JPH0928005A - Power unit for driving motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a power converter make only voltage drop operations by making the electrical energy stored in the capacitor of a motor driving hybrid power unit composed of the capacitor and a battery usable until the energy becomes zero and, at the same time, eliminating the necessity of generating a high voltage from the capacitor. SOLUTION: A serial circuit is constituted of a battery 26 and capacitor 24. A chopper 28 for propulsion power supplies the voltage of the serial circuit to a motor 30 after dropping the voltage and a chopper 32 for regeneration supplies a charging voltage to the capacitor 24 by dropping a voltage from the motor 30. A control circuit 34 controls the voltage dropping operations of the choppers 28 and 32. When the motor 30 makes propulsion power, the motor 30 is driven with a drive voltage from the chopper 34 and, when motor 30 makes regeneration, the capacitor 24 is charged with the charging voltage from the chopper 34 so that the power can be reutilized when the motor 30 make propulsion power.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for driving a motor, and more particularly to a power supply suitable for driving a power motor for an electric vehicle, an electric scooter, an electric bicycle or the like.

2. Description of the Related Art As a power supply device for driving a power motor of an electric vehicle, an electric scooter, an electric bicycle, etc., a battery and a capacitor are connected in parallel, and the output from this parallel circuit is supplied to the motor via a power converter. A hybrid power supply device has been conventionally used. In this case, the battery has a function of supplying a small current to the motor for a long time, and the capacitor has a function of supplying a large current to the motor in a short time in response to a load change of the motor. An example of such a conventional motor driving power supply device is shown in FIG. In the group 10 of a plurality of batteries and the group 12 of a plurality of capacitors connected in series to generate a high voltage, the negative (-) side has a common potential, and the positive (+) side has a current control circuit 14 in parallel. It is connected. The current control circuit 14
Is for preventing an overcurrent from flowing from the battery group 10, and the battery group 10 and the capacitor
The voltage from the parallel circuit of the group 12 is supplied to both ends of the DC motor 18 via the motor drive circuit 16 which is a power converter. The motor drive circuit 16 includes a chopper or an inverter and a control circuit for the chopper or the inverter, and can step down or boost the voltage. When the motor 18 is rotationally driven for power running, the motor drive circuit 16 steps down the voltage from the battery group 10 and the capacitor group 12 and supplies it to the motor 18. At this time, the rotation speed, torque, etc. of the motor can be controlled by controlling the degree of step-down.
Further, when the drive voltage to the motor 18 is stopped and regenerated, the motor 18 functions as a generator, so the motor drive circuit 16 boosts the generated voltage of the motor 18 to charge the capacitor group 12 (charge storage). ) Do. This charged energy is reused during power running of the motor to improve the efficiency of the entire power supply device. Another example of a conventional motor drive power supply device is shown in FIG. The difference from the conventional example of FIG. 3 is that the positive sides of the battery group 10 and the capacitor group 12 are alternately selected at high speed by the switch 20 of the semiconductor element, and the selected voltage is supplied to the motor drive circuit 16. Is. The semiconductor switch 20 includes a power transistor and an insulated gate transistor (IGB
T), a field effect transistor (FET), etc. can be used, and the switch control circuit 22 controls high-speed switching of the switch 20. In this conventional technique, as in the case of FIG.
The output voltage of 0 is stepped down and supplied to the motor 18. Also,
When the motor 18 is regenerated, the motor drive circuit 16 boosts the generated voltage of the motor 18, and the capacitor group 12 is charged via the switch 20. This charged energy (stored energy) is reused when the motor is running. Further, Japanese Patent Laying-Open No. 5-30608 discloses another conventional motor driving power source device, particularly in FIG. In this power supply device, a battery and a capacitor are connected in series during power running of the motor, and the motor is driven by the sum of the voltage of the battery and the voltage charged in the capacitor. Also,
At the time of regeneration of the motor, a battery and a capacitor are connected in parallel to charge the capacitor with the generated voltage of the motor. At this time, a leveling circuit is connected in series on the battery side to suppress charging of the battery. With such a configuration, a large amount of current is supplied to the motor by the battery and the capacitor during power running, and the capacitor is predominantly charged during regeneration.

By the way, in order to obtain the voltage for driving the motor from the capacitor, the capacitor must have a large capacity. However, even with a large-capacity capacitor, the charging (storage) energy of the capacitor is smaller than that of a battery by one digit or more, so it is necessary to effectively use the energy stored in the capacitor. Since the energy of the capacitor is half the product of the electrostatic capacity and the square of the voltage, using all the stored energy of the capacitor means using it until the voltage of the capacitor becomes zero. However, in any of the conventional techniques shown in FIGS. 3 and 4, the motor drive circuit and the motor are driven by the voltage of the capacitor, but a certain or more voltage is required to drive these. Therefore, since the motor drive circuit and the motor do not operate before the voltage of the capacitor becomes zero, the energy stored in the capacitor cannot be used up. This is the same even if a booster circuit is provided at the terminal of the capacitor, and the stored energy of the capacitor cannot be used up. Also,
The mainstream of large-capacity capacitors is electric double layer capacitors, but this capacitor can only have a voltage of about 1 to 5 volts per cell in order to prevent electrolysis of the electrolytic solution. Therefore, in order to drive the motor, the voltage must be increased to the level required by the motor, so that a plurality of electric double layer capacitors must be connected in series. In the case of an electric vehicle, an electric scooter, or an electric bicycle, the drive voltage of the motor needs to be about 24 to 300 volts. By the way, when a plurality of capacitors are connected in series, there arises a problem of voltage balance between the capacitors. This problem will be further described with reference to FIG.
For the sake of explanation, the lower and upper limits of the voltage range in which the capacitor can be used without being destroyed or deteriorated are 0 and 3 volts, respectively. Fig. 5A shows three capacitors with the same capacitance.
When connected in series as shown (initial state), the voltage on all capacitors is zero volts respectively. Next, FIG. 5B
As shown in (charging state), when the battery is charged with a 9-volt battery, the electrostatic capacitances of all the capacitors are equal, so that the voltage of each capacitor becomes 3 V. Figure 5C (self-discharge state) when the capacitor is left unconnected with the battery disconnected
As shown in, the capacitor self-discharges due to the internal resistance, but the variation in this self-discharge is very large. As time goes by, this variation in voltage becomes even greater, and in the worst case, as shown in FIG. 5D, a certain capacitor has a voltage of zero volt. In this state, when discharged, the zero-volt capacitor cannot keep the lower limit, and when charged, the three-volt capacitor cannot keep the upper limit, so charging and discharging cannot be performed. Therefore, in order to solve this problem, it is necessary to adjust the voltage of all capacitors to the lower limit or the upper limit before use. In the conventional technique, as shown in FIG. 5E, a resistor is connected in parallel to each capacitor, and the energy remaining in the capacitor after use is discharged by the resistor to make the capacitor voltage equal to the lower limit. In another conventional technique, as shown in FIG. 5F, for example, a Zener diode of 3 V is connected in parallel to each capacitor, and each capacitor is charged up to the upper limit voltage before use, so that the capacitors are aligned. However, in the conventional techniques shown in FIGS. 5E and 5F, not only extra external parts are required for each capacitor, but also energy loss occurs. Furthermore, in the prior art shown in FIG. 3 and FIG. 4, the power converter (motor drive circuit) must always perform boosting during either power running or regeneration of the motor. However, step-up is generally less efficient than step-down, and the efficiency of the entire power supply device is reduced. Further, in the conventional power supply device disclosed in FIG. 5 of JP-A-5-30608, the connection relationship between the battery and the capacitor is selectively selected between the series connection and the parallel connection according to the driving mode of the motor. A circuit to switch to was required, and the configuration became complicated.
Further, in this conventional technique, a large number of capacitors have to be connected in series because the capacitors need to generate a high voltage, which causes the above-mentioned problem of voltage variations among the capacitors. Therefore, the object of the present invention is to use the electric energy stored in the capacitor until it becomes zero, the capacitor does not need to generate high voltage, and the power converter only needs to perform the step-down operation. To provide a power supply device for use.

In order to solve the above-mentioned problems, a motor drive power source apparatus according to the invention of claim 1 receives a series circuit of a battery 26 and a capacitor 24, and a voltage of this series circuit. , A first power converter 28, 34 for supplying a drive voltage to the motor 30 and a second power converter 32, 34 for receiving a voltage from the motor 30 and supplying a charging voltage to the capacitor 24. 1st during powering
The motor 30 is driven by the drive voltage from the power converters 28 and 34.
To drive the second power converter 32 when the motor 30 is regenerated,
It is characterized in that the capacitor 24 is charged by the charging voltage from 34. In addition, the reference numbers refer to FIG. 1 or FIG.
3 shows a correspondence relationship with the embodiment of the present invention shown in FIG.
The series circuit according to claim 1 includes capacitors 24 and 1
This is a circuit in which the batteries 26 of the group (including the case of one) are connected in series, and the end of the battery opposite to the capacitor is coupled to one end of the motor 30 via the first power converter 28 and the capacitor 24 is connected. The battery side end of the second power converter 3
2 is connected to one end of the motor 30 via a capacitor 2
The other end of the battery 4 is connected to the other end of the motor 30. Further, in the series circuit according to claim 1, a first group (including one case) battery 261, a capacitor 24, and a second group (including one case) battery 262 are sequentially connected in series. Connected circuit, these first and second groups of batteries 261,
The capacitor 262 and two opposite ends thereof are respectively coupled to both ends of the motor 30 via the first power converters 281 and 282, and both ends of the capacitor are coupled to the motor 30 via the second power converter 32. It is characterized by being connected to both ends of. Further, the first and second power converters according to the first aspect are characterized by being configured by the chopper circuits 28, 32 or inverters for stepping down the voltage and the control circuit 34 thereof. The invention according to claim 1 is characterized in that a polarity reversal prevention diode 36 is connected to both ends of the capacitor 24. Further, the invention according to claim 1 is characterized in that the capacitor 24 is an electric double layer capacitor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a first preferred embodiment of the present invention. For example, one electric double layer capacitor 24 which is a general large capacity capacitor
And, for example, a plurality of batteries 26, which are storage batteries, are connected in series to form a series circuit. Battery group 26 of this series circuit
The opposite end (plus end) of the capacitor is coupled to one end (plus end) of the DC motor 30 via the power running step-down chopper 28. The common connection point of the capacitor 24 and the battery group 26 is coupled to one end of the DC motor 30 via the regenerative step-down chopper 32. The other end (minus end) of the capacitor 24 is coupled to the other end (minus end) of the motor 30. The chopper control circuit 34 controls the chopping operation of the choppers 28 and 32, and the choppers 28 and 3 are controlled.
2 and the control circuit 34 constitute a power converter. Also,
Bypass diode 36 is placed across capacitor 24.
Connect. The choppers 28 and 32 include a power transistor and an insulated gate transistor (IGBT).
And switching semiconductor devices such as field effect transistors (FETs). In addition, these choppers have a directivity of a current to be passed when conducting, in the chopper 28, in the direction from the battery group 26 to the motor 30, and in the chopper 32, in the direction from the motor 30 to the capacitor 24. Next, the operation of the embodiment shown in FIG. 1 will be described. It is assumed that the capacitor 24 is charged to a certain voltage with electric energy. During power running of the motor, the voltage of the capacitor 24 and the voltage of the battery group 26 are added, and the added voltage is stepped down by the step-down chopper 28 for power running and supplied to the DC motor 30. Therefore, the current from the capacitor 24 and the battery group 26 returns to the capacitor 24 via the chopper 28 and the motor 30, a closed circuit is formed, and the motor 30 rotates. At this time, when a large amount of electric power is required, the electric energy of the capacitor 24 helps supply electric power. In addition, the chopper 28 is connected to the control circuit 3
Conduction and non-conduction are repeated by controlling the pulse signal from No. 4, and the input is passed to the output only when it is in conduction. Therefore, the rate of step-down can be controlled by controlling the time ratio of conduction and non-conduction (that is, conduction). The average value of the electrical energy passed through at any given time corresponds to the voltage supplied to the motor 30). By this control, the rotation state of the motor 30 is controlled. At this time, since the capacitor 24 and the battery group 26 are connected in series, the voltage at the upper end of the battery group 26 is
Since at least the voltage of the battery is always sufficient, this capacitor 2 is charged until the voltage of the capacitor 24 becomes zero.
4 electric energy is available. Also, the chopper 32
Is directional, the voltage of the capacitor 24 is not supplied to the motor 30 via the chopper 32. Motor 3
At the time of regeneration of 0, the chopper 28 remains in the non-conductive state, the voltage from the battery group 26 does not pass through the chopper 28, and the drive voltage is not supplied to the motor 30. Therefore,
The motor 30 functions as a generator, supplies the generated voltage to the capacitor 24 via the chopper 32, and charges the capacitor 24. This charging voltage is reused when the motor is running. Since the generated voltage of the motor 30 is high, the chopper 32 steps down the generated voltage according to the control of the control circuit 34 according to the same principle as the chopper 28. By the way, during power running of the motor 30, the large-capacity capacitor 2
As the discharge of No. 4 progresses, the charging voltage decreases, and when the amount of stored electricity becomes zero, the polarity is reversed. Diode 36
When the polarity of the capacitor 24 is about to be reversed, the capacitor conducts to prevent this polarity reversal. During the period when the polarity of the capacitor 24 is not reversed, the diode 36 is non-conducting, so that the operation of the device of FIG. 1 is not affected. FIG. 2 is a block diagram of a second preferred embodiment of the present invention. Only the differences from the embodiment of FIG. 1 will be described below. The series circuit of capacitors and batteries is made up of a first group of batteries 261, a capacitor 24, and a second group of batteries 262. That is, the capacitor 24 is the battery group 261.
, And 262, which is equivalent to a further battery group being placed on the negative side of the capacitor 24 in the embodiment of FIG. Therefore, the step-down chopper for power running is composed of two choppers 281 and 282, and the negative end of the battery group 261 is connected to the negative end of the motor 30 via the chopper 281.
The positive end of 2 is coupled to the positive end of the motor 30 via the chopper 282. Further, both ends of the capacitor 24 are coupled to both ends of the motor 30 via a regenerative chopper 32 composed of two choppers. These four choppers are controlled by the control circuit 34, but the chopper 281
And 282 are conducting and non-conducting at the same time. In addition, the two choppers 32 also become conductive and non-conductive at the same time. It should be noted that these choppers 281, 282 and 32 also have a conduction direction. The operation of the embodiment of FIG. 2 is similar to the operation of the embodiment of FIG. 1, and when the motor 30 is in the power running mode, the battery group 261, the capacitor 24, and the battery group 262.
From the above, a current flows to the motor 30 via the chopper 282, and a return current from the motor 30 returns to the battery group 261 via the chopper 281. The degree of step-down by the choppers 281 and 282 is determined by the ratio of the conduction control period and the non-conduction control period from the control circuit 34. During regeneration of the motor, the choppers 281 and 282 become non-conductive, the generated voltage of the motor 30 is stepped down by the chopper 32, and the capacitor 24 is charged. The energy generated by this charging is used during power running of the motor. Although the two preferred embodiments of the present invention have been described above, those skilled in the art can make various modifications and changes without departing from the gist of the present invention. For example, the power converter may use an inverter instead of the chopper to step down the input voltage. Further, as the capacitor, one having a plurality of capacitors connected in parallel may be used. Further, a small number of capacitors may be connected in series instead of one capacitor. If a small number of capacitors are connected in series,
Since the variation in the voltage of each capacitor is smaller than that in the case where a large number of capacitors are connected in series, it does not matter so much.

According to the motor drive power supply device of the present invention, since the capacitor and the battery are connected in series, even if the storage voltage of the capacitor is lowered, the voltage of the entire series circuit is the same as that of the power converter and the motor. It is high enough to drive and can be used until the stored energy in the capacitor is completely zero during powering of the motor. Further, the voltage of the capacitor does not need to be as high as the battery voltage and may be low, so that it is not necessary to connect a large number of capacitors in series. Therefore, the problem of the voltage balance of the capacitors is reduced, and a large-capacity capacitor can be used with the low-voltage specification, so that the number of capacitors may be one or a small number. In this case, a special capacitor is not necessary, and an inexpensive general electric double layer capacitor can be used, so that the entire power supply device can be inexpensive. Furthermore, since the power converter does not need to perform step-up operation but only step-down operation, it is possible to improve overall efficiency and reduce power consumption. Further, since it is not necessary to switch the connection relationship between the capacitor and the battery in accordance with power running and regeneration, there is also an effect that the configuration is simpler than that of the conventional technique requiring a connection switching circuit.

[Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of a power supply device for driving a motor according to the present invention.

FIG. 2 is a block diagram of another preferred embodiment of the motor driving power supply device of the present invention.

FIG. 3 is a block diagram of an example of a conventional motor drive power supply device.

FIG. 4 is a block diagram of another example of a conventional motor drive power supply device.

FIG. 5 is a circuit diagram for explaining operations of charging and discharging a capacitor and a conventional capacitor circuit.

[Explanation of symbols]

 24 Capacitor 26 Battery 261 Battery 262 Battery 28 Powering step-down chopper 281 that constitutes the first power converter 281 Powering step-down chopper 282 that constitutes the first power converter 302 Powering step-down chopper 30 that constitutes the first power converter 30 Motor 32 Regenerative step-down chopper that constitutes the second power converter 34 Chopper control circuit that is a part of the power converter 36 Diode

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[Procedure amendment]

[Submission date] July 14, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Motor drive power supply device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for driving a motor, and more particularly to a power supply suitable for driving a power motor for an electric vehicle, an electric scooter, an electric bicycle or the like.

[0002]

2. Description of the Related Art As a power supply device for driving a power motor of an electric vehicle, an electric scooter, an electric bicycle, etc., a battery and a capacitor are connected in parallel, and the output from this parallel circuit is supplied to the motor via a power converter. A hybrid power supply device has been conventionally used. In this case, the battery has a function of supplying a small current to the motor for a long time, and the capacitor has a function of supplying a large current to the motor in a short time in response to a load change of the motor.

An example of such a conventional motor-driving power supply device is shown in FIG. In the group 10 of a plurality of batteries and the group 12 of a plurality of capacitors connected in series to generate a high voltage, the negative (−) side has a common potential,
The plus (+) side is connected in parallel via the current control circuit 14. The current control circuit 14 is used for the battery group 1
It is to prevent overcurrent from flowing from 0,
The voltage from the parallel circuit of the battery group 10 and the capacitor group 12 is the motor drive circuit 1 which is a power converter.
It is supplied to both ends of the DC motor 18 via 6. The motor drive circuit 16 includes a chopper or an inverter and a control circuit for the chopper or the inverter, and can step down or boost the voltage. When the motor 18 is rotationally driven for power running, the motor drive circuit 16 steps down the voltage from the battery group 10 and the capacitor group 12 and supplies it to the motor 18. At this time, the rotation speed, torque, etc. of the motor can be controlled by controlling the degree of step-down. Motor 1
When the drive voltage to 8 is stopped and regenerated, the motor 1
Since 8 functions as a generator, the motor drive circuit 16
Charges the power generation voltage of the motor 18 to charge (store) the capacitor group 12. This charged energy is reused during power running of the motor to improve the efficiency of the entire power supply device.

Another example of a conventional motor drive power supply device is shown in FIG. The difference from the conventional example of FIG. 3 is that the positive sides of the battery group 10 and the capacitor group 12 are alternately selected at high speed by the switch 20 of the semiconductor element, and the selected voltage is supplied to the motor drive circuit 16. Is.
A power transistor, an insulated gate transistor (IGBT), a field effect transistor (FET), or the like can be used as the semiconductor switch 20, and the switch control circuit 22 controls high-speed switching of the switch 20. In this conventional technique, as in the case of FIG. 3, the motor drive circuit 16 steps down the output voltage of the switch 20 and supplies it to the motor 18 when the motor 18 is in the power mode. Further, when the motor 18 is regenerated, the motor drive circuit 16 boosts the generated voltage of the motor 18, and the capacitor group 1 is switched through the switch 20.
Charge 2. This charged energy (stored energy) is reused when the motor is running.

Further, Japanese Laid-Open Patent Publication No. 5-30608 discloses another conventional motor drive power source device, particularly in FIG. In this power supply device, a battery and a capacitor are connected in series during power running of the motor, and the motor is driven by the sum of the voltage of the battery and the voltage charged in the capacitor. Further, when the motor is regenerated, a battery and a capacitor are connected in parallel, and the generated voltage of the motor is predominantly charged in the capacitor. At this time, a leveling circuit is connected in series on the battery side to suppress charging of the battery. With such a configuration, a large amount of current is supplied to the motor by the battery and the capacitor during power running, and the capacitor is predominantly charged during regeneration.

[0006]

By the way, in order to obtain the voltage for driving the motor from the capacitor, the capacitor must have a large capacity. However, even with a large-capacity capacitor, the charging (storage) energy of the capacitor is smaller than that of a battery by one digit or more, so it is necessary to effectively use the energy stored in the capacitor. Since the energy of the capacitor is half the product of the electrostatic capacity and the square of the voltage, using all the stored energy of the capacitor means using it until the voltage of the capacitor becomes zero. However, in any of the conventional techniques shown in FIGS. 3 and 4, the motor drive circuit and the motor are driven by the voltage of the capacitor, but a certain or more voltage is required to drive these. Therefore, since the motor drive circuit and the motor do not operate before the voltage of the capacitor becomes zero, the energy stored in the capacitor cannot be used up. This is the same even if a booster circuit is provided at the terminal of the capacitor, and the stored energy of the capacitor cannot be used up.

The mainstream of large-capacity capacitors is electric double-layer capacitors, but this capacitor has a voltage of 1 to 1 per cell in order to prevent electrolysis of the electrolytic solution.
Can only do about 5 volts. Therefore, in order to drive the motor, the voltage must be increased to the level required by the motor, so that a plurality of electric double layer capacitors must be connected in series. In the case of an electric vehicle, an electric scooter, or an electric bicycle, the drive voltage of the motor needs to be about 24 to 300 volts.

By the way, when a plurality of capacitors are connected in series, there arises a problem of voltage balance among the capacitors. This problem will be further described with reference to FIG. In addition,
For the sake of explanation, the lower and upper limits of the voltage range in which the capacitor can be used without being destroyed or deteriorated are 0 and 3 volts, respectively. When three capacitors having exactly the same capacitance are connected in series as shown in FIG. 5A (initial state), the voltage of all capacitors is zero volt. Next, as shown in FIG. 5B (charged state), when the battery is charged by a 9-volt battery, the electrostatic capacitances of all the capacitors are equal, so that the voltage of each capacitor becomes 3 V. When the battery is not connected and the capacitor is left as it is, as shown in FIG. 5C (self-discharge state), the capacitor self-discharges due to the internal resistance, but the self-discharge varies greatly. As time goes by, the variation of this voltage becomes larger, and in the worst case, as shown in FIG.
The voltage becomes zero volts. In this state, when discharged, the zero-volt capacitor cannot keep the lower limit, and when charged, the three-volt capacitor cannot keep the upper limit, so charging and discharging cannot be performed.

Therefore, in order to solve this problem, it is necessary to adjust the voltage of all capacitors to the lower limit or the upper limit before use. In the prior art, as shown in FIG. 5E, a resistor is connected in parallel to each capacitor, and the energy remaining in the capacitor after use is discharged by the resistor,
The capacitor voltage was adjusted to the lower limit. In another conventional technique, as shown in FIG. 5F, for example, a Zener diode of 3 V is connected in parallel to each capacitor, and each capacitor is charged up to the upper limit voltage before use, so that the capacitors are aligned. However, in the conventional techniques shown in FIGS. 5E and 5F, not only extra external parts are required for each capacitor, but also energy loss occurs.

Furthermore, in the prior art shown in FIGS. 3 and 4, the power converter (motor drive circuit) must always perform boosting during either power running or regeneration of the motor. However, step-up is generally less efficient than step-down, and the efficiency of the entire power supply device is reduced. Also,
In the conventional power supply device disclosed in FIG. 5 of JP-A-5-30608 described above, the connection relationship between the battery and the capacitor is selectively switched between series connection and parallel connection according to the drive mode of the motor. A circuit was required and the configuration became complicated. Further, in this conventional technique, a large number of capacitors have to be connected in series because the capacitors need to generate a high voltage, which causes the above-mentioned problem of voltage variations among the capacitors.

Therefore, an object of the present invention is that the electric energy stored in the capacitor can be used until it reaches zero, the capacitor does not need to generate a high voltage, and the power converter only needs a step-down operation. Another object of the present invention is to provide a power supply device for driving a motor.

[0012]

In order to solve the above-mentioned problems, a motor drive power source apparatus according to the invention of claim 1 receives a series circuit of a battery 26 and a capacitor 24, and a voltage of this series circuit. , A first power converter 28, 34 for supplying a drive voltage to the motor 30 and a second power converter 32, 34 for receiving a voltage from the motor 30 and supplying a charging voltage to the capacitor 24. 1st during powering
The motor 30 is driven by the drive voltage from the power converters 28 and 34.
To drive the second power converter 32 when the motor 30 is regenerated,
It is characterized in that the capacitor 24 is charged by the charging voltage from 34. In addition, the reference numbers refer to FIG. 1 or FIG.
3 shows a correspondence relationship with the embodiment of the present invention shown in FIG.

The series circuit according to the first aspect of the present invention comprises a capacitor 24 and a battery 26 of one group (including one case).
Is a circuit connected in series, the end of the battery opposite to the capacitor is coupled to one end of the motor 30 via the first power converter 28, and the end of the capacitor 24 on the battery side is the second power converter. It is characterized in that it is coupled to one end of the motor 30 via 32, and the end of the capacitor 24 opposite to the battery is coupled to the other end of the motor 30.

Further, the series circuit according to claim 1 is
This is a circuit in which a battery 261 of the first group (including the case of one), a capacitor 24, and a battery 262 of the second group (including the case of one) are sequentially connected in series. The capacitors of the two groups of batteries 261 and 262 and the two opposite ends are the first power converters 281 and 2 respectively.
82 is coupled to both ends of the motor 30 respectively, and both ends of the capacitor are coupled to the motor 30 via the second power converter 32.
It is characterized by being connected to both ends of.

Further, in the first and second power converters according to the first aspect, the chopper circuits 28 and 32 for stepping down the voltage.
Alternatively, it is characterized by comprising an inverter and its control circuit 34. The invention according to claim 1 is characterized in that a polarity reversal prevention diode 36 is connected to both ends of the capacitor 24.

Further, the invention according to claim 1 is characterized in that the capacitor 24 is an electric double layer capacitor.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a first preferred embodiment of the present invention. For example, one electric double layer capacitor 24 which is a general large capacity capacitor
And, for example, a plurality of batteries 26, which are storage batteries, are connected in series to form a series circuit. Battery group 26 of this series circuit
The opposite end (plus end) of the capacitor is coupled to one end (plus end) of the DC motor 30 via the power running step-down chopper 28. The common connection point of the capacitor 24 and the battery group 26 is coupled to one end of the DC motor 30 via the regenerative step-down chopper 32. The other end (minus end) of the capacitor 24 is coupled to the other end (minus end) of the motor 30. The chopper control circuit 34 controls the chopping operation of the choppers 28 and 32, and the choppers 28 and 3 are controlled.
2 and the control circuit 34 constitute a power converter. Also,
Bypass diode 36 is placed across capacitor 24.
Connect. The choppers 28 and 32 include a power transistor and an insulated gate transistor (IGBT).
And switching semiconductor devices such as field effect transistors (FETs). In addition, these choppers have a directivity of a current to be passed when conducting, in the chopper 28, in the direction from the battery group 26 to the motor 30, and in the chopper 32, in the direction from the motor 30 to the capacitor 24.

Next, the operation of the embodiment shown in FIG. 1 will be described. It is assumed that the capacitor 24 is charged to a certain voltage with electric energy. Capacitor 2 when the motor is running
The voltage of No. 4 and the voltage of the battery group 26 are added, and the added voltage is stepped down by the power running step-down chopper 28 and supplied to the DC motor 30. Therefore, the current from the capacitor 24 and the battery group 26 is transferred to the chopper 28.
And, it returns to the condenser 24 through the motor 30 to form a closed circuit, and the motor 30 rotates. At this time, when a large amount of electric power is required, the electric energy of the capacitor 24 helps supply electric power. Further, the chopper 28 repeats conduction and non-conduction by the control of the pulse signal from the control circuit 34, and passes the input to the output only when it is in conduction. Therefore, the chopper 28 controls the time ratio of conduction and non-conduction to reduce the voltage. The rate can be controlled (ie the average value of the electrical energy passed during conduction over time corresponds to the voltage supplied to the motor 30). By this control, the rotation state of the motor 30 is controlled. At this time, since the capacitor 24 and the battery group 26 are connected in series, even if the voltage of the capacitor 24 gradually decreases, the voltage at the upper end of the battery group 26 is always at least the voltage of the battery. This capacitor 24 until the voltage of
The electric energy of can be used. Further, since the chopper 32 is directional, the voltage of the capacitor 24 is not supplied to the motor 30 via the chopper 32.

During regeneration of the motor 30, the chopper 28 remains in a non-conducting state, the voltage from the battery group 26 does not pass through the chopper 28, and the drive voltage is not supplied to the motor 30. Therefore, the motor 30 functions as a generator, supplies the generated voltage to the capacitor 24 via the chopper 32, and charges the capacitor 24. This charging voltage is reused when the motor is running. The motor 30
Since the generated voltage is high, the chopper 32 steps down the generated voltage according to the control of the control circuit 34 according to the same principle as the chopper 28.

By the way, during the power running of the motor 30, the charging voltage decreases as the discharging of the large-capacity capacitor 24 progresses, and the polarity is reversed when the charged amount becomes zero.
The diode 36 conducts when the polarity of the capacitor 24 is about to be reversed, and prevents this polarity reversal. During the period when the polarity of the capacitor 24 is not reversed, the diode 36 is non-conducting, so that the operation of the device of FIG. 1 is not affected.

FIG. 2 is a block diagram of a second preferred embodiment of the present invention. Only the differences from the embodiment of FIG. 1 will be described below. The series circuit of the capacitor and the battery is the first of the battery.
It is composed of a group 261, a capacitor 24 and a second group 262 of batteries. That is, the capacitor 24 is arranged between the battery groups 261 and 262, which is equivalent to a further battery group being arranged on the negative side of the capacitor 24 in the embodiment of FIG. Therefore, the step-down chopper for power running is composed of two choppers 281 and 282, the negative end of the battery group 261 is coupled to the negative end of the motor 30 via the chopper 281, and the positive end of the battery group 262 is connected to the chopper 28.
It is connected to the positive end of the motor 30 via 2. Further, both ends of the capacitor 24 are coupled to both ends of the motor 30 via a regenerative chopper 32 composed of two choppers. Although these four choppers are controlled by the control circuit 34, the choppers 281 and 282 are turned on and off at the same time. In addition, the two choppers 32 also become conductive and non-conductive at the same time. It should be noted that these choppers 281, 282 and 32 also have a conduction direction.

The operation of the embodiment of FIG. 2 is similar to that of the embodiment of FIG. 1, and when the motor 30 is in the power running mode, the battery group 261, the capacitor 24 and the battery group 262 are transferred to the motor 30 via the chopper 282. Current flows,
The return current from the motor 30 returns to the battery group 261 via the chopper 281. The choppers 281 and 2
The degree of step-down by 82 is determined by the ratio of the conduction control period and the non-conduction control period from the control circuit 34. When the motor is regenerated, the choppers 281 and 282 become non-conductive,
The generated voltage of the motor 30 is stepped down by the chopper 32 to charge the capacitor 24. The energy generated by this charging is used during power running of the motor.

Although two preferred embodiments of the present invention have been described above, those skilled in the art can make various modifications and changes without departing from the gist of the present invention. For example,
The power converter may use an inverter instead of the chopper to step down the input voltage. Further, as the capacitor, one having a plurality of capacitors connected in parallel may be used. Further, a small number of capacitors may be connected in series instead of one capacitor. In the case of connecting a small number of capacitors in series, the variation in the voltage of each capacitor is smaller than that in the case of connecting a large number of capacitors in series, so it is not a serious problem.

[0024]

According to the motor drive power supply device of the present invention, since the capacitor and the battery are connected in series, even if the storage voltage of the capacitor is lowered, the voltage of the entire series circuit is the same as that of the power converter and the motor. It is high enough to drive and can be used until the stored energy in the capacitor is completely zero during powering of the motor. Further, the voltage of the capacitor does not need to be as high as the battery voltage and may be low, so that it is not necessary to connect a large number of capacitors in series. Therefore, the problem of the voltage balance of the capacitors is reduced, and a large-capacity capacitor can be used with the low-voltage specification, so that the number of capacitors may be one or a small number. In this case, a special capacitor is not necessary, and an inexpensive general electric double layer capacitor can be used, so that the entire power supply device can be inexpensive. Furthermore, since the power converter does not need to perform step-up operation but only step-down operation, it is possible to improve overall efficiency and reduce power consumption.

Further, since it is not necessary to switch the connection relationship between the capacitor and the battery in accordance with power running and regeneration, there is an effect that the configuration is simpler than that of the prior art which requires a connection switching circuit.

[Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of a power supply device for driving a motor according to the present invention.

FIG. 2 is a block diagram of another preferred embodiment of the motor driving power supply device of the present invention.

FIG. 3 is a block diagram of an example of a conventional motor drive power supply device.

FIG. 4 is a block diagram of another example of a conventional motor drive power supply device.

FIG. 5 is a circuit diagram for explaining operations of charging and discharging a capacitor and a conventional capacitor circuit.

[Explanation of reference numerals] 24 capacitor 26 battery 261 battery 262 battery 28 power-running step-down chopper 281 that constitutes the first power converter 281 power-running step-down chopper that constitutes the first power converter 282 for power running that constitutes the first power converter Step-down chopper 30 Motor 32 Step-down chopper for regeneration that constitutes the second power converter 34 Chopper control circuit that is a part of the power converter 36 Diode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuhito Onuma 4415-2 Shinyoshida-cho, Kohoku-ku, Yokohama-shi, Kanagawa Tokyo R & D Yokohama Works

Claims (6)

[Claims] 1. A series circuit of a battery and a capacitor, a first power converter that receives a voltage of the series circuit and supplies a driving voltage to a motor, and a voltage from the motor that supplies a charging voltage to the capacitor. A second power converter for driving the motor with the drive voltage from the first power converter when the motor is running, and the capacitor with the charging voltage from the second power converter when the motor is regenerated. A power supply device for driving a motor, characterized in that: 2. The series circuit according to claim 1 is a circuit in which a capacitor and a battery of one group (including a case of one) are connected in series, and a capacitor on the opposite side of the capacitor of the battery of the one group. An end portion is coupled to one end of the motor via the first power converter, an end portion of the capacitor on the battery side is coupled to the one end of the motor via the second power converter, A power supply device for driving a motor, wherein an end of the capacitor opposite to the battery is coupled to the other end of the motor. 3. The series circuit according to claim 1, wherein a battery of a first group (including the case of one), a capacitor, and
A battery of a second group (including a case of one) is sequentially connected in series, and two ends of the batteries of the first and second groups on the side opposite to the capacitor have the first power conversion. A power supply device for driving a motor, characterized in that both ends of the motor are coupled to each other via a power supply device, and both ends of the capacitor are coupled to both ends of the motor via the second power converter. 4. The power source for driving a motor, wherein the first and second power converters according to claim 1 are composed of a chopper circuit or an inverter circuit for stepping down a voltage and a control circuit thereof. apparatus. 5. A motor drive power supply device comprising a polarity reversal prevention diode connected to both ends of the capacitor according to claim 1. 6. A power supply device for driving a motor, wherein the capacitor according to claim 1 is an electric double layer capacitor.