阅读说明：本技术 一种用于电动压缩机的控制方法及控制器 (Control method and controller for electric compressor ) 是由 不公告发明人 于 2020-08-11 设计创作，主要内容包括：本发明公开了一种用于电动压缩机的控制方法及控制器,控制方法包括判断电机转速是否大于设定值,若电机转速大于设定值,则在设定的频率范围内周期性的调节载波的频率。利用本发明提出的控制方法在进行压缩机电机控制时,可以使载波频率在基准频率Fs附近规律变化,使电机逆变器输出的谐波能量分散到一定频带范围内,从而达到减小压缩机高频噪音的目的。(The invention discloses a control method and a controller for an electric compressor, wherein the control method comprises the steps of judging whether the rotating speed of a motor is greater than a set value or not, and periodically adjusting the frequency of a carrier wave in a set frequency range if the rotating speed of the motor is greater than the set value. When the control method provided by the invention is used for controlling the compressor motor, the carrier frequency can be regularly changed near the reference frequency Fs, and the harmonic energy output by the motor inverter is dispersed in a certain frequency band range, so that the aim of reducing the high-frequency noise of the compressor is fulfilled.)

1. A control method for an electric compressor is characterized by comprising the steps of judging whether the rotating speed of a motor is greater than a set value or not, periodically adjusting the frequency of a carrier wave in a set frequency range if the rotating speed of the motor is greater than the set value, and generating a driving signal for driving the compressor through the carrier wave.

2. The control method for the motor-driven compressor according to claim 1, wherein periodically adjusting the frequency of the carrier within the set frequency range includes:

configuring a frequency change factor and a carrier frequency change amount, calculating an increment value through the frequency change factor and the carrier frequency transformation amount, periodically increasing the frequency from an initial frequency value to a maximum frequency value according to the increment value, and then decreasing the frequency from the maximum frequency value to the initial frequency value,

the increment value is a product of the frequency variation factor and the carrier frequency shift amount.

3. The control method for the motor-driven compressor according to claim 2, wherein the value of the frequency variation factor is determined by a fuzzy control rule according to a phase current value.

4. The control method for the motor-driven compressor according to claim 3, wherein an allowable error maximum value and an allowable error minimum value are set,

calculating a deviation value between the current phase current value and the rated phase current value, wherein if the deviation value is larger than the maximum allowable error value, the value of the frequency change factor is 1, if the deviation value is smaller than the minimum allowable error value, the value of the frequency change factor is 0.1, and if the deviation value is between the maximum allowable error value and the minimum allowable error value, the value of the frequency change factor is determined according to a fuzzy control rule.

5. The control method for the motor-driven compressor according to claim 1, wherein periodically adjusting the frequency of the carrier within the set frequency range includes:

and configuring a frequency variation sequence, and adjusting the frequency of the carrier wave through the frequency variation sequence.

6. The control method for the motor-driven compressor according to claim 5, wherein adjusting the frequency of the carrier wave by the sequence of frequency variations includes:

adding the frequency of the carrier to the first frequency variation in the frequency variation sequence, and adding the current frequency of the carrier to the next frequency variation in the frequency variation sequence at the starting time of the next carrier period until the frequency of the carrier reaches the maximum value in the frequency range,

when the frequency of the carrier reaches the maximum value in the frequency range, subtracting the first frequency variation in the frequency variation sequence from the current frequency of the carrier, and subtracting the next frequency variation in the frequency variation sequence from the current frequency of the carrier at the starting moment of the next carrier period until the frequency of the carrier reaches the minimum value in the frequency range.

7. The control method for the motor-driven compressor as claimed in claim 6, wherein one phase current value corresponds to a set of frequency change amount sequences, and when the phase current is changed, a frequency change amount corresponding to a next carrier period is determined by a current phase current value and a current frequency value of the carrier.

8. The control method for the motor-driven compressor according to claim 1, wherein periodically adjusting the frequency of the carrier within the set frequency range includes:

and adjusting the frequency of the carrier at the starting moment of each period of the carrier.

9. The control method for the motor-driven compressor according to claim 1, wherein generating the driving signal for driving the compressor by the carrier wave includes:

and sampling the original signal according to the period of the carrier wave to generate a driving signal for driving a compressor.

10. A controller, characterized in that the controller is connected with an electric compressor, and the controller is configured to execute the control method for the electric compressor according to any one of claims 1 to 9.

Technical Field

The embodiment of the invention relates to a motor control technology, in particular to a control method and a controller for an electric compressor.

Background

The electric compressor is a heart component of an automobile air conditioning system, and the noise level of the electric compressor directly influences performance indexes of vibration, noise and the like of the whole automobile.

Electric compressor adopts no speed sensor PMSM, because there is not speed sensor, and this type of motor can't directly acquire the rotor position, also can't directly calculate the rotational speed of motor, among the prior art, in order to acquire the real-time rotor position of motor, the motor control mode of mainstream includes: a. a terminal voltage sampling method, wherein a hardware circuit is used for directly collecting the back electromotive force of the motor, and the position of a rotor of the motor is obtained through the zero crossing point position of the back electromotive force; b. and an observer method is used for reconstructing the back electromotive force and the rotating speed position of the motor by establishing an ideal model of the motor. Mature observers include a synovial observer, a full-state observer, and the like. c. And the injection method is used for injecting high-frequency voltage and current signals into the motor, estimating the actual position of the motor rotor through signal processing and controlling the motor to operate. Because of the injection method having high frequency noise, the end voltage method having torque ripple, etc., the observer method is the mainstream of the control of the non-speed permanent magnet synchronous motor at present.

When the observer method is adopted, the configuration mode of the carrier frequency influences the accuracy of rotor position identification and the high-frequency noise characteristic of the compressor motor, and how to configure the carrier frequency is an important link in the design of the compressor motor controller.

Disclosure of Invention

The invention provides a control method and a controller for an electric compressor, which aims to reduce high-frequency noise of a compressor motor.

In a first aspect, an embodiment of the present invention provides a control method for an electric compressor, including determining whether a motor rotation speed is greater than a set value, if the motor rotation speed is greater than the set value, periodically adjusting a frequency of a carrier within a set frequency range, and generating a driving signal for driving the compressor through the carrier.

In a second aspect, an embodiment of the present invention further provides a controller, configured to execute the control method for an electric compressor according to the embodiment of the present invention.

Compared with the prior art, the invention has the beneficial effects that: when the motor of the compressor is controlled, the frequency of the carrier wave is adjusted in real time, so that the frequency of the carrier wave is changed regularly within a certain range, and meanwhile, the accurate identification of the position of the motor rotor by an observer algorithm is not influenced. The harmonic energy of the harmonic current output by the inverter is dispersed in a certain frequency band range, and the peak value of the higher harmonic current power is effectively reduced, so that the high-frequency noise of the compressor motor is reduced. The control method provided by the invention is easy to realize, and has high practical value for improving the NVH (Noise, Vibration and Harshness) performance of the electric compressor in practice.

Drawings

FIG. 1 is a flowchart of a control method in an embodiment;

FIG. 2 is a waveform of a frequency spectrum of a motor phase current of a compressor using a conventional control method;

FIG. 3 is a waveform of the frequency of the phase current of the motor of the compressor employing the control method of the present application;

FIG. 4 is a flowchart of another control method in the embodiment;

fig. 5 is a block diagram of the controller in the embodiment.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

The present embodiment proposes a control method for an electric compressor, the control method including: the frequency of the carrier wave is periodically adjusted in a set frequency range, and a driving signal for driving the compressor is generated through the carrier wave.

Illustratively, in this embodiment, the driving signal is a PWM signal, and the PWM signal controls the rotation of the motor in the compressor, so as to control the refrigeration of the compressor.

For example, in this embodiment, a Sinusoidal Pulse Width Modulation (SPWM) may be used to generate the driving signal, generally, a Modulation wave in the Sinusoidal pwm technology is a sine wave, a carrier wave is a high-frequency triangular wave, and the Sinusoidal wide Pulse Modulation technology may reduce the content of high-order harmonics in the output voltage to a certain extent, so as to improve the quality of motor control. The driving signal may also be generated by referring to Space Vector Pulse Width Modulation (SVPWM), where the Modulation wave is a sine wave with third harmonic injected.

Exemplarily, in this embodiment, the frequency of the adjustment carrier is: the frequency of the control carrier wave periodically changes between the frequency minimum value and the frequency maximum value, for example, the minimum value of the carrier wave frequency is 10Khz, the maximum frequency is 11Khz, the carrier wave frequency is controlled to gradually increase from 10Khz to 11Khz, then gradually decrease from 11Khz to 10Khz, and the cycle is performed according to the rule.

For example, in this embodiment, the frequency periodicity of the control carrier may vary between the frequency minimum value and the frequency maximum value, such that the frequency of the carrier in the current period is changed at the starting time of each period of the carrier, or the frequencies of the carriers in the following periods are uniformly changed at the starting time of a certain period of the carrier.

For example, when the carrier frequency is adjusted, a fixed frequency change amount may be configured, when the carrier frequency is smaller than the maximum frequency, at the starting time of each carrier period, the frequency of the control carrier is increased by the fixed frequency, for example, by adding the current carrier frequency to the fixed frequency change amount until the maximum frequency, and when the carrier frequency reaches the maximum frequency, at the starting time of each carrier period, the frequency of the control carrier is decreased by the fixed frequency, for example, by subtracting the current carrier frequency from the fixed frequency change amount until the minimum frequency.

For example, a set of frequency variation amounts with different values may be configured, and the frequency of the control carrier is changed by a specified frequency variation amount at the start time of each carrier cycle. For example, the frequency variation amount is configured to be (K1, K2, … Kn), when the carrier frequency varies from the initial frequency and is smaller than the frequency maximum value, the frequency of the carrier is adjusted by the following equation,

f_i+1＝f_i+k_i，i＝(1、2…n)

wherein f is_iIs the current carrier frequency, f_i+1The carrier frequency corresponding to the next carrier period.

When the carrier frequency is greater than the frequency maximum, the frequency of the carrier is adjusted by the following formula until an initial carrier frequency value is reached,

f_i+1＝f_i-k_i，i＝(1、2…n)

in this embodiment, the frequency of the carrier wave is adjusted in real time, so that the carrier frequency can be regularly changed in the range of [ Fs-1kHz, Fs +1kHz ], which is close to the reference frequency Fs, and the harmonic energy of the harmonic current output by the motor inverter can be dispersed in a certain frequency band range, thereby effectively reducing the peak value of the higher harmonic current power and reducing the high-frequency noise of the compressor motor.

As an implementation, it may also be configured that the frequency variation changes randomly within a certain range, and at the start time of each carrier period, a frequency variation value is randomly generated, and the carrier frequency is changed between the frequency minimum value and the frequency maximum value in real time by overlapping the current carrier frequency with the frequency variation value.

Example two

As a preferable scheme, on the basis of the first embodiment, the control method includes:

s1, judging whether the rotating speed of the motor is greater than a set value.

And S2, if the rotating speed of the motor is greater than a set value, periodically adjusting the frequency of the carrier wave in a set frequency range.

For example, in this embodiment, if the rotation speed of the motor is less than the set value, the carrier frequency is fixed, so as to ensure the reliability of the start and low-speed operation of the compressor motor, and if the rotation speed of the motor is greater than the set value, the frequency of the carrier is periodically changed, so as to reduce the high-frequency noise of the compressor motor.

Specifically, in this step, a frequency variation factor K and a carrier frequency variation Δ f are configured, an increment value is calculated through the frequency variation factor K and the carrier frequency variation Δ f, the frequency is periodically increased from an initial frequency value to a maximum frequency value according to the increment value, and then is decreased from the maximum frequency value to the initial frequency value, wherein the increment value is a product of the frequency variation factor and the carrier frequency variation.

In the present embodiment, the frequency variation factor K is a variable value, and the carrier frequency variation Δ f is a fixed value, for example, the carrier frequency variation Δ f may be configured to be a permissible maximum value in a single carrier frequency variation.

In this embodiment, the frequency variation factor K may be determined by a fuzzy control method according to a phase current value of the compressor motor. For example, the frequency variation factor K may be determined by a one-dimensional fuzzy control method, where an input quantity of the fuzzy controller is a difference between the current phase current value and the rated phase current value, and an output quantity is a value of the frequency variation factor K.

Specifically, the process of adjusting the carrier frequency includes:

and S21, collecting the phase current value of the compressor motor, and calculating the deviation value between the current phase current value and the rated phase current value.

And S22, calculating a frequency change factor K by using the established fuzzy control table.

As an embodiment, the frequency variation factor K may be calculated by setting a maximum allowable error value Emax and a minimum allowable error value Emin.

And calculating a deviation value e between the current phase current value and the rated phase current value at each preset ADC interruption time, wherein if the deviation value e is greater than the maximum allowable error Emax, the frequency change factor K takes a value of 1. And if the deviation value e is smaller than the minimum allowable error value Emin, the frequency change factor is 0.1. And if the deviation value e is between the maximum allowable error value Emax and the minimum allowable error value Emin, determining the value of the frequency change factor according to the fuzzy control rule, wherein the value of the frequency change factor K is between 0.1 and 1.

And S23, updating the carrier frequency.

Illustratively, in this step, an increment value, i.e. K × Δ f, is first calculated according to the value of the current frequency variation factor K determined in step 3, the carrier frequency is updated at a pre-configured PWM signal interruption time, e.g. the start time of each period of the carrier, if the carrier frequency varies from the initial frequency and is less than the maximum frequency, the frequency of the carrier is updated according to the following formula,

f_i+1＝f_i+KΔf，i＝(1、2…n)

if the carrier frequency reaches the maximum frequency and the carrier frequency changes toward the initial carrier frequency value, the frequency of the carrier is adjusted by the following formula,

f_i+1＝f_i-KΔf，i＝(1、2…n)

and S3, generating a driving signal for driving the compressor through a carrier wave.

Illustratively, when the frequency of the carrier wave changes, the period of the carrier wave changes, and correspondingly, when the original signal is sampled, the sampling period changes. For example, the sinusoidal wave is sampled at the vertex positions of two triangular waves of adjacent carrier periods, and if the period of the first triangular wave is T1 and the period of the second triangular wave is T2, the sampling period is (T1+ T2)/2, and if the periods of the next adjacent triangular waves are T2 and T3, respectively, the sampling period is (T2+ T3)/2.

For example, the method for calculating the PWM waveform corresponding to the time period according to the period of each two adjacent triangular waves is the same, and taking the example of calculating the PWM waveform corresponding to the time period according to the period of the first and second triangular waves, the duty ratio of the PWM wave can be calculated by using the following formula:

in the formula, t_p1Is between the top point and the bottom point of the first triangular wave, sineTime length between intersection point of wave and triangular wave and base point of triangular wave, t_p2The time length between the bottom point and the top point of the second triangular wave and the intersection point of the sine wave and the triangular wave, T₁Is the period of the first triangular wave, T₂The period of the second triangular wave, M is the ratio of the peak value of the sine wave to the peak value of the triangular wave. Exemplarily, at t_p1And t_p2In the time period, the sine wave is located above the triangle wave, the PWM takes the high level, and in the remaining time period between the first triangle wave vertex and the second triangle wave vertex, the PWM takes the low level.

By controlling the sampling period to change along with the change of the carrier period (frequency), the waveform of the driving signal can not be seriously distorted when the carrier frequency changes, so that the effective driving of the compressor motor is ensured.

Fig. 2 is a frequency spectrum waveform diagram of the phase current of the motor of the compressor adopting the conventional control method, and fig. 3 is a frequency waveform diagram of the phase current of the motor of the compressor adopting the control method of the present application, and it can be seen from fig. 2 that when the control method of the fixed carrier frequency is adopted, the harmonic current power density of the motor of the compressor is mainly concentrated at the fixed carrier frequency and integral multiples thereof (such as 10Khz, 20Khz, 30Khz), the harmonic amplitude is large, and the electromagnetic noise interference is serious, whereas when the control method of the embodiment of the present invention is adopted, the harmonic current power density is continuously distributed in a wider frequency band interval, and the harmonic amplitude peak value is reduced because the harmonic energy is dispersed to a continuous frequency range, thereby achieving the purpose of suppressing the high-frequency noise. In this embodiment, the control method is suitable for controlling a non-speed permanent magnet synchronous motor, and in the working process of the motor, if a load changes, phase current of the motor also changes to some extent.

As an implementation, adjusting the frequency of the carrier within the set frequency range may further be:

step 1, configuring a frequency variation delta f, and adjusting the frequency of the carrier wave through the frequency variation delta f.

Illustratively, in the present embodiment, a plurality of mutually different frequency variation amounts Δ f are arranged, wherein one phase current value section corresponds to one frequency variation amount Δ f.

For example, the frequency change amount corresponding to the phase current is determined by fuzzy control, for example, the phase current of the motor is divided by intervals, and the fuzzy rule is established by taking the value section of the current of different phases as a unit.

For example, the fuzzy control rule table may be as shown in table 1:

TABLE 1

Phase current A	A>A0	A1<A<A0	A2<A<A1	A<A2
					Amount of frequency change	Minimum size	Small	Big (a)	Maximum and minimum

In the scheme, the carrier frequency can be used as input, the output voltage can be used as output, the output voltage waveform is used as a judgment basis, the fuzzy control table is obtained in a data fitting mode, and after the table is stored, when the controller works, the frequency variation corresponding to the phase current can be determined in a mode of inquiring the fuzzy control table.

For example, in the present solution, the dividing manner of the phase current intervals is not limited, and the number of the phase current intervals and the actual range of each phase current interval are determined according to the requirement.

When the carrier frequency is regulated, the interval to which the phase current belongs can be determined firstly, then the frequency variation corresponding to the interval is determined, and if the phase current is not changed, the carrier frequency is regulated and controlled by using the frequency variation all the time; if the phase current changes, the corresponding frequency change amount is determined according to the fuzzy control table, and the carrier frequency is increased or decreased by using the frequency change amount.

Specifically, after determining the required frequency variation, the manner of adjusting the frequency of the carrier wave is as follows:

at the current moment, if the carrier frequency is smaller than the maximum value of the frequency, at the starting moment of each carrier period, the frequency of the carrier is added with the selected frequency variation until the frequency of the carrier reaches the maximum value in the frequency range.

When the frequency of the carrier reaches the maximum value in the frequency range, the current frequency of the carrier is subtracted from the selected frequency variation until the frequency of the carrier reaches the minimum value in the frequency range.

And 2, sampling the original signal according to the period of the carrier wave to generate a driving signal for driving the compressor.

In the scheme, the fuzzy control strategy is adopted to adjust the numerical value of the frequency variation, when the phase current (load) of the motor is changed, the real-time change of the carrier frequency can be realized in a nonlinear adjustment mode, and then the harmonic energy output by the motor inverter is dispersed in a certain frequency band range, so that the aim of reducing the high-frequency noise of the compressor is fulfilled.

EXAMPLE III

Referring to fig. 4, as an implementable solution, on the basis of the first embodiment, the frequency of the carrier wave adjusted in the set frequency range may be:

s100, configuring a frequency variation sequence, and adjusting the frequency of the carrier wave through the frequency variation sequence.

Specifically, the configured frequency variation sequence includes a configured base point value and an inflection point value, and the value of each frequency variation in the frequency variation sequence is that a first frequency variation is configured as the base point value, increases to the inflection point value according to a fixed increment value from the beginning of the first frequency variation, and then decreases to the base point value according to the increment value.

Illustratively, the frequency variation in the frequency variation sequence is symmetric about the inflection point, for example, if the base point value is configured as 1, the increment value is configured as 2, and the inflection point value is configured as 5, the frequency variation sequence is (1, 3, 5, 3, 1).

Illustratively, the way of adjusting the frequency of the carrier by the sequence of frequency variations is:

and the starting time is the time when the frequency of the carrier wave is added to the first frequency variation in the frequency variation sequence, and the starting time of the next carrier wave period is the time when the current frequency of the carrier wave is added to the next frequency variation in the frequency variation sequence until the frequency of the carrier wave reaches the maximum value in the frequency range.

When the frequency of the carrier reaches the maximum value in the frequency range, the current frequency of the carrier is subtracted from the first frequency variation in the frequency variation sequence, and the current frequency of the carrier is subtracted from the next frequency variation in the frequency variation sequence at the starting moment of the next carrier period until the frequency of the carrier reaches the minimum value in the frequency range.

For example, if the carrier frequency is expected to rise from the minimum frequency value to the maximum frequency value quickly, the length of the frequency variation sequence is relatively short, and the inflection point value is relatively large, and if the carrier frequency is expected to rise from the minimum frequency value to the maximum frequency value slowly, the length of the frequency variation sequence is relatively long, and the inflection point value is relatively small.

Taking the process of changing from the minimum value of the carrier frequency to the maximum value of the carrier frequency as an example, when the frequency of the carrier wave is adjusted by the sequence of frequency variations, one or more groups of sequences of frequency variations may be used. When a group of frequency variation sequences is adopted, after the carrier frequency is added with the last frequency variation in the frequency variation sequences, the obtained frequency value is the maximum value of the carrier frequency; after the carrier frequency is added to the last frequency variation in a group of frequency variation sequences, if the obtained frequency value is still smaller than the maximum frequency value, the process of overlapping the carrier frequency with the frequency variation sequences is repeated, that is, the current frequency of the carrier is added to the first frequency variation in the next group of frequency variation sequences, and the current frequency of the carrier is added to the next frequency variation in the frequency variation sequences at the starting time of the next carrier period until the frequency of the carrier reaches the maximum value in the frequency range. When a plurality of sets of frequency variation sequences are used, the superposition process may be stopped when the frequency reaches the maximum value, that is, before the frequency of the carrier reaches the maximum value in the frequency range, the last frequency variation value to be superposed may not be the last frequency variation in the set of frequency variation sequences.

The process of changing the carrier frequency from the maximum value to the minimum frequency value is similar to the process of changing the carrier frequency from the minimum value to the maximum frequency value, except that the carrier frequency is changed from the minimum value to the maximum frequency value by adding the current frequency of the carrier to the frequency change amount in the frequency change amount sequence, and the carrier frequency is changed from the maximum value to the minimum frequency value by subtracting the current frequency of the carrier from the frequency change amount in the frequency change amount sequence.

And S200, sampling the original signal according to the period of the carrier wave to generate a driving signal for driving the compressor.

In the embodiment, the frequency of the carrier wave is adjusted in real time through the frequency variation sequence, so that the carrier frequency is regularly changed within a certain range, and meanwhile, the accurate identification of the observer algorithm on the position of the motor rotor is not influenced. The harmonic energy of the harmonic current output by the inverter is dispersed in a certain frequency band range, and the peak value of the higher harmonic current power is effectively reduced, so that the high-frequency noise of the compressor motor is reduced.

Example four

As an alternative, on the basis of the first and third embodiments, in this embodiment, the frequency of the carrier wave adjusted in the set frequency range may be:

step 1, configuring a frequency variation sequence, and adjusting the frequency of the carrier wave through the frequency variation sequence.

As an alternative, in the present embodiment, a plurality of sets of mutually different frequency variation sequences are configured, wherein one phase current value corresponds to one set of frequency variation sequences.

In this embodiment, the control method is particularly suitable for controlling a non-speed permanent magnet synchronous motor, and in the working process of the motor, if a load changes, phase current of the motor also changes to some extent. For example, the structure of the frequency variation sequences corresponding to different phase currents is not changed, and the base point value, the increment value and the inflection point value in each frequency variation sequence are different from each other, for example, when the phase current is 1A, the frequency variation sequence is (1, 2, 3, 4, 5, 4, 3, 2, 1), and when the phase current is 2A, the frequency variation sequence is (1, 1.5, 2, 2.5, 3, 2.5, 2, 1.5, 1).

For example, in the present embodiment, when the phase current changes, the frequency change amount corresponding to the next carrier cycle is determined according to the current phase current value and the current frequency value of the carrier.

Specifically, the frequency variation sequence corresponding to the phase current may be obtained in a calibration manner, including determining a reference point value, an inflection point value, and an incremental value in the frequency variation sequence. For example, when calibration is performed, the values of the reference point value, the inflection point value, and the increment value are determined by the waveform of the generated driving signal, for example, when calibration test is performed, when the waveform of the driving signal is close to a sine wave, the data taken by the reference point value, the inflection point value, and the increment value is considered to be more effective. After calibration is completed, a MAP of the phase current, the carrier frequency, and the frequency variation may be generated using the frequency variations in the sequence of frequency variations, and the frequency variation corresponding to the phase current may be determined from the MAP.

When the carrier frequency is regulated, a corresponding frequency variation sequence can be determined according to the phase current value, and if the phase current does not change, the carrier frequency is regulated and controlled by using the frequency variation sequence all the time; if the phase current changes, a corresponding frequency variation sequence is determined according to the phase current value, then a frequency variation corresponding to the current carrier frequency in the frequency variation sequence is inquired through a MAP (MAP) MAP, and when the carrier frequency is regulated, the frequency is increased or decreased from the frequency variation.

Specifically, after determining the frequency variation corresponding to the next carrier period, the manner of adjusting the frequency of the carrier is as follows:

at the current moment, if the carrier frequency is smaller than the maximum value of the frequency, adding the frequency variation selected by the carrier frequency in the selected frequency variation sequence, and adding the current frequency of the carrier to the next frequency variation in the frequency variation sequence at the starting moment of the next carrier period until the frequency of the carrier reaches the maximum value in the frequency range.

When the frequency of the carrier reaches the maximum value in the frequency range, the current frequency of the carrier is subtracted from the first frequency variation in the frequency variation sequence, and the current frequency of the carrier is subtracted from the next frequency variation in the frequency variation sequence at the starting moment of the next carrier period until the frequency of the carrier reaches the minimum value in the frequency range.

Taking a process of changing from a minimum value of a carrier frequency to a maximum value of the frequency as an example, when the frequency of the carrier is adjusted by the frequency change amount sequence under a certain phase current value, a plurality of sets of frequency change amount sequences with the same characteristics (including a base value, an inflection point value, and an increment value) may be adopted, and after the carrier frequency is added to a last frequency change amount in a set of frequency change amount sequences, if an obtained frequency value is still smaller than the maximum value of the frequency, the process of superimposing the carrier frequency and the frequency change amount sequence is repeated, that is, the current frequency of the carrier is added to a first frequency change amount in a next set of frequency change amount sequences, and the start time of a next carrier period is added to a next frequency change amount in the frequency change amount sequence by the current frequency of the carrier. When a plurality of groups of frequency variation sequences with the same characteristics are adopted, the superposition process can be stopped when the frequency reaches the maximum value.

The process of changing the carrier frequency from the maximum value to the minimum frequency value is similar to the process of changing the carrier frequency from the minimum value to the maximum frequency value, except that the carrier frequency is changed from the minimum value to the maximum frequency value by adding the current frequency of the carrier to the frequency change amount in the frequency change amount sequence, and the carrier frequency is changed from the maximum value to the minimum frequency value by subtracting the current frequency of the carrier from the frequency change amount in the frequency change amount sequence.

Alternatively, in this step, one phase current value corresponds to a set of frequency variation sequences, and when the phase current is varied, the required frequency variation sequence is determined by the current phase current value. For example, the frequency variation sequence corresponding to the phase current may be obtained in a calibration manner. When the carrier frequency is adjusted and controlled, a corresponding frequency variation sequence may be first determined according to the phase current value, if the phase current does not change, the carrier frequency is always adjusted and controlled by using the frequency variation sequence, if the phase current changes, the corresponding frequency variation sequence is determined according to the phase current value, and the frequency is increased or decreased from the first frequency variation of the frequency variation sequence.

And 2, sampling the original signal according to the period of the carrier wave to generate a driving signal for driving the compressor.

In this step, the manner of generating the driving signal is the same as that described in the second embodiment, and is not described herein again.

In this embodiment, the phase current is a current flowing through each phase of load of the compressor motor, and when the phase current changes, the adopted frequency variation sequence also changes correspondingly, so as to ensure that the harmonic energy of the harmonic current can be effectively dispersed in a certain frequency band range.

EXAMPLE five

The present embodiment proposes a controller, fig. 5 is a structural block diagram of the controller in the embodiment, and referring to fig. 5, the controller includes a carrier generation module 100 and a driving signal generation module 200, the carrier generation module 100 is configured to adjust a frequency of a carrier within a set frequency range, and the driving signal generation module 200 generates a driving signal for driving a compressor through the carrier.

As an implementation, the carrier generation module 100 is configured with a frequency variation factor and a carrier frequency variation, and the carrier generation module 100 calculates an increment value according to the frequency variation factor and the carrier frequency variation, periodically increases the frequency from an initial frequency value to a maximum frequency value according to the increment value, and then decreases the frequency from the maximum frequency value to the initial frequency value.

As an implementation, the carrier generation module 100 is configured with a frequency variation sequence, and the carrier generation module 100 adjusts the frequency of the carrier by the frequency variation sequence. The frequency variation sequence comprises a configured base point value and an inflection point value, wherein the value of each frequency variation in the frequency variation sequence is that a first frequency variation is configured as the base point value, the first frequency variation is increased to the inflection point value according to a fixed increment value from the beginning of the first frequency variation, and then the first frequency variation is reduced to the base point value according to the increment value.

As an implementation, the carrier generation module 100 adjusts the frequency of the carrier by the sequence of frequency variations includes:

the starting time is obtained by adding the frequency of the carrier to the first frequency variation in the frequency variation sequence, and the starting time of the next carrier period is obtained by adding the current frequency of the carrier to the next frequency variation in the frequency variation sequence until the frequency of the carrier reaches the maximum value in the frequency range,

when the frequency of the carrier reaches the maximum value in the frequency range, the current frequency of the carrier is subtracted from the first frequency variation in the frequency variation sequence, and the current frequency of the carrier is subtracted from the next frequency variation in the frequency variation sequence at the starting moment of the next carrier period until the frequency of the carrier reaches the minimum value in the frequency range.

As an implementation, the controller stores a set of frequency variation sequences, wherein one phase current value corresponds to one set of frequency variation sequences, and when the phase current varies, the carrier generation module 100 determines the frequency variation corresponding to the next carrier period according to the current phase current value and the current frequency value of the carrier.

As an implementation, the controller further stores a MAP, and the carrier generation module 100 determines a reference point value, an inflection point value, and an increment value in the frequency variation sequence corresponding to the phase current, and adjusts the frequency of the carrier by the frequency variation sequence.

In one embodiment, the controller stores a fuzzy control table, determines the frequency variation corresponding to the phase current by querying the fuzzy control table, and adjusts the frequency of the carrier wave by the frequency variation.

As one possible implementation, the driving signal generating module 200 is configured to sample the original signal according to the period of the carrier to generate the driving signal for driving the compressor.

In this embodiment, the specific execution method of the controller is the same as the content described in the above embodiments, and the beneficial effects are also the same, and the detailed execution method is not described again.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.