KR20060084068A - A electrical energy saving controller with multi-function - Google Patents

Abstract

The present invention uses two inverters (Inverters) to improve the power factor, harmonics, etc. of the input system power supply to maintain a high power (High Power Quality) while reducing the power consumption of the load multi-function electric energy saving device A current controlled voltage source inverter (CCVSI) connected in parallel to a grid inlet power supply, a voltage controlled voltage source inverter (VCVSI) connected in series between a power supply and a load, and these Topology, which consists of the DC side of the inverter connected by a DC voltage stabilizer in common, VCVSI controls the voltage of the load to the optimal voltage to maximize energy saving effect regardless of the input system voltage. Compensates reactive power and harmonics by detecting load current (distributed power sources such as solar and wind power) When the battery is added, the structure to control the demand management control and UPS function to perform the peak-cutting function of the grid power), and the reduction of the load energy consumption compared to the existing power saving device by the method proposed in the present invention. In addition, power quality, such as harmonics and reactive power compensation can be significantly improved.

The present invention is fundamentally different from the conventional structure in which the load input voltage is controlled by a tap-change method of a single winding transformer (or mutual induction reactor) for power saving, and is constituted by an inverter controlled by a semiconductor switching element. It can be compact and lightweight, and the load voltage control performance for energy saving is improved by VCVSI, and the harmonics and reactive power can be dramatically improved by CCVSI, and the energy controlled through VCVSI is controlled for voltage control. With less than 10 percent of the load rating and less than 30 percent of the load rating of energy delivered through CCVSI for reactive power and harmonic control, it is possible to produce a more compact and low cost multifunction electrical energy saver. .

Energy Saving Controller, Multi-function, Inverter

Description

Multifunctional Electric Energy Saving Controller {A Electrical Energy Saving Controller with Multi-function}

Figure 1a is a conventional step-down type energy saving controller (Step-Down type Energy Saving Controller)

Figure 1b is a conventional step-up / step-down type energy saving device (Step-Up / Down type Energy Saving Controller)

1C is a step-down type energy saving controller by using an electronic switch.

2 is a multi-functional electrical energy saving device devised in the present invention (A Electrical Energy Saving Controller with Multi-function)

Figure 3a shows a nonlinear load of 6234 [VA] (5860 [W], 2126 [Var], PF 0.94) capacity.

3B shows a nonlinear load of 3967 [VA] (3349 [W], 2126 [Var], PF 0.84) capacity.

4A shows waveforms of input voltage, current, and their effective and reactive power when an input voltage of 240 V and 50 Hz is applied to the load of [FIG. 3A].

4B shows waveforms of input voltage, current, and their effective and reactive power when an input voltage of 210 V and 50 Hz is applied to the load of [FIG. 3A].

5A shows waveforms of input voltage, current, and their effective and reactive power when an input voltage of 240 V and 50 Hz is applied to the load of [FIG. 3B].

5B shows waveforms of input voltage, current, and their effective and reactive power when an input voltage of 210 V and 50 Hz is applied to the load of [FIG. 3B].

6 is a current (power supply current, load current, CCVSI current), voltage (power supply voltage, load voltage, VCVSI voltage), active power (power supply, load, CCVSI, VCVSI) and the multifunction power saving device devised in the present invention Reactive Power (Power, Load, CCVSI) Waveforms

7 is an example of applying the multi-functional power saving device devised in the present invention to a distributed power system

<Brief description of the main parts of the drawing>

10: Current Controlled Voltage Source Inverter (CCVSI)

20: Voltage Controlled Voltage Source Inverter (VCVSI)

Ig: input power current

Ip: Primary current of single winding transformer

IL: Load Current

IC: Output Current of Current Controlled Voltage Source Inverter

Vg: input power supply voltage

VL: load voltage

VX: Voltage controlled by voltage controlled voltage source inverter

The present invention relates to a multifunctional electric energy saving device.

In general, the basic concept of electric energy saving of existing power saving devices used for electric energy saving is to save energy consumption by a ratio by dropping the voltage applied to the load. In the electricity supply regulations, the supply voltage range from the utility company is defined as up to 6 percent above and below the nominal voltage, so that the electric and electronic equipment operates or operates normally within the supply voltage range. This is possible because all equipment is regulated by device manufacturing codes to be designed and manufactured to operate normally within the Utility Voltage Range up to 10 percent above and below the rated voltage. In other words, in order to satisfy the manufacturing regulations when manufacturing the device, it is necessary to over design to guarantee the output characteristics within the available voltage range, and when the rated voltage is actually applied, unnecessary power is wasted due to excess supply, thereby saving energy. In order to maintain the proper voltage to obtain the effect by operating the power supply voltage step-down or step-down to obtain a power saving effect.

Existing power saving devices according to the power saving concept described above can be largely divided into a method using a single winding transformer (or a mutual induction reactor) and a method of controlling a load voltage by a semiconductor switch. 1A to 1C, FIG. 1A is a step-down type energy saving device for controlling a load voltage to a power saving voltage using characteristics of a single winding transformer (or mutual induction reactor). Saving Controller), and [Fig. 1B] is a step-up / down type energy saving controller for controlling the load voltage to be stepped up or down by improving [Fig. 1A]. 1C is a step-down type energy saving controller by using electronic switch to control a load voltage by a semiconductor switch, unlike FIG. 1A and FIG. 1B. These power saving devices are applied in various ways to reduce the energy consumption of the load in the place where AC power is used, from the small capacity of home use to the large capacity of industrial application.

Meanwhile, the surge in international oil prices due to the unrest of the international situation such as the Iraq war and the strengthening of greenhouse gas emission standards under the Kyoto Protocol have led to the development and dissemination of alternative energy, the reduction of energy production and consumption, and the development of automation and mobile communication systems. As a result, the improvement of power quality has emerged as a very important problem in this era. However, the existing power-saving devices that have been developed so far are simply energy-saving effect through the voltage control, the situation is not considered at all to improve the power factor or power quality (Power Quality). In particular, considering that the power supply regulation maintains a power factor of 0.9 or more, the existing devices manufactured and sold basically generate a partial power factor, and thus, it is urgent to improve the power generation capacity to reduce unnecessary power generation capacity. Therefore, unlike conventional power saving devices that only control the load voltage, the development of a multifunctional power saving device that can improve not only power saving but also the power factor and power quality of the load is urgently required.

The present invention, which was devised to solve the problems of the prior arts, differs from the attempt to reduce the electric energy through the conventional load voltage control, and the power factor and harmonics of the input system power supply using two inverters. It is to propose an effective way to drastically reduce the power consumption of the load while maintaining the system power at high power quality by improving the power supply.

In order to explain the technical problem to be achieved by the present invention, looking at the existing power saving device, [1a] is a step-down type power saving device for controlling the load voltage to the power saving voltage using the characteristics of a single winding transformer (or mutual induction reactor). This is relatively used because it can be implemented in a relatively easy way, but it is necessary to change the tap of the transformer to control the load voltage, and to do this, a servo motor or a tap-changing switch is used. Surge occurs due to energy, and there are disadvantages such as noise when operating a transformer. FIG. 1B is a step-up / type power saving device for controlling a load voltage to be stepped up or down, and the basic principle thereof is the same as that of FIG. 1A. However, since the power saving device of FIG. In the following case, in order to improve the disadvantages that cannot be controlled, the center tap is installed on the primary side to improve the pressure. On the other hand, [Fig. 1c] is a step-down type power saving device that controls the load voltage by a semiconductor switch, unlike [Fig. 1a], [Fig. 1b], the problem of spikes during tap-change which is a disadvantage of [Fig. 1a], [Fig. 1b] And transformer noise can be solved, but the energy saving effect is reduced because energy generated by controlling the voltage (Vx) that is falling for energy saving is not regenerated on the power supply side but consumed by the resistor (R). 1a] and [1b] have a small disadvantage.

Therefore, the technical problem of the present invention is a disadvantage of the conventional power saving device ([FIG. 1A], [FIG. 1B] problems such as spikes and transformer noise during tap change, which are disadvantages of the power saving device using the principle of a single winding transformer). In addition to improving the regeneration problem of control energy, which is a disadvantage of a power saving device using a semiconductor switch, as shown in FIG. 1C), the power factor, harmonics, etc. of the input system power supply may be improved to maintain high quality power. It is to devise a multifunctional electric energy saving device that can dramatically reduce the power consumption of the load.

The configuration of the multifunction electric energy saving device according to the present invention is as shown in FIG. Input grid power,

In order to remove the phase difference and harmonics of the current generated from the load and control the grid power supply with high power of 1, the four diodes are connected in parallel to the grid power supply. a current controlled voltage source inverter 10 constructed of a bridge type),

A transformer connected in series with the grid power supply and controlling a load voltage to reduce load energy;

A voltage controlled voltage source inverter 20 connected to the secondary side of the transformer and configured to have four full-conductor switches for conduction time control in which a diode is anti-parallel connected to control the transformer voltage Vx for reducing load energy;

  A DC capacitor for stabilizing the DC voltage of the inverter by commonly connecting the DC side of the current controlled voltage source inverter 10 and the voltage controlled voltage source inverter 20;

The load is connected to the remaining terminals of the primary winding of the load voltage control transformer connected in series with the grid voltage, and the ground of the load and the grid power supply is commonly grounded.

Detailed description of the invention with reference to the accompanying drawings is as follows.

Figure 1a is a conventional step-down type power saving device is a power saving device for step-down control of the load voltage is always as small as Vx than the grid voltage. This is to control the voltage of the load by the tap change of the single winding transformer to the optimum voltage to maximize the energy saving effect irrespective of the input system voltage. For this purpose, it is necessary to use a servo motor or the use of a tap-changing switch. When tap-changing, a surge occurs due to spike or reactor energy at a contact point, and there are disadvantages such as noise when operating a transformer. However, this is the most widely used device because energy saving effect is large and it can be implemented in a relatively easy way because energy generated while controlling the voltage (Vx) falling for energy saving can be regenerated as it is.

Figure 1b is a conventional step-up type power saving device, when the voltage of the system is applied less than the appropriate load voltage for reducing the load energy, so that the step-up or step-down control of the power saving device of [Fig. In order to improve, the center tap is placed on the primary side to improve the lifting pressure. Therefore, the step-down type power saving device shares the advantages and disadvantages of the [FIG. 1A], but it has the advantage that the input voltage range is wider than that of [FIG.

FIG. 1C is a step-down type power saving device using a conventional semiconductor switch, and is controlled by a semiconductor switch, so that the problem of spikes at the time of tap switching, which is a disadvantage of the method using a single winding transformer as shown in FIGS. 1A and 1B, Problems such as transformer noise can be solved, but the energy saving effect is reduced because the energy generated by controlling the voltage Vx dropping for energy saving is not regenerated on the power supply side and consumed by the resistor R [FIG. 1A], There is a small disadvantage compared to FIG. 1b.

2 is a multi-functional electric energy saving device devised in the present invention, a power saving device ([FIG. 1A], [FIG. 1B]) using a conventional single winding transformer or a power saving device for rectifying control using a semiconductor switch (FIG. Unlike 1c]), it consists of two inverters capable of bi-directional control, and has the disadvantage of the existing power saving device ([1a], [1b] as shown in FIG. 1b]. Problems such as spikes and transformer noise, and regenerative problems of control energy, which are disadvantages of power saving devices using semiconductor switches as shown in FIG. 1C), as well as improving power factor and harmonics of input system power. It is an electric energy saving device that can be controlled to maintain power and can significantly reduce the power consumption of a load.

The control of the load application voltage for the electrical energy saving of the present invention is performed by a transformer voltage (Vx) connected in series between the grid and the load. These relations are VL = Vg-Vx so that the proper load voltage required for energy saving can be maintained by the control of Vx regardless of the magnitude of the voltage applied to the system. For this purpose, the present invention uses a voltage controlled voltage source inverter unlike the conventional power saving device. . Since the inverter is bi-directional controllable, it is possible to control Vx linearly from positive voltage to negative voltage, and to control the step-up and step-down of the load voltage, and the control range of Vx is rated. Since it is in the range of the available voltage, which is in the range of 10% above and below, the capacity of the inverter for controlling it is sufficient to be 10% of the load rating, and its energy is regenerated to the power supply side through a commonly connected current controlled voltage source inverter. On the other hand, the electrical and electronic devices currently manufactured and sold are manufactured by applying a power supply factor of 0.9 or higher of the electricity supply regulation, which basically generates some power factor, and in the case of nonlinear loads, harmonics cannot be ignored. . In order to improve this, the CCVSI of the present invention is controlled to compensate for the invalid and harmonic components of the load current (Ig = IL-Ic), and since its control range is a load with a power factor of about 0.9, the capacity of the inverter is 30% of the load rating. Suffice.

Therefore, the present invention is fundamentally different from the conventional structure controlled by the tap-change method or the control rectifier circuit of the single winding transformer (or mutual induction reactor), and linearly boosts and lowers the load voltage for energy saving by VCVSI. The energy for this can be regenerated in conjunction with CCVSI, and can significantly improve harmonics and reactive power by CCVSI, and the energy controlled through VCVSI is 10 percent of the load rating for voltage control. Since the energy received through CCVSI for reactive power and harmonic control is 30% or less of the load rating, it is possible to manufacture a more compact, low cost, and multifunctional electric energy saving device.

FIG. 3A is a nonlinear load having a capacity of 6234 [VA] (5860 [W], 2126 [Var], PF 0.94) when 240V and 50 Hz voltage is applied, in order to verify the energy saving and power quality improvement effect of the present invention. A resistive load (23 Ω) and a nonlinear load (R = 20Ω, L = 10mH, C = 1000uF connected to the diode bridge rectifier circuit) are connected in parallel.

FIG. 3b is a nonlinear load having a capacity of 3967 [VA] (3349 [W], 2126 [Var], PF 0.84) when a 240 V and 50 Hz voltage is applied, and is a nonlinear device for verifying the energy saving and power quality improvement effect of the present invention. The load (R = 20Ω, L = 10mH, C = 1000uF) connected to the diode bridge rectifier circuit.

4A shows 240V and 50Hz of a nonlinear load ([FIG. 3A]) of 6234 [VA] (5860 [W], 2126 [Var], PF 0.94) capacity in order to confirm the energy saving effect by the load voltage control. This waveform shows simulation results when an input voltage is applied. All the devices used in the simulation were assumed to be ideal, and the simulation was performed using Psim software. From the figure above, it is the waveform of load input voltage (Vac) and current (Iac: 5 times magnification for display convenience) and its active power (WL) and reactive power (VarL). As shown in the figure, the waveform of the input current is severely distorted by the nonlinear load in the power consumption of 5860 [W] and 2126 [Var].

FIG. 4B shows 210V and 50Hz of a nonlinear load ([FIG. 3A]) with a capacity of 6234 [VA] (5860 [W], 2126 [Var], PF 0.94) in order to confirm the energy saving effect by the load voltage control. This waveform shows simulation results when an input voltage is applied. All the devices used in the simulation were assumed to be ideal, and the simulation was performed using Psim software. From the figure above, it is the waveform of load input voltage (Vac) and current (Iac: 5 times magnification for display convenience) and its active power (WL) and reactive power (VarL). As shown in the figure, the power consumption of 4761 [VA] (4476 [W], 1622 [Var], PF 0.94) shows about 24% energy saving effect compared to [Fig. 4A] by the load voltage drop. It can be seen that the energy saving effect is different depending on the load, the effect is the largest in the actual lighting load, the smallest in the motor load is known. However, it can be seen that there is no difference in the distortion phenomenon of the load current waveform due to the load power factor and the nonlinear load, as compared with FIG. 4A. This shows that the existing power saving device performing only load voltage control can play no role in reducing the load power factor and harmonics other than the energy saving effect.

FIG. 5A shows 240V and 50Hz of a nonlinear load ([FIG. 3B]) with a capacity of 3967 [VA] (3349 [W], 2126 [Var], and PF 0.84) in order to confirm the energy saving effect by the load voltage control. This waveform shows simulation results when an input voltage is applied. All the devices used in the simulation were assumed to be ideal, and the simulation was performed using Psim software. From the figure above, it is the waveform of load input voltage (Vac) and current (Iac: 5 times magnification for display convenience) and its active power (WL) and reactive power (VarL). As shown in the figure, the waveform of the input current is more severely distorted than the power consumption of 3349 [W] and 2126 [Var] compared to [Fig. 4A] with only a nonlinear load.

FIG. 5B shows 210V and 50Hz of a nonlinear load ([FIG. 3B]) having a capacity of 3967 [VA] (3349 [W], 2126 [Var], and PF 0.84) in order to confirm the energy saving effect by the load voltage control. This waveform shows simulation results when an input voltage is applied. All the devices used in the simulation were assumed to be ideal, and the simulation was performed using Psim software. From the figure above, it is the waveform of load input voltage (Vac) and current (Iac: 5 times magnification for display convenience) and its active power (WL) and reactive power (VarL). As can be seen in the figure, the power consumption of 3029 [VA] (2558 [W], 1622 [Var], PF 0.84) shows about 24% energy saving effect compared to [Fig. 5A] by the load voltage drop. It can be seen that the energy saving effect is different depending on the load, the effect is the largest in the actual lighting load, the smallest in the motor load is known. However, it can be seen that there is no difference in the distortion phenomenon of the load current waveform due to the load power factor and the nonlinear load as compared with FIG. 5A. This shows that the existing power saving device performing only load voltage control can play no role in reducing the load power factor and harmonics other than the energy saving effect.

FIG. 6 is a simulation result waveform of the power saving device of FIG. 2 to confirm the electric energy saving effect and the power quality improvement effect of the multifunctional power saving device devised in the present invention. All devices used in the simulation were assumed to be ideal as in [Fig. 4a] to [Fig. 5b], but the simulation was performed using the Psim software under the condition of the turn-on resistance Rsw = 36mΩ of the switch used in the inverter. . In order to confirm the utility and control characteristics of the present invention, when a voltage of 240 V and 50 Hz (rated voltage of EU, Australia, etc.) is applied, 210 V is set as an appropriate load voltage for energy saving, and 3967 [VA] ( 3349 [W], 2126 [Var], PF 0.84) Apply a nonlinear load ([Fig. 3b]), and after 0.15 seconds, 6234 [VA] (5860 [W], 2126 [Var], PF 0.94). It is a waveform of a simulation result when it increases with a load ([FIG. 3A]). From above figure, current (power current Ig, load current IL, CCVSI current Ic), voltage (power voltage Vg, load voltage VL, VCVSI voltage Vc), active power (power Wg, load WL, CCVSI Wc, VCVSI Wx) and invalid The waveform of power (power Varg, load VarL, CCVSI Varc). As shown in the figure, the power saving device of the present invention shows that the load voltage is controlled to 210 V regardless of the load fluctuation, thereby consuming 2608 [W] and 1675 [Var] (power factor 0.84). After 0.15 sec, it is controlled to 4676 [W], 1725 [Var] (power factor 0.94), and the corresponding CCVSI power is 197 [W], 1666 [Var] to 429 [W], 1730 [Var], and VCVSI. Is controlled from 260 [W] to 463 [W] and the grid input power is controlled from 2679 [W] (power factor 1) to 4630 [W] (power factor 1) while compensating for the load current distorted by the nonlinear load by CCVSI. It can be seen that the input current is controlled by the sinusoidal current. This not only shows that the control energy of VCVSI for energy saving is regenerating in connection with CCVSI, but also significantly improves harmonics and reactive power by CCVSI. It shows energy savings. This is higher than the energy saving effect of [FIG. 4A] to [FIG. 5B] that there is no loss by simply dropping only the applied voltage, and the energy saving device of the present invention is improved by reactive power in addition to the voltage drop effect in spite of inverter loss. It can be seen that there is a synergy effect of the savings. In addition, the energy controlled through VCVSI for voltage control is only 7.4 percent of the load rating, and the energy received through CCVSI for reactive power and harmonic control is only 28.5 percent of the load rating. It can be seen that it is possible to manufacture an electric energy saving device having a high quality power compensation function at a cost.

7 shows an example of applying the multifunctional power saving device devised in the present invention to a distributed power supply system. If alternative energy such as solar energy and a battery as an energy storage device are added to the power saving device of the present invention as shown in the option part of the figure, demand for peak-cutting and the like is added to the energy saving effect and power quality improvement effect of the present invention. Additional functions such as demand side management and uninterruptible power supply (UPS) in case of a grid power accident can be performed. To this end, the capacity of the VCVSI remains unchanged, but the CCVSI needs to expand the capacity of the CCVSI with only the load capacity saved by the VCVSI in order to perform the DSM and UPS functions in addition to the compensation of reactive power and harmonics. It is economical system compared to power system. In addition, energy saving by voltage control is most effective at lighting load, and in case of electric motor load, the effect is small. Therefore, in order to obtain the energy saving effect while maintaining the load characteristics optimally, the power saving device of the present invention uses lighting load and general power as shown in the figure. Consider separating the load and applying only the lighting load to the power saving device. In this case, there is no problem in applying the system since the grid-in power is already distributed and connected to the general power load and the lighting load in the distribution board. Therefore, the energy saving device of the present invention can be applied to residential or commercial buildings with a high energy saving effect of about 40 percent, so that the energy saving effect can be maximized and can be simply installed in the distribution panel of the building. It is possible to utilize the electric energy saving device having.

The present invention improves the power factor, harmonics, and the like of the input system power supply by a current controlled voltage source inverter connected in parallel to the grid inlet power supply, while maintaining a high quality power by a voltage controlled voltage source inverter connected in series between the power supply and the load. Characterized in that it can significantly reduce the power consumption of the load.

The present invention is fundamentally different from the conventional structure that is controlled by a tap-changing method or a control rectifier circuit of a single winding transformer (or mutual induction reactor), and a linear step-up and step-down control of a load voltage for energy saving is performed by VCVSI. The energy for this can be regenerated in conjunction with CCVSI, and can significantly improve harmonics and reactive power by CCVSI, and the energy controlled by VCVSI for voltage control is less than 10 percent of the load rating. In addition, the energy received through CCVSI for reactive power and harmonic control is less than 30 percent of the load rating, making it possible to manufacture an electric energy saving device with higher power compensation with a more compact and low cost.

Therefore, the present invention can be utilized as a multi-function, low-cost, high-efficiency power-saving device in all fields where a conventional power-saving device is used, and in particular, since the power saving effect by voltage control is the largest in the lighting load, the use of the lighting load is 40 percent. When applied to residential or commercial buildings, not only maximizes energy savings but also can be easily installed in the distribution panel of the building, and thus it is possible to use electric energy saving device having multi-function at low cost. In addition, the addition of alternative energy such as solar light and an energy storage device to the power saving device of the present invention, in addition to the energy saving effect and power quality improvement effect of the present invention, demand management control such as peak-cutting and system power accidents It is expected to contribute much to the national energy saving business because it can perform additional functions such as UPS in preparation.

Claims (4)

In order to control the system power supply with high quality power by eliminating phase difference and harmonics of current generated from the load in parallel with the input power supply and the system power supply, 4 switches for conduction time control with diodes in parallel and parallel are connected. a current controlled voltage source inverter 10 composed of a full bridge type, A transformer connected in series with the grid power supply and controlling a load voltage to reduce load energy; A voltage controlled voltage source inverter 20 connected to the secondary side of the transformer and configured to have four full-conductor switches for conduction time control in which a diode is anti-parallel connected to control the transformer voltage Vx for reducing load energy;   A DC capacitor for stabilizing the DC voltage of the inverter by commonly connecting the DC side of the current controlled voltage source inverter 10 and the voltage controlled voltage source inverter 20; And a structure in which a load is connected to the other terminal of the primary winding of the load voltage control transformer connected in series with the grid voltage, and the ground of the load and the grid power supply is commonly grounded. 2. A power supply according to claim 1, wherein instead of the current controlled inverter (10) and the voltage controlled inverter (20) consisting of single phases; Three-phase multi-function electric energy saving device, characterized in that the three-phase current control inverter consisting of six bridges for the conduction time control in which the diodes are connected in reverse parallel and the three-phase voltage controlled inverter connected to the three-phase system voltage . 2. The method of claim 1, further comprising: instead of connecting the entire load to the remaining terminals of the primary side winding of the load voltage control transformer connected in series with the grid voltage; The grid-input power is distributed from the distribution board to the general power load and the lighting load, and the general power load is directly connected to the grid voltage, and only the lighting load is connected to the remaining terminals of the primary winding of the load voltage control transformer. A multifunctional electric energy saving device characterized in that. According to claim 1, characterized in that it comprises a structure in which a maximum power point tracking (MPPT) converter connected to a battery and a solar cell is connected in parallel to a DC capacitor connected to the DC side of the current controlled voltage controlled voltage source inverter, distributed Multifunctional electric energy saving device with a distributed generation system function.

Images