WO2015120671A1

WO2015120671A1 - Control device or method for preventing loop oscillation

Info

Publication number: WO2015120671A1
Application number: PCT/CN2014/078349
Authority: WO
Inventors: 张骏凌
Original assignee: 深圳市中兴微电子技术有限公司
Priority date: 2014-02-11
Filing date: 2014-05-23
Publication date: 2015-08-20
Also published as: CN104836579B; CN104836579A

Abstract

The present invention relates to a control device and method for preventing loop oscillation, the device comprising: a regulation actuator, an analog-digital converter (ADC), a cost function detector, a loop filter, a control value regulator, and a digital-analog converter (DAC); the device also comprises: a first processor is used to receive a first parameter outputted by the cost function detector and perform first error modification according to the first parameter to obtain a second parameter, the second parameter being used to perform precision adjustment on the loop filter; the second parameter is outputted to the loop filter; the loop filter is used to receive the second parameter and perform filter operation according to the second parameter.

Description

Control device or method for preventing loop oscillation

The present invention relates to control techniques, and more particularly to a control apparatus and method for preventing loop oscillations. Background technique

In the process of implementing the technical solutions of the embodiments of the present application, the inventors of the present application found at least the following technical problems in the related technologies:

In the closed-loop control scenario of the digital receiver, in the control loop, the accuracy of the adjustment actuator of the analog domain is recorded as the first precision, and the analog signal after the adjustment is converted by the analog-to-digital converter (ADC) The digital signal is processed to the loop filter after a series of processing. The output precision of the loop filter is recorded as the second precision, and is adjusted and output by the control value adjuster. After the digital-to-analog converter (DAC), the digital signal is Convert to analog signal and input to the adjustment actuator. Among them, in ADC and DAC, A refers to ANALOG, which represents analog signal; D refers to DIGITAL, which represents digital signal.

Due to a series of processing, a series of errors are generated during the execution of the loop filter, or due to the requirements of the closed loop control itself, the second precision may not match the accuracy of the first precision. Generally, the second precision is higher than the first precision, thereby causing a phenomenon of loop oscillation. Only the higher second precision is adjusted to the lower first precision, so the effect of the control loop oscillation cannot be achieved. In the related art, an effective solution is not provided for this problem. Summary of the invention

In view of this, the embodiments of the present invention are intended to provide a control apparatus and method for preventing loop oscillation, which can effectively control loop oscillation and prevent loop oscillation. The technical solution of the embodiment of the present invention is implemented as follows:

A control device for preventing loop oscillation, the device comprising: an adjustment actuator, an analog to digital converter ADC, a cost function detector, a loop filter, a control value adjuster, a digital to analog converter DAC, and the device Includes:

a first processor, configured to receive a first parameter output by the cost function detector, perform a first error correction according to the first parameter to obtain a second parameter, where the second parameter is used to Performing precision adjustment; outputting the second parameter to the loop filter;

Correspondingly, the loop filter is configured to receive the second parameter, and perform a filtering operation according to the second parameter.

The device further includes:

The second processor is configured to perform a second error correction to obtain a third parameter, where the third parameter is used to perform precision adjustment on the loop filter; and output the third parameter to the loop filter;

Correspondingly, the loop filter is further configured to perform a filtering operation according to the second parameter and the third parameter.

Wherein, the first processor is further configured to: when the first parameter is 3-e(n)=c(r(n)), perform the first error correction by using an error value normalization manner, Obtaining the second parameter is ( ; 运算 the operation performed by the error value normalization manner is: wherein, the accuracy of the adjustment actuator is

Abs represents an absolute value operation.

The second processor is further configured to receive a first output value obtained by the loop filter performing the filtering operation, and a second output value obtained by receiving the control value adjuster to perform control adjustment, where The first output value is /(, and the second output value is (at, according to the f(r) and the / _c (n), and the control value is used to process and reset the loop filter Way of integrating value Performing the second error correction to obtain a third parameter of //-1); 运算 performing the operation by the control value and resetting the integrated value in the loop filter is:

^ ₌ (") + ^ (") ≠ ("-1); where, the adjustment actuator

If (ri), the precision of others.

The loop filter is further configured to perform a filtering operation according to the e ' (and the //' («-1), and the operation performed is:

!f (n, = !f'(n -1, + f * e'(n,.

The first processor, the loop filter, and the second processor perform a processing by using a central processing unit (CPU), a digital signal processor (DSP, Digital Singnal Processor), or a programmable Logic array (FPGA, Field - Programmable Gate Array) implementation.

A control method for preventing loop oscillation, the method being applied to a control device for preventing loop oscillation, the control device comprising an adjustment actuator, an analog-to-digital converter ADC, a cost function detector, a loop filter, and a control value The regulator, the digital-to-analog converter DAC:, the method includes: when the control device further includes the first processor:

The first processor receives the first parameter output by the cost function detector, according to the first

3⁄4: performing a first error correction to obtain a second parameter, where the second parameter is used to perform precision adjustment on the loop filter; and outputting the second parameter to the loop filter;

The loop filter receives the second parameter and performs a filtering operation based on the second parameter. The method includes: when the control device further includes a second processor:

The second processor performs a second error correction to obtain a third parameter, where the third parameter is used to perform precision adjustment on the loop filter; and output the third parameter to the loop filter; When the first parameter is ^ ( , J (") = c(r(")), the first error correction is performed by using an error value normalization manner, and the second parameter is obtained as ^; The operation performed by the error value normalization method is:

Wherein, the accuracy of the adjustment actuator is

0, others

Abs represents an absolute value operation.

The performing the second error correction to obtain the third parameter includes:

Receiving, by the second processor, a first output value obtained by performing the filtering operation by the loop filter, and receiving a second output value obtained by performing control adjustment by the control value adjuster, where the first output value is / (, the second output value is, according to the / (and the lf _c (n), the second error is performed by processing and resetting the integrated value in the loop filter with the control value Correcting, the third parameter is //(1); 运算 the operation performed by the control value processing and resetting the integral value in the loop filter is: wherein the ^^ is the adjustment actuator

Precision.

The performing a filtering operation according to the second parameter and the third parameter includes: a loop filter performing a filtering operation according to the _e » and the //′(« −1), and performing the operation for:

!f (n, = !f'(n -1, + f * e'(n,.

The control device of the embodiment of the present invention includes: an adjustment actuator, an ADC, a cost function detector, a loop filter, a control value adjuster, a DAC, the device further includes a first processor, the first processor is configured to receive the a first parameter outputted by the cost function detector, performing a first error correction according to the first parameter to obtain a second parameter, where the second parameter is used to perform precision adjustment on the loop filter; Output to the loop filter; correspondingly, the loop filter The wave device is configured to receive the second parameter, and perform a filtering operation according to the second parameter. Since the parameter of the filtering operation of the loop filter is the second parameter obtained by the first error correction, the error can be eliminated, the loop oscillation can be effectively controlled, and the loop oscillation phenomenon caused by the error can be prevented. DRAWINGS

1 is a schematic structural diagram of a control device for a control loop in a digital receiver of the prior art; FIG. 2 is a schematic diagram of an oscillation phenomenon in a conventional digital AGC control loop;

3 is a schematic diagram of an oscillation phenomenon of an existing AGC loop under an ETU70 channel;

4 is a schematic structural diagram of a control device according to an embodiment of the present invention;

FIG. 5 is a flowchart of a control method according to an embodiment of the present invention;

6 is a schematic structural diagram of a control device of a specific scenario according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a non-oscillation phenomenon in a static channel scenario according to an embodiment of the present invention; FIG. 8 is a schematic diagram of a non-oscillation phenomenon in an output scenario of an ETU70 channel according to an embodiment of the present invention. detailed description

The implementation of the technical solution will be further described in detail below with reference to the accompanying drawings.

Taking the closed-loop control scene of the digital receiver as an example, an existing digital closed-loop control loop in the digital receiver of the communication system is shown in FIG. 1 , including an adjustment actuator 01, an ADC 02, a cost function detector 03, Loop filter 04, control value adjuster 05, digital to analog converter DAC06. In Figure 1, the accuracy of the actuator in the analog domain is recorded as the first precision, expressed in steps. The completed analog signal r(t) is digital signal r(n) after the ADC, and the error detection output is:

e (n) = c (r (n)) ( 1 )

In the formula (1), the cost function with the digital signal r(n) as an input varies according to the closed-loop control target, and the output of the cost function has an error, and the output thereof The variance is. The existing loop filter in the control loop can be implemented by an integrator, for example the output is:

If n) = lf {n - \) + f * e {n) ( 2 )

In equation (2), / is the loop filter factor and / <1.

The existing control value adjuster is realized by the control value adjustment function, and the output of the control value adjustment after being processed by the existing control value adjuster is: lf _c (") = floor * step ( 3 )

In equation (3), floor(x) represents the largest integer with <=x, and floor(x) can also be replaced by round(x) or ceil(x). Since a series of processing, a series of errors are generated during the execution of the loop filter, or due to the requirements of the closed loop control itself, the second precision may not match the accuracy of the first precision, in order to The accuracy mismatch is eliminated, so the control value adjuster is introduced. The purpose of the control value adjustment function is to remove the portion of the high-precision loop filter output that exceeds the analog domain adjustment actuator accuracy step.

In the existing digital loop control shown in Figure 1, the loop filter bandwidth is only limited by the loop filter factor / : r = l / / indicates that this loop filter tracks the time constant of e(n) order change . In order to control the influence of the error output variance on the control loop, f generally takes "1, resulting in the accuracy of lf(n) as f*step « step, so the control value adjustment function is necessary in the digital control loop, such as the formula (3) as shown.

It is precisely because the accuracy of the loop filter output If (n) is greater than the precision step of the analog domain adjustment actuator, and as the convergence of the control loop e(n) approaches 0, the //(") converges in / / _c (") nearby. this

swing. Figure 2 shows the oscillation of the traditional digital control loop by taking the AGC loop as an example. The adjustment actuator in Figure 2 is a gain-controllable amplifier with gain control accuracy step=ldB; after loop convergence e {n) = c

±Q.5dB; take the loop filter factor f = 0.04.

Even if the existing control device introduces the control value adjuster, the loop oscillation problem caused by the mismatch of the accuracy cannot be solved. Once the loop oscillation problem occurs, the loop itself may be misjudged, and the loop is not faulty. And only the precision does not match. To this end, the embodiments of the present invention provide the following control schemes, which can completely solve this problem, avoid loop oscillation caused by the mismatch of precision, and avoid false positives, but the embodiment of the present invention is not limited to the closed-loop control scene of the digital receiver. For the closed-loop control scenario of the digital receiver, a simple scheme can be proposed to remove the oscillation phenomenon caused by the digital domain loop filter output precision in the digital closed-loop control loop being larger than the adjustment precision of the analog domain adjustment actuator. .

As shown in FIG. 4, the control device for preventing loop oscillation according to an embodiment of the present invention includes: an adjustment actuator 11, an analog-to-digital converter ADC12 that converts an analog signal output from the adjustment actuator 11 into a digital signal, and a number that outputs the ADC12. The cost function detector 13 for performing the cost function operation on the signal, the loop filter 14 for performing the filtering operation based on the parameters output from the cost function detector 13, and the control value adjuster 15 for adjusting the output of the loop filter 14 to control the value The regulator 15 performs a digital-to-analog converter DAC 16 that converts the digital signal of the control adjustment operation output into an analog signal.

The device further includes: a first processor 17, the first processor 17 is connected to the cost function detector 13 for receiving the first parameter output by the cost function detector 13, and performing the first error correction according to the first parameter Obtaining a second parameter, the second parameter is used to perform precision adjustment on the loop filter 14; and outputting the second parameter to the loop filter 14. Correspondingly, the loop filter 14 is connected to the first processor 17 for receiving the second parameter and performing a filtering operation according to the second parameter.

In a preferred embodiment of the present invention, as shown in FIG. 4, the control device for preventing loop oscillation according to the embodiment of the present invention further includes: a second processor 18, wherein the second processor 18 is configured to perform the second error correction. a third parameter, the third parameter is used to perform precision adjustment on the loop filter 14; The third parameter is output to the loop filter 14. Correspondingly, the loop filter 14 is configured to perform a filtering operation according to the second parameter and the third parameter.

In a preferred embodiment of the present invention, as shown in FIG. 4, the first processor 17 uses the first parameter as e ( , He(n) = c(r(n))H, and uses the error value. The first error correction is performed in a normalized manner, and the second parameter is 6»; 运算 the operation performed by the error value normalization method is: g' ₌ (e(?i), as(gC?3⁄4) ) > step

i 0 _f others

The description of "0, others" in the above formula (4) means that e'(«) = 0 in the case where abs( _e («)> is not satisfied.

Wherein, the said is the precision of the adjustment actuator, and abs represents an absolute value operation.

In a preferred embodiment of the present invention, as shown in FIG. 4, the second processor 18 is connected to the loop filter and the control value adjuster respectively, and is configured to receive the loop filter 14 to perform the filtering operation. a first output value obtained, and a second output value obtained by the control value adjuster 15 performing control adjustment, the first output value being / («), and the second output value being Said / / _c (, the second error correction is performed in such a manner that the control value is processed and the integral value in the loop filter is reset, and the third parameter is obtained as / / -1); And the operation performed by resetting the integral value in the loop filter is: c

n ^η , + , ^l fc, ⁿ , ^{≠ l} f , ⁿ -

The description of "lf{n), others" in the above formula (5) means that f (n) = lf n in the case of not satisfying lf _c (n) ≠lf _c (n-\) ).

Wherein, the adjustment is the accuracy of the actuator.

In a preferred embodiment of the present invention, the loop filter 14 is configured to perform a filtering operation according to the e» and the //'("-1", and the operation performed is: Lf {n) = lf {n -\^ + f * e'{n) (6) As shown in FIG. 5, the control method for preventing loop oscillation according to the embodiment of the present invention is applied to the prevention loop shown in FIG. An oscillating control device, the control device comprising an adjustment actuator, an analog to digital converter ADC, a cost function detector, a loop filter, a control value regulator, and a digital to analog converter DAC, wherein the control device further includes a first The processor includes the following steps:

Step 101: The first processor receives the first parameter output by the cost function detector, performs a first error correction according to the first parameter, and obtains a second parameter, where the second parameter is used to Performing precision adjustment; outputting the second parameter to the loop filter.

Step 102: The loop filter receives the second parameter, and performs a filtering operation according to the second parameter.

In a preferred embodiment of the present invention, performing the first error correction according to the first parameter in step 101 to obtain the second parameter specifically includes:

The first parameter is e ( , H e(n) = c(r (n)) H , and the first error correction is performed by using an error value normalization manner, and the second parameter is obtained as ^; The operation performed by the error value normalization mode is: β'ίη) = where the said actuator is

Precision, abs represents absolute value operation.

In a preferred embodiment of the present invention, when the control device further includes a second processor, the method further includes further error correction, including the following steps:

Step 201: The second processor performs a second error correction to obtain a third parameter, where the third parameter is used to perform precision adjustment on the loop filter; and output the third parameter to the loop filter.

Step 202: The loop filter performs filtering operation according to the second parameter and the third parameter.

In a preferred embodiment of the present invention, the second error correction is performed in step 201 to obtain a third The parameters specifically include:

Receiving, by the second processor, a first output value obtained by performing the filtering operation by the loop filter, and receiving a second output value obtained by performing control adjustment by the control value adjuster, where the first output value is / («), when the second output value is, according to the / («) and the lf _c (n), the method of processing and resetting the integral value in the loop filter with the control value is performed. The second error correction is performed to obtain a third parameter of //1); 运算 the operation performed by the control value processing and resetting the integral value in the loop filter is:

V', n, = ⁿ , ⁺ ^ , ^≠lfc , ⁿ - wherein, the adjustment actuator

If {n,, others precision.

In a preferred embodiment of the present invention, step 202 specifically includes:

The loop filter performs a filtering operation according to the e» and the //-1), and the operation performed is:

Lf {n) = lf {n -l) ₊ The following describes an embodiment of the present invention by taking a closed-loop control scenario of a digital receiver as an example. The control device includes both a first processor and a second processor.

The apparatus of the embodiment of the present invention as shown in FIG. 6 adds a first processor and a second processor with respect to FIG. 1. In this scenario, the first processor specifically uses an error normalization function. To achieve, the second processor specifically implements two functions of processing the control value and resetting the integral value of the loop filter, and separately processes the original error output e (and the value of the loop filter output. The processing of one processor can eliminate the error in a part of the loop, and the processing combined with the second processor can better remove the error, so that after the first processor and the second processor control the processing, the analog domain is When the accuracy of the adjustment actuator is recorded as the first accuracy, and the output accuracy of the loop filter is recorded as the second accuracy, the loop oscillation caused by the mismatch of the precision is eliminated, and the misjudgment is avoided.

Wherein, using the first processor, performing normalized error processing output is the above formula (4): e(n) _f &bs{e('n)) > step

Q, others

Through the control processing of the first processor, the above equation (4) is processed to facilitate the adjustment of the loop control.

Wherein, using the second processor, performing control value processing using the above formula (5) and resetting the integral value output in the loop filter is:

//'(„) = < ^lf , ⁿ , ⁺ ^ ~' ^l fc (")≠ ^l fc (" - I)

If « others 釆 using the above formula (6), the loop filter output is corrected to:

Lf(n) = lf'(n-\) + f*e'(n) By the control processing of the second processor, /(()) is processed by the above formulas (5) and (6), The correction is more favorable for loop control adjustment.

In this scenario, an embodiment of the present invention is used, and an AGC loop is taken as an example. FIG. 2 is a schematic diagram of an oscillation phenomenon in a conventional digital AGC control loop, and FIG. 7 is a non-oscillation method in a static channel scenario according to an embodiment of the present invention. Schematic diagram of the phenomenon, and the control value adjustment output obtained by using the embodiment of the present invention under the same conditions as in FIG. 2 is as shown in FIG. 7 , as shown in FIG. 7 , it can be visually seen that: since the adjusted second precision tends to the first precision, therefore, Loop oscillations are not obvious. The simulation results obtained by using the loop control of the prior art and the loop control of the embodiment of the present invention in the ETU70 channel are shown in FIG. 3 and FIG. 8. FIG. 3 is an oscillation phenomenon of the existing AGC loop under the ETU70 channel. FIG. 8 is a schematic diagram of a non-oscillation phenomenon in an output scenario of an ETU 70 channel according to an embodiment of the present invention. The channel conditions in FIG. 3 and FIG. 8 are the same as those in FIG. 2, and other parameters are the same. As can be seen visually in Figure 8, since the adjusted second precision tends to the first precision, the loop oscillation is not obvious.

The integrated modules described in the embodiments of the present invention may also be stored in a computer readable storage medium if they are implemented in the form of software functional modules and sold or used as separate products. Based on such understanding, the technical solution of the embodiments of the present invention is made substantially or prior to the prior art. The contributed portion may be embodied in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the various aspects of the present invention. All or part of the methods described in the examples. The foregoing storage medium includes: a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like. The medium of the code. Thus, embodiments of the invention are not limited to any specific combination of hardware and software.

Correspondingly, an embodiment of the present invention further provides a computer storage medium, wherein a computer program for executing a control method for preventing loop oscillation according to an embodiment of the present invention is stored.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Industrial applicability

The control device of the embodiment of the present invention includes: an adjustment actuator, an ADC, a cost function detector, a loop filter, a control value adjuster, a DAC, the device further includes a first processor, the first processor is configured to receive the a first parameter outputted by the cost function detector, performing a first error correction according to the first parameter to obtain a second parameter, where the second parameter is used to perform precision adjustment on the loop filter; Outputting to the loop filter; correspondingly, the loop filter is configured to receive the second parameter, and perform a filtering operation according to the second parameter. Since the parameter of the filtering operation performed by the loop filter is the second parameter obtained by the first error correction, the embodiment of the present invention can eliminate the error, effectively control the loop oscillation, and prevent the loop caused by the error. Road oscillation phenomenon.

Claims

claims

1. A control device to prevent loop oscillation, the device includes: a regulating actuator, an analog-to-digital converter ADC, a cost function detector, a loop filter, a control value regulator, a digital-to-analog converter DAC, as described The installation also includes:

A first processor, configured to receive the first parameter output by the cost function detector, perform a first error correction according to the first parameter to obtain a second parameter, and the second parameter is used to modify the loop filter Perform accuracy adjustment; Output the second parameter to the loop filter;

Correspondingly, the loop filter is used to receive the second parameter and perform a filtering operation according to the second parameter.

2. The device according to claim 1, wherein the device further includes:

The second processor is used to perform second error correction to obtain a third parameter, and the third parameter is used to perform accuracy adjustment on the loop filter; and output the third parameter to the loop filter;

Correspondingly, the loop filter is further used to perform filtering operations based on the second parameter and the third parameter.

3. The device according to claim 2, wherein the first processor is also used for the first parameter to be «), He(n) = c(r(n))H, and use an error value The first error correction is performed in a normalization manner, and the second parameter is obtained. The operation performed using the error value normalization method is:

e,^ e(n), _a bs(e(n))> _S tep^ where, the ^^ is the accuracy of the adjustment actuator,

0, others

abs represents absolute value operation.

4. The device according to claim 3, wherein the second processor is further configured to receive the first output value obtained by the loop filter performing the filtering operation, and receive the control value regulator The second output value obtained by performing control adjustment, the first output value is / («), the When the _second output value is

\f n-\); The operation performed by processing the control value and resetting the integral value in the loop filter is: lfc(n) + ^ fc(n)≠lf _c (nl), where , the ^ is the adjustment actuator n-step

(n), accuracy of others.

5. The device according to claim 4, wherein the loop filter is also used to perform a filtering operation according to the 6» and the //-1), and the operation performed is: lf(n) = lf'(nl) + f*e'(n) ₀

6. A control method for preventing loop oscillation. The method is applied to a control device for preventing loop oscillation. The control device includes an adjustment actuator, an analog-to-digital converter ADC, a cost function detector, a loop filter, Control value regulator, digital-to-analog converter DAC, when the control device further includes a first processor, the method includes:

The first processor receives the first parameter output by the cost function detector, and according to the first

¾: Perform first error correction to obtain a second parameter, the second parameter is used to perform accuracy adjustment on the loop filter; Output the second parameter to the loop filter;

The loop filter receives the second parameter and performs filtering operation according to the second parameter.

7. The device according to claim 6, wherein when the control device further includes a second processor, the method includes:

The second processor performs a second error correction to obtain a third parameter, and the third parameter is used to perform accuracy adjustment on the loop filter; output the third parameter to the loop filter; loop filtering The processor performs a filtering operation according to the second parameter and the third parameter.

8. The device according to claim 7, wherein the first error correction based on the first parameter to obtain the second parameter includes: The first parameter is w;), He(n) = c(r(n))H, the first error correction is performed using the error value normalization method, and the second parameter is obtained using the error The operation performed in value normalization mode is:

Wherein, the ^^ is the accuracy of the adjustment actuator,

0, others abs represents absolute value operation.

9. The method according to claim 8, wherein performing the second error correction to obtain the third parameter includes:

The second processor receives the first output value obtained by the loop filter performing the filtering operation, and receives the second output value obtained by the control value regulator performing control adjustment, and the first output value is /(«), when the second output value is, according to the /(«) and the lf _c (n), the control value processing and resetting the integral value in the loop filter are performed. According to the second error correction, the third parameter is obtained as // -1); The operation performed by using the control value to process and resetting the integral value in the loop filter is:

" ^ Λ"-)., where, the ^ ^ is the adjustment actuator

If in), the precision of others.

10. The method according to claim 9, wherein the filtering operation based on the second parameter and the third parameter includes:

The loop filter performs filtering operations according to 6» and //-1), and the operations performed are:

//(") = //'("_l) + /*e'(").