CN201113891Y

CN201113891Y - Electric motor vector control circuit

Info

Publication number: CN201113891Y
Application number: CNU2007201265397U
Authority: CN
Inventors: 刘兆祥
Original assignee: Hisense Beijing Electric Co Ltd
Current assignee: Hisense Shandong Refrigerator Co Ltd
Priority date: 2007-08-13
Filing date: 2007-08-13
Publication date: 2008-09-10
Anticipated expiration: 2017-08-13

Abstract

The utility model relates to a vector control circuit for a motor, in particular to a method for detecting current for frequent control of vector variable of a motor. The current detecting method provides a resistor between a power module and a CPU, and all phase currents can be determined by detecting the current in the resistor, and the sampling and switching processes can also be better dealt with. The utility model comprises the CPU and the power module, wherein the power module is connected with the CPU and a motor respectively; the utility model is characterized in that a common-ground end of the power module is connected with a resistor and the CPU respectively; the utility model is simple in circuit structure, and can accurately measure the current value of the motor at any moment, realize the accurate control of the motor and effectively avoid the abnormal shutdown and the performance variation of the motor.

Description

The vector control circuit of motor

Technical field

The utility model relates to a kind of control circuit of motor, specifically, relates to a kind of vector converter control circuit that does not have the transducer permanent magnetic brushless.

Background technology

Determining owing to the permanent magnetic brushless rotor-position in the prior art, need accurately detect the electric current of motor three-phase input, except that adopting current sensor, another method commonly used is to increase by three or two resistance holding of power model commonly, by detecting ohmically voltage, calculate the electric current that flows through on the resistance, and then the three-phase input current of definite motor, the structure more complicated of sort circuit, and cost is also than higher; A sampling and transfer process are all arranged in testing process, if the current detecting in this process less than, cancel closedown will occur or can't drive or the situation of degradation.

Summary of the invention

The purpose of this utility model is to overcome above defective, provide a resistance has been set between a kind of power model and the CPU, determine each phase current by the electric current that detects this resistance, and can handle the electric current detecting method of current value in sampling and the transfer process well.

The technical scheme of the vector control circuit of motor of the present utility model is such: it comprises CPU, power model, power model is connected with CPU, power model is connected with motor, it is characterized in that: be connected with a resistance holding of power model commonly, holding with CPU of power model is connected commonly.

Power model hold commonly and CPU between current amplifier is set.

CPU comprises PARK conversion, PARK inverse transform block, voltage signal generator, current sample module, current sample processing module, current phase modular converter, they are connected to form the loop in turn, and power model is connected between voltage signal generator and the current sample module.

Between PARK inverse transform block, voltage signal generator, the burst process module is set.

The vector control electric current and the method for no transducer permanent magnetic brushless of the present utility model, not only circuit structure is simple, and can calculate the current value in any moment of motor more exactly, simplify hardware circuit effectively, and realize accurate control motor.

Description of drawings

Fig. 1 is the block diagram of motor vector control circuit;

Fig. 2 is a sample circuit schematic diagram of the present utility model;

Fig. 3 is a current sample of the present utility model schematic diagram constantly;

Fig. 4 is the wave form varies situation schematic diagram of t1 of the present utility model, t2;

Fig. 5 is of the present utility model near the pulse duration schematic diagram of t=0 in the time period;

Fig. 6 is of the present utility model and t value time waveform figure Fig. 5 correspondence;

Fig. 7 is that the utility model t is increased to interior burst process and electric circuit inspection schematic diagram of t＞tmin time period gradually by t=0;

Fig. 8 is the schematic diagram that the utility model inserts the interpolation pulse.

Embodiment

As Fig. 1, it comprises CPU the vector control circuit of no transducer permanent magnetic brushless of the present utility model shown in 2, power model, power model is connected with CPU, power model is connected with motor M, be connected with a resistance R holding of power model commonly, holding with CPU of power model is connected commonly, power model hold commonly and CPU between current amplifier is set, CPU comprises the PARK conversion, the PARK inverse transform block, the voltage signal generator, the current sample module, the current sample processing module, the current phase modular converter, they are connected to form the loop in turn, power model is connected between voltage signal generator and the current sample module, in the PARK inverse transform block, the burst process module is set between the voltage signal generator.

Current detection circuit of the present utility model is analyzed then motor M is controlled by the electric current on the resistance R is sampled, and its sampling process is such, and as shown in figure 23, sampling is divided into two time periods, and when having only one to switch on mutually, being set at is t2 constantly; When two-phase is switched on simultaneously, set this and be t1 constantly; As shown in Figure 4, because sampling and conversion need a minimum treat time, setting the minimum treat time is tmin, and the entire process sampling process comprises the following steps:

1, CPU receives the current value in t1, t2 time period, and CPU through phase transition, determines phase current values Ia, Ib according to t1, the current detection value of t2 in the time period.

2, transform vector and control module obtain potential pulse t1, the t2 that next should be exported constantly according to phase current values Ia, Ib through the vector control processing procedure.

1, the burst process module is to step 2) in the t1, the t2 pulse that obtain handle.

2, the processing procedure with the t1 time period is an example: transform vector and control module are judged the size of t1 value, if t1 greater than tmin, does not then process; Otherwise storing this value into designated memory adds up;

When 3, the variable intermediate value that adds up when step 4) is greater than tmin, should be worth as the interpolation pulse and exported; Otherwise, next pulse value constantly of t1 is output as 0.

4, Shu Chu t1 value outputs to the voltage signal maker, and the voltage signal maker is exported the three-phase voltage value according to vector current location and t1, t2 value, through power driver module, and output voltage, drive motors operation.

5, the voltage signal maker outputs to the current sample processing module with voltage, find that the pulse value in the t1 time period is 0 if detect the back, close current sampling module then, then the current value in this moment need be predicted according to front current value constantly, otherwise then the starting current sampling module directly obtains the current value in this time period.

6, t1, the current value of t2 in the time period after the current sample processing module is sampled according to current time perhaps pass through the current forecasting value that obtains behind the forecasting process, determine the current value of t1, t2.

7, current conversion module is determined phase current Ia, Ib according to t1, t2 current value constantly, comes back to the processing that step 1) is carried out next circulation.

Predicting according to front current value constantly of step 6) is divided into that (1): t is reduced to t=0 gradually by t＞tmin and (2): t is increased to two processes of t＞tmin gradually by t=0, shown in Fig. 5,6, wherein t is reduced to t=0 gradually by t＞tmin and comprises the following steps: in the time period

1, detects ohmically electric current, get the current value I (n) and the I (n-1) in two moment in the adjacent time interval in t＞tmin time period;

2, calculation procedure 1) record two the poor f (n) of current values constantly, f (n)=(I (n)-I (n-1));

3, the situation of change of supposing the follow-up moment still continue n-1 constantly, n variation constantly carries out linear change, and predicted value Ie (n+1)=I (n)+f (n) is then arranged;

4, same step 3), Ie (n+2)=Ie (n+1)+f (n)

Wherein t is increased to t＞tmin in the time period gradually by t=0, adopts according to the data in previous cycle and carries out forecast method, as shown in Figure 7, comprises the following steps:

1, according to the method for claim 7 and 8 and 9, carry out back forecast, utilize the current sampling data in the follow-up moment that front value is constantly predicted that the value of establishing the last cycle has 6 values to be respectively 1n1,1n2,1n3,1n4,1n5,1n6, and is measurable as follows:

f(1n6)＝I(1n6)-I(1n7)

Ie(1n5)＝I(1n6)+f(1n6)

f(1n4)＝I(1n4)-I(1n6)

Ie(1n3)＝I(1n4)+f(1n4)

Ie(1n2)＝I(1n4)+2*f(1n4)

Ie(1n1)＝I(1n4)+3*f(1n4)

2,, make the current value in this cycle be approximately equal to the current value in last cycle according to the current value predicted value in previous cycle;

Ie(2n5)＝Ie(1n5)

Ie(2n3)＝Ie(1n3)

Ie(2n2)＝Ie(1n2)

Ie(2n1)＝Ie(1n1)

The size of the pulse value of the described insertion of step 4), determine by the pulse value that reality is adjacent, as shown in Figure 8, the setting sampling instant is n1, n2 ... if t (n1)+t (n2)＞tmin, can insert pulse value tr (n2)=t (n1)+t (n2), tr (n1)=0, by that analogy and tr (n5)=t (n3)+t (n4)+t (n5)＞tmin, tr (n3)=0, tr (n4)=0.

After the interpolation pulse occurring, the current forecasting value of succeeding impulse then depends on the interpolation pulse and current value last effective impulse, f (n2)=((I (n2)-I (n0))/2; Ie (n3)=I (n2)+f (n2); Ie (n4)=I (n2)+2*f (n2); F (n5)=((I (n5)-I (n2)/3; Ie (n6)=I (n5)+f (n5).

Claims

1. the vector control circuit of a motor, it comprises CPU, power model, and power model is connected with CPU, and power model is connected with motor, it is characterized in that: be connected with a resistance holding of power model commonly, holding with CPU of power model is connected commonly.

2. the vector control circuit of motor according to claim 1 is characterized in that: power model hold commonly and CPU between current amplifier is set.

3. the vector control circuit of motor according to claim 1, it is characterized in that: CPU comprises PARK conversion, PARK inverse transform block, voltage signal generator, current sample module, current sample processing module, current phase modular converter, they are connected to form the loop in turn, and power model is connected between voltage signal generator and the current sample module.

4. the vector control circuit of motor according to claim 3 is characterized in that: between PARK inverse transform block, voltage signal generator the burst process module is set.