The driving control device of brshless DC motor
Technical field
A kind of driving control device for brshless DC motor of the utility model relate generally to.More specifically, a kind of driving control device with no-load speed restriction for brshless DC motor is related to.
Background technology
BD6209FS is that ROHM company is specially for the nonshared control unit of the sine wave drive of a kind of low cost of the brshless DC motor design of the fan of driving convertible frequency air-conditioner.This nonshared control unit is devices at full hardware circuit, built-in sine-wave generator, has conventional MCU and controls incomparable antijamming capability.
Because brshless DC motor is inductive load, therefore the phase current of motor lags behind phase voltage, and namely electric machine phase current lags behind back-emf.Only have when electric machine phase current is synchronous with back-emf, the efficiency of motor just can reach optimum.Advance angle between suitable adjustment phase voltage and phase current, can make phase current and back-emf same-phase, improves the Driving Torque of motor, improves motor-driven system effectiveness.
But for the control of advance angle, it is perfect not enough that BD6209AFS does.See the simplification exemplary plot that Fig. 1, Fig. 1 are the BD6209FS controller line connections that ROHM recommends.
In FIG, controller U1 selects chip BD6209FS to realize, and controller U1 exports 6 road pwm control signals to power driver module 2, and power driver module 2 pairs of brshless DC motors 3 drive.
In the circuit that the ROHM shown in Fig. 1 recommends, the voltage of the PC mouth of the setting motor lead angle of the controller U1 of BD6209AFS is selected to be that the 5V voltage provided by the VREG mouth of U1 self gives advance angle PC mouth after divider resistance R1, R2 dividing potential drop, so the voltage of advance angle PC mouth is changeless substantially after dividing potential drop.This partial pressure value normally sets according to the voltage ratio of situation adjusting resistance device R1, R2 during Rated motor load.
Shown in the circuit that ROHM as shown in Figure 1 recommends, the PC voltage of setting advance angle can be chosen according to actual loading.Usually, the PC voltage setting advance angle is chosen according to nominal load.After being the advance angle that selection of Motor is suitable at rated loads, the advance angle of motor just can not change with the change of load, advance angle when namely motor is in Light Condition or advance angle when being in load condition all can not change with loading condition.Therefore, when empty load of motor, the PC voltage based on nominal load setting can make advance angle too large, and motor speed will be caused so too high, and motor speed can up to more than 10000r/min.Empty load of motor rotating speed is too high can exist the wearing and tearing of the components and parts such as the bearing such as adding speed motor and aging danger, and inconvenience detects, has larger negative effect to the life-span of bearing.
Particularly, for the fan load of air-conditioning, the voltage setting value of the PC mouth of setting motor lead angle is usually at 1V ~ 2.2V.When advance angle PC voltage is set to 2.2V, motor can work when nominal load under very high efficiency, if but remove nominal load (such as, air-conditioning fan and motor be not because of so when being connected), time namely unloaded, then because the voltage of PC pin obtains by based on 5V dividing potential drop, so or be 2.2V, now the no-load speed of motor will be very high, even reaches about 10000r/min, and this life-span for air conditioner fan motor has a significant impact.
In addition, if motor shaft be connected with load unreliable, under motor is just operated in zero load or underload, the rotating speed of motor also can far away higher than rotating speed during load, if long-term zero load or light running can cause the bearing wear of motor to aggravate, noise increases, and makes motor failure.
Therefore, be necessary the excessive problem causing no-load speed too high of advance angle when solving empty load of motor, propose a kind of when the setting for advance angle is fixed, the control program of limiting motor no-load speed.
Utility model content
According to one side of the present utility model, provide a kind of driving control device for brshless DC motor, comprising: drive nonshared control unit, export the driving that pwm control signal controls brshless DC motor; Motor speed controller, according to from the signal relevant to motor speed driving nonshared control unit to receive, exports the speed controling signal comprising the first control voltage level and the second control voltage level; Transistor, the speed controling signal that motor speed controller exports is input to the base stage of transistor, and according to described speed controling signal, transistor is in amplification or cut-off state; Wherein, when motor speed controller exports the speed controling signal of the first control voltage level, transistor is in cut-off state, drive the voltage only produced based on normal design for the input voltage controlling motor torque of nonshared control unit, transistor does not adjust the input voltage for controlling motor torque; When motor speed controller exports the speed controling signal of the second control voltage level, transistor, when magnifying state, drives the adjustment being subject to transistor collector output for the input voltage controlling motor torque of nonshared control unit.
Wherein, drive nonshared control unit to select the chip BD6209FS of ROHM company to realize, motor speed controller selects the chip LB8503V of SANYO company to realize.
Wherein, relevant to motor speed signal is that the FGO mouth of BD6209AFS exports the square-wave signal becoming certain relation with rotating speed.
Wherein, the first control voltage level is 0.8V; Second control voltage level is 6.2V.
Wherein, brshless DC motor is the sinusoidal wave plastic-sealing brushless DC motor of 87SWS.
Accompanying drawing explanation
By following only exemplarily and description of writing by reference to the accompanying drawings, for one, this area technical staff, example embodiment of the present utility model will better be understood and more obvious, in accompanying drawing:
Fig. 1 is the simplification exemplary plot of the BD6209FS controller line connection that ROHM recommends; And
Fig. 2 shows according to the driving control device with no-load speed restriction for brshless DC motor of the present utility model.
Embodiment
The utility model can be very high mainly for motor speed during zero load, and during bringing onto load, motor speed can normal prior art problem, the wearing and tearing of the components and parts such as rotating speed too fast acceleration motor bearings and aging when limiting to prevent empty load of motor to empty load of motor rotating speed.Principle of the present utility model is described in detail below in conjunction with accompanying drawing.
Fig. 2 shows according to the driving control device with no-load speed restriction for brshless DC motor of the present utility model.
Brshless DC motor is such as the sinusoidal wave plastic-sealing brushless DC motor of 87SWS, for driving the fan of air-conditioning.Fan is as the load of brshless DC motor.
The single-chip digital integrated chip LB8503V for DC fan motor speeds control of SANYO company and the chip BD6209FS controlled for three-phase brushless dc motor of ROHM company is such as selected according to the driving control device with no-load speed restriction for brshless DC motor of the present utility model.Certainly, the similar chip of other companies can also be selected.
Whether the LB8503V of driving control device of the present utility model is too high and at the EO3 mouth fed back values of LB8503V be the voltage signal of about 0.8 or about 6.2V based on inputted fan motor rotational speed, the voltage of this feedback enters the base stage of triode Q1 again through the rationally suitable dividing potential drop of resistor R2, R3, the amplifying circuit consisted of triode Q1 adjusts the EC control end voltage of BD6209FS, EC control end controls the level of torque of motor, and then controls the rotating speed height of motor.The utility model can adjust EC control voltage value when fan electromotor no-load speed is too high, thus achieves the restriction to rotating speed during empty load of motor.
The size of the EC mouth magnitude of voltage of the control motor torque size of the BD6209FS of the utility model driving control device directly determines the rotating speed of motor, therefore make the magnitude of voltage reducing EC mouth when empty load of motor height rotating speed by the way, then may ultimately reach the object reducing or limit fan motor rotational speed.See Fig. 2, when empty load of motor height rotating speed, by controlling the amplifying circuit of triode Q1 to make the EC mouth voltage based on VSP voltage reduce.Wherein, VSP voltage is provided by the master control borad controlling motor, and the master control borad of external control motor controls motor needs 310V high voltage source to coil power supply, and 15V low voltage voltage is to chip power supply, VSP speed electric is wherein generally 2.1V-6.5V, to control motor rotation speed.
But the adjustment should cancelled when the fan load of motor is normal the EC mouth voltage based on VSP voltage, makes motor be operated in most effective region at POL when normal load rotating speed by the advance angle circuit that BD6209FS itself is pre-set.
Effectively can solve the above-mentioned problems in the prior art like this.
The restriction principle for empty load of motor rotating speed of driving control device of the present utility model is as follows: the rotating speed of motor can export by the FGO mouth of BD6209AFS the square-wave signal becoming certain relation with rotating speed, and rotating speed is higher, and the frequency of square-wave signal is higher.The EO3 mouth of speed limit module LB8503V can judge according to R4, C2 value of the square-wave signal of FGIN mouth input and RC mouth periphery, exports corresponding magnitude of voltage.Particularly, when the square wave frequency that FGIN detects is higher than RC mouth set point, EO3 exports about 0.8V, and when the square wave frequency that FGIN detects is lower than RC mouth set point, EO3 exports about 6.2V.
When rotating speed when empty load of motor is higher than the rotating speed set, the EO3 mouth of LB8503V is made to export about 6.2V, triode Q1 is made to be operated in magnification region through divider resistance R2, R3 dividing potential drop, the EC pin voltage of the BD6209 chip being connected to resistor R5, R1 common node is dragged down by the collector access then formed by resistor R5, R1 of comprising between the collector electrode being connected on VSP voltage and triode Q1, final reduction or limiting motor rotating speed.
When machine operation is at load condition, when motor speed is less than the maximum speed of setting, the EO3 of LB8503V is made to export about 0.8V, through divider resistance R2, R3 dividing potential drop can not make triode Q1 start, triode Q1 is operated in cut-off state, the EC input voltage then controlling motor torque is only based on the normal design of BD6209 chip EC pin and the voltage produced, now, EC pin voltage produces based on being connected to the VSP voltage of EC pin via resistor R5, triode Q1 can not adjust EC control voltage, namely can not limit motor speed, and owing to having set suitable advance angle before, so time make machine operation at best efficiency point.
Driving control device of the present utility model can be reduced empty load of motor rotating speed when needing limiting motor no-load speed by the EC input voltage of adjustment based on VSP control voltage and be made to be operated in most effective region during motor load simultaneously.When not needing limiting motor no-load speed, VSP control end is connected directly to EC end and controls motor speed, and wherein, VSP magnitude of voltage is controlled by external mainboard, now, the VSP magnitude of voltage by providing external mainboard carries out step-down adjustment and has met the requirement of EC terminal voltage value.
Just driving control device of the present utility model can be realized by LB8503V and simple peripheral electron element, the high problem of empty load of motor rotating speed can be solved by the speed limit circuit of driving control device of the present utility model, ensure again that motor load point performance reaches expection requirement, and checking there is very high efficiency at POL simultaneously.
For those of ordinary skills, it is evident that, based on thinking of the present utility model, other speed limit circuit can be selected to realize driving control device of the present utility model.
Although as described herein above example embodiment, understanding can have been carried out various amendment, replacement and/or change.It will be understood by those skilled in the art that can carry out other to specific embodiment changes and/or amendment, and do not depart from the spirit or scope of the present utility model as broadly described.Therefore, which point all the present embodiment to be thought illustrative and not restrictive from.