Disclosure of Invention
The invention solves the problems that in the prior art, the condition that the PWM waveform is low in a continuous 120-degree mode easily occurs in the conventional 5-segment SVPWM modulation mode, a power device is closed during the period, and chopping is not carried out on input voltage, so that the harmonic content of the output voltage is high, the upper bridge arm and the lower bridge arm generate different heat, and the speed regulation performance of a fan and the service life of an IPM are influenced.
In order to solve the problems, the invention provides a direct current fan control method, which comprises the steps of dividing an electric cycle into 6 sectors, namely an I sector, an II sector, an III sector, an IV sector, a V sector and a VI sector, dividing each sector into n subsectors, controlling output waveforms according to different zero vectors inserted into adjacent subsectors, and splicing the output waveforms of the subsectors to form the output waveform of the electric cycle.
Different PWM waveforms are generated in the control sub-sector with zero vector, the situation that the continuous 120-degree output is 0 in the SVPWM waveform can be effectively prevented, the harmonic content in the output voltage is greatly reduced, and the speed regulation performance of the fan and the service life of the IPM are ensured.
Further, the adjacent sub-sectors refer to sub-sectors within one of the I, II, III, IV, V, and VI sectors, and/or sub-sectors between two adjacent sectors.
The arrangement of the embodiment helps to avoid outputting the same type of PWM waveforms between adjacent sub-sectors, thereby further avoiding the phenomenon that the large-angle continuous output is 0.
Further, n is 2, and there are 12 sub-sectors, which are respectively the Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb, Va, Vb, VIa, and VIb sectors.
According to the setting, the original 6 sectors are divided into 12 sectors, each sector is 30 degrees, and due to the fact that zero vectors inserted between adjacent sub-sectors are different, output waveforms between the adjacent sub-sectors are different, the phenomenon that large-angle continuous output is 0 is avoided, the speed regulation performance of the fan is effectively improved, and the service life of the IPM is effectively prolonged.
Further, zero vectors 0 are inserted into the Ia, IIa, IIIa, IVa, Va and VIa sectors, and zero vectors 7 are inserted into the Ib, IIb, IIIb, IVb, Vb and VIb sectors.
In the above technical solution, the output condition of each sub-sector level is as follows: positive, high, positive, low, positive, and high, it can be seen that, in this process, there is no case that the continuous output level of the adjacent sub-sectors is high or low, because each sub-sector is 30 °, in this technical scheme, the angle of continuously outputting the low level or the high level is 30 ° which is far lower than the angle of continuously outputting the low level or the high level in the prior art, and the harmonic content of the output voltage can be significantly reduced, wherein "positive" means outputting a normal PWM waveform, high "means outputting the high level, low" means outputting the low level, and the normal PWM waveform means outputting the high level or the low level in one carrier frequency period, specifically, in an electrical period divided into 12 sectors, outputting both the high level and the low level in one carrier frequency period of 30 ° of the sub-sectors.
Further, zero vectors 7 are inserted into the Ia, IIa, IIIa, IVa, Va and VIa sectors, and zero vectors 0 are inserted into the Ib, IIb, IIIb, IVb, Vb and VIb sectors.
In the above technical solution, the output condition of each sub-sector level is as follows: high, positive, low, positive, high and positive, it can be seen that, in the process, the continuous output level of the adjacent sub-sectors is not high, and because each sub-sector is 30 °, in the technical scheme, the angle for continuously outputting the low level or the high level is 30 ° which is far lower than the angle for continuously outputting the low level or the high level in the prior art, and the harmonic content of the output voltage can be remarkably reduced.
Further, zero vectors 0 are inserted into the Ia, IIb, IIIa, IVb, Va and VIb sectors, and zero vectors 7 are inserted into the Ib, IIa, IIIb, IVa, Vb and VIa sectors.
In the above technical solution, the output condition of each sub-sector level is as follows: just, high, just, low, just, high, just, can see that, do not have the continuous output level of adjacent sub-sector in this process and be the condition of high or be low, because each sub-sector is 30 degrees, therefore in this technical scheme, the angle of continuous output low level or high level is 30 degrees, is far less than the angle of continuous output low level, high level among the prior art, can show that reduce the harmonic content of output voltage, make harmonic content in the output voltage reduce by a wide margin, improve the wave form sine degree, upper and lower bridge arm heats more evenly, can show that improve the speed governing performance of fan and the life of IPM.
Further, zero vectors 7 are inserted into the Ia, IIb, IIIa, IVb, Va and VIb sectors, and zero vectors 0 are inserted into the Ib, IIa, IIIb, IVa, Vb and VIa sectors.
In the above technical solution, the output condition of each sub-sector level is as follows: high, positive, low, positive, and high, it can be seen that although there are cases where the output level of 2 consecutive sub-sectors is high or low in this process, since each sub-sector is 30 °, in this technical solution, the angle of the consecutive high level or low level is 60 ° which is lower than the angle of the consecutive low level or high level when all 6 sectors are constant high or all are constant low in the prior art, and the harmonic content of the output voltage can be reduced more effectively.
The invention also discloses a direct current fan control device, which comprises: the device comprises a region dividing module, a data processing module and a data processing module, wherein the region dividing module is used for dividing 6 fan-shaped regions and dividing sub-sectors in each fan-shaped region; the time acquisition module is used for acting time of the zero vector and the non-zero vector in each sub-sector; and the modulation module is used for carrying out pulse width modulation on the corresponding sub-sectors.
Through the cooperation of the modules, when the direct current fan runs, the continuous output angle of low level is greatly reduced, the harmonic content in output voltage is further reduced, the sine degree of the waveform is improved, the heating of the upper bridge arm and the lower bridge arm is more uniform, the speed regulation performance of the fan can be obviously improved, and the service life of the IPM is prolonged.
The invention also discloses an air conditioner, which comprises a computer readable storage medium and a processor, wherein the computer readable storage medium is used for storing a computer program, and the computer program is read by the processor and runs to realize the direct current fan control method.
Compared with the prior art, the air conditioner and the direct current fan control method have the same advantages, and are not repeated herein.
The invention also discloses a computer readable storage medium, which stores a computer program, and when the computer program is read and operated by a processor, the direct current fan control method is realized.
Compared with the prior art, the direct current fan control method, the direct current fan control device, the air conditioner and the computer readable storage medium have the following advantages:
in the invention, the moment when the PWM is constantly low or constantly high is divided equally into an electric cycle by dividing the original 6 fan-shaped areas and inserting the difference of zero vectors between the adjacent sub-sectors, so that the action time of the PWM which is continuously high or continuously low is reduced, a higher power factor can be ensured, and the harmonic content is reduced; meanwhile, the heat bearing of the upper and lower bridge walls of the IPM is uniform, the service life of the IPM is prolonged, the control method provided by the invention is simple to operate and has an obvious effect, the harmonic content is greatly reduced on the basis of not increasing the hardware cost, and the service life of the IPM is prolonged.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 10, the main loop of the SVPWM topology is composed of three arms (six power switching elements), upper and lower switching devices of each arm cannot be turned on simultaneously, the six switching elements are combined to have 8 switching states, the state of the upper arm when turned on is defined as 1, the state of the lower arm when turned on is defined as 0, the switching states of the three arms can form 8 switching modes of 000, 001, 010, 011, 100, 101, 110 and 111, wherein the two switching states of 000 and 111 do not generate effective current in the fan driving, so that the three switching states are called zero vectors, which are respectively zero vector 0(000) and zero vector 7(111), and the other 6 switching states are six effective vectors, which are respectively V1(001), V2(010), V3(011), V4(100), V5(101) and V6(110), and approach to a voltage circle by using 6 effective vectors and 2 zero vectors, so that an equivalent three-phase SVPWM waveform can be obtained, thereby approximating the input current as a sine wave.
The following describes a dc fan control method, an apparatus, an air conditioner, and a computer-readable storage medium according to embodiments of the present invention with reference to the accompanying drawings.
Example 1
The embodiment provides a method for controlling a direct current fan, as shown in fig. 8, an electrical cycle is divided into 6 sectors, which are an I-th sector, an II-th sector, an III-th sector, an IV-th sector, a V-th sector, and a VI-th sector, each sector is divided into n sub-sectors, n is greater than or equal to 2, different zero-vector control output waveforms are inserted into adjacent sub-sectors, and the output waveforms of the sub-sectors are spliced to form an output waveform of the electrical cycle. In the prior art, as shown in fig. 3 and 5, a constant-low control mode is adopted to enable continuous 120-degree output to be 0 in an SVPWM waveform, and in a time period when the SVPWM waveform is output to 0, an intelligent power module is in a closed state, and no chopping is performed on input voltage, which results in large harmonic content in output voltage, different heating of upper and lower bridge arms, and further influences the speed regulation performance of a fan and the service life of an IPM.
Preferably, the adjacent sub-sectors in this embodiment refer to sub-sectors within one of the I-th sector, the II-th sector, the III-th sector, the IV-th sector, the V-th sector, and the VI-th sector, and/or sub-sectors between two adjacent sectors. In the prior art, all of 6 sectors are of a constant low type or all of the constant high type, or the constant high and constant low type is set at intervals, fig. 6 shows that when all of 6 sectors are of the constant low type, an A, B, C three-phase output waveform of each sector is formed by modulation, the PWM waveforms in fig. 3 and fig. 9(a) are formed, and the output conditions are according to the level of 6 sectors: the normal PWM waveform is that the high level and the low level are output in a carrier frequency period, and the high level or the low level is not continuously output in a sector 60 DEG in an electrical period which divides an electrical period into 6 sectorsIn the case of continuous low level, in which 2 continuous sectors output low level in total of 120 °, fig. 7 shows an output waveform of A, B, C three phases for each sector when 6 sectors are all of constant high type, the PWM waveform in fig. 5 and fig. 9(b) is formed by modulation, and the output condition is as follows according to the level of 6 sectors: sector I outputs high level, sector II outputs normal PWM waveform, sector III outputs normal PWM waveform, sector IV outputs normal PWM waveform, sector V outputs normal PWM waveform, sector VI outputs high level, wherein, continuous 2 sectors appear in sector I, VI and total 120 DEG output is high level, the application does not provide output waveform with interval setting constant high and constant low type in the figure, actually, when constant low, constant high, constant low and constant high are set in sequence according to the sequence of sector I-VI, the output condition according to 6 sectors is: the first sector outputs normal PWM waveform, the second sector outputs normal PWM waveform, the third sector outputs low level, the fourth sector outputs normal PWM waveform, the V sector outputs normal PWM waveform, the VI sector outputs high level, wherein, the conditions of continuously outputting low level by 60 degrees and continuously outputting high level by 60 degrees exist, when constant high, constant low, constant high and constant low are set in sequence according to the sequence of the first-VI sectors, the output conditions of the levels according to 6 sectors are: the first sector outputs a high level, the second sector outputs a normal PWM waveform, the third sector outputs a normal PWM waveform, the fourth sector outputs a low level, the fifth sector outputs a normal PWM waveform, and the VI sector outputs a normal PWM waveform, and there are also situations where a low level is continuously output for 60 degrees and a high level is continuously output for 60 degrees, which is helpful to avoid outputting the same type of PWM waveforms between adjacent sub-sectors through the arrangement of the present embodiment, thereby further avoiding the phenomenon that a large angle continuous output is 00Denotes the action time, T, of the zero vector 0(000) in the current sector1Represents the action time, T, of the V1(001) vector in the current sector2Representing the action time, T, of the V2(010) vector in the current sector3Indicating in the current sectorAction time, T, of vector V3(011)4Represents the action time, T, of the V4(100) vector in the current sector5Represents the action time, T, of the V5(101) vector in the current sector6Represents the action time, T, of the V6(110) vector in the current sector7Represents the action time of zero vector 7(111) in the current sector, Ts represents the operation period of the current sector, Sa represents the output waveform of phase A in the current sector, Sb represents the output waveform of phase B in the current sector, Sc represents the output waveform of phase C in the current sector, T in FIGS. 2 and 4fana、Tfanb、TfancFor convenience of description, when the level output condition is described later, the normal PWM waveform is referred to as positive, the high level is referred to as high, and the low level is referred to as low.
Specifically, in this embodiment, as shown in fig. 8, n is 2, and there are 12 sub-sectors, which are respectively the Ia th sector, the Ib th sector, the IIa th sector, the IIb th sector, the IIIa th sector, the IIIb th sector, the IVa th sector, the IVb th sector, the Va th sector, the Vb th sector, the VIa th sector, and the VIb th sector. According to the setting, the original 6 sectors are divided into 12 sectors, each sector is 30 degrees, and due to the fact that zero vectors inserted between adjacent sub-sectors are different, output waveforms between the adjacent sub-sectors are different, the phenomenon that large-angle continuous output is 0 is avoided, the speed regulation performance of the fan is effectively improved, and the service life of the IPM is effectively prolonged.
Specifically, in this embodiment, a zero vector 0 is inserted into the Ia, IIa, IIIa, IVa, Va, and VIa sectors, and a zero vector 7 is inserted into the Ib, IIb, IIIb, IVb, Vb, and VIb sectors. In this technical solution, in the prior art, the zero vectors of the sub-sectors within any one of the 6 sectors are different, the zero vectors of the sub-sectors between two adjacent sectors are also different, the Ia, IIa, IIIa, IVa, Va, and VIa sectors are of a constant low type, the Ib, IIb, IIIb, IVb, Vb, and VIb sectors are of a constant high type, and the PWM waveforms generated by the above technical solution are controlled as shown in fig. 9(c), and the output waveforms are spliced in an alternating order of constant low and constant high according to the order of the 12 sub-sectors, and the level output condition is: positive, high, positive, low, positive, high, it can be seen that, in this process, there is no situation that the continuous output level of the adjacent sub-sectors is high or low, and since each sub-sector is 30 °, in this technical scheme, the angle of continuously outputting the low level or the high level is 30 °, which is far lower than the angle of continuously outputting the low level or the high level in the prior art, and the harmonic content of the output voltage can be significantly reduced.
In another embodiment of the present invention, zero vectors 7 are inserted into the Ia, IIa, IIIa, IVa, Va and VIa sectors, and zero vectors 0 are inserted into the Ib, IIb, IIIb, IVb, Vb and VIa sectors. In this technical solution, in the prior art, zero vectors of sub-sectors inside any one of 6 sectors are different, zero vectors of sub-sectors between two adjacent sectors are also different, the Ia, IIa, IIIa, IVa, Va, and VIa sectors are of a constant high type, the Ib, IIb, IIIb, IVb, Vb, and VIb sectors are of a constant low type, and waveforms output by the sub-sectors are spliced according to an order of the 12 sub-sectors according to an alternating order of constant high and constant low to obtain a level output order of each sub-sector: high, positive, low, positive, high and positive, it can be seen that, in the process, the continuous output level of the adjacent sub-sectors is not high, and because each sub-sector is 30 °, in the technical scheme, the angle for continuously outputting the low level or the high level is 30 ° which is far lower than the angle for continuously outputting the low level or the high level in the prior art, and the harmonic content of the output voltage can be remarkably reduced.
As an embodiment, zero vector 0 is inserted into the Ia, IIb, IIIa, IVb, Va and VIb sectors, and zero vector 7 is inserted into the Ib, IIa, IIIb, IVa, Vb and VIa sectors. In this technical solution, in the prior art, the zero vectors of the sub-sectors in any one of the 6 sectors are different, the zero vectors of the sub-sectors between two adjacent sectors are the same, the Ia, IIb, IIIa, IVb, Va, and VIb sectors are of a constant low type, the Ib, IIa, IIIb, IVa, Vb, and VIa sectors are of a constant high type, and the waveforms output by the sub-sectors are spliced according to the sequence of the 12 sub-sectors to obtain the level output sequence of each sub-sector: just, high, just, low, just, high, just, can see that, do not have the continuous output level of adjacent sub-sector in this process and be the condition of high or be low, because each sub-sector is 30 degrees, therefore in this technical scheme, the angle of continuous output low level or high level is 30 degrees, is far less than the angle of continuous output low level, high level among the prior art, can show that reduce the harmonic content of output voltage, make harmonic content in the output voltage reduce by a wide margin, improve the wave form sine degree, upper and lower bridge arm heats more evenly, can show that improve the speed governing performance of fan and the life of IPM.
In another embodiment, zero vector 7 is inserted into the Ia, IIb, IIIa, IVb, Va and VIb sectors, and zero vector 0 is inserted into the Ib, IIa, IIIb, IVa, Vb and VIa sectors. In this technical solution, in the prior art, the zero vectors of the sub-sectors in any one of the 6 sectors are different, the zero vectors of the sub-sectors between two adjacent sectors are the same, the Ia, IIb, IIIa, IVb, Va, and VIb sectors are of a constant high type, the Ib, IIa, IIIb, IVa, Vb, and VIa sectors are of a constant low type, and the waveforms output by the sub-sectors are spliced according to the sequence of the 12 sub-sectors to obtain the level output sequence of each sub-sector: high, positive, low, positive, and high, it can be seen that although there are cases where the output level of 2 consecutive sub-sectors is high or low in this process, since each sub-sector is 30 °, in this technical solution, the angle of the consecutive high level or low level is 60 ° which is lower than the angle of the consecutive low level or high level when all 6 sectors are constant high or all are constant low in the prior art, and the harmonic content of the output voltage can be reduced more effectively.
Specifically, the carrier of the direct current fan is a triangular wave, and the PWM wave generated in each carrier period is symmetrical about a vertex of the triangular wave. This arrangement is used to implement 5-segment control of the SVPWM.
In the above embodiment, the control method when n is 2 is mainly recited, and in fact, when n > 2, for example, n is 3, n is 4, n is 5, and the like, the control may be performed based on the control method provided in the above technical solution, and a good control effect may be obtained as well.
Specifically, in the present invention, the implementation of the control method does not require improvement of a hardware topology structure in the prior art, and the PWM pulse generated by the control method controls on and off of the IPM, and generates a corresponding voltage to control the dc fan.
Example 2
The embodiment discloses a direct current fan control device, which is used for realizing the direct current fan control method in the embodiment 1.
The direct current fan control device includes:
the device comprises a region dividing module, a data processing module and a data processing module, wherein the region dividing module is used for dividing 6 fan-shaped regions and dividing sub-sectors in each fan-shaped region;
the time acquisition module is used for acting time of the zero vector and the non-zero vector in each sub-sector;
and the modulation module is used for carrying out pulse width modulation on the corresponding sub-sectors.
Through the cooperation of the modules, when the direct current fan runs, the continuous output angle of low level is greatly reduced, the harmonic content in output voltage is further reduced, the sine degree of the waveform is improved, the heating of the upper bridge arm and the lower bridge arm is more uniform, the speed regulation performance of the fan can be obviously improved, and the service life of the IPM is prolonged.
Example 3
The embodiment discloses an air conditioner, which comprises the direct current fan control device in the embodiment 2.
The air conditioner disclosed in the present embodiment includes a computer readable storage medium storing a computer program and a processor, and when the computer program is read and executed by the processor, the method for controlling the direct current fan according to embodiment 1 is implemented.
Compared with the prior art, the air conditioner and the direct current fan control method in embodiment 1 have the same advantages, and are not described again here.
Example 4
The embodiment discloses a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is read and executed by a processor, the method for controlling a direct current fan according to embodiment 1 is implemented.
Although the present invention is disclosed above, the present invention is not limited thereto. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.