CN104038030A - A method, device and system for controlling bus ripple - Google Patents

Abstract

The embodiment of the invention discloses a method, a device and a system for controlling bus ripples. The method provided by the embodiment of the invention comprises the following steps: obtaining a first feedforward current according to the rectification input voltage, the inversion output voltage and the inversion output current, then carrying out coordinate transformation on the first feedforward current to obtain a second feedforward current, then carrying out rectification control on the second feedforward current to obtain a first feedforward voltage, and carrying out coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage; and finally, modulating the second feedforward voltage to generate a pulse signal, and inputting the pulse signal into the rectifier. According to the embodiment of the invention, the power consumed by the power units such as the inverter and the like is directly fed forward to the rectifier, so that the bus ripple can be effectively reduced, and the control efficiency of the bus ripple is improved.

Description

A method, device and system for controlling bus ripple

technical field

The invention relates to the communication field, in particular to a method, device and system for controlling bus ripple.

Background technique

Uninterruptible power supply (UPS, Uninterruptible Power System) system can provide stable and uninterrupted power supply for power electronic equipment, because it can effectively deal with power failure, continuous undervoltage and continuous overvoltage and other abnormal conditions, it is widely used in power supply in various fields middle. The voltage stabilization function of the UPS system is usually completed by the rectifier, and the frequency stabilization is completed by the inverter.

Among them, the rectifier provides a stable DC voltage to the inverter and other power units. When the inverter is unbalanced, the bus capacitor voltage will have voltage fluctuations that are consistent with the output voltage frequency (for example, 50hz or 60hz), that is, there are busbar ripples. Wave. When the bus ripple is too large, it will affect the quality of the output voltage, and the life of the filter capacitor itself will also be reduced.

In the prior art, in order to reduce bus ripple, a balance circuit is added to the bus. Please refer to FIG. 1 for details. FIG. 1 is a schematic circuit diagram of a UPS system. Shown in the dotted box in Figure 1 is the balancing circuit used in the UPS. When the inverter has an unbalanced load, such as a single-phase 50hz load, the positive bus voltage VbusP and the negative bus voltage VbusN will have a 50hz ripple. In the negative half cycle of the output current, VbusP is larger and VbusN is smaller. When VbusP is greater than a certain threshold, the switching device PWM4A is turned on, and the positive bus capacitance is discharged through PWM4A and inductor L, which causes VbusP to decrease and VbusN to increase, thereby reducing the busbar ripple. On the contrary, when VbusN is less than a certain threshold, the switching device PWM4B is turned on, and the negative bus capacitance is discharged through PWM4B and inductor L, which causes VbusP to decrease and VbusN to increase, thereby reducing the bus ripple.

In the prior art, there must be at least two switching devices (PWM4A and PWM4B in Figure 1), and at least one inductor L, these devices will increase hardware cost and volume, and adding a balancing circuit on the bus will bring switching loss and inductance Iron consumption, loss of efficiency of the whole machine.

Contents of the invention

Embodiments of the present invention provide a method, device and system for controlling bus ripple, which can effectively reduce bus ripple and improve bus ripple control efficiency.

In a first aspect, the present invention provides a method for controlling bus ripple, which may include:

Obtain rectified input voltage, inverter output voltage and inverter output current;

obtaining a first feedforward current according to the obtained rectified input voltage, inverter output voltage, and inverter output current;

performing coordinate transformation on the first feedforward current to obtain a second feedforward current;

performing rectification control by using the second feedforward current to obtain the first feedforward voltage;

performing coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage;

The second feed-forward voltage is modulated to generate a pulse signal, and the pulse signal is input to the rectifier to control the voltage of the bus capacitor.

In the first possible implementation manner of the first aspect, the second feedforward current includes: D-axis, Q-axis and Z-axis feedforward current values, and the first feedforward voltage includes: D-axis, Q-axis and Z-axis Feedforward voltage value; wherein, the second feedforward current is used for rectification control to obtain the first feedforward voltage, which specifically includes: using the D-axis feedforward current value of the second feedforward current on the D axis to perform bus voltage Control to obtain the feedforward voltage value of the D axis; use the current value of the Q axis feedforward in the second feedforward current on the Q axis to perform reactive current control to obtain the voltage value of the Q axis feedforward; use The Z-axis feed-forward current value in the second feed-forward current is subjected to bus difference control to obtain the Z-axis feed-forward voltage value.

In a second possible implementation manner of the first aspect, the second feedforward current includes: the current value of the Z-axis feedforward, and the first feedforward voltage includes: the voltage value of the Z-axis feedforward; wherein, the second feedforward The feed current is rectified and controlled to obtain the first feed-forward voltage, which specifically includes: using the Z-axis feed-forward current value in the second feed-forward current to perform bus difference control on the Z-axis to obtain the Z-axis feed-forward voltage value.

In combination with the first possible implementation of the first aspect, in the third possible implementation, before the step of using the second feed-forward current to perform rectification control, it also includes: obtaining the rectified input current, coordinate the rectified input current Transformation to obtain the rectified input current of the D-axis, Q-axis and Z-axis; coordinate transformation of the rectified input voltage to obtain the rectified input voltage of the D-axis, Q-axis and Z-axis, wherein the rectified input current includes: A phase, B phase and C-phase rectified input current, rectified input voltage includes: A-phase, B-phase and C-phase rectified input voltage;

Correspondingly, on the D axis, the current value of the D axis feedforward in the second feedforward current is used to control the bus voltage, and the voltage value of the D axis feedforward is obtained, which specifically includes: the preset bus voltage value and the current bus voltage value Do subtraction to obtain the bus voltage difference, and adjust the bus voltage difference to obtain the first input current; superimpose the first input current and the D-axis feedforward current value to obtain the first reference current; input the first reference current The D-axis current loop makes the first reference current subtract the D-axis rectified input current to obtain the first output current, and adjusts the first output current to obtain the first input voltage; the first input voltage and the D-axis rectified input The voltage is superimposed to obtain the voltage value of the D-axis feedforward.

In combination with the first possible implementation or the third possible implementation of the first aspect, in a fourth possible implementation, before the step of using the second feed-forward current to perform rectification control, it further includes: obtaining a rectification input Current, carry out coordinate transformation on the rectified input current to obtain the rectified input current of the D axis, Q axis and Z axis; carry out coordinate transformation on the rectified input voltage to obtain the rectified input voltage of the D axis, Q axis and Z axis, where the rectified input The current includes: rectified input current of phase A, phase B and phase C, and the rectified input voltage includes: rectified input voltage of phase A, phase B and phase C;

Correspondingly, on the Q-axis, the current value of the Q-axis feedforward in the second feedforward current is used for reactive current control, and the voltage value of the Q-axis feedforward is obtained, which specifically includes: obtaining the reactive current, and converting the reactive current Superimposed with the current value of the Q-axis feedforward, the second reference current is obtained; the second reference current is input into the Q-axis current loop, so that the second reference current is subtracted from the Q-axis rectified input current, and the second output current is obtained. The second output current is adjusted to obtain a second input voltage; the second input voltage is superimposed on the Q-axis rectified input voltage to obtain a Q-axis feedforward voltage value.

In combination with any of the first to fourth possible implementations of the first aspect, in a fifth possible implementation, before the step of using the second feed-forward current to perform rectification control, the method further includes: obtaining a rectified input current, Perform coordinate transformation on the rectified input current to obtain the rectified input current on the D-axis, Q-axis and Z-axis; perform coordinate transformation on the rectified input voltage to obtain the rectified input voltage on the D-axis, Q-axis and Z-axis, wherein the rectified input current includes: The rectified input current of phase A, phase B and phase C, the rectified input voltage includes: the rectified input voltage of phase A, phase B and phase C;

On the Z axis, the current value of the Z axis feedforward in the second feedforward current is used to control the busbar difference, and the voltage value of the Zaxis feedforward is obtained, which specifically includes: obtaining the positive and negative busbar voltage difference according to the positive busbar voltage and the negative busbar voltage , and adjust the positive and negative bus voltage difference to obtain the second input current; superimpose the second input current and the Z-axis feedforward current value to obtain the third reference current; input the third reference current into the Z-axis current loop, so that The third reference current is subtracted from the Z-axis rectified input current to obtain the third output current, and the third output current is adjusted to obtain the third input voltage; the third input voltage is superimposed on the Z-axis rectified input voltage to obtain the Z-axis Feedforward voltage value.

In combination with the first aspect and any one of the first to fifth possible implementations of the first aspect, in a sixth possible implementation, according to the obtained rectified input voltage, inverter output voltage and inverter output current, the obtained The first feedforward current, the first feedforward current includes the instantaneous current values of A phase, B phase and C phase feedforward, specifically including:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVA</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECA</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVB</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECB</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}<span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVC</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECC</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

Among them, _iInvActiveA , _iInvActiveB and _iInvActiveC are the instantaneous current values of A phase, B phase and C phase feedforward respectively;

u _INVA , u _INVB and u _INVC are the inverter output voltages of phase A, phase B and phase C respectively;

u _RECA , u _RECB and u _RECC are the rectified input voltages of phase A, phase B and phase C respectively;

i _Aactive , i _Bactive and i _Cactive are the inverter output currents of phase A, phase B and phase C respectively;

CosA _INV , CosB _INV and CosC _INV are the cosine values of the phase angles of the A-phase, B-phase and C-phase inverter output voltages, respectively.

In combination with the sixth possible implementation of the first aspect, in the seventh possible implementation, when the second feedforward current includes: D-axis, Q-axis and Z-axis feedforward current values, the first feedforward voltage Including: D-axis, Q-axis and Z-axis feedforward voltage values, D-axis feedforward current value i _{d feedforward} ＝i InvActiveA , Q-axis feedforward current value i q feedforward ＝i _InvActiveB , Z-axis feedforward current value i _{q feedforward} ＝i _InvActiveB , Z-axis feedforward Current value i _{z feedforward} =i _InvActiveC .

In combination with the sixth possible implementation of the first aspect, in the eighth possible implementation, when the second feedforward current includes: the current value of Z-axis feedforward, the first feedforward voltage includes: Z-axis feedforward When the voltage value is , the current value i _{z feedforward} of the Z-axis feedforward is:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; zfeedforward</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; .</span>$

In a second aspect, the present invention provides a device for controlling bus ripple, which may include:

The detection unit is used to obtain the rectified input voltage, the inverter output voltage and the inverter output current;

A data processing unit, configured to obtain the first feedforward current according to the rectified input voltage, the inverter output voltage and the inverter output current obtained by the detection unit;

a first coordinate transformation unit, configured to perform coordinate transformation on the first feedforward current to obtain a second feedforward current;

A rectification loop control unit, configured to use the second feedforward current for rectification control to obtain the first feedforward voltage;

a second coordinate transformation unit, configured to perform coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage;

The wave modulating unit is used to modulate the second feed-forward voltage to generate a pulse signal, and input the pulse signal to the rectifier to control the voltage of the bus capacitor.

In the first possible implementation manner of the second aspect, the second feedforward current includes the feedforward current values of the D axis, the Q axis, and the Z axis, and the first feedforward voltage includes the feedforward current values of the D axis, the Q axis, and the Z axis. The voltage value; the rectification loop control unit includes: a bus voltage control module, a reactive current control module and a first bus difference control module;

Among them, the bus voltage control module is specifically used to control the bus voltage on the D axis using the D-axis feed-forward current value in the second feed-forward current to obtain the D-axis feed-forward voltage value; the reactive current control module uses On the Q axis, the current value of the Q axis feedforward in the second feedforward current is used for reactive current control, and the voltage value of the Q axis feedforward is obtained; the first bus difference control module is used to adopt the second The current value of the Z-axis feedforward in the two feedforward currents is controlled by the busbar difference to obtain the voltage value of the Z-axis feedforward.

In a second possible implementation of the second aspect, the second feedforward current includes: the current value of the Z-axis feedforward, the first feedforward voltage includes: the voltage value of the Z-axis feedforward; the rectification loop control unit includes : The second bus difference control module, wherein the second bus difference control module is used to control the bus difference by using the Z-axis feed-forward current value in the second feed-forward current on the Z-axis to obtain the Z-axis feed-forward voltage value.

With reference to the first possible implementation of the second aspect, in a third possible implementation, the detection unit is also used to obtain the rectified input current; the device further includes: a third coordinate transformation unit, used to convert the rectified input The coordinate transformation of the current is carried out to obtain the rectified input current of the D-axis, Q-axis and Z-axis; the coordinate transformation of the rectified input voltage is carried out to obtain the rectified input voltage of the D-axis, Q-axis and Z-axis, wherein the rectified input current includes: A phase , The rectified input current of phase B and phase C, the rectified input voltage includes: the rectified input voltage of phase A, phase B and phase C;

The bus voltage control module is used to subtract the preset bus voltage value from the current bus voltage value to obtain the bus voltage difference, and adjust the bus voltage difference to obtain the first input current; The fed current value is superimposed to obtain the first reference current; the first reference current is input into the D-axis current loop, so that the first reference current is subtracted from the D-axis rectified input current to obtain the first output current, and the first output current is Adjust to obtain the first input voltage; superimpose the first input voltage and the D-axis rectified input voltage to obtain the D-axis feedforward voltage value.

In combination with the first possible implementation or the third possible implementation of the second aspect, in a fourth possible implementation, the detection unit is also used to obtain the rectified input current; the device further includes: a fourth coordinate The transformation unit is used to perform coordinate transformation on the rectified input current to obtain the rectified input current of the D-axis, Q-axis and Z-axis; to perform coordinate transformation on the rectified input voltage to obtain the rectified input voltage of the D-axis, Q-axis and Z-axis, wherein , the rectified input current includes: the rectified input current of A phase, B phase and C phase, and the rectified input voltage includes: the rectified input voltage of A phase, B phase and C phase;

The reactive current control module is used to obtain the reactive current, and superimpose the reactive current with the current value of the Q-axis feedforward to obtain the second reference current; input the second reference current into the Q-axis current loop, so that the second reference current Subtract the Q-axis rectified input current to obtain the second output current, adjust the second output current to obtain the second input voltage; superimpose the second input voltage and the Q-axis rectified input voltage to obtain the Q-axis feedforward voltage value.

In combination with the first possible implementation manner, the third possible implementation manner or the fourth possible implementation manner of the second aspect, in a fifth possible implementation manner, the detection unit is also used to obtain the rectified input current; The device also includes: a fifth coordinate transformation unit, which transforms the coordinates of the rectified input current to obtain the rectified input current of the D-axis, Q-axis and Z-axis; performs coordinate transformation of the rectified input voltage to obtain the D-axis, Q-axis and Z-axis The rectified input voltage, wherein, the rectified input current includes: the rectified input current of A phase, B phase and C phase, and the rectified input voltage includes: the rectified input voltage of A phase, B phase and C phase;

The first busbar difference control module is used to obtain the positive and negative busbar voltage difference according to the positive busbar voltage and the negative busbar voltage, and adjust the positive and negative busbar voltage difference to obtain the second input current; feed forward the second input current with the Z axis The current value is superimposed to obtain the third reference current; the third reference current is input into the Z-axis current loop, so that the third reference current is subtracted from the Z-axis rectified input current to obtain the third output current, and the third output current is adjusted. , to obtain the third input voltage; the third input voltage is superimposed on the Z-axis rectified input voltage to obtain the Z-axis feedforward voltage value.

With reference to the second possible implementation of the second aspect, in a sixth possible implementation, the detection unit is further configured to obtain the rectified input current;

The device also includes: a sixth coordinate transformation unit, which performs coordinate transformation on the rectified input current to obtain the rectified input current of the D-axis, Q-axis and Z-axis; performs coordinate transformation on the rectified input voltage to obtain the D-axis, Q-axis and Z-axis The rectified input voltage of the shaft, wherein the rectified input current includes: the rectified input current of A phase, B phase and C phase, and the rectified input voltage includes: the rectified input voltage of A phase, B phase and C phase;

The second busbar difference control module is used to obtain the positive and negative busbar voltage difference according to the positive busbar voltage and the negative busbar voltage, and adjust the positive and negative busbar voltage difference to obtain the second input current; feed forward the second input current with the Z axis The current value is superimposed to obtain the third reference current; the third reference current is input into the Z-axis current loop, so that the third reference current is subtracted from the Z-axis rectified input current to obtain the third output current, and the third output current is adjusted. , to obtain the third input voltage; the third input voltage is superimposed on the Z-axis rectified input voltage to obtain the Z-axis feedforward voltage value.

In combination with the second aspect or any of the first to sixth possible implementations of the second aspect, in a seventh possible implementation, the first feedforward current includes the instantaneous feedforward phases of A phase, B phase, and C phase The current value, wherein, the data processing unit is specifically used for the following data processing:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVA</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECA</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVB</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECB</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}<span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVC</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECC</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

Among them, _iInvActiveA , _iInvActiveB and _iInvActiveC are the instantaneous current values of A phase, B phase and C phase feedforward respectively;

u _INVA , u _INVB and u _INVC are the inverter output voltages of phase A, phase B and phase C respectively;

u _RECA , u _RECB and u _RECC are the rectified input voltages of phase A, phase B and phase C respectively;

i _Aactive , i _Bactive and i _Cactive are the inverter output currents of phase A, phase B and phase C respectively;

CosA _INV , CosB _INV and CosC _INV are the cosine values of the phase angles of the A-phase, B-phase and C-phase inverter output voltages, respectively.

In combination with the seventh possible implementation of the second aspect, in the eighth possible implementation, when the second feedforward current includes: D-axis, Q-axis and Z-axis feedforward current values, the first feedforward voltage Including: D-axis, Q-axis and Z-axis feedforward voltage values, D-axis feedforward current value i _{d feedforward} ＝i InvActiveA , Q-axis feedforward current value i q feedforward ＝i _InvActiveB , Z-axis feedforward current value i _{q feedforward} ＝i _InvActiveB , Z-axis feedforward Current value i _{z feedforward} =i _InvActiveC .

In combination with the seventh possible implementation of the second aspect, in the ninth possible implementation, when the second feedforward current includes: the current value of Z-axis feedforward, the first feedforward voltage includes: Z-axis feedforward When the voltage value is , the current value i _{z feedforward} of the Z-axis feedforward is:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; zfeedforward</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; .</span>$

In a third aspect, the present invention provides a system for controlling bus ripple, which may include: a rectifier, an inverter, and the device for controlling bus ripple as provided in the second aspect.

It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

In the embodiment of the present invention, the first feedforward current can be obtained according to the rectified input voltage, the inverter output voltage, and the inverter output current, and then coordinate transformation is performed on the first feedforward current to obtain the second feedforward current, and then the second feedforward current is used The current is rectified and controlled to obtain the first feedforward voltage, and coordinate transformation is performed on the first feedforward voltage to obtain the second feedforward voltage; finally, the second feedforward voltage is modulated to generate a pulse signal, and the pulse signal is input to the rectifier. In the embodiment of the present invention, the power consumed by the inverter and other power units is directly fed forward to the rectifier, so that the current of the N line of the rectifier and the inverter is basically the same, that is, the current flowing from the midpoint of the bus capacitor to the N line of the inverter The minimum, thereby effectively reducing the bus ripple, improving the dynamic performance of the rectifier, and improving the control efficiency of the bus ripple.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a schematic circuit diagram of an uninterruptible power supply system in the prior art;

FIG. 2 is a schematic flowchart of a method for controlling bus ripple in an embodiment of the present invention;

Fig. 3 is a schematic diagram of a coordinate transformation for coordinate transformation of the first feedforward current in an embodiment of the present invention;

Fig. 4 is a schematic diagram of a coordinate transformation for coordinate transformation of the first feedforward voltage in an embodiment of the present invention;

Fig. 5 is a structural schematic diagram of rectifying and controlling the second feedforward current in an embodiment of the present invention;

6 is a schematic diagram of coordinate transformation for coordinate transformation of rectified input current in an embodiment of the present invention;

7 is a schematic diagram of coordinate transformation for coordinate transformation of the rectified input voltage in an embodiment of the present invention;

Fig. 8 is a schematic diagram of another coordinate transformation for coordinate transformation of the first feedforward current in an embodiment of the present invention;

Fig. 9 is a schematic diagram of coordinate transformation for coordinate transformation of the first feedforward voltage in an embodiment of the present invention;

FIG. 10 is another structural schematic diagram of rectifying and controlling the second feedforward current in an embodiment of the present invention;

Fig. 11 is a schematic structural diagram of a device for controlling bus ripple in an embodiment of the present invention;

Fig. 12 is a schematic structural diagram of a system for controlling bus ripple in an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present invention.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects and not necessarily Describe a particular order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of practice in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The embodiment of the present invention provides a method for controlling the bus ripple, which can effectively reduce the bus ripple and improve the control efficiency of the bus ripple. In addition, a corresponding device for controlling bus ripple and a related system for controlling bus ripple are also provided. In the following, specific examples will be used to describe in detail respectively.

The method for controlling the busbar ripple provided by the embodiment of the present invention is applicable to an inverter power supply system, such as an uninterruptible power supply (UPS, Uninterruptible Power System). The embodiment of the present invention takes the application to UPS as an example to analyze and illustrate the method, It does not constitute a limitation to the present invention. Wherein, the UPS may at least include a rectifier and an inverter. The rectifier will provide a stable DC voltage to power units such as the inverter, and the inverter will convert the DC voltage into AC and output it to the load. When the inverter has an unbalanced load, the bus capacitor voltage will have ripples. In order to control the bus ripple, the embodiment of the present invention feeds forward the power consumed by power units such as the inverter to the control of the rectifier.

An embodiment of the present invention provides a method for controlling bus ripple, wherein, for convenience of description, the description will be made from the perspective of a device for controlling bus ripple. A method for controlling bus ripple provided by the present invention can obtain the first feed-forward current according to the rectified input voltage, inverter output voltage and inverter output current, and then perform coordinate transformation on the first feed-forward current to obtain the second feed-forward current Feed the current, and then use the second feedforward current for rectification control to obtain the first feedforward voltage, and perform coordinate transformation on the first feedforward voltage to obtain the second feedforward voltage; modulate the second feedforward voltage to generate a pulse signal , and input the pulse signal to the rectifier. In the embodiment of the present invention, the power consumed by the inverter and other power units is directly fed forward to the rectifier, so that the current of the N line of the rectifier and the inverter is basically the same, that is, the current flowing from the midpoint of the bus capacitor to the N line of the inverter The minimum, thereby effectively reducing the bus ripple, and improving the control efficiency of the bus ripple.

Please refer to FIG. 2. FIG. 2 is a schematic flowchart of a method for controlling bus ripple provided by an embodiment of the present invention, wherein the method for controlling bus ripple may include:

Step 101, obtaining rectified input voltage, inverter output voltage and inverter output current;

In the embodiment of the present invention, the device for controlling bus ripple can be connected between the grid terminal and the load terminal, and is used for real-time detection of rectified input voltage, inverter output voltage and inverter output current. It should be noted that the present invention is described in detail by taking the application in a three-phase power grid as an example. Correspondingly, the device for controlling bus ripple can obtain the rectified input voltage of phase A, phase B and phase C, the inverter output voltage of phase A, phase B and phase C, and the inverse voltage of phase A, phase B and phase C change the output current.

Step 102. Obtain the first feedforward current according to the obtained rectified input voltage, inverter output voltage and inverter output current, and perform coordinate transformation on the first feedforward current to obtain the second feedforward current; for example, the details may be as follows :

According to the rectified input voltage, the inverter output voltage and the inverter output current detected in step 101, the first feedforward current can be calculated.

In a three-phase power grid, the first feed-forward current multiplied by the rectified input voltage is equal to the product of the inverter output voltage and the inverter output current, and the bus ripple can be controlled to a minimum value. Specifically, the first feedforward current includes the instantaneous current value _iInvActiveA of phase A feedforward, the instantaneous current value _iInvActiveB of phase B feedforward, and the instantaneous current value _iInvActiveC of phase C feedforward, and the calculation formula can be as follows:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVA</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECA</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVB</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECB</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVC</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECC</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

Among them, _iInvActiveA , _iInvActiveB and _iInvActiveC are the instantaneous current values of A phase, B phase and C phase feedforward respectively;

u _INVA , u _INVB and u _INVC are the inverter output voltages of phase A, phase B and phase C respectively;

u _RECA , u _RECB and u _RECC are the rectified input voltages of phase A, phase B and phase C respectively;

i _Aactive , i _Bactive and i _Cactive are the inverter output currents of phase A, phase B and phase C respectively;

CosA _INV , CosB _INV and CosC _INV are the cosine values of the phase angles of the A-phase, B-phase and C-phase inverter output voltages, respectively.

After the first feedforward current is obtained, the obtained first feedforward current needs to be fed forward to the control of the rectifier, but since the first feedforward current cannot be directly fed forward to the rectifier, it is necessary to control the bus ripple The means for controlling the first feedforward current such that it can be fed forward into the algorithm of the rectifier. After obtaining the instantaneous current value i _InvActiveA of phase A feed-forward, the instantaneous current value i _InvActiveB of phase B feed-forward and the instantaneous current value i InvActiveC of _phase C feed-forward, the ABC/DQZ of i _InvActiveA , i _InvActiveB and i _InvActiveC can be performed The coordinates are transformed to obtain the second feedforward current, wherein the second feedforward current includes: D-axis, Q-axis and Z-axis feedforward current values.

It should be understood that the specific implementation of the ABC/DQZ coordinate transformation can refer to the prior art, and will not be repeated here.

Step 103: Use the second feedforward current to perform rectification control to obtain the first feedforward voltage, and perform coordinate transformation on the first feedforward voltage to obtain the second feedforward voltage; for example, the details can be as follows:

In step 102, after obtaining the feedforward current values of the D axis, Q axis, and Z axis, rectification control is performed on the feedforward current values of the D axis, Q axis, and Z axis on the D axis, Q axis, and Z axis of the rotating coordinates, A first feedforward voltage is obtained, wherein the first feedforward voltage includes: D-axis, Q-axis and Z-axis feedforward voltage values.

It should be noted that before step 103, it may also include: obtaining the rectified input current, performing coordinate transformation on the rectified input current to obtain the rectified input current of the D-axis, Q-axis and Z-axis; performing coordinate transformation on the rectified input voltage, The rectified input voltages of the D-axis, Q-axis and Z-axis are obtained, wherein the rectified input current includes: the rectified input current of the A phase, the B phase and the C phase, and the rectified input voltage includes the rectified input of the A phase, the B phase and the C phase Voltage.

Among them, the second feed-forward current is used for rectification control. For example, the bus voltage control, reactive current control and bus difference control can be respectively performed on the D axis, Q axis and Z axis of the rotating coordinates, and then the D axis, Q axis and Z axis can be obtained. Axis and Z-axis feedforward voltage values. For example, bus voltage control can be performed on the D-axis, reactive current control can be performed on the Q-axis, and bus differential control can be performed on the Z-axis. The specific implementation will be described in detail in the following embodiments and will not be repeated here. It should be understood that there is no specific limitation on whether to perform bus voltage control, reactive current control or bus difference control on each rotating coordinate axis, and it does not constitute a limitation of the present invention.

After obtaining the D-axis, Q-axis and Z-axis feedforward voltage values, the DQZ/ABC coordinate transformation can be performed on the D-axis, Q-axis and Z-axis feedforward voltage values to obtain the second feedforward voltage, where the second The feed-forward voltage includes: A-phase, B-phase and C-phase feedforward voltage values.

It should be understood that the specific implementation of the DQZ/ABC coordinate transformation can refer to the prior art, and will not be repeated here.

Step 104, modulate the second feedforward voltage to generate a pulse signal, and input the pulse signal into the rectifier to control the voltage of the bus capacitor.

By modulating the second feedforward voltage, a modulated wave is obtained, and then a pulse signal is generated through a modulation algorithm. It should be noted that there is no limitation on how to modulate the voltage to obtain a modulated wave and generate a pulse signal through a modulation algorithm. The specific implementation can refer to the prior art and will not be repeated here.

Wherein, the generated pulse signal may be a pulse width modulation (PWM, Pulse WidthModulation) pulse signal. Then, modulating the second feedforward voltage to generate a pulse signal may specifically include: performing pulse width modulation on the feedforward voltage values of phase A, phase B and phase C to obtain a PWM pulse signal.

Sending the generated PWM pulse signal to the rectifier can control the midpoint voltage of the bridge arm of the rectifier, thereby controlling the amplitude and phase of the current of the inductor L between the grid side and the rectifier, that is, ensuring that the power factor of the rectifier input is 1, and ensuring Bus voltage sum and bus voltage difference.

It can be seen from the above that the embodiment of the present invention can obtain the first feedforward current according to the rectified input voltage, the inverter output voltage and the inverter output current, and then perform coordinate transformation on the first feedforward current to obtain the second feedforward current, and then use The second feedforward current is rectified and controlled to obtain the first feedforward voltage, and the coordinate transformation of the first feedforward voltage is carried out to obtain the second feedforward voltage; finally, the second feedforward voltage is modulated to generate a pulse signal, and the pulse signal is Enter the rectifier. In the embodiment of the present invention, the power consumed by the inverter and other power units is directly fed forward to the rectifier, so that the current of the N line of the rectifier and the inverter is basically the same, that is, the current flowing from the midpoint of the bus capacitor to the N line of the inverter The minimum, thereby effectively reducing the bus ripple, improving the dynamic performance of the rectifier, and improving the control efficiency of the bus ripple.

It should be understood that the bus ripple can be controlled by instantaneous power feedforward and N line current feedforward, wherein the instantaneous power feedforward is to control the bus voltage and reactive current on the D-axis, Q-axis and Z-axis respectively. Control and bus difference control, that is, the D axis, Q axis and Z axis of the rotating coordinates are all transformed, and none of them are 0. However, the current feed-forward of the N line only performs bus difference control on the Z axis, and only transforms the Z axis of the rotating coordinates.

In order to better understand the above solutions, the present invention describes the above solutions in detail with specific application examples:

When performing instantaneous power feedforward, it may specifically include the following steps:

Step 201, respectively acquire u _INVA , u _INVB , u _INVC , u _RECA , u _RECB , u _RECC , i _Aactive , i _Bactive and i _Cactive ;

Among them, u _INVA , u _INVB and u _INVC are the inverter output voltages of phase A, phase B and phase C respectively, u _RECA , u _RECB and u _RECC are the rectified input voltages of phase A, phase B and phase C respectively, i _Aactive , i _Bactive and i _Cactive are the inverter output currents of phase A, phase B and phase C respectively.

Step 202, calculate _iInvActiveA , _iInvActiveB and _iInvActiveC , the calculation formula is as follows:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVA</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECA</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVB</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECB</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVC</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECC</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

Among them, i _InvActiveA , i _InvActiveB and i _InvActiveC are the feed-forward instantaneous current values of phase A, phase B and phase C respectively, and CosA _INV , CosB _INV and CosC _INV are the inverter output voltage phases of phase A, phase B and phase C respectively The cosine of the angle.

Step 203, perform ABC/DQZ coordinate transformation on _iInvActiveA , _iInvActiveB and _iInvActiveC to obtain i _{d feedforward} , i _{q feedforward} and i _{z feedforward} ;

Please refer to FIG. 3 for details. FIG. 3 is a schematic diagram of coordinate transformation for coordinate transformation of the first feedforward current. Wherein, i _{d feedforward} , i _{q feedforward} and i _{z feedforward} are feedforward current values of the D-axis, Q-axis and Z-axis respectively. In some embodiments, _{id feedforward} =i _InvActiveA , i _{q feedforward} =i _InvActiveB , i _{z feedforward} = i _InvActiveC .

Step 204, use _{id feedforward} , i _{q feedforward} and i _{z feedforward} to perform rectification control: use _{id feedforward} to control the bus voltage on the D axis of the rotating coordinate, and obtain the feedforward voltage value u _d1 of the D axis. On the Q axis, i _{q feedforward} is used for reactive current control, and the Q-axis feedforward voltage value u _q1 is obtained. On the Z axis of the rotating coordinate, i _{z feedforward} is used for bus difference control, and the Z axis feedforward voltage value u _z1 is obtained. ;

Step 205, perform DQZ/ABC coordinate transformation on u _d1 , u _q1 and u _z1 to obtain u _Afeedforward , u _{B feedforward} and u _Cfeedforward , then modulate u _Afeedforward , u _{B feedforward} and u _Cfeedforward to generate pulse signal PWM1A/1B , PWM2A/2B and PWM3A/3B, input the pulse signal into the rectifier to control the voltage of the bus capacitor.

For details, please refer to FIG. 4 , which is a schematic diagram of coordinate transformation for coordinate transformation of the first feedforward voltage. u _d1 , u _q1 and u _z1 are the feedforward voltage values of the D axis, Q axis and Z axis respectively, and u _Afeedforward , u _{B feedforward} and u _Cfeedforward are the feedforward voltage values of the A phase, B phase and C phase respectively.

Further, please refer to FIG. 5 . FIG. 5 is a structural schematic diagram of rectification control using _{id feedforward} , i _{q feedforward} and _{iz feedforward} .

Wherein, before step 204, it may also include: obtaining the rectified input currents of phase A, phase B and phase C: i _RECA , i _RECB and i _RECC , and performing coordinate transformation on i _RECA , i _RECB and i _RECC to obtain D The rectified input current of axis, Q axis and Z axis: i _d , i _q and i _z ; the rectified input voltage of phase A, B and C: u _RECA , u _RECB and u _RECC after ABC/DQZ coordinate transformation Get the rectified input voltages for the D, Q and Z axes: v _d , v _q and v _z . Refer to Figure 6 and Figure 7 for details, Figure 6 is a schematic diagram of coordinate transformation for ABC/DQZ coordinate transformation of rectified input current, and Figure 7 is a schematic diagram of coordinate transformation for ABC/DQZ coordinate transformation of rectified input voltage.

Please refer to Fig. 5, and refer to Figs. 3, 4, 6 and 7 together. Specifically, step 204 uses _{id feedforward} , i _{q feedforward} and _{iz feedforward} to perform rectification control, which may specifically include:

Step 204-1. On the D-axis of the rotating coordinates, use id _feedforward to control the bus voltage to obtain the D-axis feedforward voltage value u _d1 , which may specifically include:

Subtracting the preset bus voltage value v _{bus_ref} from the current bus voltage value v _bus to obtain the bus voltage difference, and adjusting the bus voltage difference proportionally (P, proportional) to obtain the first input current;

Superimpose the first input current with the current value id _feedforward of the D-axis feedforward to obtain the first reference current _idref ;

Input the first reference current _idref into the D-axis current loop, so that _idref is subtracted from the D-axis rectified input current _id to obtain the first output current, and the first output current is proportional and integral (PI, proportional and Integral) Adjust to obtain the first input voltage, and superimpose the first input voltage with the D-axis rectified input voltage v _d to obtain the D-axis feedforward voltage value u _d1 .

It should be noted that the bus voltage control is performed on the D axis of the rotating coordinates, so that when the voltage of the bus capacitor fluctuates, the voltage of the bus capacitor can be balanced, so that the voltage of the bus capacitor is stable and close to the preset bus capacitor voltage.

Step 204-2. On the Q-axis of the rotating coordinates, use i _{q feedforward} to perform reactive current control, and obtain the voltage value wave u _q2 of the Q-axis feedforward, which may specifically include:

Obtain the reactive current i _cq , and superimpose i _cq with the Q-axis feedforward current value i _{q feedforward} to obtain the second reference current i _qref ;

Input the second reference current i _qref into the Q-axis current loop, so that i _qref is subtracted from the Q-axis rectified input current i _q to obtain the second output current, and perform PI adjustment on the second output current to obtain the second input voltage. The second input voltage is superimposed on the Q-axis rectified input voltage v _q to obtain the Q-axis feedforward voltage value u _q1 .

It should be noted that the reactive current control is carried out on the Q axis of the rotating coordinates, that is, the reactive current _icq is obtained and added to the control, which can compensate the influence of the rectifying filter capacitor C on the power factor of the grid end, making the power factor close to 1.

Step 204-3. On the Z-axis of the rotating coordinates, use _{iz feedforward} to control the busbar difference, and obtain the voltage value u _z2 of the Z-axis feedforward, which may specifically include:

Obtain the current positive and negative bus voltage difference △v _pn according to the positive bus voltage and negative bus voltage, and perform P adjustment on the positive and negative bus voltage difference to obtain the second input current; specifically, after obtaining △v _pn , the current positive and negative bus voltage difference needs to be The negative bus voltage difference △v _pn is subtracted from the preset positive and negative bus voltage difference △v _ref , but △v _ref is 0, so P adjustment can be directly performed on △v _pn .

superimposing the second input current with the Z-axis feedforward current value i _{z feedforward} to obtain the third reference current i _zref ;

Input the third reference current i _zref into the Z-axis current loop, so that i _zref is subtracted from the Z-axis rectified input current i _z to obtain the third output current, and perform PI adjustment on the third output current to obtain the first input voltage. The first input voltage is superimposed on the Z-axis rectified input voltage v _z to obtain the Z-axis feedforward voltage value u _z1 .

It should be noted that the bus differential steady-state control is performed on the Z-axis of the rotating coordinates, so that when the midpoint of the bus capacitor is connected to the neutral line N, for example, when the inverter has an instantaneous unbalanced load (for example, a sudden L or LR load), it will cause long-term unbalance of positive and negative busbars, or cause overvoltage failure of unilateral busbar capacitance, and when there is a difference between positive and negative busbar capacitances, the positive and negative busbars can be balanced so that the positive and negative busbar voltage values Stable and nearly equal, that is, the positive and negative bus voltage difference △v _pn is 0.

It should be noted that the timing of steps 204-1, 204-2 and 204-3 is irrelevant.

To sum up, the embodiment of the present invention adopts _{id feedforward} , i _{q feedforward} , and _{iz feedforward} to carry out rectification control, which can ensure that each phase (phase A, phase B, and phase C) of the rectification input has a unit power factor. In the case of single-phase load, such as A-phase inverter load, the rectified input A-phase current increases, and finally the N-line current generated by the rectifier and the N-line current generated by the inverter cancel each other out, so that the single-phase load flows into the capacitor The current at the point is very small, thereby reducing the unilateral bus ripple.

When performing N-line current feedforward, the following steps may be specifically included:

For steps 301-302, reference may be made to steps 201-202, which are performed in the same way, and will not be repeated here.

Step 303, perform ABC/DQZ coordinate transformation on _iInvActiveA , _iInvActiveB and _iInvActiveC to obtain i _{z feedforward} ; where, $i_{\mathrm{zfeedforward}}=\frac{i_{\mathrm{InvActiveA}}+i_{\mathrm{InvActiveB}}+i_{\mathrm{InvActiveC}}}{3};$

For details, please refer to FIG. 8 , which is another schematic diagram of coordinate transformation for coordinate transformation of the first feedforward current. Among them, i _InvActiveA , i _InvActiveB and i _InvActiveC are the feedforward current values of phase A, phase B and phase C, and _{iz feedforward} is the current value of Z axis feedforward.

Step 304, using i _{z feedforward} to control the bus difference on the Z axis of the rotating coordinates, and obtain the voltage value u _z1 of the Z axis feedforward;

Step 305, perform DQZ/ABC coordinate transformation on u _z1 to obtain u _Cfeedforward , modulate u _Cfeedforward to generate pulse signals PWM1A/1B, PWM2A/2B, and PWM3A/3B, and input the pulse signals to the rectifier to control the bus capacitance Voltage.

For details, please refer to FIG. 9 , which is another schematic diagram of coordinate transformation for coordinate transformation of the first feedforward current. Among them, u _z1 is the voltage value of Z-axis feedforward, and u _Cfeedforward is the voltage value of C-phase feedforward.

Further, please refer to FIG. 10 . FIG. 10 is a schematic structural diagram of rectification control using _{iz feedforward} .

Wherein, before step 304, at least may further include: obtaining the rectified input currents of phase A, phase B and phase C: i _RECA , i _RECB and i _RECC , and performing coordinate transformation to obtain the currents of the D-axis, Q-axis and Z-axis Rectified input current: i _d , i _q and i _z ; rectified input voltage for phase A, phase B and phase C: u _RECA , u _RECB and u _RECC ABC/DQZ coordinate transformation to obtain D axis, Q axis and Z The rectified input voltage to the axis: v _d , v _q and v _z . Refer to Figure 6 and Figure 7 for details, Figure 6 is a schematic diagram of coordinate transformation for ABC/DQZ coordinate transformation of rectified input current, and Figure 7 is a schematic diagram of coordinate transformation for ABC/DQZ coordinate transformation of rectified input voltage.

Please refer to Fig. 10, and refer to Fig. 6 to Fig. 9 together. Specifically, in step 304, use _{iz feedforward} on the Z-axis of the rotating coordinates to perform busbar difference control to obtain the Z-axis feed-forward voltage value u _z1 , specifically May include:

Obtain the current positive and negative bus voltage difference △v _pn according to the positive bus voltage and negative bus voltage, and perform P adjustment on the positive and negative bus voltage difference to obtain the second input current; specifically, after obtaining △v _pn , the current positive and negative bus voltage difference needs to be The negative bus voltage difference △v _pn is subtracted from the preset positive and negative bus voltage difference △v _ref , but △v _ref is 0, so P adjustment can be directly performed on △v _pn .

superimposing the second input current with the Z-axis feedforward current value i _{z feedforward} to obtain the third reference current i _zref ;

Input the third reference current i _zref into the Z-axis current loop, so that i _zref is subtracted from the Z-axis rectified input current i _z to obtain the third output current, and perform PI adjustment on the third output current to obtain the first input voltage. The first input voltage is superimposed on the Z-axis rectified input voltage v _z to obtain the Z-axis feedforward voltage value u _z1 .

To sum up, after the embodiment of the present invention adopts _{iz feedforward} for rectification control, when the inverter has a single-phase load, such as the A-phase inverter with a load, the rectified input currents of A-phase, B-phase and C-phase will increase simultaneously. Large, the N-line current generated by the final rectification and the N-line current generated by the inverter cancel each other, so that the current flowing into the midpoint of the capacitor under single-phase load is very small, thereby reducing the unilateral bus ripple.

It should be noted that for its specific implementation, reference may be made to the above-mentioned embodiments, which will not be repeated here.

In order to better implement the method for controlling bus ripple provided by the embodiment of the present invention, the embodiment of the present invention further provides a device based on the above method for controlling bus ripple. The meanings of the nouns are the same as those in the above method for controlling bus ripple, and for specific implementation details, please refer to the description in the method embodiments.

In order to better implement the above solution, this embodiment provides a device 400 for controlling bus ripple, for details, refer to FIG. 11 .

A device 400 for controlling bus ripple may specifically include: a detection unit 401 , a data processing unit 402 , a first coordinate transformation unit 403 , a rectification loop control unit 404 , a second coordinate transformation unit 405 and a modulation and transmission unit 406 .

A detection unit 401, configured to obtain the rectified input voltage, the inverter output voltage and the inverter output current;

a data processing unit 402, configured to obtain a first feedforward current according to the rectified input voltage, the inverter output voltage, and the inverter output current acquired by the detection unit 401;

The first coordinate transformation unit 403 is configured to perform coordinate transformation on the first feedforward current to obtain a second feedforward current;

A rectification loop control unit 404, configured to use the second feedforward current to perform rectification control to obtain the first feedforward voltage;

The second coordinate transformation unit 405 is configured to perform coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage;

The modulating wave generating unit 406 is configured to modulate the second feedforward voltage to generate a pulse signal, and input the pulse signal into the rectifier to control the voltage of the bus capacitor.

The second feed-forward voltage includes: the feed-forward voltage values of phase A, phase B and phase C; correspondingly, the modulation wave unit 406 is used to pulse-modulate the feed-forward voltage values of phase A, phase B and phase C, A pulse width modulation (PWM, Pulse Width Modulation) pulse signal is obtained, and the PWM pulse signal is input to the rectifier to control the voltage of the bus capacitor. Sending the generated PWM pulse signal to the rectifier can control the midpoint voltage of the bridge arm of the rectifier, thereby controlling the amplitude and phase of the current of the inductor L between the grid side and the rectifier, that is, ensuring that the power factor of the rectifier input is 1, and ensuring Bus voltage sum and bus voltage difference.

Further, the detection unit 401 in the embodiment of the present invention is also used to obtain the rectified input current, wherein the rectified input current includes: A-phase, B-phase and C-phase rectified input currents.

Wherein, the first feed-forward current includes instantaneous current values fed forward by phase A, phase B and phase C. The data processing unit 402 is specifically used for the following data processing:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVA</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECA</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVB</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECB</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; InvActiveC</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; INVC</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; Active</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; RECC</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; INV</span>}}$

Among them, _iInvActiveA , _iInvActiveB and _iInvActiveC are the instantaneous current values of A phase, B phase and C phase feedforward respectively;

u _INVA , u _INVB and u _INVC are the inverter output voltages of phase A, phase B and phase C respectively;

u _RECA , u _RECB and u _RECC are the rectified input voltages of phase A, phase B and phase C respectively;

i _Aactive , i _Bactive and i _Cactive are the inverter output currents of phase A, phase B and phase C respectively;

CosA _INV , CosB _INV and CosC _INV are the cosine values of the phase angles of the A-phase, B-phase and C-phase inverter output voltages, respectively.

It should be understood that the bus ripple can be controlled by instantaneous power feedforward and N-line current feedforward, wherein the instantaneous power feedforward is to set the bus voltage control module, reactive power The current control module and the first bus difference control module perform transformation on the D-axis, Q-axis and Z-axis of the rotating coordinates, and none of them is 0. For the N line current feedforward, the second bus difference control module is only installed on the Z axis, and only the Z axis of the rotating coordinate is transformed.

When feeding forward through instantaneous power, the first feed-forward current includes: the instantaneous current value of A-phase, B-phase and C-phase feed-forward, and the second feed-forward current includes: the current value of D-axis, Q-axis and Z-axis feed-forward , the first feedforward voltage includes: D-axis, Q-axis and Z-axis feedforward voltage values.

Correspondingly, the rectification loop control unit includes: a busbar voltage control module, a reactive current control module, a first busbar difference control module, and a busbar voltage control module, which are used to adopt the D-axis front feed-forward current in the second feed-forward current on the D-axis. Feed-forward current value for bus voltage control to obtain D-axis feed-forward voltage value; reactive current control module for reactive current control on Q-axis using Q-axis feed-forward current value in the second feed-forward current , to obtain the voltage value of the Q-axis feedforward; the first bus difference control module is used to control the bus difference on the Z-axis by using the current value of the Z-axis feedforward in the second feed-forward current to obtain the voltage of the Z-axis feedforward value.

In some embodiments, the second feedforward current includes D-axis, Q-axis and Z-axis feedforward current values: _{id feedforward} , i _{q feedforward} and _{iz feedforward} , where _{id feedforward} =i _InvActiveA , i _{q feedforward} =i _InvActiveB , _{iz feedforward} =i _InvActiveC .

Embodiments of the present invention may further include: a third coordinate transformation unit, configured to perform coordinate transformation on the rectified input current to obtain rectified input currents on the D-axis, Q-axis, and Z-axis; to perform coordinate transformation on the rectified input voltage to obtain the D-axis, Q-axis, and Z-axis rectified input currents; The rectified input voltage of the Q axis and the Z axis, wherein, the rectified input current includes: the rectified input current of the A phase, the B phase and the C phase, the rectified input voltage includes: the rectified input voltage of the A phase, the B phase and the C phase, and The rectified input currents of the D-axis, Q-axis and Z-axis and the rectified input voltages of the D-axis, Q-axis and Z-axis after coordinate transformation by the third coordinate transformation unit are respectively input into the first bus voltage control module. Embodiments of the present invention may further include: a fourth coordinate transformation unit, configured to perform coordinate transformation on the rectified input current to obtain rectified input currents on the D-axis, Q-axis, and Z-axis; to perform coordinate transformation on the rectified input voltage to obtain the D-axis, Q-axis, and Z-axis rectified input currents; The rectified input voltage of the Q axis and the Z axis, wherein, the rectified input current includes: the rectified input current of the A phase, the B phase and the C phase, the rectified input voltage includes: the rectified input voltage of the A phase, the B phase and the C phase, and The rectified input currents of the D-axis, Q-axis and Z-axis and the rectified input voltages of the D-axis, Q-axis and Z-axis after coordinate transformation by the fourth coordinate transformation unit are respectively input into the reactive current control module. Embodiments of the present invention may further include: a fifth coordinate transformation unit, configured to perform coordinate transformation on the rectified input current to obtain rectified input currents on the D-axis, Q-axis, and Z-axis; to perform coordinate transformation on the rectified input voltage to obtain the D-axis, Q-axis, and Z-axis rectified input currents; The rectified input voltage of the Q axis and the Z axis, wherein, the rectified input current includes: the rectified input current of the A phase, the B phase and the C phase, the rectified input voltage includes: the rectified input voltage of the A phase, the B phase and the C phase, and The rectified input currents of the D-axis, Q-axis and Z-axis and the rectified input voltages of the D-axis, Q-axis and Z-axis after the coordinate transformation by the fifth coordinate transformation unit are respectively input into the first bus difference control module.

It should be noted that the third coordinate transformation unit, the fourth coordinate transformation unit and the fifth coordinate transformation unit all perform coordinate transformation on the rectified input current and the rectified input voltage, "third", "fourth", "fifth" is used to distinguish similar objects, and the above three can be the same coordinate transformation unit.

Specifically, the bus voltage control module is used to control the bus voltage on the D axis of the rotating coordinates by using id _feedforward to obtain the feedforward voltage value u _d1 of the D axis, which may specifically include: setting the preset bus voltage value v _{bus_ref} Subtract the current bus voltage value v _bus to obtain the bus voltage difference, and perform proportional (P, proportional) to the bus voltage difference to obtain the first input current; combine the first input current with the D-axis feedforward current value i _d The first reference current _idref is obtained by _feedforward superposition; the first reference current _idref is input into the D-axis current loop, so that _idref is subtracted from the D-axis rectified input current _id to obtain the first output current, and the first output current Proportional and Integral (PI, proportional and Integral) adjustment is performed to obtain the first input voltage, and the first input voltage is superimposed on the D-axis rectified input voltage v _d to obtain the D-axis feedforward voltage value u _d1 .

The reactive current control module is used to perform reactive current control on the Q axis of the rotating coordinates by using i _{q feedforward} to obtain the Q-axis feedforward voltage value wave u _q2 , which may specifically include: obtaining reactive current i _cq , and Superimpose i _cq with the Q-axis feedforward current value i _{q feedforward} to obtain the second reference current i _qref ; input the second reference current i _qref into the Q-axis current loop, so that i _qref is subtracted from the Q-axis rectified input current i _q Calculate to obtain the second output current, perform PI adjustment on the second output current to obtain the second input voltage, and superimpose the second input voltage and the Q-axis rectified input voltage v _q to obtain the Q-axis feedforward voltage value u _q1 .

The first bus difference control module is used to control the bus difference on the Z axis of the rotating coordinates by using _{iz feedforward} to obtain the Z-axis feedforward voltage value u _z2 , which may specifically include: obtaining according to the positive bus voltage and the negative bus voltage The current positive and negative bus voltage difference △v _pn , and adjust the positive and negative bus voltage difference by P to obtain the second input current; specifically, after obtaining △v _pn , it is necessary to compare the current positive and negative bus voltage difference △v _pn with the preset Set positive and negative bus voltage difference △v _ref to do subtraction, but △v _ref is 0, so P adjustment can be directly performed on △v _pn . Superimpose the second input current with the Z-axis feedforward current value i _{z feedforward} to obtain the third reference current i _zref ; input the third reference current i _zref into the Z-axis current loop, so that i _zref and the Z-axis rectified input current i _z Do subtraction to get the third output current, perform PI adjustment on the third output current to get the first input voltage, superimpose the first input voltage and the Z-axis rectified input voltage v _z , and get the Z-axis feedforward voltage value u _z1 .

When feeding forward through the N-line current, the first feed-forward current includes the instantaneous current values of A-phase, B-phase and C-phase feed-forward, and the second feed-forward current includes: the current value of Z-axis feed-forward, the first feed-forward voltage Including: Z-axis feed-forward voltage value.

Correspondingly, the rectification loop control unit includes: a second bus difference control module, and a second bus difference control module, which is specifically used to control the bus difference on the Z axis by using the Z-axis feed-forward current value in the second feed-forward current , to get the Z-axis feed-forward voltage value.

In some embodiments, the second feedforward current includes a Z-axis feedforward current value: iz _feedforward , where, $i_{\mathrm{zfeedforward}}=\frac{i_{\mathrm{InvActiveA}}+i_{\mathrm{InvActiveB}}+i_{\mathrm{InvActiveC}}}{3}.$

Embodiments of the present invention may further include: a sixth coordinate transformation unit, configured to perform coordinate transformation on the rectified input current to obtain rectified input currents on the D-axis, Q-axis, and Z-axis; to perform coordinate transformation on the rectified input voltage to obtain the D-axis, Q-axis, and Z-axis rectified input currents; The rectified input voltage of the Q axis and the Z axis, wherein, the rectified input current includes: the rectified input current of the A phase, the B phase and the C phase, the rectified input voltage includes: the rectified input voltage of the A phase, the B phase and the C phase, and The rectified input currents of the D-axis, Q-axis and Z-axis and the rectified input voltages of the D-axis, Q-axis and Z-axis after coordinate transformation by the third coordinate transformation unit are respectively input into the second bus voltage control module.

It should be noted that the sixth coordinate transformation unit, the above-mentioned third coordinate transformation unit, the fourth coordinate transformation unit and the fifth coordinate transformation unit all perform coordinate transformation on the rectified input current and the rectified input voltage, and the above four can be the same Coordinate transformation unit.

Specifically, the second bus difference control module is used to control the bus difference using iz _feedforward on the Z axis of the rotating coordinates to obtain the Z-axis feedforward voltage value u _z1 , which may specifically include: according to the positive bus voltage and the negative bus voltage The voltage obtains the current positive and negative bus voltage difference △v _pn , and performs P adjustment on the positive and negative bus voltage difference to obtain the second input current; specifically, after obtaining △v _pn , the current positive and negative bus voltage difference △v _pn Do subtraction operation with the preset positive and negative bus voltage difference △v _ref , but △v _ref is 0, so P adjustment can be directly performed on △v _pn . Superimpose the second input current with the Z-axis feedforward current value i _{z feedforward} to obtain the third reference current i _zref ; input the third reference current i _zref into the Z-axis current loop, so that i _zref and the Z-axis rectified input current i _z Do subtraction to get the third output current, perform PI adjustment on the third output current to get the first input voltage, superimpose the first input voltage and the Z-axis rectified input voltage v _z , and get the Z-axis feedforward voltage value u _z1 .

In addition, the rectification loop control unit also includes: a proportional P regulator, and a proportional and integral PI regulator; the P regulator is used to adjust the bus voltage difference to obtain the first input current, and to adjust the positive and negative bus voltage differences. adjusting to obtain a second input current; the PI regulator is used to adjust the first output current to obtain a first input voltage; adjust the second output current to obtain a second input voltage; and adjust the third output current , to get the third input voltage.

It can be seen from the above that the embodiment of the present invention can obtain the first feedforward current according to the rectified input voltage, the inverter output voltage and the inverter output current, and then perform coordinate transformation on the first feedforward current to obtain the second feedforward current, and then use The second feedforward current is rectified and controlled to obtain the first feedforward voltage, and coordinate transformation is performed on the first feedforward voltage to obtain the second feedforward voltage; finally, the second feedforward voltage is modulated to generate a pulse signal, and the pulse Signal input rectifier. In the embodiment of the present invention, the power consumed by the inverter and other power units is directly fed forward to the rectifier, so that the current of the N line of the rectifier and the inverter is basically the same, that is, the current flowing from the midpoint of the bus capacitor to the N line of the inverter The minimum, thereby effectively reducing the bus ripple, and improving the control efficiency of the bus ripple.

In addition, the present invention also provides a system for controlling bus ripple. Specifically, the system for controlling bus ripple may be an uninterruptible power supply (UPS, Uninterruptible Power System) system. The embodiment of the present invention takes the application in UPS as an example to describe in detail description, but not limitation of the present invention.

Please refer to FIG. 12 . FIG. 12 is a schematic structural diagram of a system for controlling bus ripple in an embodiment of the present invention. The system for controlling bus ripple may specifically include: a rectifier 500 , an inverter 600 and a device 400 for controlling bus ripple. Wherein, the rectifier 500 provides a stable DC voltage to power units such as the inverter 600, and the inverter 600 converts the DC voltage into AC power and outputs it to the load.

The device 400 for controlling the bus ripple is connected between the rectifier 500 and the inverter 600, and is used to obtain the rectified input voltage, the inverter output voltage and the inverter output current; according to the obtained rectified input voltage, inverter output voltage and inverter Change the output current to obtain the first feedforward current; perform coordinate transformation on the first feedforward current to obtain the second feedforward current; use the second feedforward current to perform rectification control to obtain the first feedforward voltage; Coordinate transformation is performed to obtain the second feedforward voltage; the second feedforward voltage is modulated to generate a pulse signal, and the pulse signal is input to the rectifier to control the voltage of the bus capacitor.

It should be noted that, the specific implementation of the device 400 for controlling bus ripple can refer to the above-mentioned embodiments, which will not be repeated here.

In the foregoing embodiments, the descriptions of each embodiment have their own emphases, and for parts not described in detail in a certain embodiment, reference may be made to relevant descriptions of other embodiments.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the above-mentioned storage The medium can be read-only memory, magnetic or optical disk, etc.

The method, device and system for controlling bus ripple provided by the present invention have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for helping Understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the embodiment of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification It should not be construed as a limitation of the invention.

Claims (20)

1. A method of controlling bus ripple, comprising:

acquiring a rectification input voltage, an inversion output voltage and an inversion output current;

obtaining a first feed-forward current according to the obtained rectified input voltage, the obtained inverted output voltage and the obtained inverted output current;

performing coordinate transformation on the first feedforward current to obtain a second feedforward current;

performing rectification control by using the second feedforward current to obtain a first feedforward voltage;

performing coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage;

and modulating the second feedforward voltage to generate a pulse signal, and inputting the pulse signal into the rectifier to control the voltage of the bus capacitor.

2. The method of claim 1, wherein the second feed forward current comprises: current values for D-axis, Q-axis, and Z-axis feed forward, the first feed forward voltage comprising: voltage values fed forward by a D axis, a Q axis and a Z axis;

the obtaining of the first feedforward voltage by performing rectification control on the second feedforward current specifically includes:

carrying out bus voltage control on the D axis by adopting the D axis feedforward current value in the second feedforward current to obtain a D axis feedforward voltage value;

performing reactive current control on the Q axis by adopting a Q axis feedforward current value in the second feedforward current to obtain a Q axis feedforward voltage value;

and carrying out bus difference control on the Z axis by adopting the current value of the Z axis feedforward in the second feedforward current to obtain the voltage value of the Z axis feedforward.

3. The method of claim 1, wherein the second feed forward current comprises: a Z-axis feed-forward current value, the first feed-forward voltage comprising: a Z-axis feed-forward voltage value;

the obtaining of the first feedforward voltage by performing rectification control on the second feedforward current specifically includes:

and carrying out bus difference control on the Z axis by adopting the current value of the Z axis feedforward in the second feedforward current to obtain the voltage value of the Z axis feedforward.

4. The method of claim 2, wherein the rectifying the input voltage comprises: rectified input voltages of phase A, phase B and phase C;

before the D-axis is subjected to bus voltage control by using the current value of the D-axis feedforward in the second feedforward current, and the voltage value of the D-axis feedforward is obtained, the method further includes:

performing coordinate transformation on the rectified input voltages of the A phase, the B phase and the C phase to obtain rectified input voltages of a D axis, a Q axis and a Z axis;

obtaining a rectified input current, the rectified input current comprising: rectified input currents of the A phase, the B phase and the C phase;

performing coordinate transformation on the rectified input currents of the A phase, the B phase and the C phase to obtain rectified input currents of a D axis, a Q axis and a Z axis;

the bus voltage control is carried out on the D axis by adopting the current value of the D axis feedforward in the second feedforward current to obtain the voltage value of the D axis feedforward, and the method specifically comprises the following steps:

subtracting a preset bus voltage value and a current bus voltage value to obtain a bus voltage difference, and adjusting the bus voltage difference to obtain a first input current;

superposing the first input current and the current value of the D-axis feedforward to obtain a first reference current;

inputting the first reference current into a D-axis current loop, so that the first reference current and the D-axis rectified input current are subjected to subtraction operation to obtain a first output current, and adjusting the first output current to obtain a first input voltage;

and superposing the first input voltage and the D-axis rectified input voltage to obtain a D-axis feedforward voltage value.

5. The method of claim 2 or 4, wherein the rectifying the input voltage comprises: rectified input voltages of phase A, phase B and phase C;

before the reactive current control is performed on the Q axis by using the Q axis feedforward current value in the second feedforward current to obtain the Q axis feedforward voltage value, the method further includes:

performing coordinate transformation on the rectified input voltages of the A phase, the B phase and the C phase to obtain rectified input voltages of a D axis, a Q axis and a Z axis;

obtaining a rectified input current, the rectified input current comprising: rectified input currents of the A phase, the B phase and the C phase;

performing coordinate transformation on the rectified input currents of the A phase, the B phase and the C phase to obtain rectified input currents of a D axis, a Q axis and a Z axis;

the method for controlling the reactive current on the Q axis by adopting the current value of the Q axis feedforward in the second feedforward current to obtain the voltage value of the Q axis feedforward specifically comprises the following steps:

obtaining reactive current, and superposing the reactive current and the current value of the Q-axis feedforward to obtain second reference current;

inputting the second reference current into a Q-axis current loop, so that the second reference current and the Q-axis rectified input current are subjected to subtraction operation to obtain a second output current, and adjusting the second output current to obtain a second input voltage;

and superposing the second input voltage and the Q-axis rectification input voltage to obtain a Q-axis feedforward voltage value.

6. The method of any of claims 2 to 5, wherein rectifying the input voltage comprises: rectified input voltages of phase A, phase B and phase C;

before the bus difference control is performed on the Z axis by adopting the current value of the Z axis feedforward in the second feedforward current to obtain the voltage value of the Z axis feedforward, the method further includes:

performing coordinate transformation on the rectified input voltages of the A phase, the B phase and the C phase to obtain rectified input voltages of a D axis, a Q axis and a Z axis;

obtaining a rectified input current, the rectified input current comprising: rectified input currents of the A phase, the B phase and the C phase;

performing coordinate transformation on the rectified input currents of the A phase, the B phase and the C phase to obtain rectified input currents of a D axis, a Q axis and a Z axis;

the bus difference control is carried out on the Z axis by adopting the current value of the Z axis feedforward in the second feedforward current to obtain the voltage value of the Z axis feedforward, and the method specifically comprises the following steps:

acquiring a positive bus voltage difference and a negative bus voltage difference according to the positive bus voltage and the negative bus voltage, and adjusting the positive bus voltage difference and the negative bus voltage difference to obtain a second input current;

superposing the second input current and the current value of the Z-axis feedforward to obtain a third reference current;

inputting the third reference current into a Z-axis current loop, so that the third reference current and the Z-axis rectified input current are subjected to subtraction operation to obtain a third output current, and adjusting the third output current to obtain a third input voltage;

and superposing the third input voltage and the Z-axis rectified input voltage to obtain a Z-axis feedforward voltage value.

7. The method of any of claims 1-6, wherein the first feed forward current comprises instantaneous current values for a-phase, B-phase, and C-phase feed forward; the obtaining of the first feedforward current according to the obtained rectified input voltage, the obtained inverted output voltage and the obtained inverted output current specifically includes:

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveA</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVA</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Aactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECA</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>A</mi> <mi>INV</mi> </msub> </mrow> </math>

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveB</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVB</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Bactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECB</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>B</mi> <mi>INV</mi> </msub> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveC</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVC</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Cactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECC</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>C</mi> <mi>INV</mi> </msub> </mrow> </math>

wherein i_InvActiveA、i_InvActiveBAnd i_InvActiveCInstantaneous current values of phase A, phase B and phase C feedforward respectively;

u_INVA、u_INVBand u_INVCThe inverter output voltages of the phase A, the phase B and the phase C are respectively;

u_RECA、u_RECBand u_RECCRectified input voltages of phase A, phase B and phase C respectively;

i_Aactive、i_Bactiveand i_CactiveThe inverter output currents of the phase A, the phase B and the phase C are respectively;

CosA_INV、CosB_INVand CosC_INVThe cosine values of the phase angles of the A-phase, B-phase and C-phase inverse output voltages are respectively.

8. The method of claim 7, further comprising:

when the second feedforward current comprises current values of D-axis feedforward, Q-axis feedforward and Z-axis feedforward and the first feedforward voltage comprises voltage values of D-axis feedforward, Q-axis feedforward and Z-axis feedforward, the current value i of the D-axis feedforward_{d feedforward}＝i_InvActiveACurrent value i of said Q-axis feedforward_{q feedforward}＝i_InvActiveBCurrent value i of said Z-axis feedforward_{z feedforward}＝i_InvActiveC。

9. The method of claim 7, further comprising:

when the second feedforward current comprises a current value of Z-axis feedforward and the first feedforward voltage comprises a voltage value of Z-axis feedforward, the current value i of the Z-axis feedforward_{z feedforward}Comprises the following steps:

$i_{\mathrm{zfeedforward}}=\frac{i_{\mathrm{InvActiveA}}+i_{\mathrm{InvActiveB}}+i_{\mathrm{InvActiveC}}}{3}.$

10. an apparatus for controlling bus ripple, comprising:

the detection unit is used for acquiring a rectification input voltage, an inversion output voltage and an inversion output current;

the data processing unit is used for obtaining a first feedforward current according to the rectified input voltage, the inversion output voltage and the inversion output current obtained by the detection unit;

the first coordinate transformation unit is used for carrying out coordinate transformation on the first feedforward current to obtain a second feedforward current;

the rectification loop control unit is used for carrying out rectification control by adopting the second feedforward current to obtain a first feedforward voltage;

the second coordinate transformation unit is used for carrying out coordinate transformation on the first feedforward voltage to obtain a second feedforward voltage;

and the modulation wave-sending unit is used for modulating the second feedforward voltage to generate a pulse signal, and the pulse signal is input into the rectifier to control the voltage of the bus capacitor.

11. The apparatus of claim 10, wherein the second feed forward current comprises: current values for D-axis, Q-axis, and Z-axis feed forward, the first feed forward voltage comprising: voltage values fed forward by a D axis, a Q axis and a Z axis;

the rectification loop control unit includes: the system comprises a bus voltage control module, a reactive current control module and a first bus difference control module;

the bus voltage control module is used for carrying out bus voltage control on a D axis by adopting a D axis feedforward current value in second feedforward current to obtain a D axis feedforward voltage value; the reactive current control module is used for performing reactive current control on the Q axis by adopting a Q axis feedforward current value in the second feedforward current to obtain a Q axis feedforward voltage value; and the first bus difference control module is used for carrying out bus difference control on the Z axis by adopting the current value of the Z axis feedforward in the second feedforward current to obtain the voltage value of the Z axis feedforward.

12. The apparatus of claim 10, wherein the second feed forward current comprises: a Z-axis feed-forward current value, the first feed-forward voltage comprising: a Z-axis feed-forward voltage value;

the rectification loop control unit includes: a second bus bar difference control module;

and the second bus difference control module is used for carrying out bus difference control on the Z axis by adopting the current value of Z axis feedforward in the second feedforward current to obtain the voltage value of Z axis feedforward.

13. The apparatus of claim 11,

the detection unit is also used for acquiring a rectified input current;

the device further comprises: the third coordinate transformation unit is used for carrying out coordinate transformation on the rectified input current to obtain rectified input currents of a D axis, a Q axis and a Z axis; and carrying out coordinate transformation on the rectified input voltage to obtain rectified input voltages of a D axis, a Q axis and a Z axis, wherein the rectified input current comprises: rectified input currents of phases A, B and C, the rectified input voltage comprising: rectified input voltages of phase A, phase B and phase C;

the bus voltage control module is used for subtracting a preset bus voltage value from a current bus voltage value to obtain a bus voltage difference, and regulating the bus voltage difference to obtain a first input current; superposing the first input current and the current value of the D-axis feedforward to obtain a first reference current; inputting the first reference current into a D-axis current loop, so that the first reference current and the D-axis rectified input current are subjected to subtraction operation to obtain a first output current, and adjusting the first output current to obtain a first input voltage; and superposing the first input voltage and the D-axis rectified input voltage to obtain a D-axis feedforward voltage value.

14. The apparatus of claim 11 or 13,

the detection unit is also used for acquiring a rectified input current;

the device further comprises: the fourth coordinate transformation unit is used for carrying out coordinate transformation on the rectified input current to obtain rectified input currents of a D axis, a Q axis and a Z axis; and carrying out coordinate transformation on the rectified input voltage to obtain rectified input voltages of a D axis, a Q axis and a Z axis, wherein the rectified input current comprises: rectified input currents of phases A, B and C, the rectified input voltage comprising: rectified input voltages of phase A, phase B and phase C;

the reactive current control module is used for acquiring reactive current and superposing the reactive current and the current value of the Q-axis feedforward to obtain second reference current; inputting the second reference current into a Q-axis current loop, so that the second reference current and the Q-axis rectified input current are subjected to subtraction operation to obtain a second output current, and adjusting the second output current to obtain a second input voltage; and superposing the second input voltage and the Q-axis rectification input voltage to obtain a Q-axis feedforward voltage value.

15. The apparatus of any one of claims 11, 13 or 14,

the detection unit is also used for acquiring a rectified input current;

the device further comprises: the fifth coordinate transformation unit is used for carrying out coordinate transformation on the rectified input current to obtain rectified input currents of a D axis, a Q axis and a Z axis; and carrying out coordinate transformation on the rectified input voltage to obtain rectified input voltages of a D axis, a Q axis and a Z axis, wherein the rectified input current comprises: rectified input currents of phases A, B and C, the rectified input voltage comprising: rectified input voltages of phase A, phase B and phase C;

the first bus bar difference control module is used for acquiring a positive bus bar voltage difference and a negative bus bar voltage difference according to the positive bus bar voltage and the negative bus bar voltage, and regulating the positive bus bar voltage difference and the negative bus bar voltage difference to obtain a second input current; superposing the second input current and the current value of the Z-axis feedforward to obtain a third reference current; inputting the third reference current into a Z-axis current loop, so that the third reference current and the Z-axis rectified input current are subjected to subtraction operation to obtain a third output current, and adjusting the third output current to obtain a third input voltage; and superposing the third input voltage and the Z-axis rectified input voltage to obtain a Z-axis feedforward voltage value.

16. The apparatus of claim 12,

the detection unit is also used for acquiring a rectified input current;

the device further comprises: a sixth coordinate transformation unit, which performs coordinate transformation on the rectified input current to obtain rectified input currents of a D axis, a Q axis and a Z axis; and carrying out coordinate transformation on the rectified input voltage to obtain rectified input voltages of a D axis, a Q axis and a Z axis, wherein the rectified input current comprises: rectified input currents of phases A, B and C, the rectified input voltage comprising: rectified input voltages of phase A, phase B and phase C;

the second bus difference control module is used for acquiring a positive bus voltage difference and a negative bus voltage difference according to the positive bus voltage and the negative bus voltage, and regulating the positive bus voltage difference and the negative bus voltage difference to obtain a second input current; superposing the second input current and the current value of the Z-axis feedforward to obtain a third reference current; inputting the third reference current into a Z-axis current loop, so that the third reference current and the Z-axis rectified input current are subjected to subtraction operation to obtain a third output current, and adjusting the third output current to obtain a third input voltage; and superposing the third input voltage and the Z-axis rectified input voltage to obtain a Z-axis feedforward voltage value.

17. The apparatus according to any one of claims 10 to 16, wherein the first feedforward current comprises instantaneous current values of a-phase, B-phase and C-phase feedforward, wherein the data processing unit is specifically configured to perform the following data processing:

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveA</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVA</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Aactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECA</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>A</mi> <mi>INV</mi> </msub> </mrow> </math>

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveB</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVB</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Bactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECB</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>B</mi> <mi>INV</mi> </msub> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>i</mi> <mi>InvActiveC</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>u</mi> <mi>INVC</mi> </msub> <mo>&CenterDot;</mo> <msub> <mi>i</mi> <mi>Cactive</mi> </msub> </mrow> <msub> <mi>u</mi> <mi>RECC</mi> </msub> </mfrac> <mo>&CenterDot;</mo> <mi>Cos</mi> <msub> <mi>C</mi> <mi>INV</mi> </msub> </mrow> </math>

wherein i_InvActiveA、i_InvActiveBAnd i_InvActiveCInstantaneous current values of phase A, phase B and phase C feedforward respectively;

u_INVA、u_INVBand u_INVCThe inverter output voltages of the phase A, the phase B and the phase C are respectively;

u_RECA、u_RECBand u_RECCRectified input voltages of phase A, phase B and phase C respectively;

i_Aactive、i_Bactiveand i_CactiveThe inverter output currents of the phase A, the phase B and the phase C are respectively;

CosA_INV、CosB_INVand CosC_INVThe cosine values of the phase angles of the A-phase, B-phase and C-phase inverse output voltages are respectively.

18. The apparatus of claim 17,

when the second feed forward current comprises: current values of D-, Q-and Z-axis feedforward, the first feedforwardThe voltages include: d-axis, Q-axis and Z-axis feedforward voltage values, and current value i of D-axis feedforward_{d feedforward}＝i_InvActiveACurrent value i of said Q-axis feedforward_{q feedforward}＝i_InvActiveBCurrent value i of said Z-axis feedforward_{z feedforward}＝i_InvActiveC。

19. The apparatus of claim 17, further comprising:

when the second feed forward current comprises: a Z-axis feed-forward current value, the first feed-forward voltage comprising: the current value i of Z-axis feedforward_{z feedforward}Comprises the following steps:

$i_{\mathrm{zfeedforward}}=\frac{i_{\mathrm{InvActiveA}}+i_{\mathrm{InvActiveB}}+i_{\mathrm{InvActiveC}}}{3}.$

20. a system for controlling bus ripple, comprising:

rectifier, inverter and device for controlling a bus ripple according to any of claims 10 to 19.