CN112821849A

CN112821849A - Motor control device and method

Info

Publication number: CN112821849A
Application number: CN202110085992.2A
Authority: CN
Inventors: 毛薇薇; 陈炜杰
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2021-05-18

Abstract

The invention provides a motor control device and a motor control method, and relates to the technical field of motor control. The motor control device comprises a bus, a current sampling module, a voltage sampling module, a signal processing module and an adjusting module; the current sampling module is used for collecting current on a bus, the voltage sampling module is used for collecting voltage of the bus, the signal processing module is used for calculating instantaneous power of the current motor and comparing the instantaneous power with preset target power to adjust the duty ratio of output PWM, and the adjusting module is connected with the output end of the signal processing module and receives the duty ratio of the PWM output from the signal processing module so as to control the running state of the motor. Therefore, the current and voltage acquisition positions are arranged in front of the input end of the motor, and compared with the scheme of acquiring the voltage parameters and the current parameters of the rear end of the motor, the interference of the motor on the sampling data during reversing is reduced, and the more accurate sampling data is obtained, so that the control on the motor is favorably realized.

Description

Motor control device and method

Technical Field

The invention relates to the technical field of motor control, in particular to a motor control device and method.

Background

The motor is widely used in many fields as a power source of various mechanical devices, and a user can control the motor through a controller in the mechanical device according to actual requirements, so that the working state of the motor can reach a state expected by the user.

The general motor has the limitation of input power, the motor is damaged when exceeding the maximum power, accidents can be caused when the motor is serious, and the rotating speed of the motor needs to be controlled to a certain extent under the requirements of power saving, noise and environmental protection. Therefore, in order to control the motor, the current state of the motor generally needs to be obtained. The existing motor is controlled by acquiring feedback voltage through a rear-end feedback point, but the accuracy of data sampled by the existing motor control device is poor, and the control of the motor is not facilitated.

Disclosure of Invention

The invention solves the problem that the data sampled by the existing motor control device has poor precision and is not beneficial to realizing the control of the motor.

In order to solve the above problems, the present invention provides a motor control device including: the device comprises a bus, a current sampling module, a voltage sampling module, a signal processing module and an adjusting module;

the current sampling module is electrically connected with the bus and used for collecting current on the bus, the voltage sampling module is electrically connected with the bus and used for collecting voltage of the bus, the signal processing module is connected with the output end of the current sampling module and the output end of the voltage sampling module and used for calculating current instantaneous power of the motor and comparing the instantaneous power with preset target power to adjust the duty ratio of output PWM, and the adjusting module is connected with the output end of the signal processing module and used for receiving the duty ratio of the PWM output by the signal processing module so as to control the running state of the motor.

Like this, current sampling module, voltage sampling module all are connected with the generating line, and what current sampling module and voltage sampling module gathered is the electric current and the voltage of generating line, and the collection position that is equivalent to electric current and voltage is put before the motor input, for the scheme of the voltage parameter and the current parameter of gathering the motor rear end, to the interference of sampling data when reducing the motor switching-over, obtain more accurate sampling data to be favorable to realizing the control to the motor.

Optionally, the current sampling module includes a sampling resistor, a first filter circuit and a second filter circuit, the sampling resistor is electrically connected to the bus, one end of the sampling resistor is connected to one end of the first filter circuit, and the other end of the sampling resistor is connected to one end of the second filter circuit; the other ends of the first filter circuit and the second filter circuit are used as the output end of the current sampling module, and the capacitor of the first filter circuit and the capacitor of the second filter circuit are in short circuit grounding.

Therefore, the collection position for collecting the current is placed in front of the input end of the motor, so that the interference is reduced, the collection is facilitated, a more accurate current value is obtained, and the follow-up control on the motor is facilitated.

Optionally, the voltage sampling module includes a voltage dropping component and a third filter circuit, one end of the voltage dropping component is connected to the live wire, the other end of the voltage dropping component is connected to the third filter circuit and serves as an output end of the voltage sampling module, and the other end of the third filter circuit is grounded.

Therefore, the voltage sampling module is used for collecting the voltage parameters at the front end of the motor, so that the voltage parameters with higher precision can be obtained, and the subsequent control on the state of the motor is facilitated.

Optionally, the signal processing module includes a power metering chip, and the power metering chip is configured to receive data of the current sampling module and the voltage sampling module and calculate to obtain preliminary power data.

Therefore, the voltage parameter and the current parameter obtained by the acquisition unit are preprocessed by the power metering chip to obtain preliminary power data, so that the calculation of subsequent instantaneous power values is facilitated.

Optionally, the signal processing module further includes a single chip, and the single chip is connected to the output end of the power metering chip.

Therefore, preliminary power data are obtained after the power metering chip is used for preprocessing, and the current instantaneous power value is obtained after the single chip microcomputer is used for processing. And calculating the current power value inside the single chip microcomputer, judging whether the instantaneous power value of the current motor meets the range of the target power, and if not, adjusting the duty ratio output of PWM. The preprocessed data are input into the single chip microcomputer, so that the calculation difficulty of the single chip microcomputer is greatly reduced, and the calculation is simpler.

Optionally, the adjusting module includes a power switch chip and a semiconductor type field effect transistor, and the adjusting module is electrically connected to the motor.

Therefore, the small signals output by other units are converted into large signals by arranging the adjusting unit, so that the operation of the motor is controlled, and the control on the state of the motor is facilitated.

Secondly, the invention also discloses a motor control method, which is applied to the motor control device and comprises the following steps:

respectively collecting the current and the voltage of a bus through the current sampling module and the voltage sampling module;

calculating the instantaneous power of the motor at present according to the voltage and the current through the signal processing module, comparing the instantaneous power with a preset target power, and adjusting the duty ratio of the output PWM;

and receiving the duty ratio of the PWM output from the signal processing module through the adjusting module so as to control the running state of the motor.

Therefore, compared with the scheme of collecting the current and the voltage at the rear end of the motor, the method has the advantages that the current and the voltage of the bus are collected respectively, namely, the current and the voltage at the front end of the motor are collected, the interference on sampling data during the reversing of the motor is reduced, accurate sampling data are obtained, accurate real-time instantaneous power is obtained through calculation, and the current state of the motor is reflected through the instantaneous power. Secondly, the duty ratio of the PWM is continuously adjusted by comparing the instantaneous power with the preset target power, so that the current instantaneous power reaches the preset target power, the motor is well controlled, and the motor can stably run.

Optionally, the current sampling module and the voltage sampling module respectively collect current and voltage of a bus, where the voltage is an alternating current voltage and the current is an alternating current.

Therefore, accurate sampling data are obtained by collecting the alternating voltage and the alternating current at the front end of the motor, accurate real-time instantaneous power is obtained through calculation, and the current state of the motor is reflected through the instantaneous power, so that the motor is controlled.

Optionally, the calculating, by the signal processing module, the current instantaneous power of the motor according to the voltage and the current, and comparing the instantaneous power with a preset target power to adjust a duty ratio of PWM includes:

judging whether the instantaneous power meets a target power;

and when the instantaneous power does not meet the target power, adjusting the duty ratio of PWM output to the motor, and recalculating the instantaneous power of the current motor until the instantaneous power reaches the preset target power.

Therefore, the duty ratio of the PWM is judged to be increased or decreased according to the difference between the instantaneous power and the target power by comparing the instantaneous power and the target power, so that the duty ratio control of the PWM is favorably adjusted subsequently, and the running state of the motor is adjusted.

Alternatively, the determining whether the instantaneous power satisfies a target power,

when the instantaneous power is greater than the target power, reducing a duty ratio of PWM output to a motor;

when the instantaneous power is less than the target power, increasing a duty ratio of the PWM output to the motor.

In this way, when the instantaneous power is greater than the target power, the duty ratio of the PWM is increased, namely the current motor is possibly overloaded, and the power of the motor is reduced by reducing the duty ratio of the PWM, so that the motor is not damaged; and when the instantaneous power is smaller than the target power, increasing the duty ratio of the PWM to meet the normal motor power so that the motor is in a normal working state.

The invention also discloses a motor control method, which is applied to the motor control device and comprises the following steps:

collecting the current of a bus through the current sampling module;

comparing the current with a preset current value and adjusting the duty ratio of PWM through the signal processing module;

Therefore, the interference of the motor on the sampling data during the reversing is reduced by collecting the current parameters at the front end of the motor, so that more accurate sampling data is obtained, more accurate real-time current is obtained through calculation, and the current state of the motor is reflected through the change of the current. Secondly, the duty ratio of PWM is continuously adjusted through the change of current, so that the current reaches a preset current value, the motor is well controlled, and the motor can stably run.

Optionally, the comparing, by the signal processing module, the current with a preset current value and adjusting a duty ratio of PWM includes:

when the current is larger than the preset current value, reducing the duty ratio of PWM output to the motor;

and when the current is smaller than the preset current value, increasing the duty ratio of PWM output to the motor.

In this way, when the current is larger than the preset current value, the duty ratio of the PWM is increased, namely the current motor is possibly overloaded, and the power of the motor is reduced by reducing the duty ratio of the PWM, so that the motor is not damaged; and when the current is smaller than the preset current, increasing the duty ratio of the PWM to meet the normal motor power so that the motor is in a normal working state.

Drawings

Fig. 1 is a schematic structural diagram of a motor control device according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart illustrating a motor control method according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart illustrating a motor control method according to another embodiment of the present invention;

fig. 4 is a flow chart illustrating a motor control method according to still another embodiment of the present invention.

Description of reference numerals:

10-a voltage sampling module; 11-sampling resistance; 12-a first filter circuit; 13-a second filter circuit; 20-a voltage sampling module; 21-a pressure reducing component; 22-a third filter circuit; 30-a signal processing module; 31-a power metering chip; 32-a single chip microcomputer; 40-an adjustment module; r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; r5-fifth resistor; r6-sixth resistance; r7 — seventh resistor; c1 — first capacitance; c2 — second capacitance; c3-third capacitance.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein.

The general motor has the limitation of input power, the motor is damaged when exceeding the maximum power, accidents can be caused when the motor is serious, and the rotating speed of the motor needs to be controlled to a certain extent under the requirements of power saving and environmental protection. Therefore, in order to control the motor, the current state of the motor generally needs to be obtained. When the existing motor state is judged, the acquired data is inaccurate in precision and not beneficial to control of the motor.

The existing state of obtaining the motor is at the upper end or the lower extreme of motor, a small resistor is strung, then the electric current of motor can flow through the resistance, if there is the state of short circuit or other disconnection, the electric current can increase or reduce, then the electric current flows through the small resistor, voltage on the resistance can change, gather above voltage, if do so the precision is gathered inaccurately, the motor disturbs very greatly in the switching-over, be a very stable wave form, can very serious interference, the precision also can not be very high. The upper end or the lower end of the motor here means that a small resistor is connected in series with the motor at a position close to the motor, the small resistor being arranged in front of the motor, or the small resistor being arranged behind the motor.

In addition, in order to master the current state of the motor, the current after collecting the bus voltage and the IPM (Intelligent Power Module) Module is generally difficult to collect, and the collection is interfered in each PWM switch. The acquisition voltage needs to be kept out of interference. And each model of motor is different. Every kind of motor need debug alone, and sampling accuracy is poor, because gather the voltage on the feedback resistance, this voltage is not invariable always, and the change is undulant great, and the burr is more. In addition, the collected voltage cannot be directly used and can be used after software filtering. The software algorithm requires time and therefore there is a lag in the sampling time.

In view of the above situation, the present invention provides a solution idea by sampling the ac voltage and the ac current at the front end of the motor. Compared with the scheme of collecting the voltage parameter and the current parameter at the rear end of the motor, the method reduces the interference on the sampling data when the motor is commutated, obtains more accurate sampling data, and is favorable for realizing the control of the motor.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a motor control device according to an embodiment of the present invention. The invention discloses a motor control device, comprising: the bus, the current sampling module 10, the voltage sampling module 20, the signal processing module 30 and the adjusting module 40;

the current sampling module 10 is electrically connected with a bus and used for collecting current on the bus, the voltage sampling module 20 is electrically connected with the bus and used for collecting voltage of the bus, the signal processing module 30 is connected with the output end of the current sampling module 10 and the output end of the voltage sampling module 20 and used for calculating the current instantaneous power of the motor and comparing the instantaneous power with the preset target power to adjust the duty ratio of the output PWM, and the adjusting module 40 is connected with the output end of the signal processing module 30 and used for receiving the duty ratio of the PWM output from the signal processing module 30 so as to control the running state of the motor.

The bus comprises a zero line and a live line, the current sampling module samples current on the zero line, and the voltage sampling module samples voltage between the live line and the zero line. It should be noted that, when the motor rotates, the live wire and the zero line are communicated, so there is also current on the zero line, and the current sampling module can acquire the current of the zero line.

In the case of zero line grounding, grounding here means zero potential of the internal circuit board circuit, and is not safe grounding. As shown in the figure, it is only a schematic diagram, in an actual circuit, for example, the surge protector can be terminated at the power supply of the bus, which is equivalent to a large resistor for protecting the bus voltage from being stable. The person skilled in the art can select the choice according to the actual situation, which is not limited in this respect.

In addition, it should be noted that, because the alternating current is used for power supply and detection, the live wire and the zero wire can be connected in a replaceable manner, and the live wire and the zero wire can also be used in reverse connection in practical application.

Optionally, the current sampling module 10 includes a sampling resistor 11, a first filter circuit 12, and a second filter circuit 13, where the sampling resistor 11 is electrically connected to the bus, one end of the sampling resistor 11 is connected to one end of the first filter circuit 12, and the other end of the sampling resistor 11 is connected to one end of the second filter circuit 13; the other ends of the first filter circuit 12 and the second filter circuit 13 are used as the output end of the current sampling module 10, and the capacitance of the first filter circuit 12 and the capacitance of the second filter circuit 13 are in short circuit connection with the ground.

Optionally, the current sampling module 10 includes a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a second capacitor C2, the second resistor R2 is electrically connected to a zero line, one end of the second resistor R2 is connected to one end of the first resistor R1, the other end of the second resistor R2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the second capacitor C2, the other end of the first resistor R1 is connected to the first capacitor C1, and the first capacitor C1 and the second capacitor C2 are shorted to ground. The other ends of the first resistor R1 and the third resistor R3 are connected to the input end of the signal processing module 30 as the output of the current sampling module. The second resistor R2 is a sampling resistor, the first filter circuit 12 includes a first resistor R1 and a first capacitor C1, and the second filter circuit 13 includes a third resistor R3 and a second capacitor C2.

The first filter circuit and the second filter circuit are both low-pass filter circuits. When the frequency of the input signal is low, the impedance of the capacitor is high relative to the impedance of the resistor, and therefore most of the input voltage drops across the capacitor (and across the load, in parallel with the capacitor). When the input frequency is high, the impedance of the capacitance is low relative to the impedance of the resistor, which means that the voltage over the resistor decreases and less voltage is transmitted to the load. Thus, low frequency signals pass and high frequency signals are blocked.

The second resistor R2 is a sampling resistor, the sampling resistor R2 is generally in the milliohm level, and the resistance value of the sampling resistor is required to be relatively small, so that the heating value of the resistor is small. When current flows through R2, voltage changes occur, and the voltage changes enter the first A/D converter of the power metering chip after passing through the filter circuit consisting of R1, R3, C1 and C2.

Optionally, the voltage sampling module 20 includes a voltage dropping component 21 and a third filter circuit 22, one end of the voltage dropping component 21 is connected to the hot line, the other end of the voltage dropping component 21 is connected to the third filter circuit 22 and serves as an output end of the voltage sampling module 20, and the other end of the third filter circuit 22 is grounded.

Optionally, for the arrangement of the voltage dropping component, the voltage dropping component includes a voltage dropping resistor, and for the number of the voltage dropping resistors, for example, one, two, or more may be arranged, which is beneficial to reduce the incoming voltage.

Optionally, the voltage sampling module 20 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a third capacitor C3, one end of the fifth resistor R5 is connected to the live line, the other end of the fifth resistor R5 is sequentially connected in series to the sixth resistor R6 and the seventh resistor R7, the other end of the seventh resistor R7 is connected to one ends of the fourth resistor R4 and the third capacitor C3 and serves as an output end of the voltage sampling module, the output end of the voltage sampling module is connected to the input end of the signal processing module 30, and the other ends of the fourth resistor R4 and the third capacitor C3 are short-circuited and grounded.

The voltage reduction resistor is a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7, and voltage signals are reduced through R5, R6 and R7 and enter a second A/D converter of the power metering chip after passing through a third filter circuit formed by R4 and C3.

Optionally, the current and voltage are collected on the zero line and the live line respectively, the voltage of the live line and the voltage of the zero line are collected, so that the live line and the zero line can be collected only by a reference, and the zero potential of the internal circuit board needs to be connected with the live line.

Optionally, the signal processing module 30 includes a power metering chip 31, and the power metering chip 31 is configured to receive data of the current sampling module 10 and the voltage sampling module 20 and calculate to obtain preliminary power data.

Optionally, the power metering chip may be, for example, HLW8012, SA9904B, CS5463, or the like. The type of the power metering chip is not limited, as long as the data collected by the current sampling module 10 and the voltage sampling module 20 can be processed to obtain preliminary power data.

Optionally, the power metering chip 31 includes a first a/D converter and a second a/D converter, the first a/D converter is connected to the output end of the current sampling module 10 for preprocessing data of the current sampling module 10, and the second a/D converter is connected to the output end of the voltage sampling module 20 for preprocessing data of the voltage sampling module 20.

The method comprises the steps that initial power data are obtained through a power metering chip according to collected voltage parameters and current parameters, alternating current and alternating voltage are obtained through collection, the alternating current and the alternating voltage have phases, general phase calculation is complex, and the initial power data are obtained after preprocessing is carried out on the power metering chip. Through the processing of the power metering chip, the processing speed is higher. In addition, the first A/D converter and the second A/D converter are integrated on an integrated circuit, and compared with the scheme that the first A/D converter and the second A/D converter are respectively and independently a chip, the occupied space of the circuit is saved. For the selection of the power metering chip, there are many chips of different models and brands, and those skilled in the art can select the power metering chip according to actual needs, which is not limited herein.

Therefore, the voltage parameter and the current parameter are preprocessed through the first A/D converter and the second A/D converter to obtain preliminary power data, and calculation of subsequent instantaneous power values is facilitated.

Optionally, the signal processing module 30 further includes a single chip microcomputer 32, and the single chip microcomputer 32 is connected to an output end of the power metering chip 31.

Optionally, the adjusting module 40 includes a power switch chip and a semiconductor type field effect transistor, and the adjusting module 40 is electrically connected to the motor. The adjusting module 40 and the motor electrical connection may be connected in series or in parallel.

The adjusting unit comprises a power switch chip and a semiconductor field effect transistor, the adjusting module is a power adjusting part, and the power adjusting part adjusts power output to the motor according to PWM input by the single chip microcomputer. The semiconductor field effect transistor comprises an MOS transistor, the PWM signal directly acts in the MOS transistor, and the MOS transistor also directly outputs the PWM signal to control the motor without adjusting the voltage. The single chip microcomputer outputs PWM to the power switch chip and the semiconductor field effect transistor without adjusting voltage. The output of the singlechip is a small signal, and the PWM signal output by the singlechip is input to the adjusting unit and converted into a large signal, so that the operation of the motor is controlled.

Therefore, the small signals output by other units are converted into large signals by arranging the adjusting module, so that the operation of the motor is controlled, and the control on the state of the motor is facilitated.

The invention discloses a motor control device, which comprises a current sampling module, a voltage sampling module, a first A/D converter, a second A/D converter, a singlechip, an adjusting module, a zero line and a live wire, the adjusting module comprises a power switch chip and a semiconductor type field effect transistor, the current sampling module 10 comprises a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1 and a second capacitor C2, the second resistor R2 is electrically connected with a zero line, one end of the second resistor R2 is connected with one end of the first resistor R1, the other end of the second resistor R2 is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with one end of a second capacitor C2, the other end of the first resistor R1 is connected with the first capacitor C1, and the first capacitor C1 and the second capacitor C2 are shorted to the ground. The other ends of the first resistor R1 and the third resistor R3 are connected with the first A/D converter as the output of the current sampling module. The voltage sampling module 20 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a third capacitor C3, one end of the fifth resistor R5 is connected to the live wire, the other end of the fifth resistor R5 is sequentially connected to the sixth resistor R6 and the seventh resistor R7 in series, the other end of the seventh resistor R7 is connected to one ends of the fourth resistor R4 and the third capacitor C3 and serves as an output end of the voltage sampling module, the output end of the voltage sampling module is connected to the first a/D converter, and the other ends of the fourth resistor R4 and the third capacitor C3 are short-circuited and grounded. The single chip microcomputer 32 is connected with the output ends of the first A/D converter and the second A/D converter. The output end of the single chip microcomputer is connected with the adjusting module 40, and the adjusting module 40 is connected with the motor in parallel. The live wire and the neutral wire are connected through a motor, wherein M represents the motor.

Referring to fig. 2, fig. 2 is a schematic flow chart of a motor control method according to an embodiment of the present invention. The invention discloses a motor control method, which is applied to the motor control device and comprises the following steps:

s10, respectively collecting the current and the voltage of the bus through the current sampling module and the voltage sampling module;

the current sampling module and the voltage sampling module are used for respectively acquiring the current and the voltage of a bus, namely the acquired voltage and current refer to the current value and the voltage value which do not pass through a motor, a power switch chip and a semiconductor type field effect transistor are arranged in front of the motor, and the voltage value and the current value in front of the power switch chip and the semiconductor type field effect transistor are acquired, namely the acquisition positions of the voltage and the current are arranged in front of the input end of the motor. The collected voltage is an alternating voltage, the collected current is an alternating current, and the collected current is a single-phase alternating current and a single-phase alternating voltage.

S20, calculating the current instantaneous power of the motor according to the voltage and the current through the signal processing module, comparing the instantaneous power with a preset target power, and adjusting the duty ratio of the output PWM;

the signal processing module comprises a power metering chip and a single chip microcomputer, primary power data are obtained through the power metering chip according to the collected voltage and current, the alternating current and the alternating voltage are obtained through collection, the alternating current and the alternating voltage can have phases, general phase calculation can be complex, the primary power data are obtained after the power metering chip is used for preprocessing, and the current instantaneous power value is obtained through the single chip microcomputer processing. And comparing the instantaneous power with a preset target power, and if the acquired power is inconsistent with the target power, adjusting the duty ratio of the PWM, namely the duty ratio is adjustable.

And S30, receiving the PWM duty ratio output by the signal processing module through the adjusting module so as to control the running state of the motor.

And transmitting the adjusted PWM duty ratio to an adjusting module, and controlling the running state of the motor through the adjusting module.

Because the motor is an interference source, the interference brought by the motor at the rear end can be better overcome by collecting the front-end alternating voltage and alternating current, and the accuracy of collecting the voltage or the current at the rear end is not high. In addition, the front end has the advantages that various consumptions of the sampling later stage are also calculated, and the reflected data are relatively comprehensive. If the data is collected at the back end, the consumption caused by the sampling points cannot be counted.

Optionally, in S10, the current sampling module and the voltage sampling module respectively collect current and voltage of a bus, where the voltage is an ac voltage and the current is an ac current.

Referring to fig. 3, fig. 3 is a schematic flow chart of a motor control method according to another embodiment of the present invention. Optionally, the S20, calculating, by the signal processing module, an instantaneous power of the motor according to the voltage and the current, and comparing the instantaneous power with a preset target power to adjust a PWM duty ratio, includes:

and S21, judging whether the instantaneous power meets the target power.

And judging whether the instantaneous power meets the target power or not refers to comparing the instantaneous power with the target power value, wherein the target power is a preset value and can be set according to actual needs. Of course, the preset target power can also be set to be a preset range, and the normal operation of the motor can be satisfied as long as the preset target power is within the range allowed by the error.

And S22, when the instantaneous power does not meet the target power, adjusting the duty ratio of PWM output to the motor, and recalculating the instantaneous power of the current motor until the instantaneous power reaches the preset target power.

When the instantaneous power does not meet the target power, the current instantaneous power is not in the range of the target power value, when the instantaneous power is not in the range of the target power value, the duty ratio of PWM is adjusted, a PWM signal is output, after the PWM is changed, the instantaneous power of the motor is changed, then the current and the voltage of the front end of the motor are collected again, the current instantaneous power is recalculated, the magnitude of the instantaneous power and the target power is compared, the duty ratio of the PWM is continuously adjusted, the PWM signal is continuously output until the instantaneous power is adjusted to be in the range of the target power value, and the duty ratio of the last PWM is constantly output.

For example, for setting the target power, several preset values may be set in the program according to different motors, for example, when the duty ratio of the PWM of a 500W motor is 30%, the idle power should be 100W (preset value), i.e. the target power is 100W. When the duty ratio of PWM is 30%, the acquired instantaneous power is greater than or less than 100W, which indicates that the motor is currently in a loaded state, and then the duty ratio of the PWM signal is increased or decreased through a set of algorithm according to the acquired instantaneous power to change the power or the rotating speed of the motor.

It should be noted that, after the instantaneous power reaches the preset target power, the detection is not stopped, but the detection is continued all the time, the judgment is carried out all the time in a circulating manner, the magnitude of the instantaneous power and the magnitude of the target power are compared, when the instantaneous power does not meet the target power, the duty ratio of the PWM output to the motor is readjusted, and when the instantaneous power reaches the range of the target power value, the duty ratio of the final PWM is constantly output.

Optionally, the S20, calculating, by the signal processing module, an instantaneous power of the motor according to the voltage and the current, and comparing the instantaneous power with a preset target power to adjust a duty ratio of PWM, further includes:

and S23, when the instantaneous power meets the target power, outputting the current constant duty ratio to control the motor.

And when the instantaneous power meets the range of the target power value, the duty ratio of PWM is not adjusted any more, and finally the constant duty ratio of PWM is output.

Therefore, when the instantaneous power meets the target power, the rotating speed of the current motor can be judged to meet the normal working requirement, and the motor is in a stable running state, so that the stable running of the motor is facilitated.

Alternatively, the step S21, determining whether the instantaneous power meets the target power,

Generally, the increase of the PWM means that the duty ratio is a little higher, the voltage is adjusted to be high, the rotating speed of the motor is fast, and the power of the motor is high. It should be noted that, for the adjustment of the duty ratio, a person skilled in the art may actually need to adjust the duty ratio, for example, the duty ratio of each adjustment may be changed in a constant amplitude or in an unequal amplitude, when the difference between the current instantaneous power and the target power is large, the duty ratio may be adjusted to be large, and when the instantaneous power is close to the target power, the duty ratio may be adjusted to be relatively small, so that the adjustment is relatively accurate, and thus the instantaneous power of the motor may be as close to the target power as possible, or may be equal to the target power, so that the state of the motor reaches the optimal operating state.

Similarly, when the instantaneous power is greater than the target power, it is considered that the motor may be in an overload or short-circuit state, and therefore the duty ratio of the PWM needs to be reduced or stopped, so as to ensure that the motor can work normally without being damaged.

Alternatively, the step S23, when the instantaneous power meets the target power, outputting the current duty ratio constantly to control the motor,

when the instantaneous power is equal to the target power, the duty cycle of the PWM is kept constant.

Therefore, when the instantaneous power is equal to the target power, the duty ratio of the output PWM is unchanged, and the current duty ratio is output to control the motor, so that the motor can stably run, and the running state reaches a better state.

Optionally, referring to fig. 4, fig. 4 is a schematic flowchart of a motor control method according to still another embodiment of the present invention. The invention also discloses a motor control method, which is applied to the motor control device and comprises the following steps:

s100, collecting the current of a bus through the current sampling module;

s200, comparing the current with a preset current value through the signal processing module and adjusting the duty ratio of PWM;

and S300, receiving the duty ratio of the PWM output from the signal processing module through the adjusting module so as to control the running state of the motor.

Optionally, the 200, comparing the current with a preset current value and adjusting a duty ratio of PWM by the signal processing module, includes:

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.

Claims

1. A motor control apparatus, comprising: the device comprises a bus, a current sampling module (10), a voltage sampling module (20), a signal processing module (30) and an adjusting module (40);

the current sampling module (10) is electrically connected with the bus and used for collecting current on the bus, the voltage sampling module (20) is electrically connected with the bus and used for collecting voltage of the bus, the signal processing module (30) is connected with the output end of the current sampling module (10) and the output end of the voltage sampling module (20) and used for calculating instantaneous power of the current motor and comparing the instantaneous power with preset target power to adjust the duty ratio of output PWM, and the adjusting module (40) is connected with the output end of the signal processing module (30) and used for receiving the duty ratio of the PWM output by the signal processing module (30) so as to control the running state of the motor.

2. The motor control device according to claim 1, wherein the current sampling module (10) comprises a sampling resistor (11), a first filter circuit (12) and a second filter circuit (13), the sampling resistor (11) is electrically connected with the bus, one end of the sampling resistor (11) is connected with one end of the first filter circuit (12), and the other end is connected with one end of the second filter circuit (13); the other ends of the first filter circuit (12) and the second filter circuit (13) are used as the output end of the current sampling module (10), and the capacitor of the first filter circuit (12) and the capacitor of the second filter circuit (13) are in short circuit grounding.

3. The motor control device according to claim 1 or 2, characterized in that the voltage sampling module (20) comprises a voltage dropping component (21) and a third filter circuit (22), one end of the voltage dropping component (21) is connected to the live wire, the other end is connected with the third filter circuit (22) and serves as the output end of the voltage sampling module (20), and the other end of the third filter circuit (22) is grounded.

4. The motor control device according to claim 1, characterized in that the signal processing module (30) comprises a power metering chip (31), and the power metering chip (31) is used for receiving data of the current sampling module (10) and the voltage sampling module (20) to calculate preliminary power data.

5. The motor control device according to claim 4, characterized in that the signal processing module (30) further comprises a single chip microcomputer (32), and the single chip microcomputer (32) is connected with the output end of the power metering chip (31).

6. The motor control device according to claim 5, wherein the regulation module (40) includes a power switch chip and a semiconductor type field effect transistor, and the regulation module (40) is electrically connected to the motor.

7. A motor control method applied to the motor control device according to any one of claims 1 to 6, characterized by comprising:

calculating the instantaneous power of the current motor according to the voltage and the current through the signal processing module, comparing the instantaneous power with a preset target power, and adjusting the duty ratio of the output PWM;

8. The motor control method according to claim 7, wherein the current sampling module and the voltage sampling module respectively collect a current and a voltage of a bus, wherein the voltage is an alternating current voltage, and the current is an alternating current.

9. The motor control method according to claim 7, wherein the step of calculating, by the signal processing module, the instantaneous power of the motor according to the voltage and the current, and comparing the instantaneous power with a preset target power to adjust the duty ratio of the PWM comprises:

judging whether the instantaneous power meets a target power;

10. The motor control method according to claim 9, wherein in the determining whether the instantaneous power satisfies a target power,

when the instantaneous power is greater than the target power, decreasing a duty ratio of a PWM output to the motor;

increasing a duty ratio of the PWM output to the motor when the instantaneous power is less than the target power.

11. A motor control method applied to the motor control device according to any one of claims 1 to 6, characterized by comprising:

collecting the current of a bus through the current sampling module;

12. The method according to claim 11, wherein the comparing the current with a preset current value and adjusting the duty ratio of the PWM by the signal processing module comprises:

when the current is greater than the preset current value, reducing the duty ratio of PWM output to the motor;