阅读说明：本技术 一种电压测量方法及其应用装置 (Voltage measuring method and application device thereof ) 是由 吴刚 于 2021-09-13 设计创作，主要内容包括：本发明提供的电压测量方法及其应用装置,应用于测控技术领域,该方法首先获取采样电路的当前采样电压和实际采样比例,然后根据所得当前采样电压和实际采样比例,计算待测量电路的当前工作电压。由于本发明提供的电压测量方法中,所使用的实际采样比例是基于待测量电路输出校验工作电压时采样电路的校验采样电压以及该校验工作电压计算得到的,采样比例并非依赖于采样电阻的阻值计算得到,因此,可以避免电阻阻值偏差的影响,进而提高电压测量的准确度。(The invention provides a voltage measuring method and an application device thereof, which are applied to the technical field of measurement and control. In the voltage measuring method provided by the invention, the used actual sampling proportion is calculated based on the calibration sampling voltage of the sampling circuit when the circuit to be measured outputs the calibration working voltage and the calibration working voltage, and the sampling proportion is not calculated depending on the resistance value of the sampling resistor, so that the influence of the resistance value deviation of the resistor can be avoided, and the accuracy of voltage measurement is further improved.)

1. A voltage measurement method, comprising:

acquiring the current sampling voltage and the actual sampling proportion of a sampling circuit;

the actual sampling proportion is calculated based on the calibration sampling voltage of the sampling circuit when the circuit to be measured outputs the calibration working voltage and the calibration working voltage;

and calculating the current working voltage of the circuit to be measured according to the current sampling voltage and the actual sampling proportion.

2. The voltage measurement method according to claim 1, wherein the process of obtaining the actual sampling ratio includes:

acquiring sampling voltage of the sampling circuit when the circuit to be measured outputs the checking working voltage to obtain checking sampling voltage;

and determining the actual sampling proportion of the sampling circuit based on the checking working voltage and the checking sampling voltage.

3. The voltage measurement method according to claim 2, characterized in that the circuit to be measured is a three-phase circuit;

the obtaining of the sampling voltage of the sampling circuit when the to-be-measured circuit outputs the checking working voltage to obtain a checking sampling voltage includes:

acquiring sampling voltage of a target phase of the sampling circuit when the circuit to be measured outputs the checking working voltage of each phase independently, and acquiring checking sampling voltage of the target phase;

wherein the target phase is any two of the three phases.

4. The voltage measurement method of claim 3, wherein the determining an actual sampling proportion of the sampling circuit based on the verify operating voltage and the verify sampling voltage comprises:

determining a first actual sampling proportion of the sampling circuit according to the following formula:

wherein K represents a first actual sampling proportion of the sampling circuit;

U_a1、U_b1、U_c1respectively representing that the circuit to be measured independently outputs the check working voltage of the corresponding phase;

U_mjwhen the circuit to be measured outputs the checking working voltage of each phase independently, the checking sampling voltage of the first target phase of the sampling circuit is represented, and j is 1,2 and 3;

U_njand when the circuit to be measured outputs the checking working voltage of each phase independently, the checking sampling voltage of the second target phase of the sampling circuit is shown.

5. The voltage measurement method according to claim 3, wherein the obtaining of the sampling voltage of the target phase of the sampling circuit when the circuit to be measured outputs the calibration operating voltage of each phase separately to obtain the calibration sampling voltage of the target phase comprises:

respectively taking each phase in the three-phase circuit as a reference phase;

controlling the circuit to be measured to output a checking working voltage of a reference phase;

and acquiring the sampling voltage of the target phase of the sampling circuit when the to-be-measured circuit outputs the checking working voltage of the reference phase, and acquiring the checking sampling voltage of the target phase.

6. The voltage measurement method of claim 4, wherein the determining an actual sampling proportion of the sampling circuit based on the verify operating voltage and the verify sampling voltage further comprises:

performing inverse operation on the first actual sampling proportion;

and taking the inverse matrix obtained by the inverse operation as a second actual sampling proportion of the sampling circuit.

7. The voltage measurement method according to claim 2, wherein the circuit to be inspected is a single-phase circuit;

the determining an actual sampling proportion of the sampling circuit based on the verification operating voltage and the verification sampling voltage includes:

and taking the ratio of the verification sampling voltage to the verification working voltage as the actual sampling proportion of the sampling circuit.

8. The voltage measurement method according to claim 1, wherein the calculating a current operating voltage of the circuit to be measured according to the current sampling voltage and the actual sampling ratio comprises:

calculating a quotient of the current sampling voltage and the actual sampling proportion, or calculating a product of the current sampling voltage and an inverse of the actual sampling proportion;

and taking the quotient or the product as the current working voltage of the circuit to be measured.

9. A voltage measurement device, comprising: a sampling circuit and a controller, wherein,

the sampling circuit is connected with a circuit to be measured;

the controller is connected to the circuit to be measured and the sampling circuit, respectively, and performs the voltage measuring method of any one of claims 1 to 8.

10. The voltage measurement device of claim 9, wherein the sampling circuit comprises a three-phase sampling circuit or a single-phase sampling circuit.

11. A medium voltage inverter, comprising: a rectifier transformer, a plurality of power conversion units and a voltage measuring device according to any one of claims 9 to 10,

the input end of each power conversion unit is connected with the corresponding secondary winding of the corresponding phase in the rectifier transformer;

the output ends of the power conversion units belonging to the same phase are cascaded to obtain a cascaded circuit of the corresponding phase;

a sampling circuit in the voltage measuring device is respectively connected with each cascade circuit;

and a controller in the voltage measuring device is connected with each power conversion unit.

Technical Field

The invention relates to the technical field of measurement and control, in particular to a voltage measurement method and an application device thereof.

Background

In many application scenarios, there is a very high requirement for precision in measuring the operating voltage of the circuit, and it is necessary to control the error of voltage measurement within a very small range, taking the medium-voltage frequency converter shown in fig. 1 as an example, the secondary winding of the rectifier transformer is connected with a cascaded power conversion unit, and the power is supplied to the power-consuming load through the cascaded power conversion unit. In practical application, the secondary winding of the rectifier transformer often has an unbalanced impedance condition, which causes an unbalanced output voltage of the cascaded power conversion unit, and in order to obtain the degree of unbalance of the output voltage, the output voltage of the medium voltage frequency converter needs to be measured.

Further, in the prior art shown in fig. 1, the sampling circuit is connected to the cascaded power conversion units to collect corresponding sampling voltages, and meanwhile, the sampling circuit is corresponding to a sampling ratio set based on the resistance value of the resistor, and the output voltage of the medium voltage inverter can be obtained by back calculation according to the obtained sampling voltage and the sampling ratio.

However, the inventor researches and discovers that in practical application, a certain deviation inevitably exists in the resistance value of a sampling resistor in a sampling circuit, so that the sampling voltage obtained based on the sampling proportion is inaccurate, the control on the voltage unbalance degree of the medium-voltage frequency converter is further influenced, and the practical application requirements are difficult to meet.

Disclosure of Invention

The invention provides a voltage measuring method and an application device thereof, which are used for calculating the actual sampling proportion of a sampling circuit based on a checking working voltage and the checking sampling voltage of the sampling circuit when a circuit to be measured outputs the checking working voltage, determining the sampling proportion without depending on the resistance value of a sampling resistor, offsetting the influence of the resistance value deviation of the resistor and further improving the accuracy of voltage measurement.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

in a first aspect, the present invention provides a voltage measurement method, including:

acquiring the current sampling voltage and the actual sampling proportion of a sampling circuit;

the actual sampling proportion is calculated based on the calibration sampling voltage of the sampling circuit when the circuit to be measured outputs the calibration working voltage and the calibration working voltage;

and calculating the current working voltage of the circuit to be measured according to the current sampling voltage and the actual sampling proportion.

Optionally, the process of obtaining the actual sampling ratio includes:

acquiring sampling voltage of the sampling circuit when the circuit to be measured outputs the checking working voltage to obtain checking sampling voltage;

and determining the actual sampling proportion of the sampling circuit based on the checking working voltage and the checking sampling voltage.

Optionally, the circuit to be measured is a three-phase circuit;

the obtaining of the sampling voltage of the sampling circuit when the to-be-measured circuit outputs the checking working voltage to obtain a checking sampling voltage includes:

acquiring sampling voltage of a target phase of the sampling circuit when the circuit to be measured outputs the checking working voltage of each phase independently, and acquiring checking sampling voltage of the target phase;

wherein the target phase is any two of the three phases.

Optionally, the determining an actual sampling ratio of the sampling circuit based on the verification operating voltage and the verification sampling voltage includes:

determining a first actual sampling proportion of the sampling circuit according to the following formula:

wherein K represents a first actual sampling proportion of the sampling circuit;

U_a1、U_b1、U_c1respectively representing that the circuit to be measured independently outputs the check working voltage of the corresponding phase;

U_mjwhen the circuit to be measured outputs the checking working voltage of each phase independently, the checking sampling voltage of the first target phase of the sampling circuit is represented, and j is 1,2 and 3;

U_njand when the circuit to be measured outputs the checking working voltage of each phase independently, the checking sampling voltage of the second target phase of the sampling circuit is shown.

Optionally, the obtaining of the sampling voltage of the target phase of the sampling circuit when the circuit to be measured outputs the calibration operating voltage of each phase separately, to obtain the calibration sampling voltage of the target phase, includes:

respectively taking each phase in the three-phase circuit as a reference phase;

controlling the circuit to be measured to output a checking working voltage of a reference phase;

and acquiring the sampling voltage of the target phase of the sampling circuit when the to-be-measured circuit outputs the checking working voltage of the reference phase, and acquiring the checking sampling voltage of the target phase.

Optionally, the determining an actual sampling ratio of the sampling circuit based on the verification operating voltage and the verification sampling voltage further includes:

performing inverse operation on the first actual sampling proportion;

and taking the inverse matrix obtained by the inverse operation as a second actual sampling proportion of the sampling circuit.

Optionally, the circuit to be detected is a single-phase circuit;

the determining an actual sampling proportion of the sampling circuit based on the verification operating voltage and the verification sampling voltage includes:

and taking the ratio of the verification sampling voltage to the verification working voltage as the actual sampling proportion of the sampling circuit.

Optionally, the calculating the current working voltage of the circuit to be measured according to the current sampling voltage and the actual sampling ratio includes:

calculating a quotient of the current sampling voltage and the actual sampling proportion, or calculating a product of the current sampling voltage and an inverse of the actual sampling proportion;

and taking the quotient or the product as the current working voltage of the circuit to be measured.

In a second aspect, the present invention provides a voltage measuring device comprising: a sampling circuit and a controller, wherein,

the sampling circuit is connected with a circuit to be measured;

the controller is connected to the circuit to be measured and the sampling circuit, respectively, and executes the voltage measuring method according to any one of the first aspect of the present invention.

Optionally, the sampling circuit includes a three-phase sampling circuit or a single-phase sampling circuit.

In a third aspect, the present invention provides a medium voltage inverter, including: a rectifier transformer, a plurality of power conversion units, and a voltage measuring device according to any one of the second aspect of the present invention, wherein,

the input end of each power conversion unit is connected with the corresponding secondary winding of the corresponding phase in the rectifier transformer;

the output ends of the power conversion units belonging to the same phase are cascaded to obtain a cascaded circuit of the corresponding phase;

a sampling circuit in the voltage measuring device is respectively connected with each cascade circuit;

and a controller in the voltage measuring device is connected with each power conversion unit.

The voltage measuring method provided by the invention comprises the steps of firstly obtaining the current sampling voltage and the actual sampling proportion of the sampling circuit, and then calculating the current working voltage of the circuit to be measured according to the obtained current sampling voltage and the actual sampling proportion. In the voltage measuring method provided by the invention, the used actual sampling proportion is calculated based on the calibration sampling voltage of the sampling circuit when the circuit to be measured outputs the calibration working voltage and the calibration working voltage, and the sampling proportion is not calculated depending on the resistance value of the sampling resistor, so that the influence of the resistance value deviation of the resistor can be avoided, and the accuracy of voltage measurement is further improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an intermediate frequency transformer in the prior art;

FIG. 2 is a flow chart of a voltage measurement method according to an embodiment of the present invention;

fig. 3 is a flowchart of an actual sampling ratio obtaining method of a sampling circuit according to an embodiment of the present invention;

fig. 4 is a block diagram of a controller in the voltage measuring apparatus according to the embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The voltage measuring method provided by the embodiment of the invention can be applied to electronic equipment, and the electronic equipment can be electronic equipment which can acquire data and execute corresponding control programs, such as a single chip microcomputer, a microcontroller, a DSP and the like. Referring to fig. 2, fig. 2 is a flowchart of a voltage measurement method according to an embodiment of the present invention, where the flowchart of the voltage measurement method according to the embodiment may include:

and S100, acquiring the current sampling voltage and the actual sampling proportion of the sampling circuit.

As shown in fig. 1, a sampling circuit in the prior art is implemented based on a voltage division principle, for example, a sampling resistor R1 is 1 Ω, and a sampling resistor R2 is 99 Ω, in which case, a theoretical sampling ratio of the sampling circuit is 1/100, and further, both ends of the sampling resistor R1 are also used as sampling voltage output ends to feed back sampling voltages, and after the controller obtains the sampling voltages, the controller can calculate a working voltage corresponding to a circuit to be measured according to the theoretical sampling ratio. For example, the sampling voltage is 1V, and 1/(1/100) ═ 100V, that is, the operating voltage of the circuit to be measured is 100V.

However, in practical applications, the resistance value of the sampling resistor is often deviated from the nominal value, so that the real sampling ratio is different from the theoretical sampling ratio, and the theoretical sampling ratio still used in the calculation process inevitably causes inaccuracy of the voltage measurement result.

In order to solve the above problems, in the voltage measurement method provided in the embodiments of the present invention, a theoretical sampling ratio of the sampling circuit is not used, but an actual sampling ratio of the sampling circuit is used, and more importantly, the actual sampling ratio is obtained based on an actual verification result, and under a condition that the circuit to be measured is controlled to output a known verification operating voltage, a verification sampling voltage of the sampling circuit is obtained, and further, the actual sampling ratio of the sampling circuit is obtained based on the verification sampling voltage and the verification operating voltage. The specific acquisition process for the actual sampling ratio will be developed in the following, and will not be described in detail here.

Optionally, the obtaining of the current sampling voltage of the sampling circuit may be implemented based on the prior art, which is not limited in the present invention.

And S110, calculating the current working voltage of the circuit to be measured according to the current sampling voltage and the actual sampling proportion.

Optionally, after obtaining the current sampling voltage and the actual sampling ratio, a quotient of the current sampling voltage and the actual sampling ratio may be calculated, that is, the current sampling voltage is divided by the actual sampling ratio, or a product of the current sampling voltage and an inverse of the actual sampling ratio is calculated, and the quotient or the product is the current working voltage of the circuit to be measured.

In summary, in the voltage measurement method provided by the present invention, the actual sampling ratio is calculated based on the calibration sampling voltage of the sampling circuit when the circuit to be measured outputs the calibration working voltage and the calibration working voltage, and the sampling ratio is not calculated depending on the nominal resistance of the sampling resistor, so that the influence of the resistance deviation of the resistor can be avoided, and the accuracy of voltage measurement can be further improved.

It is conceivable that, for a certain sampling circuit, the resistance values of the sampling resistors inside the certain sampling circuit are determined, and therefore, in practical application, as long as the actual sampling proportion of the sampling circuit is determined in advance, in a subsequent use process, recalculation is not needed, and the actual sampling proportion obtained by calculation is directly used.

The following describes the process of acquiring the actual sampling ratio of the sampling circuit according to the embodiment of the present invention. Optionally, referring to fig. 3, fig. 3 is a flowchart of another voltage measurement method provided in the embodiment of the present invention, where the flowchart may include:

s200, acquiring sampling voltage of the sampling circuit when the to-be-measured circuit outputs the checking working voltage, and obtaining the checking sampling voltage.

In order to obtain the actual sampling proportion of the sampling circuit, a known calibration working voltage needs to be preset, the preset calibration working voltage can be set based on the actual working voltage of the circuit to be measured, the rated working voltage of the circuit to be measured can be selected, and any determined voltage value lower than the rated working voltage can be selected as the calibration working voltage.

Further, the circuit to be measured is controlled to output the verification working voltage, or when the circuit to be measured is controlled to work with the verification voltage, the sampling circuit necessarily feeds back the corresponding sampling voltage.

It is conceivable that the circuit to be measured in practical application may be a three-phase circuit or a single-phase circuit, and the three-phase circuit is different from the single-phase circuit in the specific processing manner in this step.

Specifically, if the circuit to be measured is a three-phase circuit, the phase a, the phase b, and the phase c in the three-phase circuit are respectively used as reference phases, the circuit to be measured is controlled to output the calibration operating voltage of the reference phase, and the sampling voltage of the target phase of the sampling circuit is obtained under the condition that the circuit to be measured outputs the calibration operating voltage of the reference phase, so that the calibration sampling voltage of the target phase can be obtained. The target phase described in this embodiment may be any two of three phases.

It should be noted that the target phase mentioned in this embodiment may include the aforementioned reference phase, or may be another two phases other than the reference phase. For example, a phase a is used as a reference phase, and a circuit to be measured is controlled to output a phase a calibration operating voltage, in this case, based on the basic principle of a three-phase circuit, it can be known that corresponding sampling voltages exist in three phases of a sampling circuit at the same time, and the sampling voltages of the phases are respectively obtained, that is, the calibration sampling voltage of the corresponding phase is obtained, based on which, the phase a and the phase b can be selected as target phases, the phase b and the phase c can be selected as target phases, and certainly, the phase a and the phase c can also be selected as target phases. By analogy, the circuit to be measured is controlled to output the b-phase check working voltage and the c-phase check working voltage respectively, and corresponding check sampling voltages can be obtained respectively.

It should be noted that when the circuit to be measured outputs the check operating voltages of the phases, the target selects the same two phases, for example, when the reference phase is the a phase, the target phase selects the b phase and the c phase, and then when the b phase and the c phase are taken as the reference phase, the b phase and the c phase are also selected as the target phase.

Optionally, it is simpler to control the circuit to be measured to output the verification operating voltage when the circuit to be measured is a single-phase circuit, and the voltage fed back by the sampling circuit is the corresponding sampling voltage, i.e. the reference phase and the target phase are the same phase, which is not described in detail herein.

And S210, determining the actual sampling proportion of the sampling circuit based on the checking working voltage and the checking sampling voltage.

First, a case where the circuit to be measured is a three-phase circuit will be described. Specifically, if any two phases of the three phases are collected as a target phase to obtain a calibration sampling voltage of the target phase under the condition that the circuit to be measured outputs any reference phase calibration working voltage, the following voltage balance equation can be constructed on the basis of the obtained calibration working voltage and the calibration sampling voltage based on the linear superposition principle:

wherein, U_a1、U_b1、U_c1Respectively representing the reference phase checking working voltage independently output by the circuit to be measured;

U_mjwhen the circuit to be tested outputs the reference phase check working voltage independently, the check sampling voltage of the first target phase of the sampling circuit is represented, and j is 1,2 and 3;

U_njwhen the circuit to be measured outputs the reference phase checking working voltage independently, the checking sampling voltage of a second target phase of the sampling circuit is shown;

U_a、U_b、U_crespectively representing the actual working voltage of the circuit to be measured;

k represents the first actual sampling proportion of the sampling circuit;

U_mwhen the circuit to be measured outputs three-phase actual working voltage at the same time, the sampling voltage of a first target phase of the sampling circuit is represented;

U_nand the sampling voltage of the second target phase of the sampling circuit is shown when the circuit to be measured outputs three-phase actual working voltage simultaneously.

It should be noted that "1" in the above equation represents the positive and negative sequence components in the three-phase check operating voltage, and the zero sequence component is not considered. By U_m1/U_aFor example, a per unit verification sampling voltage when the a-phase verification operating voltage acts alone is shown.

After the above balance equation is constructed based on the calibration working voltage and the calibration sampling voltage, the coefficient K is the actual sampling proportion of the sampling circuit mentioned in the present application, and this embodiment defines it as the first actual sampling proportion. According to the construction process of the voltage balance equation, in practical application, the voltage which can be collected is U_mAnd U_n，U_a、U_b、U_cIs a parameter to be calculated, and adopts the first actual sampling proportion to calculate U_a、U_b、U_cIt is inconvenient, therefore, to perform inverse operation on the first actual sampling ratio on the basis of the first actual sampling ratio, and the obtained inverse matrix is the second actual sampling ratio.

Directly obtaining U under the condition of adopting a second actual sampling proportion_mAnd U_nAnd the actual working voltage of the three phases can be directly calculated by utilizing matrix multiplication.

Further, for the case that the circuit to be measured is a single-phase circuit, the following voltage balance equation can be constructed:

U_g＝L×U_d

wherein, U_gRepresenting a verify sampling voltage;

U_drepresenting a verify operating voltage;

l represents the actual sampling ratio.

Based on the single-phase voltage balance equation, the ratio of the sampling voltage to the checking working voltage, namely the actual sampling proportion of the sampling circuit, is checked.

Optionally, an embodiment of the present invention further provides a voltage measurement apparatus, where the voltage measurement apparatus includes a sampling circuit and a controller, the sampling circuit is connected to the circuit to be measured, and the controller is respectively connected to the sampling circuit and the circuit to be measured. The sampling circuit may be a three-phase sampling circuit or a single-phase sampling circuit, and is specifically selected based on a circuit to be measured, and as for the specific circuit topology of the sampling circuit, the sampling circuit may be implemented based on the prior art, and details are not repeated here.

Referring to fig. 4, fig. 4 is a block diagram of a controller in a voltage measuring device according to an embodiment of the present invention, and as shown in fig. 4, the block diagram may include: at least one processor 100, at least one communication interface 200, at least one memory 300, and at least one communication bus 400;

in the embodiment of the present invention, the number of the processor 100, the communication interface 200, the memory 300, and the communication bus 400 is at least one, and the processor 100, the communication interface 200, and the memory 300 complete the communication with each other through the communication bus 400; it is clear that the communication connections shown by the processor 100, the communication interface 200, the memory 300 and the communication bus 400 shown in fig. 4 are merely optional;

optionally, the communication interface 200 may be an interface of a communication module, such as an interface of a GSM module;

the processor 100 may be a central processing unit CPU or an application Specific Integrated circuit asic or one or more Integrated circuits configured to implement embodiments of the present invention.

The memory 300, which stores application programs, may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

The processor 100 is specifically configured to execute an application program in the memory to implement any embodiment of the voltage measurement method described above.

Optionally, an embodiment of the present invention further provides a medium voltage frequency converter, including: rectifier transformer, a plurality of power conversion units and voltage measurement device that any one of the embodiments provided above, wherein,

the input end of each power conversion unit is connected with the corresponding secondary winding of the corresponding phase in the rectifier transformer;

the output ends of the power conversion units belonging to the same phase are cascaded to obtain a cascaded circuit of the corresponding phase;

the sampling circuit in the voltage measuring device is respectively connected with each cascade circuit;

and a controller in the voltage measuring device is connected with each power conversion unit.

The term "include" and variations thereof as used herein are open-ended, i.e., "including but not limited to". The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions for other terms will be given in the following description.

It should be noted that the terms "first", "second", and the like in the present disclosure are only used for distinguishing different devices, modules or units, and are not used for limiting the order or interdependence relationship of the functions performed by the devices, modules or units.

It is noted that references to "a", "an", and "the" modifications in this disclosure are intended to be illustrative rather than limiting, and that those skilled in the art will recognize that "one or more" may be used unless the context clearly dictates otherwise.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.