JPS61135375A - Pwm type power rectifier - Google Patents

Abstract

PURPOSE:To reduce a vibration noise and mechanical fatigue by obtaining the resonance frequency of a machine system, and automatically regulating the carrier frequency of a PWM power reactor to a frequency displaced from the resonance frequency. CONSTITUTION:An acceleration pickup 13 is provided at a robot arm 4, and a servo controller 5 inputs frequency/amplitude data through a low pass filter 14, an A/D converter 15 and an FET analyzer 15. The resonance frequency of a machine system is automatically analyzed, a carrier frequency is set to the frequency displaced from the resonance frequency, and a PWM power reactor 1 is controlled through a carrier frequency setter 11, a D/A converter 12 and a voltage control oscillator 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PWM (pulse width variable 1i14) forward converter, and more particularly to an automatic carrier frequency setting device.

Conventional technology PWM power converters are generally PWM inverters, that is, low-high-voltage power converters. -CVCF or v
The Vvy power supply is used as a source for uninterruptible power supplies or for variable speed motors. Other 'PWM universal power converters and PWM universal power converters have been proposed, and this forward converter uses non-uniform PWM to control the conduction period of the main circuit switch for AC input to reduce ripples. It is possible to reduce the voltage and obtain variable voltage DC power next time. This PWM type power converter is suitable as a DC'gt motor power source for a DC servo control system for precise control of robots and the like.

Two problems solved by the invention: When using a conventional PWM system forward converter as a power source for a servo motor, etc., and using the 1lli current electric motor to drive a machine such as a robot arm, the When the natural resonance frequency of the TA system matches the carrier frequency of the PWM universal converter or its harmonics, the rotation of the VC-DC motor and the mechanical system resonate, and a large vibration noise is generated. There is a risk of increased fatigue and loss.

In this case, the carrier frequency has traditionally been adjusted by shifting it to a higher or lower 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 nature condition type size form.
1ieL, 7t, it becomes a cut-and-try adjustment in the condition, which becomes a troublesome adjustment work, and 1) The resonance frequency changes due to a change in the load on the mechanical system, which may require readjustment.

Means and Effects for Solving Problems The present invention provides a PWM universal converter that detects the acceleration of a mechanical system when an impulse or step speed control output is applied to the DC motor. A high-speed 7-Lier transform device for finding the resonant frequency of the system, a frequency setting device for setting all external f'L nine-frequency carrier frequencies from the resonant frequency of the mechanical system, and a gold-plated device.

This makes it possible to automatically set a carrier frequency that avoids resonance between the mechanical system and the 1a1-movement of the DC motor.

Embodiment FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention. P
WM forward converter 1 is voltage controlled 1rL7t [IL with flowing power
The speed of the flow motor 2 is controlled, the flow motor 2 is decelerated by the gear mechanism 3, and the robot arm 4 is driven by the Bunbe power. In the drive device for the nine robot arms, the thermistor control does not include speed control and position control of the DC motor 2, which has a servo control device 5 such as a combinator as the control center.

The servo control device 5 sets the speed in the speed setter 6 to output a speed command (output voltage command) of the iPWM forward converter 1 from the setter 6, and outputs a speed command (output voltage command) to the PWM forward converter 1 given by this speed command.
obtains a voltage output that corresponds to a predetermined acceleration speed through feedback control that compares the speed detection value of the speed detector (for example, a Parnu pickup) 7 of the DC motor 2 with the speed phase. Yes
, the sensor control unit 1t5 uses the detection unit 8 of the position detector (encoder, resolver) 8 to control the position of the robot arm 4.

The speed setting value is controlled by comparison with the position data taken in through the current position counter 9 and set by the program.

In the servo control device described above, a circuit consisting of 10 to 16 circuits is added for carrier frequency setting. Voltage controlled oscillator (VCO) 10 as a carrier of PWM forward converter 1
The excavated output of lrL is produced, and the output frequency of this voltage controlled oscillator 10 is changed from the servo control device 5 to the carrier frequency setter 11 and its setting directly by the analog 11! D to convert to f
Automatically set via the /A converter 12. Next, the robot arm 4 is provided with an acceleration pickup 13, and this pickup 13: c! Vibration of the bracket arm 4 is detected. This detection signal is extracted as a digital quantity through a low-pass filter 14 and an A/D converter 15.

Novel detection is performed for each frequency component using L in the converter) 16. This detection signal for each frequency component is sent to the servo control device 5.
The signal is taken in and subjected to the above-mentioned calculation for automatic carrier frequency setting.

The automatic setting operation of the carrier frequency in the above-mentioned configuration will be fully explained below.

First, the servo control device t5 sets the carrier frequency fc by the pressure-reducing circle generator 10 to an appropriate value (I (for example, fa=2
kHz). In this state, the servo control device fi
5 continuously gives the two impulse-like (or step-like) speed commands shown in Fig. 742 to the full speed setter 6, and the vibration of the robot arm 4 at this time (shown in Fig. 2B) is converted into an acceleration shock. 13, and from this vibration detection signal, a low frequency component is extracted through an α-pass filter 14, and is taken into an FFT analyzer 16 together with the speed setting value of the speed setting device 6 via an A/D converter 15. FFT analyzer 16: 9 motors 2. The frequency characteristics of the mechanisms of the deceleration mechanism 3 and the robot arm 4 are fully analyzed.

This frequency characteristic is illustrated in FIG. 3. As shown in FIG. 3, the frequency characteristic has a plurality of peak points. This frequency analysis is performed for the 1st to 20th
Find the resonant frequency and its amplitude up to the following degree.

The servo control device 15 analyzes it with the FFT analyzer 16, imports nine frequency-amplitude data, extracts the two resonance frequencies fL and fH closest to the tentatively set carrier frequency fc from each resonance frequency, and uses this resonance frequency 'L. , f
[Adjust the carrier frequency fc to approximately the middle of [=]. These two frequencies, as shown in FIG.
, extract fH.

This period tjJL number fc', which is approximately medium j-, is newly set as 1 section. The carrier Lm e a f c' may be determined using any of the following equations.

f c' == (f L + rH) / 2rc' = 藝τ
= i fc': fL + Δf In the above equation, Δf is a constant value. Based on this L, the number of resonance cycles tL of the 4-mechanical system is automatically analyzed.

Out of this empathic frequency A7?1. By setting the carrier frequency to the frequency, it is possible to eliminate the rotational vibration of the 1ILa motor and the resonance of the mechanical system, and to reduce the generation of sound and mechanical fatigue.

In addition, in the embodiment, the carrier frequency is calculated and extracted by the servo control device from the resonance frequency of the mechanical system even when the harmonics and the load of the arm change, and the carrier frequency is determined. Yes, it will definitely be more effective in reducing common loss noise, etc.

Adjustment of the IL carrier frequency fc is not limited to the voltage control of the voltage control generator 10, and as shown in FIG.
It is also possible to take out a carrier pulse with a mortality of 50% as the final Rk2m counter of the counter 18 and set it with the preset all carrier frequency setter 11 of the counter 18.

Effects of the Invention As described above, according to the present invention, the PWM forward converter I/c
Therefore, in a device that operates a mechanical system using a DC motor as a drive source, find the resonance frequency of one mechanical system.

In order to automatically adjust the carrier frequency of the PWM forward converter from this shared frequency to the external critical wave number, it can be used in the servo control system of robots etc.
7. Can be performed easily and reliably.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a drinking water system according to an embodiment of the present invention. Figure 2 (N is a speed command waveform diagram for carrier frequency setting, m2 Figure 031 is Figure 2 (mechanical system imaging output waveform diagram for Aj, Figure 3 is a mechanical system imaging frequency characteristic diagram, 4
The figure is a frequency characteristic diagram illustrating carrier frequency setting, and FIG. 5 is a circuit diagram showing another embodiment of carrier frequency setting. l...P W M 1lili converter, 2... DC motor, 3... Reduction mechanism, 4... Robot arm,
5... Servo control device, 10... Voltage controlled oscillator,
DESCRIPTION OF SYMBOLS 11...Carrier frequency setter, 12...D/A converter, 13...Acceleration pickup, 14°...Low pass filter, 15...°・Gun converter, 16...FFT
Analyzer, 17...Reference generator % 18...Preset counter.

Claims (1)

[Claims] PW that supplies DC power to the DC motor that drives the mechanical system
In the M-type forward converter, a fast Fourier transform device for determining a resonance frequency of the mechanical system from an acceleration detection signal of the mechanical system when an impulse or step-like speed control output is given to the DC motor; A PWM type forward converter, comprising: a frequency setting device that sets a carrier frequency of the forward converter to a frequency that deviates from a resonant frequency.