JPH07256147A - Controller of motor for centrifugal machine - Google Patents

Abstract

PURPOSE:To smooth starting and stopping of a motor by using an AC phase control element of a controller which uses a boosting converter in order to decrease the content of higher harmonic currents for an AC power source. CONSTITUTION:This controller has the boosting converter 22 which operates to decrease the contents of the higher harmonic currents for the AC power source 21, a smoothing capacitor 24 which is charged by the boosting converter 22 and an inverter device 26 which controls voltage by pulse width modulation with this smoothing capacitor 24 as a power source. The controller is provided with a switching element 25 for controlling the charging voltage of the smoothing capacitor 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a control device for a centrifuge motor which is driven and controlled by a pulse width modulation type inverter.

[0002]

2. Description of the Related Art An inverter for a centrifuge has a high rotational speed of a motor to be driven, and an on / off control pattern for PWM control of a switching element constituting an inverter device is not created by a sequential arithmetic processing by a microcomputer. Since it is difficult to catch up with time in the high-speed rotation range, a method is used in which an on / off control pattern of a switching element is calculated in advance, stored in a ROM, and read out by a clock pulse or the like.

Further, in the above-mentioned method of reading ROM data, for example, 360 degrees of PWM control is 204
When expressed with 8 data, a clock pulse with a frequency of 6.9 MHZ or higher is required to rotate the motor at 200,000 rotations. To accelerate and settle a stationary motor to 200,000 rotations, A pulse oscillator that can output an arbitrary frequency in the range of approximately 10 KHZ to 6.9 MHZ is required, and a phase locked loop (P
LL) is used by switching the capacity of the capacitor that determines the oscillation frequency range of the voltage controlled oscillator in the PLL.

Further, a drive circuit operated by a common control power supply for transmitting an ON / OFF signal is provided to the switching element of the upper arm of the switching element which constitutes the inverter device. In the case where energy is supplied by the capacitor charged through the switching element of the lower arm that faces the arm, the switching element of the lower arm must be turned on and off at all times, so the oscillation frequency transiently changes when the capacitor of the oscillator is switched. ON in the ROM because
The off control pattern is provided with a sufficiently long dead time to prevent a short circuit.

[0005]

Therefore, in the conventional motor control device for a centrifuge, when a boost converter is used to reduce the harmonic current content with respect to the AC power source, the boost converter charges the battery. Since the smoothing capacitor has a charging voltage higher than the peak value of the power supply voltage, the duty due to PWM control cannot be fully reduced especially when the motor is started or decelerated, and the voltage applied to the motor is high, enabling smooth start / stop. It had the drawback of not having it.

Further, when the boundary of the oscillation frequency range of one capacitor of the voltage controlled oscillator in the PLL is the settling speed, the overshooting or undershooting of the rotating speed generated during the process of acceleration / settling or deceleration / settling of the motor. Therefore, since it is out of the oscillation frequency range of one capacitor, it is necessary to switch the connection to another capacitor, which causes a problem that control becomes complicated and quick settling cannot be performed.

Further, a dead time is set to be long so as not to prevent the short circuit of the upper and lower arms of the switching element in the on / off control pattern in the ROM due to the transient fluctuation of the oscillation frequency generated when the capacitor is switched. Therefore, there is a drawback that the voltage utilization rate of the PWM control becomes low and a sufficient voltage cannot be applied to the motor.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and one object of the present invention is to start and stop the motor in a centrifuge motor control device of this type. It is to provide a control device having smooth characteristics.

Another object of the present invention is to provide an oscillating device in a PLL oscillator which oscillates by switching a plurality of capacitors, by which simple control and quick settling can be expected regardless of the settling speed. is there.

Another object of the present invention is to provide a control device which does not reduce the voltage utilization rate of PWM control without extending the dead time due to frequency fluctuations occurring when switching capacitors.

[0011]

SUMMARY OF THE INVENTION The above object is to provide a step-up converter that operates so as to reduce the harmonic current content in an AC power source, a smoothing capacitor charged by the step-up converter, and the smoothing capacitor. This is achieved by providing an inverter device that performs voltage control by pulse width modulation using the power source as a power source and an AC phase control element that adjusts the charging voltage of the smoothing capacitor.

Further, the above-mentioned object is a ROM in which ON / OFF control pattern data of a switching element which constitutes an inverter device for driving a motor is written, and this ROM.
In a counter provided for periodically reading OM data and a PLL that outputs an oscillation pulse to this counter, an oscillation pulse of an arbitrary frequency is output.
A selector is provided to switch and connect one of a plurality of capacitors that define the oscillation frequency range of the voltage controlled oscillator in the PLL to the voltage controlled oscillator, and the ranges of the oscillation frequencies of the plurality of capacitors overlap each other. It is achieved by determining the capacitance of each capacitor.

A further object of the present invention is to provide a drive circuit operated by a common control power supply for transmitting an on / off signal to each switching element of the upper arm of the above switching element. In the one that obtains the power supply voltage by the energy of the capacitor charged when the switching element of the arm is turned on, the on / off signal is given only to the switching element of the lower arm, and the switching element of the upper arm is turned on. This is achieved by providing the OFF control pattern in ROM.

[0014]

In the centrifuge motor control device configured as described above, the operation of the boost converter is stopped in the low speed rotation region when the motor is started and stopped, and the smoothing by the pulse width modulation and AC phase control element is performed. The voltage applied to the motor is suppressed by adjusting the charging voltage of the capacitor for use in the motor.When the motor is in the high-speed rotation region, the AC phase control element is turned on and the boost converter is operated, and the motor is pulse-width modulated to control the motor. Suppresses the voltage applied to.

Further, the present apparatus operates to select a capacitor whose settling speed is within a range sufficiently inside the oscillation frequency range of the voltage controlled oscillator in the PLL so that the accelerating / settling speed is set.

Further, the present control device provides an ON / OFF signal only to the switching element of the lower arm for a predetermined time before and after the operation of the selector switching the connection of the capacitor which determines the oscillation frequency range of the voltage controlled oscillator, The switching element of the arm operates so as to turn it off.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings. In the block diagram shown in FIG. 1, which is a specific embodiment of the present invention, 21 is an AC power source, 22 is an AC side connected to an AC power source 21 via a reactor 23, and a DC side is connected to a smoothing capacitor 24. A bidirectional power converter for a power supply, which is a boost converter in which switching elements such as bipolar transistors IGBT and FET are connected in reverse parallel to respective rectifying elements constituting the freewheeling rectifier circuit. Is a switching element serving as an AC phase control element such as a triac or thyristor for adjusting the charging voltage of the smoothing capacitor connected between the reactor 23 and the smoothing capacitor by phase control, and 26 is an induction motor on the AC side. Rotor 2 for centrifugal separation
In the return rectifier circuit connected to the motor 28 for driving 7 and connected to the smoothing capacitor 24 on the direct current side, each rectifying element forming the return rectifier circuit has the same type as the bidirectional power converter 22 for power supply. It is a bidirectional power converter for a motor which serves as an inverter device to which a switching element is connected.

In the PWM inverter control of the switching element of the motor bidirectional power converter 26, 29
Is a ROM that stores the ON / OFF pulse pattern of the switching element, and the logical values of “1” and “0” of the output data of the data output line of the ROM 29 are the pulse patterns. The clock of the counter 30 is sequentially read by the output of the counter 30 connected to the address line, and the clock of the counter 30 is a PLL that becomes an oscillator.
It is applied by the clock output of the pulse generator 31, and the clock output frequency of the PLL pulse generator 31 is controlled by the timer LSI 32. Reference numeral 33 is a latch that prevents time irregularity of data read from the ROM 29 and synchronizes it. Reference numeral 34 is a gate driver that drives the photocoupler 35 in accordance with the output logic of the latch 33. ON / OFF of the six switching elements of the bidirectional power converter 26 is controlled. The smoothing capacitor 24 has an anode line 24a and a cathode line 24.
Indicated by b. In controlling the switching element of the bidirectional power converter 22 for power supply, 36 is a power factor correction control IC.
The pulse width control output of this IC is amplified by the gate driver 38 via the pattern switch 37 and drives the photocoupler 39. The signal output of the photocoupler 39 controls ON / OFF of the four switching elements of the power bidirectional power converter 22. Power factor correction control I
In C36, the power-source phase-direction power converter 22 is the reactor 2
In the forward direction operation in cooperation with No. 3, a step-up converter that charges the smoothing capacitor 24 to a constant voltage while the motor 28 is running with a current having a low harmonic current content similar to the voltage waveform of the AC power supply 21. The motor 28 discharges the smoothing capacitor 24 during regeneration and serves as a step-down converter that maintains a constant voltage so that a reverse operation can be performed by a V by an insulating transformer or the like.
A power supply voltage waveform is obtained by the sensor 40, a power supply current waveform is obtained by the I sensor 41 such as a hall current sensor, and a CV sensor 42 formed by a combination of V-F and F-V converters insulated by a photo coupler or the like is used as a smoothing capacitor. The charging voltage signal of 24 is inputted as a sensor input signal. 43 is an analog switch, the above-described forward operation of the bidirectional power converter 22 for power supply,
The signal output of the I-sensor 41 is the attenuator 4 so that the reverse operation can be performed by the same control action of the power factor correction control IC.
The signal level can be switched by 4 and the CV sensor 4
The signal output of 2 is provided by the differential amplifier 45 so that it can be switched and selected from the subtraction signal based on the reference voltage source 46. By the signal output of the I / O LSI 47,
The switching is performed in conjunction with the pattern switch 37.

Reference numeral 48 is a positive / negative cycle detector of the power source which detects the positive / negative cycle state of the AC power source 21 and outputs a logic signal to the pattern switch 37, and 49 is the I / O LSI 47 of the signal output. AC phase control element 2 for outputting to
A 0-cross circuit that outputs a 0-cross signal of the AC power supply 21 for phase control of 5 is denoted by 51. A PLL pulse generator 31 that outputs the signal output to the timer LSI 32.
It is an oscillator that serves as a reference clock source for the. The AC phase control element 25 is connected to the timer LSI 3 via the photo coupler 50.
2 signal output. The power supply control circuit 52 is a circuit that supplies drive power to the gate drivers 34 and 38, and when an abnormality such as an overcurrent of the bidirectional power converters 22 and 26 or an arm short circuit occurs, or the AC power supply 2
In order to prevent the ON signal from being applied to the switching elements of the bidirectional power converters 22 and 26 until the preparation of the operation of the entire control device is completed after the power is turned on in 1 and when the control state is switched during other operation. It is provided.

Reference numeral 53 is a rotation sensor for detecting the rotation speed of the rotor 27, 54 is a counter circuit for measuring the rotation speed of the rotor 27, and 55 is a timer LSI 32, I / O.
It is a centrifuge control CPU that controls the LSI 47 and the counter circuit 54. Reference numeral 100 indicates a control means for performing on / off control of the switching elements of the bidirectional power converters 22 and 26.

As described above, the V sensor 40, the I sensor 41, the CV sensor 42, the photocouplers 35, 39 and 5 are used.
By the insulation signal transmission means of 0, the reference voltage is insulated between the bidirectional power converters 22 and 26, which are power circuits, and the control means 100, and the AC phase control element 25 or the bidirectional power converter 22. The control means 1 is controlled by noise generated by the high-speed switching operation of the switching elements in
00 is prevented from being affected by a malfunction or the like. Further, in order to prevent the other devices connected to the AC power source 21 from being adversely affected, in FIG. 2 showing a part of another embodiment of the present invention, parts having the same functions as those in FIG. The same reference numerals are given, in order to prevent these noises from being transmitted to the AC power supply 1, the reactor 23 is provided on both lines of the AC power supply 21, and the low frequency filter 56 of the common mode choke coil is provided. The same high-frequency filter 57 and common mode noise bypass capacitors 58a and 58b whose common connection ends are connected to the ground 60 and normal mode noise bypass capacitors 59a and 59b may be used. 87 is a snubber circuit of an AC phase control element composed of a resistor and a capacitor connected in series.

Next, the operation of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. 3 to 15, parts having the same functions as those in FIG. 1 are designated by the same reference numerals.

FIG. 5 shows the number of revolutions of the rotor 27, that is, the motor 2 suitable for the control device for the motor for the centrifuge according to the present invention.
8 is a graph showing a lapse of time of the number of rotations of 8 and a mode I
Is a process of gradually accelerating the rotor 27 from a stationary state by a slow accelerator, and since it corresponds to this slow accelerator and smooth start cannot be performed only by the PWM control, the PAM control is also used. That is, the motor 28 performs the PAM control for adjusting the charging voltage of the smoothing capacitor 24 by the AC phase control element 25 and the PWM control for the bidirectional power converter 26, and the centrifuge control CPU 55 causes the motor 2 to operate.
8 is controlled along the curve of FIG. Figure 6 for PAM control
The CPU for centrifuge control
55 crosses the 0 cross circuit 49 via the I / O LSI 47.
Using the rising point 60a of the zero cross signal 60 as a reference signal, the timer LSI 32 is caused to perform a delay trigger operation at time t1, and further the time t1 is changed as necessary to trigger the AC phase control element 25 at a desired conduction angle. As a result of applying the signal 61, a current 63 whose phase is controlled with respect to the voltage waveform 62 of the AC power supply 21 flows and the charging voltage of the smoothing capacitor 24 is adjusted. The trigger signal 61 is turned off at the falling point 60b of the 0-cross signal 60. As shown in the waveform example of the three-phase PWM inverter in FIG. 7, the PWM control is performed by turning on / off the switching elements 26 u, v, w, x, y, and z of the triangular carrier wave 64 and the sine wave signal wave 65. The pattern is obtained in advance and stored in the ROM 29.
n66, Evn67, and Ewn68 are the ON signals of the switching elements 26u, v, and w, respectively, and the OFF signals of the switching elements x, y, and z corresponding to the upper and lower sides, respectively, and eUV6
9, eVW70 and eWU71 represent voltage waveforms output during the lines UV, VW and WV connected to the motor 28, respectively. In FIG. 7, the case of 21 carrier duty 50% in the combination of the triangular carrier wave 64 and the sine wave signal wave 65 is illustrated.

The operation of the control device 100 relating to the PWM control will be described with reference to FIG. 3. The data stored in the ROM 29 is the PLL pulse generator which is a D type slip flop such as 74HC374 which becomes the latch / gate drivers 33 and 34. Inversion signal 7 of the output signal of 31
2, the photocoupler 35 is synchronously latched by the CK terminal and drives the switching element u, v, w, x, y, z of the bidirectional power converter 26. ROM 29
Data output terminals O1 to O6 correspond to 1D to 6D of the latch gate drivers 33 and 34 as shown in FIG.
For ~ 6Q, they correspond to u ~ z, for example RO
When the O1 terminal of M29 becomes the logic "0" level, the 1Q terminals of the latch gate drivers 33 and 34 also have the logic "0".
Then, the LED 35 is turned on via the resistor 80, and the switching transistor u is turned on. The OC terminals of the latch / gate drivers 33 and 34 are for switching the 0 output to high impedance.
When the output control line 85 of is "Hi", the impedance becomes high impedance and all the photocouplers are turned off. As an example, the drive circuit between the switching element 26u and the photocoupler 35u of the transistor is provided with an appropriate power supply VCCU whose emitter E of the switching element 226u is used as the reference potential GNDU, as shown in FIG.
When a current flows through the light emitting diode 35u of u, the opposing phototransistor is turned on, and the knot gate 75 becomes the resistor 7
The bias of No. 4 disappears, the output becomes "Hi" level, the base current flows to the transistor 77 through the resistor 76, and the switching element 26u passes through the braking resistor 78.
A voltage bias is applied to the gate G of
On the other hand, when the current of the light emitting diode 35u disappears, the output of the knot gate 75 is similarly inverted to the “LO” level, the charge of the gate G is discharged through the transistor 79, and the gate G is turned off. The drive circuit portion is shown at 132. ROM2
For reading the data of 9, the counter 30 in which three 74HC193 are connected in three cascades counts up at the rising edge of the pulse output signal 73 of the PLL pulse generator 31, and the signal output of the count terminals of Q _{0 to} Q ₁₀ is R
This is done by outputting to the address lines A _{0 to} A ₁₀ of the OM 29. In this case, 11 address lines are used for driving by dividing the ON / OFF pattern for 360 degrees by 2048 in FIG. As shown in FIG.
The latching operation is added by the falling signal 72 of the pulse signal 73 of ON / OFF due to a slight timing shift of the data read output read at the rising of the pulse signal 73 of the PLL pulse generator 31 of the ROM 29 of O1 to O6. This is to avoid a so-called arm short-circuit phenomenon in which the pattern is broken and the switching elements of the same arm of the bidirectional power conversion element 25, for example, u and x are simultaneously turned on. The CLR terminal of the counter 30 is R
A count clear terminal for reading the data of the OM 29 from the address 0, and the control line 8 of the I / O LSI 47.
When 6 is “Hi”, it is cleared. The pulse output signal 73 of the PLL pulse generator 31 is 74HC404.
6 is output from the VCOOUT terminal by the PLL element 69, and the timer LSI 32 such as UPD8253 outputs the oscillator 5
The oscillation output of 1 is divided by the frequency dividing function 32a and output as the reference signal 70 to the SIN terminal of the PLL element 69, while the pulse output signal 73 of the PLL pulse generator 31 is divided by the timer LSI 32 by the frequency dividing function 32b. And outputs it as a comparison signal 71 to the CIN terminal of the PLL element 69,
An error signal is output from the PC terminal by the phase comparator, a voltage bias is applied to the VCOIN terminal through a low pass filter 81 composed of a combination of a resistor and a capacitor, and an oscillation output can be obtained by a VCO 82 (voltage control oscillator). Therefore, the oscillation output has a frequency obtained by multiplying the frequency of the reference signal 70 by the reciprocal of the frequency division ratio of the frequency dividing function 32b. VCO 82
In the case of an ultracentrifuge, it is necessary to rotate the motor in the range of 0 to 200 Kmin to ¹ , and preferably 10
It is necessary to cover a wide range from KHZ to 6.9 MHZ, and several kinds of external capacitor capacities of the PLL element 69 are switched and used. For this purpose, for example, 74HC40
An analog multiplexer 83, which serves as a selector such as 51, connects one end to each of the X1 to X5 terminals.
One of the capacitors C1, C2, C3, C4, and C5 indicated by 1 is selected from the X terminal and connected to the PLL element 69. Note that the capacitor C0 is always connected so that the oscillation output of the PLL element 69 does not fluctuate significantly while switching the connection of the capacitor.

In the mode I, since the rotation speed of the motor 28 is low, the frequency of the pulse output signal of the pulse generator 31 is also low, and the C of the analog multiplexer 83 from the I / OLSI 47 via the capacitor connection switching line signal 84.
A selection signal is given to the SEL terminal, and the capacitor C1 having the smallest capacitance is selected.

As described above, in mode I,
The power supplied to the motor 28 is adjusted by the PAM control by the AC phase control element 25 and the PWM control by the pulse pattern stored in the ROM 29, and an appropriate slip frequency f1 is given to the motor 28 by the PLL pulse generator 31 and smoothly. The rotor 27 is gradually accelerated by the slow accelerator. In this mode I, the phase-controlled current 63 flows, but since the current value is small,
The content of harmonic current is small and there is no problem affecting other equipment. In order to match the actual rotational speed of the motor 28 with the elapsed time of the rotational speed of the rotor 27 in mode I, the difference between the elapsed time of the predetermined rotational speed and the current rotational speed of the motor 28 is calculated by PID calculation or the like. From the result, the above timer L
This is based on a well-known method of determining the slip frequency f1 by the PLL pulse generator 31 and the delay trigger operation of time SI of SI32.

Next, the mode II of FIG. 5 is a process of rapidly accelerating the rotor 27 to the target settling speed N0.
While the switching elements u, v, x, y of the bidirectional power converter 22 for the power supply shown in (4) were all in the off state in the mode I, they are systematically linked to the AC power supply 21 and have a voltage waveform of the power supply. Since it operates as a step-up converter so that a similar current flows and performs a forward operation in which the smoothing capacitor 24 is charged to a constant voltage, an on / off operation is performed as described below.

The operation of the control device 100 relating to the above control will be described with reference to FIG. 4. PWM for operating as a step-up converter from the O terminal of the power factor correction control IC 36.
The control signal 88 is output to the pattern switch 37, and the signal 88, the signal of the P terminal which becomes the logic "1" at the positive cycle of the power source positive / negative cycle detector 48 and the signal of the N terminal which becomes the logic "1" at the negative cycle. The output is AND gates 89, 90, 91, 9
The signal obtained by logical product of 2 is output to the data selector 93 such as 74HC158 and the select signal line 94 of the I / O LSI 47 is kept at "0" level in this case, so that the signal at the input terminal A is logically output from the Y terminal. Inverted and output, the gate driver 38 drives the photocoupler 39 via the drive current limiting resistor 95. The pulse pattern output from the pattern switch 37 to the switching elements U, V, X, Y of the bidirectional power converter 22 for power supply is shown in FIG. 9, and the photocoupler 39 and the drive circuit of the switching element are the same as those in FIG. Will be things. The positive cycle refers to the case where the a-terminal of the AC power supply has a high potential and the b-terminal has a low potential in FIG.

Next, the generation of the PWM control signal 88 will be described. The control IC of the power factor correction control IC 36.
When an example of using FA5331 manufactured by Fuji Electric Co., Ltd. is shown as 96, as shown in the functional block diagram of FIG. 10, the parts having the same functions are designated by the same numbers, and V
The output of the sensor 40 is supplied to the V terminal through the full-wave rectification circuit 97, and the voltage waveform of the AC power supply 21 serving as a reference is given to
From the sensor 41, a full-wave rectification circuit 98 is passed, and a current feedback signal divided by a voltage divider 102, which is a voltage division output of the resistors 99 and 101, is input to an XA terminal of an analog switch 43 such as 74HC4053, and X is input. The charging voltage signal of the smoothing capacitor 24 is output from the output terminal, is input from the CV sensor 42 to the YA terminal of the analog switch 43 as a feedback signal, and is output from the Y output terminal. The CV sensor 42 converts the voltage-divided output of the smoothing capacitor 24 by the resistors 103 and 123 into a pulse output having a frequency proportional to the voltage by the V / F converter 104, and isolates this signal at the ground level of the signal by the photocoupler 105. , V / F converter 105 restores the voltage signal proportional to the frequency, and outputs the voltage of the smoothing capacitor 24 to the YA terminal of the analog switch 43 while maintaining insulation. In the analog switch 43, the signal XA input is transmitted to X and the signal YA input is transmitted to Y because the logic level of the select signal line 94 is “0”. The charging voltage of the smoothing capacitor 24 is compared and amplified with the reference voltage 110 by the resistors 106 and 107, the filter capacitor 108 and the OPAMP 109, and the charging voltage of the smoothing capacitor 24 is, for example, 17 when the voltage of the AC power supply 21 is 100V.
It is kept constant at 0 to 180 V, and the power supply current at that time becomes similar to the power supply voltage. That is, the error signal output VFB from the OPAMP 109 is equal to the power supply voltage V and the multiplier MUL111.
Is multiplied by the resistor 112, the capacitor 114, the resistor 112, the capacitor 114,
The output IFB is output as a PWM control signal from the O terminal which is compared by the PWM comparator 120 with the sawtooth wave signal of the oscillator 119 including the resistor 117 and the capacitor 118 due to the amplification action of 115 and the OPAMP 116. Therefore, for example, when the AC power supply 21 has a positive cycle,
The switching element X of the bidirectional power transformer 22 for power supply is turned on in response to the PWM control signal 88 output from the O terminal.
When turned off, a boost converter is formed in the circuit including the reactor 23 and the smoothing capacitor 24, and the charging voltage of the smoothing capacitor 24 is the power supply voltage, the motor 2
It is kept constant regardless of the magnitude of the load that becomes the driving force of No. 6, the power supply current is similar to the power supply voltage of the AC power supply 21, and there is almost no content of harmonic current. Voltage divider 10
It is the motor 2 that divides the signal output of the I sensor by 2
This is because the regenerative current is smaller than the power running current due to the loss of 8 and therefore the I input of the control IC 96 is made large during regeneration to reduce the distortion of the power supply current waveform with respect to a minute regenerative current.

Reference numeral 121 is a knot gate, which is I /
The logic output “0” of the control signal line 122 of the OLSI 47 enables the output of the data selector and the operation of the control IC 96.

In the mode II of FIG. 5, the charging voltage of the smoothing capacitor 24 is kept constant as described above, so that the V / f control for the motor 28 is performed by the three-phase PWM inverter of FIG. As shown in the waveform example, the amplitude of the sine wave signal wave 65, that is, the duty of the voltage applied to the motor is changed stepwise, and the read block of the pattern stored in the ROM 29 for each block is changed to V / f. V is controlled by a timer LSI
The dividing ratio of the frequency dividing function 32b of 32 is sequentially increased, and the capacitors C1 to C5 connected to the PLL element 69 are selected and switched. The motor 28 is provided with an appropriate sliding frequency corresponding to the rotational speed thereof until the target settling rotational speed NO. To accelerate.

FIG. 11 shows the contents of the blocks stored in the ROM 29. The small block n0 PWM is shown in FIG.
This is an example in which V is controlled in 32 steps in which O is the minimum duty and n0PWM31 is the maximum duty, while the difference between the middle blocks n0PWM and n1PWM is the difference in the number of carriers of the triangular carrier wave 64 in FIG. As the number of rotations increases, the number of times the switching elements of the bidirectional power converter 26 are switched becomes unreasonably large, and it is necessary to properly manage the temperature rise of the elements due to the switching loss. As the number of carriers of the triangular carrier wave 64 decreases, the number of carriers of n3 is set smaller than that of n0. Note that n
Since n3 is used in the high-speed rotation range with respect to 0, the range of duty PWM0 to PWM31 is also a high division content. The change of the read block of the small block is selected by the control line 124 connected to the A11 to A15 line VSEL of the address line of the ROM 29 from the I / O LSI 47 of FIG. , A16 to A18 of address line
It is adapted to be selected by the control line 125 connected to the line FSEL.

FIG. 12 shows the frequency output from the VCOOUT 73 with respect to the voltage bias VCOIN of the linear scale in the logarithmic scale using the capacitors C1 to C5 connected to the PLL element 69 in the PLL pulse generator 31 as parameters for the control of f. Is shown in
In order to accelerate and settle the motor from the stationary state to the maximum number of rotations, the capacitors are placed in order from C1 to C2, C3, C4, C5.
PLL pulse generator 3
The oscillation frequency of 1 is increased. Further, in this case, the oscillation frequency ranges of the capacitors are sufficiently overlapped with each other, and for example, when accelerating and settling up to the above-described maximum rotation speed, it is possible to select and switch between the capacitors C1 to C3 to C5. is there. For example, when the control rotation speed of the motor 28 is between Na and Nb, the capacitor C2 is selected and the frequency required for f control is output. For example, when the control settling rotation speed is just Nb. At the time of acceleration settling, taking into consideration that the target rotational speed Nb is settled with some overshoot of the rotational speed, the capacitor C
2, the range of use is limited so that Na to Nb is inside the rotational speed range Na 'to Nb' that can actually be covered, and an oscillation output with a stable frequency can be promptly obtained when the connection of the selected capacitor is switched. In order to suppress the change in VCOIN as much as possible, the rotational speed ranges of the capacitors that can be covered are sufficiently overlapped. As described above, the capacitor selection is performed by the capacitor connection switching signal 84 of the I / O LSI 47.

Next, the mode III in FIG. 5 is a process of keeping the rotor 27 constant at the target settling speed N0, and the bidirectional power converter 22 for power supply is system-linked to the AC power supply 21 as in the mode III. The smoothing capacitor 2 operates as a boost converter so that a current similar to the voltage waveform of the power supply flows.
4 is charged to a constant voltage, a forward operation is performed. For example, if N0 is the maximum operating speed of the centrifuge, the small block of the ROM 29 has a minimum carrier number and maximum duty of n3PW.
When M31 is selected, the capacitor C5 connected to the PLL element 69 is selected, a high frequency f is given, and the target rotation speed N0 and the motor are controlled so that the rotation speed of the motor 28 is kept constant at the target settling rotation speed N0. The CPU 55 for centrifuge control calculates PID of the current difference in the number of revolutions of the motor 28, determines the slip frequency f1 of the motor 28 from the result, and controls the frequency division function 32b of the timer LSI 32 corresponding thereto by instructing the frequency division ratio. To do.

Next, mode IV in FIG. 5 is a process in which the rotor 27 is rapidly decelerated by regenerative braking, and the bidirectional power converter 22 for power supply shown in FIG. 4 is systematically linked to the AC power supply 21. The converter operates as a step-down converter so that a current similar to the voltage waveform of the power source returns to the power source, and reverse operation is performed in which a rise in the charging voltage of the smoothing capacitor 24 due to power generation of the motor 28 is suppressed and a constant voltage is maintained. The operation of the control device 100 relating to the above control will be described with reference to FIG.
In this case, since the select signal line 94 of the LSI 47 is maintained at the "1" level, the signal at the input terminal B of the data selector 93 is logically inverted and output from the Y terminal and output from the pattern switch 37 to the bidirectional power converter for power supply. The signals of the pattern shown in FIG. 13 are output to the switching elements u, v, x, y of 22.

The generation of the PWM control signal 88 will be described. Since the S input terminal of the analog switch 43 is also at "1" level, the signal directly input from the I sensor 41 to the XB terminal through the full wave rectifier circuit 98 is obtained. The signal output from the X output terminal, and the signal obtained by subtracting the charging voltage signal of the smoothing capacitor 24 from the reference voltage 126 by the differential amplifier 45 is input to the YB terminal of the analog switch 43 from the CV sensor 42, and the smoothing capacitor is input from the Y terminal. It is input to the power factor correction control IC 36 as a feedback signal of the charging voltage of 24, and 127 is OPAMP in the differential amplifier 45, 12
Reference numerals 8, 129, 130, and 131 denote resistors for differential amplification. When the charging voltage of the smoothing capacitor 24 increases, the output voltage of the differential amplifier 45 decreases, and the output of the CV sensor 42 in FIG. Here, if you replace the above output,
The OPAMP 109 compares and amplifies the reference voltage 110, and the charging voltage of the smoothing capacitor 24 is kept constant at 160V to 170V when the voltage of the AC power supply 21 is 100V, and the current returned to the power supply at that time is the same control as described above. PWM control signal 8 by the control action of IC96
Therefore, when the AC power supply 21 is in a positive cycle, the switching element Y of the power supply bidirectional power converter 22 is output from the O terminal of the control IC 96 as P.
Since the switching element U is turned on / off in response to the WM control signal 88 and the switching element U is kept on in the cycle of this polarity, a step-down converter is formed in the circuit including the reactor 23 and the smoothing capacitor 24, and the smoothing capacitor is formed. The charging voltage is maintained constant regardless of the power supply voltage and the amount of power generation for decelerating the rotor 27 of the motor 26, and the current regenerated by the AC power supply 21 becomes similar to the power supply voltage, and the content of the harmonic current is There is almost no. Mode I of FIG.
In II, as described above, the smoothing capacitor 24
To the charging voltage of the motor 26 by the bidirectional power converter 26
The same V / f control as in the case of mode II is performed in order to increase the power generation voltage of, and a negative slip frequency f1 is applied to decelerate.

Next, the mode V is the rotor 27 of the mode IV.
After the rapid deceleration process, the rotor 27 is gradually decelerated from the rotating state to the stationary state by the slow dexel. Since the rotation speed of the motor 26 is low, the deceleration force is applied to the motor 26 not by dynamic braking but by DC braking. Control to stop smoothly. Therefore, the power supply bidirectional power converter 22 may operate as a step-up converter as described above to perform forward operation, or if the power required for DC braking is small, the switching elements U, V, X, Y may be replaced. It is also possible to turn off all and operate as a simple front wave rectifier.
Further, a smoothing capacitor 24 is provided by the AC phase control element 25.
Adjust the charging voltage of and combine with ROM control DC braking to select a wide range of braking control. FIG. 14 shows an example of an on / off pattern output to the switching element of the bidirectional power converter 26 for DC braking. In order to adjust the braking force, the correspondence between the triangular carrier 145 and the comparison signal 146 is changed so that an appropriate PWM duty can be arbitrarily selected. In FIG. 11, BPWM0 to BPWM31 stored in the ROM 29 can be selected. The middle block hits the DC braking part, and 32 levels of duty can be selected. FIG. 14 shows an example in which the number of carriers is 16 and the duty is 40%.

In mode V, depending on the type of sample to be centrifuged and the separation conditions, as shown in FIG. 15, the dexel pattern A is more gentle than deceleration by natural deceleration.
There is a case where the motor is decelerated by a deceleration curve like the above. At this time, the charging voltage of the smoothing capacitor 24 is adjusted by the AC phase control element 25 similar to that in the mode I described above, and the bidirectional power converter 26 drives the motor 26. However, an operation method that smoothly and gradually decelerates is used.

In the description of the embodiments of the present invention, the bidirectional power converter 22 for the power supply has been described by taking the case of a single phase as an example.
Those skilled in the art can easily understand that the function can be realized by the same configuration even in the case of three-phase alternating current. Further, in the description of the embodiments of the present invention, the same function can be realized even if the AC phase control element 25 is located at the position indicated by 132 in FIG. 1, and the type is self-erasing such as a transistor or GTO. It is also possible to use an element having an arc capability. On the other hand, the freewheeling rectifier circuits of the power supply bidirectional power converter 22 and the bidirectional power converter 26 may be provided parasitically or intentionally built in the switching elements constituting the existing converter. Can be used, and GTO as above
It is obvious that elements having self-extinguishing ability such as can be used within the concept of the present invention.

In the present invention, the bidirectional power converter for power supply 2
2 and the power supply for switching control of the switching elements U, V, u, v, w of the upper arm of the bidirectional power converter 26, the switching elements X, Y, x, of the lower arm.
FIG. 16 shows an embodiment in which a power supply for switching control of y and z and a reference potential are used in common. FIG. 16 shows the case of the bidirectional power converter 26, and FIG.
Further, the parts having the same functions as those in FIG. 8 are denoted by the same reference numerals, and the drive circuit 132 of the switching element 26u will be described as an example, and 133 will be a drive in which the cathode line 24b of the smoothing capacitor 24 is used as a reference potential. A common power source serving as a common control power source for the circuits 132 and 134, 135, 136, 137, 138, and the reverse blocking diode 13
9 and a drive circuit 132, for example, an aluminum electrolytic capacitor 140 for accumulating drive electric energy is connected in series, and the other end of the capacitor 140 has a switching element 26u.
Of the drive circuit 132, and the power supplies VCCU and GNDU of the drive circuit 132 are connected in parallel to both ends of the capacitor 140. Therefore, the switching element 26x
When the power is turned on, the common power supply 133 is connected to the diode 139,
The capacitor 140 is charged along the route of the capacitor 140 and the switching element 26x, and the switching element 26x
When the switch is turned off, the cathode side of the capacitor 140 becomes a floating state, and the drive electric energy of the drive circuit 132 of the switching element 26u that operates in complementary pair with the switching element 26x is stored in the capacitor 140. Switching elements 26y, 26v, 26z
The same applies to and 26w, and reverse blocking diodes 141 and 142 and capacitors 143 and 149 are connected and configured as shown in the drawing. As described above, since the drive circuits 132, 134, 135 of the upper arm are driven by the charges charged in the capacitors 140, 143, 144, respectively, the switching circuits 6x, 26y, 26z of the lower arm are It is necessary to repeat the switching operation frequently without pausing, and the on / off pattern of the DC braking shown in FIG. 14 is devised so as to satisfy the above constraint condition.

Further, in the present invention, regarding the control of f for giving the slip to the motor 28, the capacitors C1 to C1 connected to the PLL element 69 in the PLL pulse generator 31 are connected.
When C5 is selectively switched, the frequency of the pulse output signal 73 transiently fluctuates due to the time constant of the low-pass filter 81, etc., so that, for example, in the lower arm of the bidirectional power converter 26 facing the switching element 26u of the upper arm. With regard to on / off of the switching element 26x, a dead time set so as not to cause an arm short circuit at a normal frequency may become insufficient, which may cause an arm short circuit phenomenon. Therefore, when switching a capacitor as shown in FIG. ,
While the frequency of the pulse output signal 73 is stable immediately before switching and after switching, for a predetermined time of about 200 msec, the switching elements 26u, 26v, 26 of the upper arm are provided.
All of the w are turned off, and the switching element 2 of the lower arm
The 6x, 26y, and 26z drive-control the bidirectional power converter 26 at a time by a pattern in which switching operation is repeated without stopping. It should be noted that this switching pattern is written in the middle block at the position indicated by ARMPAT 150 in the explanatory view showing the stored contents of the ROM 29 in FIG. The same applies to the bidirectional power converter 22 for power supply, and according to the present embodiment, it is not necessary to provide power supplies for the reference electric potentials of the drive circuits of the upper arm, which are independent of each other, and the control unit can be simplified. This is effective for downsizing the equipment.

FIG. 18 is a block diagram showing another specific embodiment according to the present invention. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and mainly the boost converter 22. And a discharge unit 151 for discharging the energy charged in the smoothing capacitor 24 by the regenerative action of the motor 28. In the boost converter 22 shown in FIG. , 15
3, 154 are boosting switching elements such as transistors, FETs, and IGBTs, and the switching elements are turned on.
A photocoupler for transmitting an OFF signal, 155 is a diode, and in the discharge unit 151, 156 is a power resistor for discharge and 157 is a switching element 15 for controlling discharge.
The switching element is the same as that of No. 3, and is a photocoupler that transmits an on / off signal to the switching element 157. In the case of this configuration, the boost converter 22 operates so as to reduce the harmonic component of the current flowing from the AC power supply 21, but does not have the function of returning the charging charge of the smoothing capacitor 24 to the AC power supply 21, so that As described above, the discharging unit 151 discharges the electric charge charged in the smoothing capacitor 24. Switching element 153 of boost converter 22
Since the photocoupler 154 for transmitting the ON / OFF signal to the ON / OFF signal may operate without depending on the positive / negative cycle of the AC power supply, the switching element X of the boost converter 22 shown in FIG. , Y is driven by a signal obtained by ORing the signals for OR gate 159.

Further, the photocoupler 1 for transmitting the ON / OFF signal to the switching element 157 of the discharge unit 151.
58 is controlled by the I / O LSI 47, and the CPU 55 for centrifuge control detects the charging voltage of the smoothing capacitor 24 by the CV sensor 42.
60, via the I / O LSI 47, and when the voltage exceeds a predetermined voltage, the switching element 157 is turned on, and the charge stored in the smoothing capacitor is discharged through the resistor 156.

[0044]

According to the present invention, a step-up converter that operates so as to reduce the harmonic current content in an AC power source, a smoothing capacitor charged by the boost converter, and a power source for the smoothing capacitor are provided. As an AC phase control element for adjusting the charging voltage of the smoothing capacitor is provided to the one provided with the inverter device for controlling the voltage by pulse width modulation, the start / stop characteristics of the motor can be smoothed. Further, according to the present invention, the RO in which the ON / OFF control pattern data of the switching element forming the inverter device for driving the motor is written.
With respect to the counter provided for periodically reading the data of M, the oscillation frequency ranges of the plurality of capacitors that determine the oscillation frequency range of the voltage controlled oscillator in the PLL that outputs the oscillation pulse to the counter overlap each other. Since the capacity is set to 1, the settling speed does not depend on the setting, the control is not complicated, and the settling speed can be set quickly. Further, according to the present invention, a drive circuit operated by a common control power source for transmitting an ON / OFF signal is provided to each switching element of the upper arm of the above switching element, and the drive circuit is provided from the control power source to the opposite side. In the one that obtains the power supply voltage by the energy of the capacitor charged when the switching element of the arm is turned on, the on / off signal is given only to the switching element of the lower arm, and the switching element of the upper arm is turned on. The off control pattern is provided in the ROM, and the on / off operation is performed for a predetermined time before and after the operation of switching the connection of the capacitor that determines the oscillation frequency range of the voltage controlled oscillator by the selector.
Since the switching element is turned on / off by the off control pattern, it is not necessary to extend the dead time due to the frequency fluctuation generated when switching the capacitor, and there is an effect that the voltage utilization rate of the PWM control is not lowered.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing another embodiment of part of FIG.

FIG. 3 is a block diagram showing a detailed embodiment of FIG.

FIG. 4 is a block diagram showing a detailed embodiment of FIG.

FIG. 5 is an explanatory diagram showing the elapsed time of the rotation speed of the motor.

FIG. 6 is an explanatory diagram showing an operation status diagram of PAM control.

FIG. 7 is an explanatory diagram showing an example of a waveform of a three-phase PWM inverter.

FIG. 8 is a drive circuit diagram of a switching element.

FIG. 9 is an explanatory diagram of ON / OFF patterns of the switching elements during the powering operation of the bidirectional power converter for power supply.

FIG. 10 is a functional block diagram of a control IC.

FIG. 11 is an explanatory diagram showing storage contents of a ROM.

FIG. 12: VC with the capacitance of the capacitor as a parameter
It is explanatory drawing which showed the relationship of the output frequency with respect to the input bias voltage of O.

FIG. 13 is an explanatory diagram of ON / OFF patterns of the switching elements during the regenerative operation of the bidirectional power converter for power supply.

FIG. 14 shows that the DC braking of the three-phase PWM inverter is turned on.
It is an off pattern explanatory view.

FIG. 15 is an explanatory diagram of a deceleration pattern.

FIG. 16 is an embodiment showing a power supply circuit of a drive circuit.

FIG. 17 is an ON / OFF control pattern diagram at the time of switching capacitors.

FIG. 18 is a block diagram showing another specific example of the present invention.

[Explanation of symbols]

21 is an AC power source, 22 is a boost converter, 24 is a smoothing capacitor, 26 is an inverter device, 25 is a switching element, 26 is an inverter device, 28 is a motor, 29 is a ROM, 30 is a counter, 31 is an oscillator, 151 is a capacitor. , 83 is a selector, 132 is a drive circuit, 13
3 is a control power supply, 139, 141 and 142 are diodes,
Reference numerals 140, 143 and 144 are capacitors, and 150 is a pattern.

Front page continuation (72) Inventor Shinji Watanabe 1060 Takeda, Katsuta-shi, Ibaraki Hitachi Koki Co., Ltd. (72) Inventor Tokuyasu Matsufuji 1060 Takeda, Katsuta-shi, Ibaraki Hitachi Koki Co., Ltd. Yoshinori 1060 Takeda, Katsuta City, Ibaraki Hitachi Koki Co., Ltd.

Claims (3)

[Claims] 1. A step-up converter that operates so as to reduce a harmonic current content with respect to an AC power source, a smoothing capacitor charged by the boost converter, and a voltage by pulse width modulation using the smoothing capacitor as a power source. In the one provided with an inverter device for controlling, a switching element such as an AC phase control element for controlling the charging voltage of the smoothing capacitor is provided, and when the motor is in a low speed rotation region, the operation of the boost converter is stopped and the pulse width is increased. The voltage applied to the motor is controlled by modulating and controlling the charging voltage of the smoothing capacitor by the switching element, and the switching element is maintained in the conductive state in the high speed rotation region of the motor and the boost converter is operated to perform pulse width modulation. A centrifuge model characterized by controlling the voltage applied to the motor. Data control device. 2. A ROM in which ON / OFF control pattern data of a switching element forming an inverter device for driving a motor is written, a counter provided for periodically reading the data in the ROM, and the counter. An oscillator for outputting an oscillation pulse, wherein the oscillator outputs an oscillation pulse of an arbitrary frequency by a phase-locked loop, and a plurality of capacitors for defining an oscillation frequency range of the voltage-controlled oscillator in the phase-locked loop. And a selector for switching and connecting one of the capacitors to the voltage controlled oscillator, and the capacitance of each capacitor is determined so that the oscillation frequency ranges of the plurality of capacitors overlap each other. Centrifuge motor control device. 3. A drive circuit operated by a common control power supply for transmitting a signal for turning on / off to each switching element of the upper arm, wherein the drive circuit is a lower arm facing the diode and the upper arm from the control power supply. In the one which is supplied with energy by the capacitor charged through the switching element, the ON / OFF signal is given only to the switching element of the lower arm for a predetermined time before and after the operation of switching the connection by the selector, The switching element of the upper arm is turned on to turn it off.
3. The centrifuge motor control device according to claim 2, further comprising control means for reading an off control pattern from the ROM.