JPH0634617B2 - Three-phase multiplication type power supply device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-phase multiplication type power supply including a three-phase multiplier that can be used in a drive circuit of a three-phase brushless motor such as a synchronous AC servo motor and a linear servo motor. Regarding the device.

2. Description of the Related Art In recent years, synchronous AC servomotors have become increasingly popular as next-generation DC servomotors because they are brushless and maintenance-free. The synchronous AC servomotor mainly uses three-phase windings, and in order to reduce torque ripple, noise during driving, vibration, etc., a method of using a three-phase sine wave that alternates the winding current is used. In order to obtain the required torque, the amplitude of the three-phase sine current of the winding is controlled, but the three-phase sine signal that is the reference of the winding current is the result of multiplication of the position sensor output and the winding current amplitude command. It is generally used, and conventionally, this three-phase multiplication has been realized by two single-phase multipliers and an adding and inverting device of their outputs.

An example of the above-described conventional three-phase multiplier will be described below with reference to the drawings. FIG. 2 is a circuit block diagram of a conventional three-phase multiplier. Reference numerals 10 and 11 are four-phenomenon multipliers, and S1 and S2 are their output voltages. Reference numeral 12 is a summing inverter, and S3 is its output voltage. P1 and P2 are
The position signal voltage of the sine wave from the encoder having a phase difference of 2 / 3π is used as the X input of the four phenomenon multipliers 10 and 11, respectively. W is a Y input of the four-phenomenon multipliers 10 and 11, and is a voltage for instructing the magnitude and direction of the winding current.

The operation of the conventional three-phase multiplier configured as described above will be described below.

Now, S1, S2 and S3 are the results of multiplication, addition and inversion of P1, P2 and W, and can be expressed as follows.

S1 = W · P1 S2 = W · P2 S3 = −W (P1 + P2) where P1 and P2 have an amplitude of 1 volt and a sinusoidal variation with respect to the position function α, Then, a three-phase sine wave signal having an amplitude W is obtained. If a current proportional to S1 to S3 is made to flow through the winding, the direction and magnitude of the winding current can be controlled by W. That is, the rotation direction and torque of the motor can be controlled by W.

Problems to be Solved by the Invention However, in the above-described configuration, two four-phenomenon multipliers are required, and unless one four-phenomenon multiplier is adjusted in two places, accurate multiplication results can be obtained. Can't get Therefore, even if these are configured in the IC, not only the number of pins and the chip area increase but also the external semi-fixed resistance increases, that is, the cost increases.
This hinders the realization of this function in the IC, and at the same time, causes misalignment of the motor due to offset adjustment error, secular change, vibration, and the like.

In view of the above problems, the present invention provides a three-phase multiplication type power supply device including an inexpensive and three-phase multiplier suitable for IC without adjustment and with high accuracy.

Means for Solving the Problems In order to solve the above problems, the three-phase multiplier of the three-phase multiplication type power supply device according to the present invention has three differential amplifiers A, which receive the three-phase signals V1, V2 and V3. B and the signals V1, V2, V3
3 differential amplifiers C and D having V4, V5 and V6 inverted, a current source E for controlling output currents of the three differential amplifiers A and C, and a period during which the current source E is OFF. A current source F for controlling only the output currents of the three differential amplifiers B and D by turning on only, and current mirror circuits G, H, and J having the sum of the output currents of the three differential amplifiers A and D as inputs, respectively. ,
M1, M2, M which are the differences between the sum of the output currents of the three differential amplifiers B and C and the outputs of the cant mirror circuits G, H, J.
A three-phase output section that outputs 3 is provided.

Operation According to the present invention, the current of the current source E or F is directly distributed by the three differential amplifiers A to D having good symmetry by the above-described configuration, and then the current is supplied by using the current mirror circuits G, H, and J. By adding and subtracting, it is possible to obtain an inexpensive three-phase multiplier that does not require offset adjustment and is highly accurate, and is therefore suitable for IC implementation.

Embodiment A three-phase multiplier of a three-phase multiplication type power supply apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram of a three-phase multiplier of a three-phase multiplication type power supply device according to an embodiment of the present invention. In FIG. 1, reference numerals 1 and 2 denote three differential amplifiers A and B, which are supplied with three-phase position signal voltages V1, V2 and V3 obtained from an encoder. Reference numerals 3 and 4 denote three differential amplifiers C and D, V1 to
The voltages V4, V5, and V6, which are obtained by inverting V3, are input. Reference numerals 5 and 6 are current sources E and F, and reference numerals 7, 8, and 9 are current mirror circuits G, H, and J. I1 to I12 are collector currents of the three differential amplifiers 1 to 4. I13, I1
5, I17 are input currents of the current mirror circuits 7, 8, 9 and I14, I16, I18 are output currents. I
Reference numerals 19 and I20 are currents of the current sources 5 and 6, and command the magnitude direction of the winding current. M1 to M3 are output currents of the three-phase multiplier and three-phase position signal voltages V1 to V6 and winding current command I
It is the result of multiplication with 19 or I20.

Regarding the three-phase multiplier configured as described above, the first
The operation will be described with reference to the drawings.

First, it is assumed that the amplitudes of the three-phase position signal voltages V1 to V6 are well aligned and that this is a, and V1 to V6 can be expressed as shown below.

The input current of the three-phase position signal voltages V1 to V6 is the output current I1.
~ I12 is very small compared to I12
9, I20 are three-phase currents I1 to I1 depending on V1 to V6
It is divided into two and I1 to I12 are approximated as shown below.

Here, b and e are current amplitudes, and d and f are direct current components. b and e can be made large when the amplitude a of V1 to V6 is large, and conversely, d and f are the amplitude a of V1 to V6.
Grows when is small. When the amplitudes of V1 to V6 become very large, the above approximation formula does not hold, d and f become very small, and I1 to I12 represent the amplitudes b and e of the sine waveform.
Is saturated and becomes trapezoidal and changes periodically.

I1 + I2 + I3 = I7 + I8 + I9 = I19 I4 + I5 + I6 = I10 + I11 + I12 = I20 I1, I2, ... I12 ≧ 0 Further, the following relationship is established from the characteristics of the current mirror circuit.

I1 + I10 = I13 = I14 I2 + I11 = I15 = I16 I3 + I12 = I17 = I18 Now, if I20 does not flow when I19 flows, I20 = I4 = I5 = I6 = I10 = I11 = I12 =
Becomes 0, The following three-phase multiplication output is obtained. The amplitude b depends on the magnitude of I19 and the amplitude a of the three-phase position signal voltage, but is proportional to the magnitude of I19 if a is constant.

On the contrary, if I19 does not flow when I20 flows, I19 = I1 = I2 = I3 = I7 = I8 = I9 = 0, The following three-phase multiplication output is obtained. The negative sign means the reversal of polarity, and I19 is passed and I20 is not passed, or I
The polarity of the three-phase multiplication output can be inverted depending on whether 20 is supplied and I19 is not supplied. Also, three-phase multiplication output M
1 to M3 have no offset current, and are alternating three-phase currents with uniform amplitude.

In order to perform accurate three-phase multiplication, three differential amplifiers 1 to
4, the symmetry of the current distribution, the symmetry of the input / output currents of the current mirror circuits 7 to 9 and the accuracy of the current sources 5 and 6 are required. can get.

As described above, according to this embodiment, the three-phase position signal voltage V
1, V2, V3 as input, 3 differential amplifiers 1, 2, V1, V2, V3 inverted V4, V5, V6 as input 3 differential amplifiers 3, 4, and 3 differential amplifiers 1,3
The current source 5 for controlling the collector current of the three differential amplifiers 2, which is turned on only while the current source 5 is off.
A current source 6 for controlling the collector current of 4 and current mirror circuits 7, 8 and 9 which receive the sum of the collector currents of the 3 differential amplifiers 1 and 4, respectively, and 3 differential amplifiers 2 and 3
Of the collector current of the current mirror circuit 7,
By providing a three-phase output section that outputs M1, M2, and M3, which are differences from the outputs of 8 and 9,
19 or the current I20 of the current source 6 and the three-phase position signal voltages V1, V2, V3 (V4, V5, V6) can be multiplied with no adjustment and with high accuracy.

In the embodiment, the sum of the collector currents of the three differential amplifiers 1 and 4 is used as the input of the current mirror circuits 7 to 9 and the sum of the collector currents of the three differential amplifiers 2 and 3 and the outputs of the current mirror circuits 7 to 9. The difference between and the three-phase multiplication outputs M1 to M3 is used, but the sum of the collector currents of the three differential amplifiers 2 and 3 is input to the current mirror circuits 7 to 9, and the sum of the collector currents of the three differential amplifiers 1 and 4 is used. And the output of the current mirror circuits 7 to 9 may be used as three-phase multiplication outputs M'1 to M'3. At this time. M1 = -M1 ', M2 = -M2', M3 = -M3 'and the same effect can be obtained only by reversing the polarities.

Further, in FIG. 1, the three differential amplifier is composed of NPN type transistors, but in the same manner, it may be composed of PNP type transistors, and further may be composed of field effect transistors. Of course, the individual transistors may be Darlington-connected, and as a result, the configuration may be such that three differential operations are performed.

As described above, according to the present invention, the three-phase position signal voltages V1, V
Two differential amplifiers A and B having inputs 2 and V3;
The three differential amplifiers C and D that receive V4, V5 and V6, which are the inverses of V1, V2 and V3, the current source E that controls the output currents of the three differential amplifiers A and C, and the current source E are A current source F for controlling the output currents of the three differential amplifiers B and D, and a current mirror circuit G for inputting the sum of the output currents of the three differential amplifiers A and D, respectively. , H, J, and a three-phase output section that outputs M1, M2, M3, which is the difference between the sum of the output currents of the three differential amplifiers B and C and the output of the current mirror circuits G, H, J. By providing the above, it is possible to obtain a three-phase multiplication type power supply device having no adjustment and good accuracy, and thus having a three-phase multiplier suitable for IC implementation.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a three-phase multiplier of a three-phase multiplication type power supply device according to an embodiment of the present invention, and FIG. 2 is a circuit block diagram of a conventional three-phase multiplier. 1 to 4 ... 3 differential amplifiers A to D, 5, 6 ... current source E,
F, 7-9 ... Current mirror circuit, V1-V6 ... 3
Phase position signal voltage, M1 to M3 ... 3-phase multiplication output 10,
11 ... Four-phenomenon multiplier, 12 ... Adding and inverting device.

Claims (1)

[Claims] 1. Three-phase signal V1, V2, V3 as input
Control the differential amplifiers A and B, three differential amplifiers C and D that receive the signals V4, V5 and V6 which are the inverted signals V1, V2 and V3, and the output currents of the three differential amplifiers A and C. A current source E for controlling the output currents of the three differential amplifiers B and D for a period during which the current source E is off, and outputs of A and D of the three differential amplifiers. Current mirror circuits G, H, and J whose input is the sum of currents
And M1, M which is the difference between the sum of the output currents of the three differential amplifiers B and C and the outputs of the cant mirror circuits G, H, J.
A three-phase multiplication type power supply device comprising a three-phase output section that outputs M2 and M3 signals.