JP3541238B2 - Power supply for motor drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor-driving power supply, particularly a power supply suitable for driving the power motor of an electric vehicle, an electric scooter, an electric bicycle, etc. SOLUTION: The output terminal of a first power converter 28 is linked to a motor 18, while the input terminal of the first power converter 28 is connected to batteries 26 and the series circuit of a capacitor 24 via a switching circuit 72. The switching circuit 72 links both ends of the batteries 26 or of the series circuit selectively to the first power converter 28. The input terminal of a second power converter 32 is linked to a motor 18 and its output terminal is linked in such a way as to be able to charge the capacitor. A control circuit 73 controls the first power converter 28, second power converter 32 and switching circuit 72 in accordance with the state of acceleration, etc. This control circuit 73 controls the on/off of the switching circuit 72 in compliance with power required by the motor 18 to adjust power to be supplied from the capacitor 24 to the motor 18.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device for driving a motor, and particularly to a power supply device suitable for driving a power motor for an electric vehicle, an electric scooter, an electric bicycle, or the like.
[0002]
[Prior art]
As a power supply device for driving a power motor for an electric vehicle, an electric scooter, or an electric bicycle, a hybrid power supply device in which a battery and a capacitor are connected in parallel and an output from the parallel circuit is supplied to the motor through a power converter. Many have been proposed in the past. In this case, the capacitor performs a function of supplying a large amount of electric power to the motor in a short time in accordance with a load change of the motor, and the battery performs a function of supplying an average amount of electric power to the motor over a long period of time while having a small electric power. This is to reduce the peak load of the battery, extend the life of the battery, and substantially increase the power capacity.
[0003]
FIG. 8 shows an example of such a conventional motor drive power supply device. The group 10 of a plurality of batteries connected in series to generate a high voltage and the group 12 of a plurality of capacitors connected in series have a common potential on the negative (-) side and current control on the plus (+) side. They are connected in parallel via a circuit 14. The current control circuit 14 is for preventing an overcurrent from flowing from the battery group 10, and the voltage from the parallel circuit of the battery group 10 and the capacitor group 12 is supplied to a power converter which is a motor drive circuit. The power is supplied to both ends of the DC motor 18 via the DC motor 16. The power converter 16 is a chopper or an inverter, and its operation is controlled by a control circuit (not shown).
[0004]
FIG. 9 shows an example in which a chopper is used for the power converter 16. The input / output terminals 40 and 42 correspond to the two left terminals of the power converter 16, and the input / output terminals 54 and 56 correspond to the right two terminals of the power converter 16. Between terminals 40 and 42, the drain-source (or collector-emitter) of transistors 44 and 46 such as a power transistor, an insulated gate transistor (IGBT) and a field effect transistor (FET) are connected in series as shown. , The gates (or bases) of these transistors receive a control pulse signal from the control circuit. Diodes 48 and 50 are connected in reverse polarity between the collector and the emitter (or between the drain and the source) of the transistors 44 and 46, and a common connection point of the diodes 48 and 50 is connected through a choke coil 52 to a terminal. 54. Further, an electrolytic capacitor 41 is connected between the terminals 40 and 42 in order to stabilize the voltage fluctuation of the power supply caused by the operation of the transistor as the switching element.
[0005]
During power running for rotating the motor 18, the transistor 46 in the power converter 16 is always non-conductive, and the transistor 44 repeats conduction and non-conduction in response to a control pulse signal from the control circuit. Therefore, the power converter 16 reduces the voltage from the parallel circuit of the battery group 10 and the capacitor group 12 according to the conduction / non-conduction time ratio of the control pulse signal, that is, the duty cycle, and supplies the voltage to the motor 18. I do. Further, at the time of regeneration in which the supply of the drive voltage to the motor 18 is stopped, the motor 18 functions as a generator. During this time, the control circuit constantly controls the transistor 44 in the power converter 16 to be non-conductive, and the transistor 46 repeats conductive and non-conductive according to a control pulse signal from the control circuit. Therefore, the power converter 16 boosts the voltage (regenerative voltage) generated by the motor 18 to charge (store) the capacitor group 12. The energy charged in the capacitor group 12 is reused during power running of the motor to improve the efficiency of the entire power supply. Further, at the time of power running, by controlling the degree of step-down of the power converter 16 in accordance with the duty cycle of the control pulse signal, it is possible to control the rotation speed and torque of the motor.
[0006]
FIG. 10 shows another example of a conventional power supply device for driving a motor. The difference from the prior art of FIG. 8 is that the plus side of the battery group 10 and the capacitor group 12 is alternately and rapidly selected by the semiconductor switch 20 and the selected voltage is supplied to the power converter 16. . Note that 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 prior art, similarly to the case of FIG. 8, when the motor 18 is running, the power converter 16 reduces the output voltage of the switch 20 and supplies it to the motor 18. During regeneration of the motor 18, the power converter 16 boosts the voltage generated by the motor 18 and charges the capacitor group 12 via the switch 20. This charged energy (storage energy) is reused when the motor is running, as in the prior art of FIG.
[0007]
By the way, in order to obtain electric power for driving a motor from a capacitor, the capacitor must have a large capacity. However, even with a large-capacity capacitor, the charging energy of the capacitor is at least one order of magnitude smaller than that of the battery, so it is necessary to effectively use the energy stored in the capacitor. Using all the stored energy of the capacitor means using it until the voltage of the capacitor becomes zero. However, in the related art shown in FIGS. 8 and 10, the motor 18 is driven by the power converter 16 using the voltage of the capacitor 12, but this drive requires a certain voltage or more. Therefore, the power converter 16 and the motor 18 stop operating before the voltage of the capacitor 12 becomes zero, so that the stored energy of the capacitor 12 cannot be used up. This is the same even if a booster circuit is provided at the terminal of the capacitor 12, and the stored energy of the capacitor 12 cannot be used up.
[0008]
The mainstream of large-capacity capacitors are electric double-layer capacitors. However, this capacitor can only reduce the voltage per cell to about 1 to 5 volts 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, and a plurality of electric double layer capacitors must be connected in series. However, there is a problem of voltage balance in each capacitor. This problem is caused by the fact that the capacitors self-discharge due to the internal resistance after charging all the capacitors connected in series, and the variation in the self-discharge is extremely large. As a result, the voltage of a certain capacitor becomes zero volt over time. In this state, when discharged, the zero volt capacitor cannot maintain the lower limit, and when charged, another capacitor cannot maintain the upper limit, so that charging and discharging cannot be performed.
[0009]
In order to solve the problem that the stored energy of the capacitor cannot be used up and the problem of connecting a plurality of capacitors in series, a motor drive power supply device shown in FIG. 11 has been proposed. In this power supply device, when the motor 18 is running, the first power converter 28 reduces the voltage of the series circuit of the battery 26 and the capacitor 24 and supplies the motor 18 with a drive voltage. Further, at the time of regeneration of the motor 18, the second power converter 32 receives the generated voltage from the motor 18, reduces the voltage, and supplies the capacitor 24 with the charging voltage. Note that the step-down operation of the power converters 28 and 32 is controlled by a control pulse signal from the control circuit 34. Further, a diode 36 for preventing polarity reversal is connected to both ends of the capacitor 24. When the discharge of the capacitor 24 progresses during the power running of the motor 18, the charging voltage decreases, and eventually the polarity is inverted when the charged amount becomes zero. However, this diode 36 becomes conductive when the polarity of the capacitor 24 is to be inverted. This polarity inversion is prevented. However, during a period in which the polarity of the capacitor 24 is not inverted, the diode 36 is non-conductive, so that the operation of the power supply device is not affected.
[0010]
According to the power supply device for driving a motor shown in FIG. 11, since the capacitor 24 and the battery group 26 are connected in series, even if the storage voltage of the capacitor 24 decreases, the voltage of the entire series circuit can be reduced by the power converter 28 and It is high enough to drive the motor 18 and can be used until the stored energy of the capacitor 24 becomes completely zero when the motor 18 is running. Further, since the voltage of the capacitor 24 does not need to be high like the voltage of the battery group 26 and may be low, there is no need to connect a large number of capacitors in series. Therefore, the problem of voltage balance of the capacitor is reduced, and a large-capacity capacitor can be used with a low voltage specification. Therefore, an inexpensive electric double layer capacitor can be used as the capacitor 24.
[0011]
Note that the first power converter 28 and the second power converter 32 perform power conversion by one-way step-down, unlike the power converter 16 of FIGS. 8 and 10. Each of the first and second power converters is one of a chopper circuit and a DC / DC converter, or the first power converter is an inverter and the second power converter is an AC / DC inverter. As an example, the case of a chopper is shown in FIG. In FIG. 12, a series circuit of a transistor 62 similar to the above-described transistor 44 or 46 and a choke coil 66 is connected between an input terminal 58 and an output terminal 68, and a common connection point of the transistor 62 and the coil 66 is provided. And a diode 64 is connected between the input terminal 60 and the output terminal 70. The gate (or base) of the transistor 62 is controlled by a control pulse signal from the control circuit 34, and the transistor 62 is turned on and off alternately, so that the input terminals 58 and 60 are connected according to the duty cycle of the control pulse signal. , And output it between the output terminals 68 and 70. Note that an electrolytic capacitor 59 is connected between the terminals 58 and 59 in order to stabilize the voltage fluctuation of the power supply caused by the operation of the transistor as the switching element.
[0012]
[Problems to be solved by the present invention]
By the way, in the conventional motor driving power supply device shown in FIG. 11, a current always flows through the capacitor 24 during the power running of the motor 18, that is, during the discharging period of the capacitor 24, unless the voltage of the capacitor 24 is zero. The distribution of the power running power of the battery 26 and the capacitor 24 is equal to the current flowing through the battery 26 and the capacitor 24, so that the respective voltage ratios are obtained, and this distribution ratio cannot be arbitrarily changed. Therefore, even if the required power is small enough that all the required power of the motor 18 can be covered by the battery 24, the power charged in the capacitor 24 is wasted.
[0013]
This state will be further described with reference to FIG. In the case of the power supply circuit of FIG. 11, acceleration (from time 0 to time t1), speed maintenance (from time t1 to time t2), deceleration (from time t2 to time t3) between the battery 26 and the capacitor 24. 13), the power is shared as shown in FIG. It should be noted that the area B (point area) indicates the power shared by the battery 26, the area C1 (positive vertical line area) indicates the power shared by the capacitor 24 by discharging, and the area C2 (negative part). (A vertical line area) indicates an area where the capacitor 24 is charged with the regenerative electric power of the motor. As described above, the power sharing cannot be arbitrarily changed since the currents flowing through the battery 26 and the capacitor 24 are equal.
[0014]
There is no problem if the storage capacity of the energy of the capacitor 24 is large. However, since the energy density of the capacitor 24 is one order of magnitude lower than that of the battery 26, when unnecessary, the storage energy of the capacitor 24 is wastefully consumed. In this case, there is a problem that the remaining energy of the capacitor 24 is small when large power is needed. That is, when the required power of the motor 18 is large, the discharge power from the capacitor 24 is increased, and when the required power is small, the discharge power from the capacitor 24 is reduced. Well used and desirable.
[0015]
Therefore, an object of the present invention is to make it possible to use the stored energy of the capacitor during the power running of the motor until the stored energy of the capacitor becomes completely zero, and to arbitrarily control the ratio of the power burden of the battery and the capacitor to further improve the stored energy of the capacitor. It is an object of the present invention to provide a motor drive power supply device that can be used in a general purpose.
[0016]
[Means for Solving the Problems]
As means for solving the above problems,Claim 1According to the inventionAs shown in FIG. 1 and FIG.
A series circuit of a battery 26 and a capacitor 24;,
A first power converter 28 having an output coupled to the motor 18;,
The input terminal of the first power converter 28 is connected to both ends of the battery 26 orthe aboveSwitch circuit 72 selectively coupled to both ends of a series circuitOr75 and,
A second power converter 32 having an input coupled to the motor 18 and an output coupled to charge the capacitor 24;,
First power converter 28, second power converter 32, and switch circuit 72Or 75And a control circuit 73 for controlling
The control circuit 73 operates when the motor 18 is running.ButDepending on the power you needthe aboveSwitch circuit 72Or 75Controls conduction and non-conduction ofAnd,For the power required by motor 18Power obtained from capacitor 24Of battery and power of battery 26To adjust.
[0017]
ContractStated in claim 2According to the inventionAs shown in FIG.
A series circuit of a battery 26 and a capacitor 24;,
One of the first input / output terminals is connected to the capacitor of the battery 26 through the first switch circuit 77.IsA first power converter 16 coupled to the opposite end (plus end) and having a second input / output end coupled to the motor 18;,
The other of the first input / output terminals of the first power converter 16 is connected to the other end (minus terminal) of the battery 26 or the battery of the capacitor 24.IsA second switch circuit 72 selectively coupled to the opposite end (minus end);,
A second power converter 32 having an input coupled to the first input / output terminal of the first power converter 16 and an output coupled to charge the capacitor 24;,
It comprises a first switch circuit 77, a second switch circuit 72, a control circuit 73 for controlling the first power converter 16 and the second power converter 32.
The control circuit 73 closes the first switch circuit 77 when the motor 18 is running,ButControls the conduction and non-conduction of the second switch circuit 72 according to the required powerAnd,For the power required by motor 18Power obtained from capacitor 24Of battery and power of battery 26To adjust.
[0018]
ContractStated in claim 3According to the inventionAs shown in FIG.
A series circuit of a battery 26 and a capacitor 24;,
A first input / output terminal coupled to both ends of the series circuit via a switch circuit 77, and a second input / output terminal coupled to the first power converter 16 coupled to the motor 18;,
A second power converter 320 having an input terminal coupled to the first input / output terminal of the first power converter 16, an output terminal coupled to charge the capacitor 24, and an insulation between the input terminal and the output terminal;,
It includes a switch circuit 77, a control circuit 73 for controlling the first power converter 16 and the second power converter 320.
The control circuit 73 closes the switch circuit 77 when the motor 18 is running,ButControls the second power converter 320 according to the required powerAnd,For the power required by motor 18Power obtained from capacitor 24And the ratio of the power of the battery 26 toadjust.
[0019]
ContractStated in claim 4According to the inventionAs shown in FIG. 7, the motor drive power supply device
A series circuit of a battery 26 and a capacitor 24;,
A first power converter having an input coupled to both ends of the series circuit and an output coupled to the motor 18;28When,
The input terminal is coupled to the motor 18 and the output terminal is coupled to charge the capacitor 24.Consists of DC / DC converterWith the second power converter 320,
1st power converter28And a control circuit 73 for controlling the second power converter 320.
When the motor 18 is running, the control circuit 73ButControls the second power converter 320 according to the required powerAnd,For the power required by motor 18Power obtained from capacitor 24And the ratio of the power of the battery 26 toadjust.
[0020]
Embodiments and Examples of the Invention
FIG. 1 is a block diagram of a first preferred embodiment of a power supply device for driving a motor according to the present invention, and has portions similar to those of the power supply device of FIG. For example, one lightning double-layer capacitor 24, which is a general large-capacity capacitor, and a plurality of batteries 26, which are storage batteries, for example, are connected in series to form a series circuit. The opposite end (positive end) of the capacitor 24 of the battery group 26 of this series circuit is coupled to one of the left input ends (upper end) of the unidirectional first power converter 28, and the negative end of the capacitor 24 is connected to a switch. Through a circuit 72, it is coupled to the other (lower) left input terminal of the first power converter 28. The switch elements of the switch circuit 72 are, for example, a relay, a contactor, a power transistor, an insulated gate transistor (IGBT), and a field effect transistor (FET). The opening and closing of the switch circuit 72 is controlled by a control signal from the control circuit 73. A common connection point of the capacitor 24 and the battery group 26 and a common connection point of the first power converter 28 and the switch circuit 72 are coupled to the left output terminal of the unidirectional second power converter 32. Further, a bypass diode 36 for preventing polarity reversal is connected to both ends of the series circuit of the capacitor 24 and the switch circuit 72. The motor 30 is coupled to a right output terminal of the first power converter 28 and a right input terminal of the second power converter 32. The control circuit 73 also controls the operation of the power converters 28 and 32.
[0021]
The first power converter 28 is a unidirectional chopper or an inverter that reduces the voltage from the series circuit of the capacitor 24 and the battery group 26 or the voltage from only the battery 26 and supplies the voltage to the motor 18 when the motor 18 is running. It is. The second power converter 32 is a unidirectional chopper or an AC / DC converter that reduces the voltage generated by the motor 18 and supplies the voltage to the capacitor 24 during regeneration of the motor 18. When the first and second power converters are choppers, the circuit shown in FIG. 12 can be used. In this case, the terminals 58 and 60 are input terminals, and the terminals 68 and 70 are output terminals. The gate (or emitter) of the transistor 62 receives a control signal from the control circuit 73.
[0022]
1st power converter28, The operating power of the second power converter 32 and the control circuit 73 may be obtained directly from the battery 26 or the series circuit of the battery 26 and the capacitor 24, or the output of the battery 26 or the series circuit may be obtained through the DC / DC converter. You can get it. Further, an auxiliary power source different from the battery 26 may be provided and obtained from the auxiliary power source. Further, it may be obtained from the power running power of the first power converter 28 or from the regenerative power of the second power converter 32.
[0023]
When the motor drive power supply device of the present invention is used in an electric vehicle, the control circuit 73 controls conduction / non-conduction of the power converters 28 and 32 according to the states of the accelerator 74, the brake 76, and the clutch 78. This is a circuit that supplies a signal and also supplies an open / close control signal to the switch circuit 72, and can be configured by, for example, a microprocessor system. That is, the control circuit 73 determines that either the regenerative state or the powering state is performed in a state where the clutch 78 is engaged. In this state, when the accelerator 74 is on and the brake 76 is off, it is determined that the vehicle is in a powering state. In other cases, that is, regardless of whether the accelerator 74 and the brake 76 are both off or regardless of the accelerator 74, If the brake 76 is on, it is determined that the vehicle is in a regenerative state. The control circuit 73 generates an appropriate control signal according to this determination.
[0024]
Next, the operation of the first embodiment of FIG. 1 will be further described with reference to FIG. 2 showing the state of sharing of the power consumed by the motor 18. Note that, in FIG. 2, similarly to FIG. 13, the area B indicates the power area shared by the battery group 26, the area C1 indicates the area shared by the capacitor 24, and the area C2 indicates charging of the capacitor 24 by the regenerative voltage. Show. When the control circuit 73 determines that the motor 18 is in the power running state, the control circuit 73 keeps the transistor 62 in the second power converter 32 non-conductive and stops the operation of the second power converter 32. Let it. Therefore, the second power converter 32 is as if it were not connected. The control circuit 73 detects a voltage and a current supplied to the motor 18 in a power running state of the motor 18 (a detection circuit is not shown), and also detects a state of the accelerator 74 to determine how much power the motor 18 requires. Judge whether to do.
[0025]
When the required power of the motor 18 is small, such as from the time point 0 to the time point t1 shown in FIG. 2, all the power can be supplied only by the battery group 26, so the control circuit 73 opens the switch circuit 72 ( Non-conducting). Therefore, only the battery group 26 supplies power to the first power converter 28 via the diode 36. The first power converter 28 steps down this voltage and supplies it to the motor 18.
[0026]
In relation to the setting of the accelerator 74, if the level at which power must be supplied from the capacitor 24 (set value), that is, the level that cannot be met by the power sharing of only the battery, is reached, the control circuit 73 returns at time t1. When it is determined, the control circuit 73 closes (turns on) the switch circuit 72. Therefore, a certain voltage based on the electric energy charged in the capacitor 24 and the voltage of the battery group 26 are added, and the added voltage is stepped down by the first power converter 28 and supplied to the DC motor 18. . Therefore, current from the capacitor 24 and the battery group 26 returns to the capacitor 24 via the first power converter 16, the motor 18, and the switch circuit 72, and a closed circuit is formed, so that the motor 18 rotates.
[0027]
Further, when the required power of the motor 18 becomes less than the set value at the time point t2 in relation to the setting of the accelerator 74, the control circuit 73 turns off the switch circuit 72 again. Therefore, the capacitor 24 is disconnected, and only the battery group 26 is stepped down by the first power converter 28 to supply power to the motor 18. This state continues until time t3. Since the power running period of the motor 18 is from the time point 0 to the time point t3, the control circuit 73 controls the supply to the first power converter 28 based on the relationship between the state of the accelerator 74 and the power supplied to the motor 18. By controlling the duty cycle of the pulse signal, the rotational state of the motor 18 is controlled as desired by the driver. Further, the control circuit 73 has a function of controlling a control pulse signal supplied to the power converter 28 so that the operation of the motor does not change even if the voltage of the power supply changes.
[0028]
Since the capacitor 24 and the battery group 26 are connected in series while the switch circuit 72 is conducting, the voltage at the upper end of the battery group 26 is always at least the voltage of the battery even if the voltage of the capacitor 24 is sequentially reduced. Is sufficient, so that the electric energy of the capacitor 24 can be used until the voltage of the capacitor 24 becomes zero. By the way, during the power running of the motor 18 between the time points t1 and t2, as the discharge of the large-capacity capacitor 24 progresses, the charging voltage decreases, and when the charged amount becomes zero, the polarity is reversed. 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 inverted, the diode 36 is non-conductive, and while the switch circuit 72 is non-conductive, the diode 36 is conductive, so that the operation of the device of FIG. 1 is not affected. .
[0029]
At time t3, when the control circuit 73 determines that the motor 18 is in the regenerative state, the control circuit 73 turns on the switch circuit 72, turns off the transistor 62 in the first power converter 28, and performs the operation. To stop. Further, the control circuit 73 causes the transistor 62 in the second power converter 32 to be repeatedly turned on and off with an appropriate duty cycle to operate the second power converter 32. Therefore, the voltage from the capacitor 24 and the battery group 26 does not pass through the first power converter 28, and no drive voltage is supplied to the motor 18. Therefore, the motor 18 functions as a generator and generates a generated voltage, that is, a regenerative voltage. This regenerative voltage is supplied to the capacitor 24 via the second power converter 32, and charges the capacitor 24. This charging voltage is reused when the motor is running.
[0030]
FIG. 3 is a block diagram of a second preferred embodiment of the present invention. Since the second embodiment is similar to the first embodiment shown in FIG. 1, only different points will be described below. In the embodiment of FIG. 1, the switch circuit 72 is a single-pole single-throw switch connected between the negative terminal of the capacitor 24 and the common potential terminal (lower left terminal) of the first power converter 28. In the embodiment of FIG. 3, a double pole single throw switch circuit 75 is used in place of the switch circuit 72, and fixed terminals are connected to respective ends of the capacitor 24, and movable terminals are connected to a common potential terminal of the first power converter 28. Connected. If the required power of the motor 18 is small during the powering period of the motor 18, the switch circuit 75 selects the minus end of the battery group 26 and disconnects the capacitor 24 under the control of the control circuit 73. When the required power of the motor 18 is large, the switch circuit 75 selects the negative terminal of the capacitor 24 under the control of the control circuit 73, and the first power converter 28 connects the series circuit of the capacitor 24 and the battery group 26. To receive power from. Other operations during the powering period are the same as those in the embodiment of FIG. Further, during the regeneration period, the control circuit 73 stops the operation of the first power converter 28, so that the selection of the switch circuit 75 may be any.
[0031]
FIG. 4 is a block diagram of a third preferred embodiment of the present invention. In the third embodiment, the capacitor 24 and the battery group 26 are connected in series. The plus end of the battery group 26 of this series circuit is coupled to one (upper side) of the left input / output terminal of the bidirectional first power converter 16 via the first semiconductor switch circuit 77, and the minus end of the capacitor 24 is connected. The other end is below the other input / output terminal (lower side) on the left side of the first power converter 16 and the lower output terminal on the left side of the unidirectional second power converter 32 via the second switch circuit 72, that is, , Coupled to a reference potential source. The right input terminal of the second power converter 32 is coupled to the left input / output terminal of the first power converter 16, and the left output terminal of the second power converter 32 is connected via the second switch circuit 72. The capacitor 24 is connected so as to be chargeable. The left input / output end of the first power converter 16 is coupled to the motor 18. A bypass diode 36 for preventing polarity reversal is connected to both ends of the series circuit of the capacitor 24 and the second switch circuit 72. A control circuit 73 similar to that of FIG. 1 controls the first switch circuit 77, the second switch circuit 72, the first power converter 16, and the second power converter 32. Note that no other circuit, for example, the second power converter 32 is connected between the connection of the first power converter 16 and the motor 18, so that a predetermined optimum power supply of the first power converter 16 and the motor 18 is set. Note that the combination can be used as it is without breaking the matching. Also, the first power converter 16 can use the chopper shown in FIG. 9, and the second power converter 32 can use the chopper shown in FIG.
[0032]
During power running of the motor 18, the control circuit 73 maintains the switch circuit 77 in a conductive state, stops the operation of the second power converter 32, and supplies the first power converter 16 with a control pulse signal having an appropriate duty cycle. Then, the first power converter 16 can reduce the input voltage from the left side and supply it to the motor 18. If the required power of the motor 18 is lower than the set value during the power running, only the power from the battery group 26 is sufficient, so the control circuit 73 turns off the switch circuit 72. Therefore, the current from the battery group 26 is applied to the first power converter 16 via the first switch circuit 77, and the return current from the first power converter 16 returns to the battery group 26 via the diode 36. . When the required power of the motor 18 becomes higher than the set value, the control circuit 73 makes the switch circuit 72 conductive because the first power converter 16 receives power from both the battery group 26 and the capacitor 24. Therefore, the current from the series circuit of the battery group 26 and the capacitor 24 is applied to the first power converter 16 via the first switch circuit 77, and the return current from the first power converter 16 is applied to the second switch circuit. Returning to capacitor 24 via 72. The operation of the diode 36 is the same as in the first and second embodiments.
[0033]
At the time of regeneration of the motor 18, the control circuit 73 turns off the first switch circuit 77, turns on the second switch circuit 72, and appropriately operates the second power converter 32. Note that the first power converter 16 does not receive power from the battery group 26 due to the non-conduction of the switch circuit 77, and therefore cannot supply power to the motor 18. Therefore, the second power converter 32 receives the regenerative power of the motor 18 via the first power converter 16, appropriately lowers the voltage, and charges the capacitor 24.
[0034]
Regardless of whether the power converter 16 is a chopper or an inverter, if the power supply voltage for the chopper or the inverter is higher than the electromotive force of the motor 18, the time ratio between the conduction and non-conduction of the switching element (transistor) will be described. By adjusting the (shock coefficient), regenerative power control at boosting is possible. However, when the power supply voltage is lower than the electromotive force of the motor 18, the chopper or the inverter merely acts as a rectifier, and the control of the regenerative power becomes impossible. However, the second power converter 32 controls the regenerative power to control the regenerative power. There is no problem because the capacitor 24 can be charged. Therefore, after the power generated by the motor 18 is rectified (in an uncontrollable state) by the first power converter 16, the voltage may be reduced (in a controllable state) by the second power converter 32, or After boosting (in a controllable state) by one power converter 16, it may be stepped down (in a controllable state) by second power converter 32. Also, in this embodiment, by insulating the input and output terminals of the second power converter 32, the switch circuits 77 and 72 are turned on and the second power converter 32 is operated even when the motor 18 is stopped. Thereby, the capacitor 24 can be charged from the battery group 26.
[0035]
FIG. 5 is a block diagram of a fourth preferred embodiment of the present invention. This embodiment is similar to the embodiment of FIG. 4 without the second switch circuit 72, except that the second power converter 320 has an input side (right terminal) and an output side (left terminal). It is composed of a general DC / DC converter with the insulation between them. Further, the second power converter 320 may insulate between the first input / output terminal and the second input / output terminal of the first power converter 16 without insulating between the input side and the output side. . FIG. 6 is a diagram showing the state of the power supplied to the motor 18 in the embodiment of FIG. 5, where the area C indicates the power supply from the capacitor 24 and the area B indicates the power supply from the battery group 26. At the time of power running of the motor 18 during the period from time 0 to time t3, the switch circuit 77 is turned on. When the required power of the motor 18 is small (time 0 to t1 and time t2 to t3), the second power converter 320 Is operated to partially return the electric power from the series circuit of the battery 26 and the capacitor 24 to the capacitor 24 via the second power converter 320, which is different from the embodiment of FIG. Therefore, the capacitor 24 can substantially reduce the discharge power of the capacitor 24 by the difference between the discharge and the charge, so that the stored energy of the capacitor 24 can be preserved when the required power of the motor is small. In this case, according to the control of the operation of the second power converter 320, the discharge current from the series circuit of the battery 26 and the capacitor 24 can be continuously and arbitrarily controlled.
[0036]
Further, during power running, when the required power of the motor 18 is large (time period from t1 to t2), the control circuit 73 stops the operation of the second power converter 320 and stops charging the capacitor 24. Therefore, electric power from both the battery 26 and the capacitor 24 can be supplied to the motor 18 via the first power converter 16. When the input side and the output side of the second power converter 320 are not insulated, when the first power converter 16 and the second power converter between the input and the output that are not insulated are simultaneously operated, the switch circuit Via the 77 and the second power converter, the battery 26 is short-circuited and no longer operates. Therefore, it is necessary to insulate the input side and the output side of the second power converter 320.
[0037]
During the regeneration period of the motor 18, the control circuit 73 makes the switch circuit 77 non-conductive and the regenerative power of the motor 18 is supplied to the first power converter 16 and the second power converter 320, as in the case of the embodiment of FIG. The capacitor 24 may be charged via the capacitor. However, when the switch circuit 77 is turned on, the regenerative power can be returned to both the capacitor 24 and the battery 26. In this case, when the control circuit 73 increases the power passing through the second power converter 320, the distribution amount of the regenerative power of the capacitor 24 increases. Conversely, when the passing power decreases, the distribution of the regenerative power to the battery 26 increases. The amount increases. Returning the regenerative power to the capacitor 24 that is almost fully charged results in an overvoltage, but in such a case, a part of the regenerative power can be returned to the battery 26. Note that this regeneration state is shown during the period from time t3 to t6 in FIG. 6, and the switch circuit 77 is turned on during the period from time t4 to t5 to return the regenerative power to the battery 26. In the embodiment of FIG. 5, unlike the embodiment of FIG. 4, the capacitor 24 can be charged from the battery 26 while the motor 18 is operating.
[0038]
FIG. 7 is a block diagram of a fifth preferred embodiment of the present invention. This embodiment is similar to the embodiment of FIG. 1, but does not use the switch circuit 72 and uses a DC / DC converter in which the input side and the output side are insulated for the second power converter 320. The operation of the second power converter 320 is the same as that of the embodiment of FIG. 5, but receives the regenerative power of the motor 16 directly without passing through the first power converter 16. Other operations are the same as those in FIG.
[0039]
Although the preferred embodiment of the present invention has been described above, various modifications and changes can be made by those skilled in the art without departing from the spirit of the present invention. The motor may be a DC brushless motor, an AC induction motor, or an AC synchronous motor other than the motor described in the embodiment (DC motor), and may be a single-phase motor or a three-phase motor. For the first power converter, a chopper or an inverter corresponding to these motors can be used, and for the second converter, a chopper or a DC / DC converter can be used. As the capacitor, a capacitor in which a plurality of capacitors are connected in parallel may be used. Furthermore, a small number of capacitors may be connected in series instead of one capacitor. When a small number of capacitors are connected in series, 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, so there is not much problem. The ratio of the power sharing between the battery and the capacitor is not limited to the ratio shown in FIGS. 2 and 13, and various modifications are possible. The switch 72 in FIG. 1, the switch 75 in FIG. 3, and the switch 72 in FIG. 4 can be kept in a non-conductive state during a period in which the required power of the motor is determined to be small, or can be turned on / off at a high speed. It can also be switched (similar to the prior art switch 20 in FIG. 10). In this case, the higher the conduction ratio, the more capacitors are used, and the lower the conduction ratio, the more batteries are used.
[0040]
[Effects of the present invention]
As described above, according to the motor drive power supply device of the present invention, since the battery and the capacitor are used in series, the stored energy of the capacitor can be used until the stored energy of the capacitor becomes completely zero when the motor is running. When a capacitor is connected in series to a battery and discharged, the capacity of theMinuteOnly the voltage can be raised. Here, if the power supplied to the first power converter is the same,,Voltage increasedMinuteOnly, the discharge current of the battery, that is, the load can be reduced. Also, according to the required power of the motor during power running, the switch circuitOr a second power converter comprising a DC / DC converterSeparates the capacitor from the series circuit of the battery and the capacitor, and controls the power supplied from the battery to the capacitor during power running, so the ratio of the power burden on the battery and the capacitor can be arbitrarily controlled to further improve the stored energy of the capacitor Can be used When the electric vehicle travels in an urban area, acceleration (powering) and deceleration (regeneration) are repeated as appropriate, and discharging (powering) and charging (regeneration) of the capacitor are repeated in accordance with acceleration / deceleration. Therefore, the capacitor maintains a voltage range reflecting the running state, and the effect of reducing the load on the battery during power running is also maintained.
[Brief description of the drawings]
FIG. 1 is a block diagram of a first preferred embodiment of a motor drive power supply device of the present invention.
FIG. 2 is a diagram showing motor required power for explaining the operation of FIG. 1;
FIG. 3 is a block diagram of a second preferred embodiment of the motor drive power supply device of the present invention.
FIG. 4 is a block diagram of a third preferred embodiment of the motor drive power supply device of the present invention.
FIG. 5 is a block diagram of a fourth preferred embodiment of the motor drive power supply device of the present invention.
FIG. 6 is a diagram showing motor required power for explaining the operation of FIG. 5;
FIG. 7 is a block diagram of a fifth preferred embodiment of the motor drive power supply device of the present invention.
FIG. 8 is a block diagram of an example of a conventional motor drive power supply device.
FIG. 9 is a circuit diagram of an example of a power converter.
FIG. 10 is a block diagram of another example of the conventional motor drive power supply device.
FIG. 11 is a block diagram of still another example of a conventional motor drive power supply device.
FIG. 12 is a circuit diagram of another example of the power converter.
FIG. 13 is a diagram showing motor required power for explaining the operation of FIG. 11;
[Explanation of symbols]
16 1st power converter
18 motor
24 capacitors
26 batteries
28 1st power converter
32 Second power converter
36 diode
72 switch circuit
73 Control circuit
74 Accelerator
75 switch circuit
76 Brake
77 switch circuit
78 clutch
320 second power converter

Claims (4)

A series circuit of a battery and a capacitor,
A first power converter having an output coupled to the motor;
A switch circuit for selectively coupling an input terminal of the first power converter to both ends of the battery or both ends of the series circuit;
A second power converter having an input coupled to the motor and an output coupled to charge the capacitor;
A control circuit that controls the first power converter, the second power converter, and the switch circuit;
The control circuit, the power running time of the motor, according to the power which the motor requires to control conduction and non-conduction of the switch circuit, power of the power and the battery obtained from the capacitor to the power that the motor requires A power supply device for driving a motor, characterized by adjusting the ratio of A series circuit of a battery and a capacitor,
One of the first output end and the capacitor of the battery through the first switch circuit is coupled to the opposite end, a first power converter second input terminal is coupled to the motor,
A second switch circuit for selectively coupling the opposite end of the other of said first input and output terminals of the first power converter and the battery of the other end or the capacitor of the battery,
A second power converter having an input coupled to the first input / output terminal of the first power converter and an output coupled to charge the capacitor;
A control circuit for controlling the first switch circuit, the second switch circuit, the first power converter, and the second power converter;
The control circuit, the power running time of the motor, close the first switch circuit, according to the power that the motor needs to control conduction and non-conduction of the second switching circuit, to power the motor requires And adjusting the ratio between the power obtained from the capacitor and the power of the battery . A series circuit of a battery and a capacitor,
A first power converter having a first input / output terminal coupled to both ends of the series circuit via a switch circuit, and a second input / output terminal coupled to the motor;
A second power converter having an input terminal coupled to the first input / output terminal of the first power converter, an output terminal coupled to charge the capacitor, and an insulation between the input terminal and the output terminal; When,
A control circuit for controlling the switch circuit, the first power converter, and the second power converter,
The control circuit, the power running time of the motor, close the switch circuit controls the second power converter according to the power which the motor needs to obtain from the capacitor to the power that the motor requires power A power supply device for driving a motor , wherein the ratio between the power of the battery and the power of the battery is adjusted. A series circuit of a battery and a capacitor,
A first power converter having an input coupled to both ends of the series circuit and an output coupled to the motor;
A second power converter comprising a DC / DC converter having an input coupled to the motor and an output coupled to charge the capacitor;
A control circuit for controlling the first power converter and the second power converter,
The control circuit, the power running time of the motor, controls the second power converter according to the power which the motor is required for the power the motor required by the power of the power and the battery obtained from the capacitor A power supply for driving a motor, characterized in that the ratio is adjusted.

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