JP3465680B2 - Inverter device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable frequency, variable voltage type inverter device. 2. Description of the Related Art For example, when an AC motor is driven by an inverter, the output frequency of the inverter is gradually increased from the start time t1 to the time t2 of the motor as shown in FIG. 6, and as shown in FIG. Keeping the ratio of frequency and voltage constant by increasing the output voltage as the frequency increases V
/ F Constant control is performed. In this V / F constant control, as shown in FIG. 7, an output voltage at a predetermined rotational speed is determined by a reference frequency fb and a reference voltage Vb. However, the V / F constant control as described above is a control in which the output voltage is determined when the output frequency is determined. When the output frequency is fixed and the output voltage is changed. On the contrary, when the output voltage is fixed and the output frequency is changed, it is necessary to change the reference voltage Vb and the reference frequency fb in any case. In order to perform desired torque control by changing these reference voltages (also referred to as base voltages) and reference frequencies (also referred to as base frequencies) to vary the voltages at the current output frequency. For example, it is necessary to predict and change the actual change in the output voltage from the ratio when the base voltage is changed. Also, the base voltage must be changed each time the frequency changes. Therefore, the change of the base frequency and the base voltage is
There was a problem that it could not be done easily. In Japanese Patent Laid-Open No. 9-9680, there is one in which a voltage corresponding to a frequency is stored and the voltage can be selected by designating the frequency. The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an inverter device which can easily perform desired torque control without changing the base voltage and the base frequency. [0009] The present invention converts a three-phase alternating current into a direct current, and turns this direct current on and off by a plurality of switching elements , thereby driving a predetermined duty ratio. an inverter apparatus for controlling an electric motor to give a signal, the
Control that independently controls the frequency and voltage of the drive signal
Control means, frequency setting means for enabling external input of the frequency of the drive signal, and voltage setting means for enabling external input of the voltage of the drive signal ,
The control means has a preset base voltage and base frequency.
A reference value output processing unit for reading out and outputting, and a frequency conversion unit that accepts a set frequency externally input by the frequency setting means and changes according to the value of the set frequency
And the corresponding frequency according to the input of the set frequency.
The drive signal is a value obtained by multiplying the base frequency by a wave number conversion coefficient.
And frequency changing means for changing the frequency of the issue, accepting a set voltage that is externally input by the voltage setting means alone, the
It has a voltage conversion coefficient that changes according to the set voltage value.
As the set voltage is input, the corresponding voltage conversion coefficient is
A voltage changing means for changing the voltage of the drive signal by a value applied to the base voltage; and a frequency change from the frequency changing means.
Value and a voltage change value from the voltage change means, respectively.
And the switching element based on the frequency change value.
Control the off-period of the child and based on the voltage change value
Pulse generation that controls the ON period of the switching element
And a processing means . For this reason, since the frequency and voltage of the drive signal are completely and independently controlled, it is very effective for the intended operation of the load. DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> FIG. 1 is a schematic configuration diagram of an inverter device according to the present embodiment. In this embodiment, the frequency and the voltage are controlled independently, and the output signal for controlling the inverter main body by the external input voltage value Ei from the voltage Vb (base voltage) as a single reference is multiplied by Ki. (K0, K1, ...). In addition to changing the voltage, the frequency fb (base frequency) serving as a reference is rp times (r0, r1,...) Times the frequency of the output signal for controlling the inverter body by the external input frequency value Fi. …) As shown in FIG. 1, the inverter device 1 is an AC that inputs a three-phase power source and converts it into a predetermined DC voltage.
A DC converter 2 and a plurality of switching elements A,
B,... And an output signal Vout1 from the control unit 3,
These switching elements A, by Vout2,.
Drive signal Q1, duty ratio with B,.
And an inverter main body 5 for sending out Q2 to the electric motor 4. The control unit 3 (CPU) is connected to a frequency setting unit 6, a voltage setting unit 7, and a rotation sensor (not shown) for detecting the rotation speed of the electric motor 4. The frequency setting unit 6 and the voltage setting unit 7 described above are
For example, it is preferable to use an operation unit (operation panel) or a volume. The control unit 3 reads a base voltage Vb and a base frequency fb stored in advance upon starting (start instruction), sends a reference value output processing unit 10, a frequency change processing unit 11, and a voltage change A processing unit 12 and a pulse generation processing unit 13 are provided. The control unit 3 also has an I / F 14 for connecting the frequency setting unit 6 and the frequency change processing unit 11.
I / F connecting the voltage setting unit 7 and the voltage change processing unit 12
15. The frequency change processing unit 11 reads the external input frequency setting value Fi set by the frequency setting unit 6 upon activation, and determines the base frequency fb from the reference value output processing unit 10 as follows.
Change in coefficient r p times corresponding to the external input frequency set value Fi, and sends the frequency change value fi to the pulse generation section 13. The aforementioned coefficient r p (r0, r1, r2,...)
Is the external input frequency set value Fi (F0, F1, F2,
...) and to a coefficient r p may be stored in the memory as was the correspondence table, or may be stored in the memory in the linear function coefficients r p is determined once the external input frequency set value Fi. The voltage change processing unit 12 reads the external input voltage setting value Ei set by the voltage setting unit 7 upon activation,
An output voltage change value Vi obtained by changing the base voltage Vb from the reference value output processing unit 10 to a factor Ki times corresponding to the external input voltage setting value Ei is sent to the pulse generation processing unit 13. The above-mentioned coefficient Ki (K0, K1, K2,...)
Is the external input voltage set value Ei (E0, E1, E2,...)
May be stored in the memory as a table corresponding to the coefficient Ki, or may be stored in the memory as a linear function in which the coefficient Ki is determined when the external input voltage set value Ei is determined. The pulse generation processing unit 13 receives the frequency change value fi from the frequency change processing unit 11 alone, and changes the off period of the output signal to the inverter body 5 generated from the PWM signal based on this change value. To do. The pulse generation processing unit 13 receives the output voltage change value Vi from the voltage change processing unit 12 alone, and determines the ON period of the output signal to the inverter body generated from the PWM signal based on this change value. change. The operation of the inverter device 1 of the first embodiment configured as described above will be described. The control unit 3 switches on the switching elements A, B, C,... Of the inverter body 1 in order. In general, the frequency is the time from when one switching element is turned on to when it is on, and the voltage is its on width. That is, the frequency change processing unit 11 is connected to FIG.
As shown in FIG. 4, the base frequency fb is fixed, and the frequency change value fi obtained by changing the OFF time T1 according to the input frequency setting value Fi set by the frequency setting unit 6 is obtained. This change, read the external input frequency set value Fi, and base frequency fb from the reference value output processing section 10 is changed by a factor r p times corresponding to the external input frequency set value Fi. As shown in FIG. 2, the voltage change processing unit fixes the base voltage Vb and sets the external input voltage set value Ei (voltage Vb in consideration of the allowable range of the voltage command) set by the voltage setting unit 7. Output voltage change value V by changing the ON width independently (independently) according to the value determined by the ratio of
i is obtained. For example, the voltage change processing unit 12 has an external input voltage setting value Ei determined by the external voltage setting unit 7.
And the coefficient Ki obtained from the set value Ei and the linear function of the conversion is used as the base voltage Vb from the reference value output processing unit 10.
The output voltage Vout (output voltage change value Vi) applied to is obtained. As shown in FIG. 3, when the input signal from the voltage setting section 7 = V0 input → the output voltage Vout is the reference voltage Vb, the K0 times input signal = V1 input → the output voltage Vout is the reference. K1 times input signal with respect to voltage Vb = V2 input → Output voltage Vout is K2 times with respect to the reference voltage Vb. Input signal: external input voltage set value voltage Vb: pulse on width Output voltage: pulse on width When the external input voltage set value Ei from the voltage setting unit 7 is input, a coefficient Ki corresponding to the set value is obtained.
The coefficient Ki is multiplied by Ki (K0 times, K1 times, K2 times,...) With respect to the reference voltage Vb, and the ratio of the coefficient Ki to the base voltage Vb (or base frequency) changes. Accordingly, when the ON width shown in FIG. 2 is, for example, when the input signal = V0 is input → the output voltage Vout is a reference voltage Vb, the K0 times input signal = V1 is input → the output voltage Vout is the reference voltage Vb. On the other hand, when K1 times input signal = V2 is input, the output voltage Vout is twice as wide as the reference voltage Vb. <Second Preferred Embodiment> FIG. 4 is a schematic configuration diagram of an inverter device according to a second preferred embodiment. In the inverter device 20 of the second embodiment, when the variable frequency and the variable voltage are separately controlled, the current output voltage (the original output voltage in the V / f constant control) is multiplied by a coefficient,
Variable control (V / f proportional control). The inverter device 20 of the second embodiment includes an AC-DC converter 2 similar to that of the first embodiment,
The inverter main body 5 is provided, and the control unit 22 includes a reference value output processing unit 10, a pulse generation processing unit 13, an I / F 14 and an I / F 15 (not shown) . The control unit 22 includes a voltage change processing unit 25 and a frequency change processing unit 24 used in the present embodiment.
With. The voltage change processing unit 25 includes a V / f constant control processing unit 26 and a pulse generation processing unit 13 from the inverter body 5.
Are input as the current output voltage Vin from the V / f constant control processing unit 26 and the base voltage from the reference value output processing unit 10. Vb and the external input voltage set value Ei from the voltage setting unit 6 are input. Then, a new output voltage change value Vi is obtained by multiplying the external input voltage set value Ei and a coefficient Ki determined by a linear function stored in advance by the current output voltage Vin (voltage on the V / f pattern). By outputting this to the pulse generation processing unit 13, a new output voltage Vout (Vou
t1, Vout2,... The frequency change processing unit 24 outputs an output signal Vo sent from the pulse generation processing unit 13 to the inverter body 5.
The on / off period of ut1, Vout2,... is input as the current frequency from the V / f constant control processing unit 26, the base frequency fb from the reference value output processing unit 10, and the external input frequency from the frequency setting unit 7 Enter the set value Fi. [0037] Then, with the external input frequency set value Fi stored in advance the coefficients r p which is determined by a linear function and a new change frequency fi toward the current frequency Fin, and outputs it to the pulse generation section 13 Thus, an output signal having a new frequency is obtained. The coefficients used for such V · f proportional control will be described with reference to FIG. For example, when the input signal (external input voltage set value Ei ) from the voltage setting unit 6 is input signal = V0 ′ input → Vout = Vin− (Vin × 100%) = 0 (v) Input signal = V1 ′ At the time of input → Vout = Vin− (Vin × 0%) = Vin (v) At the time of input signal = V2 ′ input → Vout = Vin + (Vin × 100%) = 2Vin
(V) performing a Do conversion process you'll say. Therefore, an expensive vector inverter need not be used when torque control is performed on a longitudinal winding machine such as a wire. In particular, V · f proportional control basically uses V / f.
f Since the frequency and voltage can be varied under constant control, this is particularly effective in preventing torque (voltage) commands from being excessively applied in voltage control during load start / stop deceleration. It also prevents overexcitation (overvoltage command) at low frequencies. In order to operate the voltage setting unit 6 and the frequency setting unit 7 , the control unit has a function of monitoring and displaying output signals from a torque sensor (not shown) and a rotation sensor (not shown). It is preferable that the operator inputs the external input voltage and the external input frequency while watching the monitor. Furthermore, a mode determination process is provided in the control unit,
When this mode determination processing unit is connected to an operation unit (not shown: keyboard, etc.) and the mode determination processing unit is in a normal mode (when frequency alone or voltage independent control is not performed), a voltage change processing unit, frequency change Without starting the processing unit, the base voltage and the base frequency from the reference value output processing unit are sent directly to the pulse processing unit 13, and the pulse generation processing unit 13 receives the output signal from the rotation sensor, the base voltage and the base frequency. An output signal may be generated. In addition, in the single control mode (frequency single voltage single control is performed), the frequency,
Control the voltage independently. Furthermore, the voltage command may not only change the ratio of the reference voltage but also change the direct voltage command. As described above, according to the present invention, since the frequency and voltage of the drive signal are completely and independently controlled, the effect that arbitrary torque control is possible is obtained. ing. That is, it is very effective for intentionally operating the load.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an inverter device according to a first embodiment; FIG. 2 is a waveform diagram for explaining frequency variation and voltage variation in the first embodiment. FIG. 3 is an explanatory diagram illustrating coefficient conversion of an external input signal according to the first embodiment. FIG. 4 is a schematic configuration diagram of an inverter device according to a second embodiment. FIG. 5 is an explanatory diagram illustrating V · f proportional control. FIG. 6 is an explanatory diagram for explaining a conventional frequency change. FIG. 7 is an explanatory diagram for explaining a conventional voltage change. [Description of Symbols] 2 AC-DC converter 3 Control unit 4 Electric motor 5 Inverter body 6 Frequency setting unit 7 Voltage setting unit 8 Rotation sensor 10 Reference value output processing unit 11 Frequency change processing unit 12 Voltage change processing unit 13 Pulse generation processing unit

──────────────────────────────────────────────────── ----- Continuation of the front page (56) References JP 2000-166259 (JP, A) JP 10-23756 (JP, A) JP 4-285490 (JP, A) JP 8-182202 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02P 7/63

Claims (1)

(57) Claims The claim: 1. A three-phase AC is converted to DC, by turning on and off the direct current a plurality of switching elements, controls the electric motor to obtain a driving signal of a predetermined duty ratio In the inverter device, the frequency and voltage of the drive signal are controlled independently.
Control means, frequency setting means for enabling external input of the frequency of the drive signal, and voltage setting means for enabling external input of the voltage of the drive signal , the control means comprising: Read the preset base voltage and base frequency
A reference value output processing unit for output, and a frequency that is received externally by the frequency setting means and that changes according to the value of the set frequency.
A number conversion coefficient, and with the input of the set frequency,
The value obtained by multiplying the corresponding frequency conversion coefficient by the base frequency
A frequency changing means for changing the frequency of the drive signal; and a voltage conversion unit that accepts the set voltage externally input by the voltage setting means and changes according to the value of the set voltage.
Corresponding to the input of the set voltage
The drive signal power is a value obtained by multiplying the base voltage by a conversion coefficient.
Voltage changing means for changing pressure, frequency change value from the frequency changing means, voltage change
Each receiving a voltage change value from the means, and said frequency
Based on the changed value, the switching element is turned off.
And controlling the switching element based on the voltage change value.
An inverter device comprising: pulse generation processing means for controlling a period during which the child is on .