JP2002218784A - Low-inductance motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an AC reactor, and make a DC reactor compact in size, and also to operated a low-inductance motor driven circuit with high efficiency, and enhance regeneration efficiency. SOLUTION: This controller 1 is arranged between a DC power source E and the drive circuit 2 of a multiphase low inductance motor M, and this controller comprises a step-up/step-down chopper 3, which is connected in parallel with the DC power source E, a power control reactor 6 which is connected between a p point where the two switching transistors 4a and 4b of the step up/step down chopper 3 are connected with each other and an output end 13 of the controller 1, and a smoothing capacitor 7 for generating an intermediate voltage, which is connected between the output end 13 and the negative side of the DC power source E, and this makes the motor M carry out power run or brakes it regeneratively, by changing the intermediate voltage generated in the smoothing capacitor 7, by changing the duty ratio by the switching of each switching transistor 4a and 4b of the step-up/step-down chopper 3, to thereby control the DC current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a drive circuit of a low-inductance motor such as a high-speed motor used in an aircraft or a rocket, and more particularly to a motor for powering or regenerating electric power during braking. The present invention relates to a control device provided between a DC power supply and the motor drive circuit.

[0002]

2. Description of the Related Art Conventionally, when driving a three-phase low-inductance motor M such as a high-speed motor of this type, for example, an axial gap motor, a drive by a voltage-type inverter shown in FIG. 13 is driven by a current source inverter.

In driving by the voltage source inverter shown in FIG. 12, a device 20 disposed between a DC power source E and a three-phase low inductance motor M is connected directly to the motor drive circuit 21 from the DC power source E, The motor drive circuit 2
The three-phase low-inductance motor M is driven via a one- to three-phase AC reactor 22.

In driving by the current source inverter shown in FIG. 13, a device 30 disposed between a DC power supply E and a three-phase low-inductance motor M includes a switching transistor in which a diode is connected in parallel in a reverse direction to a switching transistor. An element 31 and a diode 32 connected in series;
Switching element 3 similar to switching element 31
3 and a diode 34 connected in series are connected to a bridge circuit and connected to a DC power source E.
The three-phase low-inductance motor M is driven by connecting a connection point between the respective switching elements 31 and 33 and the diodes 32 and 34 to a motor drive circuit 36 via a DC reactor 35.

[0005]

However, the driving by the conventional voltage type inverter device 20 and the driving by the current type inverter device 30 have the following problems. That is, the drive by the voltage source inverter device 20 requires the external AC reactor 22,
This external reactor 22 has a large shape and is expensive, and it is necessary to increase the current margin of the element. Therefore, a large-capacity element is required and is expensive.

[0006] Further, the drive by the current source inverter device 30 requires a DC reactor 35, which has a large shape and is expensive. Further, in the motor drive circuit 36, since a reverse blocking diode is connected in series to the switching transistor,
The conduction loss was large, and the efficiency of the inverter device 30 itself was low.

The present invention has been made in view of such a point.
The purpose is to solve the above problems, eliminate the AC reactor, reduce the size of the DC reactor, and use the minimum necessary switching element for the motor drive circuit to operate the motor drive circuit with high efficiency. Another object of the present invention is to provide a low-inductance motor control device that improves the regeneration efficiency of the motor.

[0008]

According to a first aspect of the present invention, there is provided a control device provided between a DC power supply and a multi-phase low-inductance motor.

In the control device, two switching transistors connected in parallel to the DC power supply are connected in series, and diodes are respectively connected to the switching transistors in parallel in opposite directions. A step-up / step-down chopper including a current smoothing reactor having one end connected to a point where the switching transistors are connected to each other, and an intermediate voltage generator connected to the other end of the current smoothing reactor and the negative side of the DC power supply. And a voltage source inverter having the intermediate voltage as an input, and controlling the direct current by changing the duty ratio by switching of the respective switching transistors of the step-up / step-down chopper. A control device that changes the generated intermediate voltage and powers or regeneratively brakes the motor That.

[0010] In the control device, the multi-phase low-inductance motor is a three-phase low-inductance motor.

The multi-phase low-inductance motor is a three-phase magnet type low-inductance motor.
The control device operates as a current type inverter during power running and as a variable DC intermediate voltage type inverter during regeneration.

Further, a control unit having a battery management function is provided, and when the DC power supply is a battery, detection signals from a voltage detector and a current detector for detecting the voltage and current of the DC power supply are provided to the control unit. This is a device for inputting and managing the state of the battery during powering and regeneration.

Further, a control unit having an output control function is provided, and a detection signal from a voltage detector for detecting the voltage of the capacitor for generating the intermediate voltage and a current detector for detecting the phase current of the low inductance motor are provided. And a detection signal from a rotation detector for detecting the number of rotations of the motor are input to the control unit, and control the switching elements in the inverter to raise the motor during power running and regeneration. A device that operates with efficiency.

Since the low-inductance motor control device of the present invention is configured as described above, the duty ratio of the step-up / step-down chopper is changed by the ratio of the on-time of the switching of each switching transistor to the switching cycle. Thus, the DC intermediate voltage generated in the capacitor is changed to power or regenerate the low inductance motor. In other words, the switching of the switching transistor is changed to positively change the intermediate voltage generated in the capacitor.

Further, the control device of the present invention operates as a current source inverter during power running with a high load power factor, but otherwise operates according to the magnitude of the DC intermediate voltage according to the output voltage. Adjust the time and regenerative time. In particular, when the DC intermediate voltage is optimally controlled at the time of power running and regeneration of the motor, the efficiency and power factor of the motor are improved, and the size of the entire system is reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a main configuration circuit diagram showing an embodiment of a low inductance motor control device of the present invention, which is applied to a motor drive circuit which is a DC intermediate voltage variable voltage type inverter having pseudo current type current control. .

In FIG. 1, a low inductance motor control device 1 includes a DC power supply E via power supply terminals 11 and 12.
And a three-phase low-inductance motor M. The control device 1 includes a DC current smoothing reactor 6.
And a step-up / step-down chopper 3 connected in parallel to the DC power supply E, and a smoothing capacitor 7 for generating an intermediate voltage.
And a voltage source inverter 2 having the intermediate voltage as an input.

The step-up / step-down chopper 3 has two switching transistors 4a and 4b connected in series such that the emitter of the transistor 4a is connected to the collector of the transistor 4b, and the switching transistors 4a and 4b are connected. Diodes 5a and 5b are connected in parallel in opposite directions, respectively. One end of a current smoothing reactor 6 is connected to a point p where the two switching transistors 4a and 4b are connected in series with each other. The smoothing capacitor 7 is connected to the other end (output end 13) of the reactor 6 and the negative side of the DC power supply E.

A control unit (not shown) applies a switching control signal to each of the bases 4c and 4d of the switching transistors 4a and 4b of the step-up / step-down chopper 3, and controls the ratio of the on-time of switching to the switching period. To change the duty ratio, thereby changing the DC intermediate voltage generated in the smoothing capacitor 7, and powering or regeneratively braking the motor M via the voltage source inverter 2.

The control operation of the circuit diagram of FIG. 1 will be described. During power running, only one switching transistor 4a of the step-up / step-down chopper 3 is controlled to be switched, and the other switching transistor 4b is turned off. At this time, due to the switching operation of the switching transistor 4a, the DC reactor 6 repeatedly stores and releases energy. When the energy of the DC reactor 6 is charged, the smoothing capacitor 7 is charged and the output terminal 13 is charged.
A DC intermediate voltage is generated on the positive side, and the DC voltage is supplied to the voltage source inverter 2 to drive the motor M.

FIG. 2 shows one drive waveform of each signal when the motor M is operated in power mode (switching control is performed only at S7 to set IDC to a constant value, and S8 is turned off). The switching command of the voltage source inverter circuit unit 2 included in the control device 1 is a 120-degree conduction drive, and the switching elements S1, S2, and S2 are controlled so that the phase voltage and the line current are in phase.
A drive signal is given to S3, S4, S5, and S6. Specifically, for example, for the upper switching elements S1, S2, and S3, from the point A where the U-phase voltage and the W-phase voltage cross,
Until the point B where the U-phase voltage and the V-phase voltage cross (120
(Corresponding to the phase angle in degrees) is the switching element S
1 so that an ON signal is instructed. During the subsequent 120 degrees, the switching element S2 on the V-phase side is set to instruct an ON signal. Further, during the next 120 degrees, the W-phase upper switching element S3 is set to instruct an ON signal, and this operation is sequentially repeated for the motor phase voltage.

Similarly, for the lower switching elements S4, S5, S6 of the voltage type inverter circuit section 2, U
From the point C where the phase voltage and the W phase voltage cross, the U phase voltage and V
Until the phase voltage crosses to the point D (corresponding to a phase angle of 120 degrees), an ON signal is set to be instructed to the U-phase lower switching element S4. During the next 120 degrees, it is set so as to instruct the V-phase lower switching element S5 to issue an ON signal. Further, during the next 120 degrees, the ON signal is set to the W-phase lower switching element S6, and this operation is sequentially repeated for the motor phase voltage.

As described above, FIG.
The switching command shown in (f) is output. As a result,
The output current of the control device 1 is represented by (g) to (i) in FIG.
And the harmonic component can be reduced.
The motor voltage waveform can be approximated to a sine wave,
Since the switching loss can be reduced, the motor M can be driven with high efficiency.

At the time of regenerative braking, only the other switching transistor 4b of the step-up / step-down chopper 3 performs switching control, and one switching transistor 4a is turned off. At this time, by the switching operation of the switching transistor 4b, a DC voltage is generated between the collector and the emitter of the switching transistor 4b with the collector side (point p) being a positive electrode, and the generated DC voltage is used to generate the diode 5a. , Power can be regenerated to the DC power supply E.

In the voltage source inverter 20 shown in FIG.
When the motor rotation speed is low and the induced voltage of the motor M is small,
Since the voltage of the DC power supply E is significantly higher than the peak value of the motor induced voltage, the difference between the voltage of the DC power supply E and the motor induced voltage is increased, thereby reducing the motor efficiency. FIG. 3 shows a case where the motor M is operated for regenerative operation.
It is one drive waveform of each part signal of the circuit diagram in FIG. 2 (S7 is in an off state, switching control is performed only in S8, and IDC is set to a constant value). In this case, the voltage type inverter 2
The phase and amplitude of the motor output current are controlled by WM (pulse width modulation) control. The DC intermediate voltage is controlled to a minimum necessary voltage by the step-up / step-down chopper 3, and the inverter output current is controlled by the voltage-source inverter circuit unit 2 so as to have a reverse phase to the motor phase voltage. As a result, it is possible to improve the motor efficiency by reducing the difference between the DC intermediate voltage and the motor induced voltage.

As described above, the switching of the buck-boost chopper 3 is controlled in accordance with the power running operation or the regenerative braking operation.
The output voltage can be changed.

FIG. 4 is a table showing conversion efficiency, element conduction loss, and switching loss in a system including the low-inductance motor control device 1, the DC power supply E, the inverter 2 as a motor drive circuit, and the motor M according to the present embodiment. And Fig. 5 are results of calculating approximate values of AC reactor loss and DC reactor loss. The calculation conditions were as follows: motor inductance: 0.3 mH, DC power supply voltage: 300
V, carrier frequency: 18 kHz, converter capacity: 50 k
A comparison between the drive by the voltage-type inverter and the drive by the current-type inverter shown in FIGS. As a result, in the system including the low-inductance motor control device 1 of the present embodiment and the like, good results were obtained.

The three-phase low inductance motor M
Is a three-phase magnet type low-inductance motor, the low-inductance motor control device 1 operates as a current source inverter during power running and as a variable DC intermediate voltage source inverter during regeneration.

Next, examples of the present embodiment will be described. [Embodiment 1] FIG. 5 is a main structural circuit diagram showing a first embodiment of a low inductance motor control device according to the present invention. The same reference numerals are given to the same components as those shown in FIG. The description is omitted.

In FIG. 5, the control device 1 includes a battery management unit 8a for managing the DC power supply E therein, a voltage management unit 8b for managing (or controlling) the voltage of the smoothing capacitor 7, A control unit 8 comprising an output control unit 8c for controlling the output of the motor M is provided. The control unit 8 detects a voltage and a current of the DC power supply E, and outputs detection signals from the voltage detector 11a and the current detector 11b to the battery management unit. And a detection signal from a voltage detector 12a and a current detector 12b for detecting a voltage of the smoothing capacitor 7 and a current flowing through the DC current smoothing reactor 6, respectively, to the voltage management unit 8a. The detection signal from the voltage detector 12a, the detection signals from the current detectors 13a and 13b for detecting the line current of the motor M, Rotation detector 1 for detecting the rotational speed of the M
And the detection signal from 3c is input to the output control unit 8c.

In this embodiment, the voltage of the smoothing capacitor 7 is set to be slightly higher than the voltage required for driving the low-inductance motor M regardless of the voltage of the DC power supply E. The step-up / step-down chopper 3 is operated. Thus, even if the motor M is driven by the voltage source inverter 2, the current ripple does not increase unnecessarily as shown in FIG. 6, and a current waveform having a small ripple is obtained as shown in FIG. Therefore, harmonic loss in the motor M is suppressed, and high-efficiency operation can be performed.

At this time, if it is a high efficiency operation that the motor M is driven by a magnet motor or the like in the induced voltage and the current in the same phase, the current is controlled by the step-up / step-down chopper 3 and the voltage type inverter is controlled. 2 operates as a 1-pulse 120-degree conduction type inverter that only determines the phase in which the current flows. In this case, with the current waveform as shown in FIG. 8, high-efficiency operation with ultra-low loss and minimizing switching of the voltage-source inverter 2 can be performed.

In the regenerative operation, energy returns from the motor M to the smoothing capacitor 7 via the voltage source inverter 2, so that the voltage of the capacitor 7 increases. Since the chopper 3 returns the energy from the DC source E so as to maintain the voltage of the capacitor 7 at a voltage suitable for regeneration, a highly efficient regenerative operation in which the switching loss of the voltage source inverter 2 is suppressed can be performed. .

The battery management unit 8a manages the state of the battery during power running and regeneration of the motor M, and the voltage management unit 8b controls switching of the step-up / step-down chopper 3. The output control unit 8c controls the switching of the switching elements in the inverter 2 to operate the motor with high efficiency during power running and regeneration. Further, the energy management is separated into an output control unit 8c that controls the voltage source inverter 2 using the voltage of the smoothing capacitor 7 as a parameter and a voltage management unit 8b that manages the voltage of the step-up / step-down chopper 3. Since the interference can be achieved, the control is facilitated, and the assembling is simplified in manufacturing.

When the DC power source E is a battery (for example, a storage battery), the battery management unit 8a of the control unit 8 can also be incorporated in the step-up / step-down chopper 3, and the control device 1 has a high function and is simplified. it can.

According to the present embodiment, the features are as follows. (1) By positively varying the voltage of the smoothing capacitor 7, the low inductance motor M can be driven with high efficiency. (2) When a current flows in the same phase as the induced voltage, the operation at the time of power running is set as a current source operation, and the switching of the inverter 2 can be minimized to drive the inverter 2 with high efficiency. (3) Even during regeneration, the switching of the inverter 2 can be minimized by driving the voltage of the smoothing capacitor 7 to be positively varied, thereby enabling high-efficiency driving.

(4) By using the voltage of the smoothing capacitor 7 as a parameter, it is possible to control the output control unit 8c of the inverter 2 and the voltage management unit 8b of the step-up / step-down chopper 3 to be separated and non-interfering. (5) When the DC source E is a battery, the battery management unit 8a can also be incorporated in the step-up / step-down chopper 3.

[Embodiment 2] FIG. 9 is a main configuration circuit diagram showing a second embodiment of the low inductance motor control device according to the present invention. The same components as those shown in FIG. The description is omitted here. In FIG. 9, the plurality of low-inductance motors M (A) and M (B) are disposed between one DC source E and a plurality (two in this embodiment) of low-inductance motors M (A) and M (B). And the same number of control devices 1
(A) and 1 (B).

In the present embodiment, in addition to the description of the first embodiment, in the case of propulsion of a vehicle or a ship, the motors M (A) and M (B) disposed on the left and right sides thereof One of the motors M (A) and M (B) changes its direction and the driving state by changing the direction of the vehicle or ship by rotating one at a high speed and the other at a low speed. Accordingly, highly efficient driving can be performed. In this case, (Motor M
If (the rotation speed of (A))> (the rotation speed of the motor M (B)), (the voltage of the smoothing capacitor 7 of the control device 1 (A))> (the smoothing capacitor of the control device 1 (B)) 7), a high-efficiency operation is performed.

According to the present embodiment, the features thereof are as follows in addition to the features (1) to (5) of the first embodiment. (6) Even in the operation of the plurality of low-inductance motors M, M, an optimum operating voltage can be realized for each of them.

[Embodiment 3] FIG. 10 is a main configuration circuit diagram showing a third embodiment of the low-inductance motor control device of the present invention. The same components as those shown in FIG. The description is omitted here. In FIG.
Instead of the DC power supply E of FIG. 5, a DC power storage unit C is connected, and a flywheel FW or an engine is connected to the low inductance motor M, so that the motor M can be used as a generator. Further, the control unit 8 is provided with a capacitor management unit 8d, and detects detection signals from the voltage detector 11a and the current detector 11b which detect the voltage and the current of the DC power storage unit C, respectively. Is entered.

In this embodiment, when a member made of an electric double layer capacitor or the like is provided as the power storage unit C, the step-up / step-down chopper 3 is provided with a capacitor management unit such as an overvoltage protection for the power storage unit C. 8d can be incorporated, and the low-inductance motor control device can be simplified.

According to the present embodiment, the features are the same as the features (1) to (5) of the first embodiment, except that the DC power supply E is replaced with a power storage unit. The following is added. (6) The power storage unit can be an electric double-layer capacitor or the like, and its management function can be shared by the step-up / step-down chopper 3.

[Embodiment 4] FIG. 11 is a main configuration circuit diagram showing a fourth embodiment of a low inductance motor control device according to the present invention. The same components as those shown in FIG. The description is omitted here. In FIG.
By changing the DC power supply E of FIG. 1 in the first embodiment, a power storage unit C is connected, and 3
A low-inductance motor control device 1 using a three-phase AC power supply as a power source, showing a case where the phase AC power supply EAC is connected via a system direct inverter 20.

In this embodiment, a three-phase AC power supply EAC
Is converted into a direct current by the system direct inverter 20 and connected to both ends of the power storage unit C. The control device 1 is connected in series between the system direct inverter 20 and the low inductance motor M. Have been. In this case, the operations (actions and effects) of the respective units of the control device 1 and the characteristics thereof are as described in the first embodiment.

As described above, as a field to which the system including the low-inductance motor control device 1 of the present embodiment is applied, a) when applied to a vehicle, b) when applied to a flywheel power storage, etc., c). It may be applied to a secondary battery system.

A) When the present invention is applied to a vehicle, the DC intermediate voltages of the control devices 1 in the left and right systems can be independently controlled when turning a wheel, so that a more efficient system can be obtained. b) When applied to flywheel power storage or the like, the most efficient driving method can be selected both during charging and discharging. c) When applied to a secondary battery system, direct current is output, so that the secondary battery can be managed.

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, and may be implemented by means of another mode that performs a similar function. Various changes and additions are possible. For example, the present invention can be applied to a case where a power supply is a commercial three-phase AC and a DC voltage is generated using a three-phase step-down converter.

[0049]

As is apparent from the above description, according to the low inductance motor control device of the present invention, the control device has two switching transistors connected in parallel to the DC power supply and connected in series. A step-up / step-down chopper comprising a current smoothing reactor having one end connected to a point where a diode is connected in parallel to the switching transistor in the opposite direction and the two switching transistors are connected to each other; A capacitor for generating an intermediate voltage connected to the other end of the current smoothing reactor and the negative side of the DC power supply, and a voltage source inverter having the intermediate voltage as an input; By controlling the DC current by changing the duty ratio by switching of the switching transistor, the Changing the intermediate voltage generated in the capacitors, since the power running or regenerative braking the motor, removes the AC reactor, along with miniaturization of the DC reactor,
Using a switching element having a minimum necessary capacity in the motor drive circuit, the motor drive circuit can be operated with high efficiency, and the regenerative efficiency of the motor can be improved.

At the same time, the control device of the present invention can adjust the intermediate voltage generated in the control device even during the regenerative braking of the motor, so that the motor regeneration efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a main configuration circuit diagram showing one embodiment of a low inductance motor control device of the present invention.

FIG. 2 is a diagram showing waveforms of various parts of an inverter during a power running operation.

FIG. 3 is a diagram showing waveforms of various parts of the inverter during regenerative operation.

FIG. 4 calculates conversion efficiency, element conduction loss, switching loss, AC reactor loss, DC reactor loss, and the like in a low-inductance motor control device, a DC power supply, a motor drive circuit, and a system including the motor described in the present embodiment. This is the table shown.

FIG. 5 is a main configuration circuit diagram showing a first example of the embodiment of the low inductance motor control device of the present invention.

FIG. 6 shows a motor driving current (1) having a large unnecessary ripple.
It is a figure which shows the waveform (per phase).

FIG. 7 is a diagram showing a waveform of a motor drive current (per phase) having a small ripple.

FIG. 8 is a diagram showing a waveform of a drive current (per phase) for operating a low inductance motor with high efficiency.

FIG. 9 is a main configuration circuit diagram showing a second embodiment of the present invention.

FIG. 10 is a main configuration circuit diagram showing a third embodiment of the present invention.

FIG. 11 is a main configuration circuit diagram showing a fourth embodiment of the present invention.

FIG. 12 is a circuit diagram of a conventional voltage source inverter for driving a low inductance motor.

FIG. 13 is a circuit diagram of a conventional current source inverter for driving a low inductance motor.

[Explanation of symbols]

1, 1 (A), 1 (B) Low-inductance motor control device 2, 20, 30 Inverter 3 Buck-boost chopper 4a, 4b Switching transistor 4c, 4d Base 5a, 5b Diode 6 DC current control reactor 7 DC intermediate voltage generation smoothing Capacitor for control 8 Control unit 8a Battery management unit 8b Voltage management unit 8c Output control unit 8d Capacitor management unit 20 System direct inverter 21, 36 Motor drive circuit E DC power supply EAC Three-phase AC power supply M, M (A), M (B) Low inductance motor

Claims (5)

[Claims] 1. A control device provided between a DC power supply and a multi-phase low inductance motor, wherein the control device includes two switching transistors connected in parallel to the DC power supply and connected in series. A step-up / step-down chopper comprising a current smoothing reactor having one end connected to a point where a diode is connected in parallel to the switching transistor in the opposite direction and the two switching transistors are connected to each other; A capacitor for generating an intermediate voltage connected to the other end of the current smoothing reactor and the negative side of the DC power supply, and a voltage source inverter having the intermediate voltage as an input;
By controlling the direct current by changing the duty ratio by switching of each switching transistor of the step-up / step-down chopper, the intermediate voltage generated in the capacitor is changed, and the motor is powered or regeneratively braked. Inductance motor control device. 2. A motor according to claim 1, wherein said multi-phase low-inductance motor is a three-phase low-inductance motor.
2. The low-inductance motor control device according to 1. 3. The multi-phase low-inductance motor is a three-phase magnet type low-inductance motor, and operates as a current source inverter during power running and as a variable DC intermediate voltage source inverter during regeneration. Item 2. A low inductance motor control device according to item 1. 4. A control unit having a battery management function, wherein, when the DC power supply is a battery, the control unit detects detection signals from a voltage detector and a current detector for detecting a voltage and a current thereof, respectively. The low-inductance motor control device according to claim 1, wherein a state of the battery at the time of powering and regeneration is managed by inputting to a unit. 5. A control unit having an output control function, a detection signal from a voltage detector for detecting a voltage of the capacitor for generating the intermediate voltage, and a current detection for detecting a phase current of the low inductance motor. A detection signal from the motor and a detection signal from a rotation detector for detecting the number of rotations of the motor are input to the control unit, and control the switching elements in the inverter to control the motor during power running and regeneration. The low-inductance motor control device according to claim 1, wherein the device is operated with high efficiency.