CN102694483A - LC (inductance/capacitance) resonance drive circuit for ultrasonic motor and control method of LC resonance drive circuit - Google Patents

Abstract

The invention relates to an LC (inductance/capacitance) resonance drive circuit for ultrasonic motor and a control method of the LC resonance drive circuit. According to the capacitance load characteristic of the ultrasonic motor, inductors are serially connected and matched to form a transformer-free drive circuit with an ultrasonic motor body and LC resonance boosting. Furthermore, the invention provides a method for fixing all circuit parameters and changing a drive signal frequency, a duty ratio and a resonance cycle only, and thus the drive control of the ultrasonic motor is realized. By adopting the USR30 ultrasonic motor, experimental verification is carried out.

Description

A kind of LC resonance drive circuit and control method thereof that is used for supersonic motor

Technical field

The present invention relates to supersonic motor, relate in particular to the Drive Control Technique field of supersonic motor.

Background technology

Supersonic motor is the drive unit of a kind of novel concept of occurring of recent two decades; Compare with traditional electromagnetic machine; It has that power density is big, no electromagnetic interference, low speed high torque, action response are fast, the operation noiseless, do not have characteristics such as input self-locking, and these advantages make supersonic motor control the field in ordinary movement such as high-end motion control field such as Aero-Space, robot, precise machining equipment, Medical Devices, bioengineering and household electrical appliance, automotive electronics and all have a wide range of applications.

At present, the volume of supersonic motor driving governor is bigger, receives very big restriction in some applications.Document [1], has proposed to utilize the transformerless type drive circuit of LC resonance, and has carried out simulation analysis through simplifying the equivalent electric circuit of supersonic motor according to the capacitive load characteristic of motor.Document [2] has been studied the method for designing of resonance drive circuit, and each harmonic amplitude and energy ratio and the relation of drive signal duty ratio resonant between the cycle in the output signal have been described.The research of above-mentioned document is that the research of supersonic motor power resonance formula drive circuit provides better basis; But given drive circuit can only make machine operation in definite working point of designing in advance; Controlled variables such as motor driven voltage frequency are all unadjustable, seriously limited the practical application of such circuit.Document [3] has carried out desk study adjustable aspect controlled, analyzes to realize that the frequency off-line is regulated selecting different resistance, inductance value.But because the inductance in the circuit is a power inductance, becomes inductance value and be difficult for online accurate realization, adjustable controlled still the remaining of power resonance formula drive circuit further studied.Relevant references is following:

[1] Gu Juping, Hu Minqiang, Shi Bin, etc. the research of supersonic motor resonance step-up formula Driving technique, Proceedings of the CSEE, 2002,22 (8): 49-52.

[2] Li Huafeng, Zhao Chunsheng. based on the research of the Driven by Ultrasonic Motors device of LC resonance, Proceedings of the CSEE, 2005,25 (23): 144-148.

[3] Gan Yunhua, Jin Long, Wang Xinjian, etc. the VFC characteristic of supersonic motor self-oscillation drive circuit, Proceedings of the CSEE, 2008,28 (9): 93-96.

Summary of the invention

The purpose of this invention is to provide a kind of LC resonance drive circuit and control method thereof that is used for supersonic motor, in order to solve the problem of the poor effect that has the drive controlling method now.

For realizing above-mentioned purpose; Circuit arrangement of the present invention is: a kind of LC resonance drive circuit that is used for supersonic motor; The A of driving supersonic motor, the AC side of B two phase bridge drive circuits are all gone here and there and being provided with series connection coupling inductance; Said A, B two phase bridge drive circuits are respectively arranged with the Boost booster circuit that is used to regulate corresponding phase bridge drive circuit DC bus-bar voltage; The power switch pipe of said Boost booster circuit is in series with a diode, and said diode cathode connects on the series connection point of said series connection coupling inductance L and supersonic motor equivalent capacity C.

The switching tube of said A, B two phase bridge drive circuits is MOSFET.

Method scheme of the present invention is: LC resonance drive circuit control method, and the inductance value of fixing series connection coupling inductance, driving signal frequency, duty ratio and cycle through changing said power switch pipe make output waveform adjustable.

The present invention through series connection coupling inductance, constitutes the transformerless type drive circuit of the LC resonance step-up of being participated in by the supersonic motor body according to the capacitive load characteristic of supersonic motor.Further, the present invention proposes fixing all circuit parameters, only change the method for driving signal frequency, duty ratio resonant cycle, realize drive controlling supersonic motor.Adopt USR30 type supersonic motor, carried out experimental verification.

Description of drawings

Fig. 1 is the LC resonance drive circuit;

Fig. 2 is the relation of motor resonance frequency and switch drive frequency;

Fig. 3 is the simulation waveform of different cycles, different duty;

Fig. 4 is a supersonic motor drive controlling structured flowchart;

Fig. 5 is the B drive waveforms and the harmonic wave of 40% duty ratio mutually;

Fig. 6 is two phase measured waveforms.

Embodiment

Below in conjunction with accompanying drawing the present invention is done further detailed explanation.

Resonant circuit embodiment

The A of driving supersonic motor, the AC side of B two phase bridge drive circuits are all gone here and there and being provided with series connection coupling inductance L; Said A, B two phase bridge drive circuits are respectively arranged with the Boost booster circuit that is used to regulate corresponding phase bridge drive circuit DC bus-bar voltage; It is characterized in that; The power switch pipe Q of said Boost booster circuit is in series with a diode D1, on the series connection point of said series connection coupling inductance L of the anodal connection of diode D1 and capacitor C.

Supersonic motor (USM) can be thought to be capacitive near resonance frequency, can equivalence be a capacitor C.The Boost according to the invention LC resonance drive circuit that boosts is as shown in Figure 1.Because there is an inverse parallel body diode MOSFET device Q inside, when capacitor C (being supersonic motor) voltage inversion, can pass through this diode discharge, makes output voltage have only positive half wave.In order to be very difficult for this to happen, Ultrafast recovery diode of series connection makes can form complete vibration at switch off period LC in circuit.Switch is meant power switch pipe Q.

The circuit working principle is: when switch Q conducting, power supply is to the inductance L energy storage; When switch breaks off, in the inductance energy stored to capacitor C discharge and with its resonance, entire circuit is the LC series resonant circuit of band initial condition.The key reason of Boost boosting unit booster tension has two: the one, have the effect that voltage pump is risen after the inductance L energy storage, and the 2nd, capacitor C can maintain output voltage, so the selection of duty ratio plays a crucial role to output voltage amplitude and effective value.The selection of series connection coupling inductance is confirmed by following formula:

$L=\frac{{(1-D)}^2{T}^2}{{\left(2\mathrm{k\π}\right)}^{2}C}---\left(1\right)$

In the formula, k is the complete cycle ripple number at blocking interval resonance, and D is a duty ratio, and T is a switch periods.

Method embodiment

In case the coupling inductance is selected, the LC resonance frequency just immobilizes, and changes the duty ratio of harmonic wave through the driving signal frequency of adjustment Driven MOSFET, and the equivalent effect of discontinuous sine wave changes, thereby regulates motor speed, reaches the control purpose.Switching drive signal frequency f and motor resonance frequency f _USRRelation is as shown in the formula (referring to Fig. 2):

$f=f_{\mathrm{USR}}\frac{(1-D)}{k}---\left(2\right)$

Can find out that according to formula (1), (2) by-pass cock signal dutyfactor D, switching signal frequency f and conducting cycle k can realize the speed regulating control of supersonic motor.With the following formula equivalent transformation be:

$f=\frac{1}{T}=\frac{1-D}{2\mathrm{\πk}}\sqrt{\frac{1}{\mathrm{LC}}}---\left(3\right)$

Keep following formula to set up, two parameter values that only need to change among f, D, the k get final product.Three kinds of possible speed regulating methods are arranged.First kind: keep D constant, regulate f and k.This method frequency range and amplitude are bigger, do not wait to tens kHz from several kHz, and speed adjustable range are little, because the many more distortions of cycle are serious more.Second kind: keep k constant, regulate f and D.This method can realize continuous speed adjustment, and precision is high.The third: keep f constant, regulate k and D.The duty ratio that this method calculates possibly be a negative value, does not meet actual conditions.It is thus clear that method two is desirable mode of speed regulation.With the second method is example, utilizes Miltisim10 to carry out emulation testing, analyzes gained waveform and data, draws to draw a conclusion: select the signal that duty ratio is little, cycle is few, to guarantee enough boost capability and to reduce effect of nonlinear as far as possible.Waveform is as shown in Figure 3.

Checking below experimentizes.The experimental circuit structure is as shown in Figure 4.Adopt general PWM generation chip TL494 to produce two-way frequency and all adjustable signal PWM1 and the PWM2 of pulsewidth; Through the frequency-halving circuit that constitutes by two rising edge d type flip flop CD4013; Generate the pwm signal of 90 ° of two phases, four road mutual deviations, amplify Driven MOSFET work through special-purpose MOSFET chip for driving IR4427; The LC resonance thereby the Boost that completion is participated in by the supersonic motor body boosts is to reach the purpose of drive controlling supersonic motor operation.

Because the motor equivalent capacity converts and obtains, and when motor moved, dynamic capacity can't directly be measured,, be met the coupling inductance of resonance frequency so, revise the coupling inductance parameters according to measurement data under static state.Table 1 is equivalent capacity terminal voltage peak-to-peak value Vpp (V), voltage effective value Vrms (V), driving frequency (kHz) that records and the resonance frequency (kHz) that converts and obtain.Fig. 5 is the drive waveforms resonant waveform of two cycle 40% duty ratios of B phase of actual measurement.Owing to when the conversion equivalent capacity, ignored other parameters, just do not consider the influence of other parameters such as resistance during emulation testing, so the waveform that experiment obtains is not a self-sustained oscillation, but decay is arranged.Fig. 6 is the motor two phase terminal voltage harmonic waves of actual measurement.Can find out that by measurement parameter and waveform effectively move for making motor, can select two cycle duty ratios is big slightly resonance frequency, to guarantee enough resonance frequencys and voltage effective value.

Table 1 liang equivalent capacitance terminal measured data of experiment

It is constant that the present invention has provided all circuit parameters such as fixed inductance value; Only change power switch driving signal frequency, duty ratio and cycle; So that sine wave changes, thereby realize that motor driven voltage is adjustable controlled, and then realize the method for motor speed control.Hardware circuit through TL494 constitutes verifies the feasibility of the method, carried out good try in the miniaturization of supersonic motor drive controlling, aspect microminiaturized.

The present invention proposes a kind of new drive controlling method: promptly on all circuit parameter basis of invariable such as fixed inductance value; Only change power switch driving signal frequency, duty ratio resonant cycle; Change so that drive the sinusoidal wave equivalent effect of supersonic motor; Thereby realize that motor driven voltage is adjustable controlled, and then realize motor speed control.Carry out emulation testing on this basis and build hardware circuit, through experimental verification the feasibility of this method, and reliable foundation is provided for better driving control supersonic motor.

Claims (3)

1. LC resonance drive circuit that is used for supersonic motor; The A of driving supersonic motor, the AC side of B two phase bridge drive circuits are all gone here and there and being provided with series connection coupling inductance; Said A, B two phase bridge drive circuits are respectively arranged with the Boost booster circuit that is used to regulate corresponding phase bridge drive circuit DC bus-bar voltage; It is characterized in that; The power switch pipe of said Boost booster circuit is in series with a diode, and said diode cathode connects on the series connection point of said series connection coupling inductance L and supersonic motor equivalent capacity C.

2. a kind of LC resonance drive circuit that is used for supersonic motor according to claim 1 is characterized in that the switching tube of said A, B two phase bridge drive circuits is MOSFET.

3. the control method of a LC resonance drive circuit is characterized in that, the inductance value of fixing series connection coupling inductance, and driving signal frequency, duty ratio and cycle through changing said power switch pipe make output waveform adjustable.

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