KR20160002300A - Power compensating apparatus including active dc-link circuit and method for compensating power using active dc-link circuit - Google Patents

Abstract

A power compensation apparatus includes: an active DC stage circuit supplying driving power to a load end after receiving power from a system; and a control unit controlling the active DC stage circuit. According to one embodiment of the present invention, the control unit can control the active DC stage circuit to compensate harmonic components of a system current. Also, according to one embodiment of the present invention, the control unit can control the active DC stage circuit to supply compensation power to the load end in a section where the system does not supply power to the load end. Also, the power compensation apparatus includes: the active DC stage circuit which receives power from a power source and supplies the driving power to the load; and the control unit controlling the active DC stage terminal. The control unit can control the active DC stage circuit to compensate harmonics power or the fundamental wave of the switching frequency of the load or the power source generating a current including switching ripples.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a power compensating apparatus including an active DC circuit and a power compensation method using an active DC circuit. BACKGROUND OF THE INVENTION < RTI ID = 0.0 >

Embodiments relate to a power compensation method using an active DC circuit and a power compensation method using an active DC circuit. More specifically, the present invention relates to a method of compensating a power of a harmonic component or the like, a switching frequency ripple, To a power compensation apparatus and a power compensation method.

Diode rectification systems are generally used in grid-connected systems such as home appliances, such as washing machines and refrigerators, and large-capacity motor drive systems.

Referring to FIG. 1, the conventional diode rectification system 100 transmits power generated in the system stage 110 to the load stage 130 via the diode rectifier 120. Since the output voltage of the diode rectifier 120, that is, the voltage of the node between the diode rectifier 120 and the initial charging circuit 140 is defined as the maximum value of the line-to-line voltage, harmonics of the grid frequency A second harmonic in the case of a single phase, and a sixth harmonic in the case of a three-phase) component enters the DC stage 150. Therefore, in order to prevent the harmonic component from affecting the negative terminal 130, a harmonic component is absorbed into the DC capacitor 160 by using a large-capacity DC short-circuit capacitor 160.

In general, when an electrolytic capacitor having the largest capacitance per unit volume is used as the DC capacitor 160 for securing a large capacitance, the reliability of the entire system is deteriorated due to a high failure rate, and other types of long- There arises a problem of price and volume. In addition, when a large-capacity capacitor is used as the DC capacitor 160, a pre-charging circuit 140 is additionally required.

FIG. 2 shows an embodiment of a motor-driven three-phase diode rectification system in which an inductor L _dc is used as an input stage DC filter. The input stage means the part of the rectification system excluding the lower stage. In the system of Figure 2, the grid current (current flowing between the inductor L _g and the EMI filter 270), when using a dc capacitor 260 having a capacitance of several thousands of μF without an inductor L _dc , As shown in Fig. 1B, and it generates a lot of harmonic components and adversely affects other devices. Therefore, the inductor it is possible to attenuate the harmonic content of the current system as shown in Figure 3b, by using the (L _dc), can satisfy the regulation system _{(IEC61000-3-12 R sce. Min> 250} ). However, input stage filters also have the drawback of increasing the overall system weight and cost.

To solve this problem, a system using a small capacity DC terminal capacitance has been studied, and a system with a small DC terminal capacitance can be manufactured with an intensive and cost competitive circuit because the DC terminal capacitor does not take up a large volume. However, due to the low capacitance, the DC short-circuit voltage (the voltage across the DC short-circuit capacitor) is shaken to the maximum value of the line-to-line voltage, and the resonant frequency due to the DC capacitor and the inductor deviates from the bandwidth of the controller, Likewise, the system becomes unstable.

Therefore, the conventional control technique actively copes with active damping control at the lower stage. As a result, the grid current and the DC short-circuit voltage are relatively stable as shown in FIG. 4B, And the operating performance is deteriorated. Also, when there is a restriction on switching and sampling periods in the inverter of the lower stage due to the motor driving algorithm such as sensorless control, the performance of the conventional active control technique is remarkably degraded.

Korean Registered Patent No. 10-1321236

According to an aspect of the present invention, a large-capacity direct-current capacitor can be substituted and the input stage filter can be reduced, and the output quality on the load side or the operation area can be avoided.

Further, according to an aspect of the present invention, the harmonic compensation control of the system stage current can be separated from the load stage.

Further, according to one aspect of the present invention, it is possible to provide a necessary torque at the lower stage by always providing a constant power at the lower stage.

Further, according to one aspect of the present invention, it is possible to compensate the switching frequency ripple of the ripple-containing current source or the ripple-containing current load.

The power compensation apparatus according to an embodiment includes: an active DC stage circuit that is supplied with electric power from a system and supplies drive power to a load stage using the electric power; And a control unit electrically connected to the active DC circuit to control the active DC circuit, wherein the active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground, Wherein the control unit includes a harmonic compensation control unit for controlling the active DC circuit so that the active DC circuit compensates harmonic components of the grid current by controlling the grid current, The harmonic components of the grid current are compensated by extracting the harmonic components from the voltage signals at both ends.

The power compensation apparatus according to an embodiment includes: an active DC stage circuit that is supplied with electric power from a system and supplies drive power to a load stage using the electric power; And a control unit electrically connected to the active DC circuit to control the active DC circuit, wherein the controller controls the active DC circuit so that the active DC circuit controls the grid current by controlling the grid current, And the grid current compensation controller controls the DC current circuit so that the active DC cir- cuit circuit supplies the compensation power to the sub-stage in an interval in which power is not supplied from the system to the sub- And a sub-stage power compensation controller for controlling the active DC circuit.

The power compensation apparatus according to an embodiment includes: an active DC circuit that receives power from a power source and supplies driving power to the load using the power; And a control unit electrically connected to the active DC circuit to control the active DC circuit, wherein at least one of the power source and the load generates a current including a switching ripple, And a switching ripple compensation control unit for controlling the active DC circuit so that the circuit compensates the fundamental wave or the harmonic power of the switching frequency of the ripple-containing power supply or the ripple-containing load.

A power compensation method according to an embodiment includes powering an active DC circuit from a system; Compensating a harmonic component of the grid current by controlling the grid current using the active DC stage circuit; And supplying power to the load using the active DC circuit, wherein the active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground, Compensating for the harmonic component of the first capacitor includes extracting the harmonic component from the voltage signal across the first capacitor.

In one embodiment, extracting the harmonic component from the voltage signal across the first capacitor comprises bandpass filtering the voltage signal across the first capacitor.

In one embodiment, compensating for the harmonic component of the grid current comprises: amplifying the extracted harmonic component; And summing the amplified harmonic components.

In one embodiment, the method further comprises reducing resonance by controlling the grid current using the active DC stage circuit.

In one embodiment, reducing the resonance by controlling the grid current comprises high pass filtering the voltage signal across the first capacitor.

In one embodiment, reducing resonance by controlling the grid current comprises: summing the harmonic components extracted from the voltage signal across the first capacitor; Subtracting the voltage signal across the first capacitor from the summed harmonic component; And amplifying the summed harmonic component subtracted by the voltage signal across the high-pass filtered first capacitor.

In one embodiment, the step of compensating for the harmonic component of the grid current comprises the steps of: detecting an output power of a lower stage electrically connected to the active DC stage; And controlling the grid current in real time based on the detected output power of the lower stage.

A power compensation method according to an embodiment includes powering an active DC circuit from a system; Adjusting the harmonic component of the grid current by controlling the grid current using the active DC stage circuit; And a step of supplying power to the load using the active DC step circuit, wherein the step of adjusting the harmonic component of the grid current comprises the step of supplying power from the system And supplying the compensating power to the sub-stage using the active DC circuit in an unreceivable section.

In one embodiment, the step of supplying the compensating power to the negative terminal comprises: detecting an output power of the negative terminal; And calculating a current command of the lower stage based on the detected output power of the lower stage.

In one embodiment, the active DC stage circuit includes a first capacitor, one end of which is electrically connected to the system and the other end of which is connected to ground, and the step of supplying the compensating power to the sub- And maintaining the voltage above a predetermined minimum value.

In one embodiment, the step of removing the harmonic component of the grid current comprises the step of: using the grid voltage, the predetermined minimum value of the voltage across the first capacitor and the output power of the lower voltage terminal, And a step of calculating a command of a voltage across both terminals.

A power compensation method according to an exemplary embodiment includes: supplying power from a power source to an active DC circuit; Compensating a fundamental wave or a harmonic power of a switching frequency of a load electrically connected to the power source or the active DC circuit using the active DC circuit; And powering the load using the active DC stage circuit, wherein at least one of the power source and the load generates a current comprising switching ripple.

In one embodiment, compensating for the fundamental or harmonic power of the switching frequency may comprise: comparing the switching frequency of the inductor current included in the active DC circuit with the switching frequency of the ripple-containing power supply or the ripple- Controlling the power supply or the switching frequency of the ripple-containing load to be higher than the switching frequency of the power supply or the ripple-containing load.

In one embodiment, the switching frequency of the inductor current included in the active DC circuit is controlled to be equal to or higher than the switching frequency of the ripple-containing power supply or the ripple-containing load or higher than the switching frequency of the ripple- The step includes bandpass filtering the current signal flowing through the ripple-containing power supply or the ripple-containing load.

The power compensating apparatus according to an embodiment of the present invention can store energy to suppress resonance of an input terminal or compensate harmonic components of an input / output current, so that the lower terminal can operate independently of harmonic power generated at an input terminal, It is possible to secure the output and the operation area of the vehicle.

Also, the power compensation apparatus according to an embodiment of the present invention can realize a system having high reliability by using a low failure rate and a high number of elements.

Also, since the power compensation apparatus according to the embodiment of the present invention can compensate the switching frequency ripple, the additional capacitor ripple current can be reduced.

Figure 1 schematically shows the structure of a conventional diode rectification system.
Figure 2 shows a three-phase diode rectifier system for motor drive using an inductor as the input stage DC filter.
Figures 3a and 3b show the current and voltage of a 380V three-phase diode rectification system using a large DC stage capacitor.
Figures 4A and 4B show the current, voltage and torque of the load side motor of a 380V three-phase diode rectifier system using a small DC dc capacitor and input stage filter.
5A and 5B show a diode rectification system including a power compensation device according to embodiments of the present invention.
6 is a detailed block diagram of a control unit of the power compensation apparatus according to an embodiment of the present invention.
7A to 7D show a three-phase diode rectification system including a power compensation device according to embodiments of the present invention.
8 shows current, voltage and torque waveforms of a three-phase diode rectification system including a power compensation device employing a step-up active dc circuit according to an embodiment of the present invention.
Fig. 9 shows an IEC61000-3-12 R _{sce . min} = 250 and a harmonic component of a three-phase diode rectification system including a power compensation device according to an embodiment of the present invention.
10 is a detailed block diagram of a control unit of a three-phase diode rectification system including a power compensation apparatus according to an embodiment of the present invention.
11 shows voltage and current waveforms of a three-phase diode rectification system including a power compensation device according to an embodiment of the present invention.
12 shows waveforms of the DC short-circuit voltage and the grid current according to the bottom-end power of the single-phase diode rectification system using a small-capacity DC capacitor.
13 shows a single-phase diode rectification system including a power compensation device according to an embodiment of the present invention.
FIG. 14 shows voltage, current, and power waveforms according to the minimum value of the DC short-circuit voltage of the single-phase diode rectification system including the power compensation apparatus according to an embodiment of the present invention.
15 is a detailed block diagram of a control unit of a single-phase diode rectification system of a power compensation apparatus according to an embodiment of the present invention.
16 shows voltage, current and power waveforms of a single-phase diode rectification system including a power compensation device according to an embodiment of the present invention.
17 is a block diagram illustrating a connection relationship between a power compensation device, a power source, and a load according to an embodiment of the present invention.
18 is a detailed block diagram of a control unit of the power compensation apparatus according to an embodiment of the present invention.
FIG. 19 shows a pass band of a band-pass filter included in a control unit of the power compensation apparatus according to an embodiment of the present invention.
20 is a graph showing a result of reducing switching noise by minimum frequency switching using a power compensation apparatus according to an embodiment of the present invention.
FIG. 21 is a graph illustrating a result of switching noise reduction in high frequency switching using a power compensation apparatus according to an embodiment of the present invention. Referring to FIG.

Hereinafter, the structure and characteristics of the present invention will be described with reference to examples, but the present invention is not limited to these examples. Where similar reference numerals are used in the several figures, like reference numerals refer to the same or similar functions for various embodiments.

5A and 5B illustrate a diode rectification system including an active DC stage circuit in accordance with embodiments of the present invention.

5A, the diode rectification system 5000 includes a system stage 5010, an EMI (Electromagnetic Interference) filter 5020, a diode rectifier 5030, a power compensation device 5080, and a load bottom 5090 And the power compensating apparatus 5080 may include an active DC circuit 5040, a measuring unit 5050, a control unit 5060, and a gate driver 5070.

The system stage 5010 may be a single phase system as shown in FIG. 5A, or a three phase system like the system stage shown in FIG. The system stage 5010 supplies necessary power at the lower stage 5090, the EMI filter 5020 reduces harmonics over 150kHz, and the diode rectifier 5030 rectifies the system voltage.

The active dc circuit 5040 and the measuring unit 5050 for controlling the same are connected to the control unit 5060 and the gate driver 5070 through the active damping control 5070, which is the load 5090 of the circuit including the conventional small capacity DC capacitor, It is possible not only to suppress the resonance occurring at the input stage including the configuration from the system stage 5010 to the active DC circuit 5040 but also to suppress the resonance of the system frequency included in the system current of the system stage 5010 It also serves to compensate for harmonic components. Specifically, the measurement unit 5050 measures the output of the load stage 5090 and the input / output voltage and current in the active DC circuit 5040 and transmits the measurement result to the control unit 5060. The control unit 5060 controls the harmonic component compensation And / or resonance suppression control, and the gate driver 5070 applies the control result to the active DC circuit 5040.

As shown in FIG. 5B, the diode rectification system 5100 may further include an AC filter 5110 or a DC filter 5120. Because the diode rectification system 5100 includes the active DC stage circuit 5130, the AC filter 5110 and the DC filter 5120 can use a smaller value element than the filter used in the conventional diode rectifier circuit, It is also possible to remove it as shown in FIG. 5A.

6 is a detailed block diagram of a control unit 5060 (FIG. 5) in a power compensation apparatus 5080 (FIG. 5) according to an embodiment of the present invention. The controller 5060 may include an internal dc voltage controller 610, a harmonic compensation controller 620, and a current controller 630.

The voltage and current information measured by the measuring unit 5050 is transmitted to the internal dc voltage control unit 610 or the harmonic compensation control unit 620. The internal dc voltage controller 610 maintains the average value of the internal dc voltage of the active dc circuit (for example, both ends of the capacitor C _dc2 of Fig. 7A) to a specific value, Performs harmonic power control to improve the harmonics generated in the system current of the input terminal. The output of the internal dc voltage control unit 610 and the harmonic compensation control unit 620 are input to the current control unit 630. The current control unit 630 receives the output of the harmonic compensation control unit 620 and the output of the internal dc voltage control unit 610, To the gate driver 5070 an output command for controlling the current in the active DC circuit 5040 (FIG. The gate driver 5070 transfers the switching signal to the switching element inside the active DC circuit 5040 (FIG. 5) based on the input output command.

Therefore, the harmonic compensation control can be separated from the load stage by supplying the power for improving the harmonics generated at the system end through the power compensation apparatus according to the embodiments of the present invention. Therefore, the conventional diode rectifier using the large capacity capacitor and the input stage filter The same subordinate output as the system can be obtained. In addition, active dc circuits all use small capacity or intensive devices, which can reduce the volume of the system as a whole. Unlike electrolytic capacitors, a high number of circuit designs are possible.

7A to 7D show a three-phase diode rectification system including a power compensation device according to embodiments of the present invention. FIGS. 7A to 7D respectively show active DC stages of a boost type, a buck type, a buck-boost type, and an H-bridge lift-up type, The circuit structure can be determined depending on the application of the entire system. The rectifying system of Figs. 7B to 7D may include the measuring unit, the control unit, and the gate driver (not shown) shown in Fig. 7A in addition to each active dc circuit. Hereinafter, the operation and detailed control of the three-phase diode rectification system will be described with reference to the step-up active dc circuit of Fig. 7a.

7A, the active DC circuit 740 of the power compensation device 700 according to an embodiment of the present invention includes an internal DC capacitor C _{dc2 in} addition to the DC capacitor C _dc1 of the entire system And the harmonic power generated in the system stage is transmitted to the internal DC capacitor C _dc2 to compensate for the harmonic power. The harmonic power compensation control controls the current flowing in the inductor L _x by alternately turning on and off the switches S ₁ and S ₂ for controlling the current in the active DC circuit 740, Energy is transmitted. The active DC circuit 740 can compensate for the harmonic power of the system end even if a large capacity element is not used. Since the control of the active dc circuit 740 is operated separately from the control of the dump terminal 750, it is possible to switch at a relatively high frequency, which can reduce the size of the inductor (L _x ) It can be secured.

The control unit of the power compensation apparatus 700 shown in FIG. 7A can largely include three parts. The internal DC voltage controller 710 controls the active DC _cascade circuit 740 such that the average voltage of the internal DC voltage V _dc2 is maintained at a constant value and the harmonic compensation controller 720 controls the DC voltage V _dc1 To extract the harmonic components included in the received signal and provide compensation power. The internal DC voltage V _dc2 means a voltage across the internal dc capacitor C _dc2 and the dc voltage V _dc1 means a voltage across the dc capacitor C _dc1 . The output P _dc2 of the internal dc voltage control unit 710 and the output _{d damp} of the harmonic compensation control unit 720 compensate for the amount of power required to control the internal dc voltage C _dc2 and harmonics of the system stage The amount of power required to achieve the required power. The sum of the required total power amount, that is, the sum of the output P _dc2 and the output P _damp is divided by the DC short-circuit voltage V _dc1 to obtain the reference current of the inductor L _x current of the active DC circuit, to obtain the _x ^ref), and a current control unit 730 calculates an average voltage across the required switch (S ₂₎ to control the inductor current (I _x) with the current command (I _x ^ref). The calculated voltage is transmitted to the gate driver and the gate driver outputs the on / off control signal of the switches S ₁ and S ₂ for synthesizing the voltage across the switch S ₂ to the voltage calculated by the current controller 730 And apply it to the circuit.

In one embodiment, the harmonic compensation control unit 720 may further include a resonance compensation control unit that controls the active DC circuit so that the active DC circuit reduces the resonance generated at the input end by controlling the grid current. 7A, the measurement unit detects the output power P _inv of the lower stage terminal 750 electrically connected to the active DC circuit 740, and the harmonic compensation control unit 720 detects the output power It is possible to control the system current in real time based on the output power P _inv using feedback from the measurement unit and the output power P _inv of the subsystem 750.

8 shows waveforms of current, voltage and torque of the three-phase diode rectification system shown in Fig. 7A. As compared to Figure 4b showing a resulting waveform of the three-phase diode rectifier system containing only a small capacity capacitor, the load motor torque shown in Fig. 8, the ripple is not nearly exist and the DC bus voltage (V _dc1) change the width seen that the smaller the . On the other hand, it can be confirmed that a large amount of harmonic components are contained in the internal direct current terminal voltage (V _dc2 ), which is a result of compensating the harmonic power generated in the system terminal by the internal DC capacitor (C _dc2 Energy change. At this time, the inductor current (I _x ) is the waveform shown at the bottom.

Fig. 9 shows an IEC61000-3-12 R _{sce . min} = 250 specified with the harmonic component of the three-phase diode rectifier system comprising an active DC stage circuit according to one embodiment of the present invention: a (in%) by comparing the graphs, figures are shown in Table 1 below.

Harmonic I ₂ I ₄ I ₅ I ₆ I ₇ I ₈ I ₁₀ I ₁₁ I ₁₂ I ₁₃ T HD P WHD Specified Value (%) 8 4 31 2.7 20 2 1.6 12 1.3 7 37 38 Measuring harmonics (%) 0.05 0.05 28.03 0.05 9.06 0.02 0.03 9.9 0.04 5.06 32.54 37.9

_Referring to FIG. 9 and Table 1, the harmonic components generated in the three-phase diode rectification system including the power compensating apparatus according to the embodiment of the present invention satisfy the requirements of IEC61000-3-12 R _sce.min = 250 system .

10 is a detailed block diagram of a control unit of an active DC circuit of a three-phase diode rectification system according to an embodiment of the present invention. The internal dc voltage controller 1010 may include a voltage controller (PI) for making the voltage command (V _dc2 ^* ) and the average value error of the voltage zero. The harmonic compensation control unit 1020 may include a portion for outputting a current (I _6nh ) for harmonic compensation control. The harmonic compensation control unit 1020 may further include a resonance compensation control unit for controlling the active DC circuit so that the active DC circuit controls the grid current to reduce the resonance. And outputting the current I _res .

First, the resonance compensation control unit includes a high pass filter (HPF) that receives a voltage across the DC capacitor C _dc1 as an input, and at least one harmonic component extractor that extracts a harmonic component from a voltage signal across the DC capacitor C _dc1 A band pass filter (BPF), an adder for summing the outputs of the at least one band pass filter, a subtracter for subtracting the output of the high pass filter from an output of the adder, and an amplifier (k _R ) for amplifying the output of the subtractor. _Which removes the direct current (DC) component from the direct-current voltage V _dc1 .

The portion for outputting the current I _6nh of the harmonic compensation control unit 1020 is a harmonic component of the system frequency f ₁ (for example, 60 Hz) from the voltage signal across the dc capacitor C _dc1 , And 2n harmonics (n = 1, 2, ...) in the case of a single phase). ? _{Bw1 ,? Bw2,? Bw3} , ... of the band-pass filter (BPF) (6f ₁ ), 2? (6 2? F ₁ ), 2? (6? 3? F ₁ ), and [rad], and? can be 0.1 or less so that only the frequency component can be extracted. Thus, for example, three-phase, voltage (v _dc6n) has been exists only 6n harmonic components, the component obtained by subtracting the output of the HPF in the voltage (v _dc6n) is an upcoming voltage (v _res). Voltage (v _res) can be obtained for most of the resonance frequency component becomes present, the voltage (v _res) a current (I _res) which amplifies the gain of the _R k.

Harmonic compensation control section 1020 is the output of the band pass filter (BPF), respectively, _{k 1, k 2, k 3} , ... , And the gain k _n can be adjusted as needed. k _n (n = 1, 2, 3, ...) is k _R The larger the value of k _n , the greater the degree of injection of the harmonic component. The harmonic compensation control unit 1020 may further include an adder that sums the outputs of the one or more amplifiers. k _n are all the same, the current (I _6nh ) and the voltage (v _dc6n ) can be expressed by the following equation (1).

[Formula 1]

In this case, P _inv is the output power of the negative stage, and? Is a proportional constant. P _inv / V _dc1 Is equal to the output current I _inv of the negative _terminal , and v _dc6n / V _dc1 is a value normalized by dividing the 6n harmonic component by V _dc1 . That is, I _6nh Means that the output current at the lower stage is supplied at a multiple of the 6n harmonic component of V _dc1 . Since the lower stage side always has a characteristic of outputting a constant power load, the sum of the DC dc component and the V _dc1 harmonic inverse component flows. 11 shows the voltage and current waveforms of a three-phase diode rectifier system including an active DC circuit in the case where? In Equation 1 is 1. Fig. If α is 1, it means that it supplies the same percentage of current as the 6n harmonic component of V _dc1 , so it is canceled with I _inv so that only the direct current component exists in the current I _diode from the diode rectifier. On the other hand, if α is greater than 1, the harmonic component flows into the diode rectifier current (I _diode ), which means that the harmonic component of the grid current changes. Harmonic power injection in an active DC stage circuit can therefore form a current waveform that meets the system requirements. Typically, IEC61000-3-12 R _{sce . min} satisfies the system requirement of 250, α has a value between 4 and 5.

The power compensation apparatus according to an embodiment of the present invention can also be applied to a single-phase diode rectification system. Figure 12 shows the current, voltage and power waveforms of a single phase diode rectifier system including a conventional low capacity DC stage capacitor.

12, when the system stage power and the input stage power are in the form of a sine wave square (a product of a sine wave voltage and a sine wave current), the system current is formed as a sinusoidal wave. However, Power ripple increases. In addition, the DC terminal voltage varies greatly depending on the power at the lower stage, and even the minimum value of the DC terminal voltage (V _dcmin ) may drop to 0V.

On the other hand, as shown by the solid line in FIG. 12, if the output of the negative terminal in the specific section is controlled to be zero, the system current can not be formed as a sinusoidal wave, but a waveform sufficient to satisfy the system specification can be maintained, Is maintained at a constant value (100 V in the case of the solid line waveform in Fig. 12), so that the speed control can be relatively stably performed even in the load side high-speed operation control requiring a relatively high output voltage. However, since there is no power transmission between the system stage and the lower stage in the section where the output of the lower stage remains at 0, without the additional power source, the torque necessary for the load can not be provided.

13 shows a single-phase diode rectification system including a power compensation device according to an embodiment of the present invention. The control unit of the power compensation device of the single phase diode rectification system 1300 may include an internal direct current voltage control unit 1310, a grid current compensation control unit 1320 and a current control unit 1330. The internal direct current voltage control unit 1310, And the current controller 1330 are the same as the internal DC voltage controller 710 and the current controller 730 of FIG. 7A. The grid current compensation control unit 1320 may include a lower stage power compensation controller 1340 and the lower stage power compensation controller 1340 may not supply power from the system stage to the lower stage, The power of the active dc circuit is supplied to the lower stage side to compensate the torque required at the lower stage. That is, the load can maintain a constant output due to the sub-bottom stage power compensation controller 1340 of the power compensation apparatus according to an embodiment of the present invention.

FIG. 14 shows voltage, current, and power waveforms according to the minimum value of the DC short-circuit voltage of the single-phase diode rectification system including the power compensation apparatus according to an embodiment of the present invention. The units of voltage, current, and power shown in Fig. 14 are [V], [A], and [W], respectively. Referring to FIG. 14, although the maximum value of the grid current in the conduction period, that is, the period in which the grid current is not 0 A, is larger than that in the prior art, the power is constantly supplied to the lower stage through the active DC circuit, So that it has an advantage of ensuring a stable output in controlling the load of the motor or the like.

15 is a detailed block diagram of a control unit of a power compensation apparatus according to an embodiment of the present invention. The internal dc voltage controller 1510 and the current controller 1530 operate in the same manner as the internal dc voltage controller 1010 and the current controller 1030 shown in Fig. In the single-phase diode rectification system shown in Fig. 15, the grid current compensation controller 1520 can control the active dc circuit to regulate unwanted noise frequency components including the harmonic components of the grid current, and in one embodiment, Components can be reduced or eliminated.

In addition, one end connected to the grid and electrically, and the other end capacitor connected with a ground; to (C _dc1 13) voltage of the DC bus voltage (V _dc1) of both ends can be maintained above a minimum value (V _{dc1 _ min)} pre-set The sub-stage power compensation controller included in the system current compensation controller 1520 controls the active DC circuit. Specifically, the sub-stage power compensation controller supplies power to the load using an active DC circuit. The grid current compensation controller 1520 may include a reference calculation unit and a voltage controller (PI). Command calculation section (References Calculation) is the grid voltage (V _g), a DC terminal voltage of the minimum value (V _{dc1 _ min)} and the sub-bottom of the output power (P _inv) the input received instruction bus voltage direct current thereof based on (V _dc1 ^* ) And the grid current command I _g ^* can be calculated and output. Here, I _m, which indicates the magnitude of the grid current command (I _g ^* ), can be calculated using the fact that the input power within the period of the system is equal to the output power (P _inv ) at the lower stage. The input power is equal to the product of the system voltage Vg and the grid current command I _g ^* . The command _Vdc1 ^* of the output DC voltage is input to the voltage controller PI and the voltage controller PI controls the DC voltage _Vdc1 to maintain the DC voltage _Vdc1 at the command value _Vdc1 ^* And outputs a command (I _dc1 ^* ) of the capacitor current. The sub-stage power compensation controller included in the grid current compensation controller 1520 calculates the current command I _inv ^* at the lower stage based on the output power P _inv of the lower stage, and the current command I _inv ^* The output power P _inv of the lower stage can be obtained by dividing the output power P _inv by the DC voltage V _dc1 . The direct current voltage command (V _dc1 ^* ) and the grid current command (I _g ^* ) can be calculated by the following equations 2 and 3, respectively.

[Formula 2]

[Formula 3]

The inductor current command I _x ^* which is the input of the current controller 1530 is obtained by summing the output I _dc of the internal dc voltage controller 1510 and the output I _comp of the grid current compensation controller 1520 have. The current controller 1530 receives the inductor current command I _x ^* and the actual inductor current I _x and outputs the DC terminal voltage V _dc1 and the grid current I _g to the direct current voltage command V _dc1 ^* ) And a voltage command (V _x ^* ) at both ends of the switch (S ₂ ; FIG. 13) of the active DC circuit for making the system current command I _g ^* .

16 illustrates voltage, current, and power waveforms through simulations of a single-phase diode rectifier system including an active DC stage circuit in accordance with an embodiment of the present invention. It can be seen that a constant power is supplied to the lower stage while the DC voltage (V _dc1 ) is maintained above a certain value. Even if there is a section where the DC voltage is kept near the minimum value, harmonic components of the system current satisfy the system regulations It can be confirmed that the following is sufficient.

The active DC circuit may be controlled to reduce the harmonic components of the switching frequency (e.g., several tens of kHz). The DC short-circuit utilizing capacitor C _dc1 shown in Fig. 17 connects two current sources. In this case, the two current sources may include a switching ripple component as well as a DC component. That is, the switching frequency included in the current source differs depending on the characteristics of the connected device or the power source. In particular, if a combination of a continuous current source - a discontinuous current load, a discontinuous current source - a continuous current load, or a discrete current source - a discontinuous current load, a smoothing capacitor C _dc1 ), The smoothing capacitor C _dc1 must have a large capacitance to smooth out the discontinuous current. The higher the value of the harmonic current rms (root mean square) of the discontinuous current device and the lower the switching frequency, the larger the capacitance of the smoothing capacitor C _dc1 . That is, in the conventional technique, the switching ripple (or the harmonic current component) existing between the current i _in and the current i _out is absorbed by the large-capacity smoothing capacitor C _dc1 .

On the other hand, when the power compensating apparatus 1740 according to the embodiment of the present invention is connected between the current source and the current load as shown in FIG. 17, there is a difference between the input current i _in and the load current i _out Harmonic current components can be compensated by the active DC circuit included in the power compensator 1740 so that the harmonic current flowing to the smoothing capacitor C _dc1 can be reduced and thus a smaller capacity capacitor can be used The voltage pulsation of the DC link stage and the rms amplitude of the harmonic current flowing to the capacitor C _dc1 can be reduced.

5A, the power compensating apparatus 1740 is connected to the active DC circuit shown in FIG. 17 by a measuring unit, a control unit, and a gate driver (not shown). The power supply 1710 or the load 1720 connected to the active DC circuit may be a ripple-containing power supply or a ripple-containing load that generates a current including a switching ripple, respectively, and the switching ripple is discontinuous or continuous.

18 is a detailed block diagram of a control unit of the power compensation apparatus according to an embodiment of the present invention, and can be used to reduce switching harmonics. The internal DC voltage controller 1810 controls the internal DC voltage V _dc2 of the active DC circuit to follow the voltage command V _dc2 ^* and can be set to operate in a low frequency band. The current control unit 1830 operates in the same manner as the current control unit 1030 of FIG. Active DC short circuit is the switching frequency of the inductors comprises an (L _x), the switching ripple compensation control section 1820 includes a switch (S _1, S ₂₎ comprises the active DC stage circuit as shown in Figure 17, i.e., inductor (Lx) equal to the switching frequency of the current and the switching frequency of the ripple-containing power or ripple containing load, or can be increased control than that, a switch (S _1, S _{2)-containing} power or ripple ripple the more highly controlling the switching frequency of the High order harmonics of the load can be eliminated.

In one embodiment, the switching ripple compensation control section 1820 contains a current (I _in) band pass filter (BPF), or ripple of extracting the fundamental wave or the harmonic band of the switching frequency of the ripple-containing power in a signal passing through the ripple contained power load And a band-pass filter (BPF) for extracting a fundamental wave or a harmonic band of the switching frequency of the ripple-containing load from the current (I _out ) flowing in the ripple-containing load.

Referring to Fig. 19, an example of a pass band of the band-pass filter (BPF) shown in Fig. 18 is shown. The band pass filter (BPF) eliminates the DC and / or existing current control band frequencies and does not include them in the harmonic compensation power so as not to compromise the control performance of previously designed circuits. Also, by not passing the frequency of the active DC short harmonic band (or the switching frequency of the switching element of the active DC circuit), the active DC circuit can be stably controlled.

20 is a graph showing a simulation result of reducing switching ripple by minimum frequency switching using an active DC circuit according to an embodiment of the present invention. The units of current shown in Fig. 20 are all [A], and the switching frequency of the inductor current (i _x ) of the active DC circuit is controlled to be the same as the switching frequency of the ripple-containing current source or the ripple-containing current load. 20, the average of the current (i _Cdc1 ) of the DC capacitor C _dc1 (FIG. 17) is 0 [A], and the fundamental wave components of the switching ripple are canceled by the lower two graphs have.

FIG. 21 is a graph showing simulation results in which switching noise is reduced by high-frequency switching using an active DC circuit according to an embodiment of the present invention. The units of the current shown in Fig. 15 are all [A], and by controlling the switching frequency of the inductor current ( _ix ) of the active DC circuit to be higher than the switching frequency of the ripple-containing current source or the ripple- Referring to the two graphs, it can be seen that higher harmonics of the switching frequency are canceled.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

610: Internal direct current voltage control unit
620: Harmonic compensation control section
630:

Claims (33)

An active DC stage circuit which receives power from the system and supplies drive power to the load stage using the power; And
And a control unit electrically connected to the active DC circuit to control the active DC circuit,
The active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground,
Wherein the control unit includes a harmonic compensation control unit for controlling the active DC circuit so that the active DC circuit compensates harmonic components of the grid current by controlling the grid current,
Wherein the harmonic compensation controller compensates harmonic components of the grid current by extracting a harmonic component from a voltage signal across the first capacitor. The method according to claim 1,
Wherein the harmonic compensation controller comprises at least one band pass filter for extracting a harmonic component from a voltage signal across the first capacitor. 3. The method of claim 2,
Wherein the harmonic compensation controller comprises:
Further comprising at least one first amplifier for amplifying the output of the at least one band pass filter. The method of claim 3,
Wherein the harmonic compensation controller comprises:
And a first adder for summing outputs of the one or more first amplifiers. 5. The method of claim 4,
Wherein the harmonic compensation control unit further comprises a resonance compensation control unit for controlling the active DC circuit so that the active DC circuit reduces the resonance by controlling the grid current. 6. The method of claim 5,
Wherein the resonance compensation control unit includes a high-pass filter that receives a voltage across the first capacitor as an input. The method according to claim 6,
The resonance compensation control unit includes:
A second adder for summing outputs of the at least one band pass filter; And
And a subtracter for subtracting the output of the high pass filter from the output of the second adder. 8. The method of claim 7,
The resonance compensation control unit includes:
And a second amplifier for amplifying the output of the subtracter. The method according to claim 1,
Wherein the harmonic compensation control unit receives the output power of the lower stage and controls the system current in real time based on the output power of the lower stage. The method according to claim 1,
Wherein the active DC circuit includes a second capacitor through which harmonic power generated in the system is transmitted and a switch for controlling a current in the active DC circuit,
Wherein,
An internal DC voltage controller controlling the active DC circuit so that a voltage between both ends of the second capacitor is maintained at a constant value; And
Further comprising a current controller for calculating an average voltage across the switch based on the output of the harmonic compensation controller and the output of the internal dc voltage controller.
An active DC stage circuit which receives power from the system and supplies drive power to the load stage using the power; And
And a control unit electrically connected to the active DC circuit to control the active DC circuit,
Wherein the control unit includes a grid current compensation controller for controlling the active DC circuit so that the active DC circuit adjusts harmonics of the grid current by controlling the grid current,
Wherein the grid current compensation control unit controls the active DC circuit so that the active DC circuit supplies the compensating power to the sub-stage in a period in which power is not supplied from the system to the sub- The power compensation device comprising: 12. The method of claim 11,
And the subordinate-stage power compensation controller calculates the current command at the lower stage based on the output power at the lower stage. 12. The method of claim 11,
The active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground,
And the sub-stage power compensation controller controls the active DC circuit so that the voltage across the first capacitor is maintained at a predetermined minimum value or more. 14. The method of claim 13,
Wherein the grid current compensation control section calculates a command current based on the grid voltage, the preset minimum value of the voltage across the first capacitor and the output power at the lower voltage terminal, and calculates a command for the voltage across the first capacitor Wherein the power compensating unit comprises: 12. The method of claim 11,
Wherein the active DC circuit includes a second capacitor through which harmonic power generated in the system is transmitted and a switch for controlling a current in the active DC circuit,
Wherein,
An internal DC voltage controller controlling the active DC circuit so that a voltage between both ends of the second capacitor is maintained at a constant value; And
Further comprising a current controller for calculating an average voltage across the switch based on the output of the harmonic compensation controller and the output of the internal dc voltage controller.
An active DC circuit that receives power from a power source and supplies driving power to the load using the power; And
And a control unit electrically connected to the active DC circuit to control the active DC circuit,
Wherein at least one of the power source and the load generates a current comprising a switching ripple,
Wherein the control section includes a switching ripple compensation control section for controlling the active DC circuit so that the active DC circuit compensates the fundamental wave or harmonic power of the switching frequency of the ripple- Compensation device. 17. The method of claim 16,
Wherein the active DC stage circuit includes an inductor,
Wherein the switching ripple compensation control unit controls the switching frequency of the inductor current to be equal to or higher than the switching frequency of the ripple-containing power supply or the ripple-containing load, Compensation device. 18. The method of claim 17,
And the switching ripple compensation control unit includes a band-pass filter for extracting a fundamental wave or a harmonic band of the switching frequency of the ripple-containing power supply or the ripple-containing load in the current signal flowing in the ripple- . 17. The method of claim 16,
Wherein the active DC circuit includes a second capacitor through which fundamental or harmonic power of the switching frequency is transmitted and a switch for controlling a current in the active DC circuit,
Wherein,
An internal DC voltage controller controlling the active DC circuit so that a voltage between both ends of the second capacitor is maintained at a constant value; And
Further comprising a current control unit for calculating an average voltage across the switch based on the output of the switching ripple compensation control unit and the output of the internal DC voltage control unit.
Supplying power from the system to the active DC circuit;
Compensating a harmonic component of the grid current by controlling the grid current using the active DC stage circuit; And
And supplying power to the load using the active DC circuit,
Wherein the active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground,
Wherein compensating for harmonics of the grid current comprises:
And extracting a harmonic component from a voltage signal across the first capacitor. 21. The method of claim 20,
The step of extracting a harmonic component from a voltage signal across the first capacitor comprises:
And bandpass filtering the voltage signal across the first capacitor. ≪ Desc / Clms Page number 19 > 21. The method of claim 20,
Wherein compensating for harmonics of the grid current comprises:
Amplifying the extracted harmonic components; And
And summing the amplified harmonic components. ≪ Desc / Clms Page number 21 > 23. The method of claim 22,
Further comprising reducing resonance by controlling the grid current using the active DC stage circuit. 24. The method of claim 23,
Wherein the step of reducing resonance by controlling the grid current comprises:
And high-pass filtering the voltage signal across the first capacitor. 25. The method of claim 24,
Wherein the step of reducing resonance by controlling the grid current comprises:
Summing the harmonic components extracted from the voltage signal across the first capacitor;
Subtracting the voltage signal across the first capacitor from the summed harmonic component; And
Further comprising: amplifying the summed harmonic component of the high-pass filtered voltage signal across the first capacitor. 21. The method of claim 20,
Wherein compensating for harmonics of the grid current comprises:
Detecting an output power of a lower stage electrically connected to the active DC stage circuit; And
And controlling the grid current in real time based on the detected output power of the lower stage.
Supplying power from the system to the active DC circuit;
Adjusting the harmonic component of the grid current by controlling the grid current using the active DC stage circuit; And
And supplying power to the load using the active DC circuit,
Wherein adjusting the harmonic component of the grid current comprises:
And supplying a compensating power to the sub-stage using the active DC circuit in a period in which the sub-stage electrically connected to the active DC circuit is not supplied with power from the system. . 28. The method of claim 27,
The step of supplying the compensating power to the sub-
Detecting an output power of the lower stage; And
And calculating a current command of the lower stage based on the detected output power of the lower stage. 28. The method of claim 27,
Wherein the active DC circuit includes a first capacitor whose one end is electrically connected to the system and the other end is connected to ground,
The step of supplying the compensating power to the sub-
And maintaining a voltage across the first capacitor to a predetermined minimum value. 30. The method of claim 29,
Wherein removing harmonic components of the grid current comprises:
Further comprising calculating a command of a grid current command and a voltage across the first capacitor using the grid voltage, the preset minimum value of the voltage across the first capacitor, and the output power of the lower capacitor, Power compensation method.
Supplying power from the power source to the active DC circuit;
Compensating a fundamental wave or a harmonic power of a switching frequency of a load electrically connected to the power source or the active DC circuit using the active DC circuit; And
And supplying power to the load using the active DC circuit,
Wherein at least one of the power source and the load generates a current comprising a switching ripple. 32. The method of claim 31,
Wherein compensating the fundamental or harmonic power of the switching frequency comprises:
And controlling the switching frequency of the inductor current included in the active DC circuit to be equal to or higher than the switching frequency of the ripple-containing power supply or the ripple-containing load or higher than the switching frequency of the ripple- Lt; / RTI > 33. The method of claim 32,
Controlling the switching frequency of the inductor current included in the active DC circuit to be higher than the switching frequency of the ripple-containing power supply or the ripple-containing load, or higher than the switching frequency of the ripple-containing power supply or the ripple-
And band-pass filtering the current signal flowing through the ripple-containing power supply or the ripple-containing load.

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