current attenuated by supplying a current to the integer resistor.