CN112103967A - Adaptive AC and/or DC power supply - Google Patents

Abstract

The present application relates to adaptive AC and/or DC power supplies. Embodiments of an adaptive power supply for accommodating instances in which power is generated too much for load demand and instances in which power is generated too little for load demand are disclosed.

Description

Adaptive AC and/or DC power supply

The application is a divisional application of an invention patent application with a national application number of 201480039158.8, the application date of the invention patent application is 7/8/2014, and the invention name is 'adaptive AC and/or DC power supply'.

Technical Field

The present disclosure relates to power generation circuits for use with power systems with or without renewable energy sources, which may sometimes vary in availability.

Background

In a conventional power system, a power generation company may generate electrical energy to power a load center in a centralized and unidirectional manner. In general, the basic "load following" control method involves the arrangement by which power generation follows the energy demand. Thus, a balance between power generation and power demand (e.g., "load") may be employed to achieve a stable power generation system. However, in view of the increasing use of distributed renewable energy sources (such as wind and solar), less concentrated and dynamic power generation systems may emerge. For example, renewable energy sources may be installed in a distributed manner, where the actual location of solar and/or wind power generation capacity is unknown to the utility company. Thus, electric utilities may not be able to accurately determine total power generation, particularly in view of geographically varying wind speeds, clouds, and the like. While power generation and load may be moderated by temporary energy storage facilities (such as a reservoir for storing potential energy) and/or chemical energy storage facilities (such as batteries), these solutions can be problematic. For example, chemical storage can be prohibitively expensive. In another example, a reservoir for potential energy storage may be susceptible to geographic restrictions.

Drawings

The claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. The claimed subject matter, together with its objects, features, and/or advantages, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

fig. 1a shows a simplified control schematic of a series reactive power compensator for output voltage support in transmission according to an embodiment.

Fig. 1b shows a simplified control schematic of a series reactive power compensator as a central dimming system based on a power inverter circuit according to an embodiment.

Fig. 1c shows a simplified control schematic of a series reactive power compensator as an electric spring according to an embodiment.

Fig. 2 shows a single-phase version of an electrical spring based half-bridge power inverter and low-pass inductor-capacitor filter and underland snubber circuit according to an embodiment.

Fig. 3a shows a schematic diagram of a single phase power system according to an embodiment.

Fig. 3b shows a schematic diagram of a single-phase power system including the use of an electric spring circuit according to an embodiment.

Fig. 4 shows a single-phase electric spring for a three-phase system according to an embodiment.

Fig. 5 shows a three-phase electric spring according to an embodiment.

Fig. 6 shows an adaptive power supply for a single-phase system according to an embodiment.

Fig. 7 shows an adaptive power supply for a three-phase system according to an embodiment.

Fig. 8 shows an electrical spring mounted on the high-voltage side of a step-down transformer according to an embodiment.

Fig. 9 shows another adaptive power supply according to an embodiment.

Fig. 10 illustrates an adaptive DC power supply according to an embodiment.

Fig. 11 illustrates an adaptive DC power supply established with a standard power outlet according to an embodiment.

Fig. 12 illustrates an adaptive AC and/or DC power supply forming part of a power supply infrastructure, according to an embodiment.

Fig. 13 illustrates a DC bus power supply according to an embodiment.

Fig. 14 shows a setting of a future power supply according to an embodiment.

Fig. 15 illustrates an accessible mechanism for changing an input voltage reference by an external subject (such as a utility company and an authority) according to an embodiment.

In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals may designate like parts throughout to indicate corresponding or analogous elements. For simplicity and/or clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, it is to be understood that other embodiments may be utilized and structural and/or logical changes may be made without departing from the scope of the claimed subject matter. It should also be noted that directions and references (such as, for example, up, down, top, bottom, over, above, etc.) may be used to facilitate the discussion of the figures and are not intended to limit the application of the claimed subject matter. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the claimed subject matter is intended to be defined by the appended claims and their equivalents.

Detailed Description

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, methods, devices, or systems known to those of ordinary skill in the art have not been described in detail so as not to obscure claimed subject matter.

Reference throughout this specification to one embodiment, implementation, one example, embodiment, and so on may mean that a particular feature, structure, or characteristic described in connection with the particular implementation or embodiment may be included in at least one implementation or embodiment of claimed subject matter. Thus, the appearances of such phrases in various places throughout this specification are not necessarily intended to refer to the same embodiment or to any one particular embodiment described. Furthermore, it is to be understood that the particular features, structures, or characteristics described may be combined in various ways in one or more embodiments. In general, of course, these and other issues may vary depending on the particular context. Thus, a particular context of description or use of these terms may provide helpful guidance regarding inferences that will be made regarding that particular context.

Similarly, the terms "and," "and/or," and "or" as used herein may include various meanings that will again depend, at least in part, on the context in which the terms are used. Typically, "and/or" and "or" if used to associate lists (such as A, B or C) is intended to mean A, B or C (used herein in an exclusive sense) and A, B and C. Furthermore, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in the singular or may be used to describe some combination of features, structures, or characteristics.

Embodiments may include various methods of power management on the demand side. A review of the literature for the period of 2005 to 2012 shows that the management of the demand side (e.g., load) (or sometimes referred to as demand response) [1], [2] can be broadly summarized as:

scheduling of delay tolerant power demand tasks [3-5]

Use of energy storage to mitigate peak demand [6]

Real-time pricing [7-9]

Direct load control or on-off control of smart loads [10-12]

While the above-identified approaches may have particular advantages, at least some approaches may suffer from certain limitations. For example, while it may be practical to schedule power demand in advance by day or even hour, the response to real-time power fluctuations may be more problematic. Furthermore, while energy storage may represent one or more relatively advantageous solutions, the use of batteries may be relatively expensive. Furthermore, such solutions as the use of a reservoir (where water is pushed upwards for later conversion from potential energy to electrical energy) may be more practical in mountainous areas and less practical in low lying areas. In other instances, for example, real-time pricing may be relatively effective to curtail the power needs of a large number of price-sensitive consumers, but may not be suitable for ordinary household consumers.

In some circumstances, power companies may employ direct load control to shed (shed) power loads to avoid power system crashes. However, such centralized control strategies may not be effective for use with future power grids that may include relatively decentralized and intermittently available renewable energy sources that provide electrical energy at the input side of the power distribution network. While on-off control of electrical loads, such as water heaters and air conditioners, has been proposed, such an approach can be overly intrusive and cause considerable inconvenience to consumers. Recent work based on wide area measurements of real-time tracking of node voltage levels (e.g., for use by data centers for central and regional control of distributed areas) has been examined. Such real-time tracking of node voltage levels is typically based on information and communication technologies (ITC), such as wireless communication, satellite synchronization and internet/intranet control. In some instances, this approach may be effective under normal operating conditions, but may be more difficult to implement in weather emergencies or in the event of wireless communication system failure during unfavorable atmospheric conditions (such as a strong solar storm). In other instances, the use of the internet infrastructure may also be undesirable, for example due to hacking of the server involved in reporting node voltage levels.

Recent innovations in load response may be related to the development of "electric springs" [13], [14 ]. The electrical spring may comprise circuitry for a power electronics based power controller that employs "input voltage control" for regulating the supply voltage of the power system. In this particular context, it should be understood that the term demand is intended to refer to an electronic load and that the use of the term demand throughout should be interpreted in a manner consistent with such understanding. Similarly, the term controlling is intended to mean at least partially controlling and/or at least partially adjustable. Again, the use of the term control throughout should be interpreted in a manner consistent with such understanding. Likewise, the term "based on" (such as a description that X is "based on" Y or that X may be "based on" Y) is intended to indicate that X is based, at least in part, on Y or may be based, at least in part, on Y; however, there may be other factors or considerations that may not necessarily have been explicitly expressed. Again, the use of the term "based on" throughout should be interpreted in a manner consistent with such understanding.

Since power inverter circuits are commonly used in power system applications, it may be useful to determine the difference between input and output control methods. For example, FIG. 1a shows (V) for output voltage support in transmission_ORegulated) series reactive power compensator, and fig. 1b shows (V) as a central dimming system based on a power inverter circuit_ORegulated) series reactive power compensator. In fig. 1 and 2, the direction of active power (e.g. current) flow is highlighted. In FIGS. 1 and 2, the output terminal (V)_O) Refers to the output direction of the power flow.

FIG. 1c shows (V) as an electric spring_SRegulated) series reactive power compensator. Unlike the examples illustrated in fig. 1a and 1b, the electric spring is controlled with an input voltage, wherein the input (V) is_S) Refers to the input of the active power flow. For example, the input power terminal may refer to a power main (e.g., a bus).

In a particular embodiment, the electrical spring comprises a switched mode power inverter, a low pass filter, and an input voltage control for regulating the input AC voltage (typically the node voltage of the local AC mains). A single phase version of the electrical springs based on a half bridge power inverter and a low pass inductor-capacitor filter and an underland snubber circuit is shown in fig. 2. In principle, a circuit (such as that of fig. 2) may be able to accommodate both active and reactive power, thus giving the circuit the ability to contribute voltage and frequency stability, at least in theory, in the power system. In some embodiments, the half-bridge, full-bridge, and multi-stage power inverters may form one or more electrical spring circuits. Furthermore, it has been demonstrated in practice that the use of electrical springs can allow load demand to follow intermittent power generation [14] and also enable reductions in energy storage requirements in power systems [15 ]. With the incorporation of droop control [16], electrical springs can be distributed across the grid to provide distributed stability support to the grid.

In an embodiment, the use of one or more electrical springs is present on the "demand side". For example, the electrical spring may be associated with a non-critical load, which may be characterized as an electrical load capable of tolerating a certain variation of the supply voltage. The electrical spring may be embedded into an appliance (such as an electric water heater and/or refrigerator) to form a smart load that may be adaptive to fluctuating power supplies. In embodiments, we describe an improved concept of an electrical spring on the "power supply side" and extending and incorporating the electrical spring concept to form a "smart power supply". Unlike some embodiments that may take, for example, only "input voltage controlled" electrical springs, the improved smart power supply may take "input voltage and/or output voltage" control. Further, for example, an electrical spring may be considered to be associated with a power source as opposed to an electrical load.

Embodiments may relate to a power system infrastructure for AC or DC power sources that may incorporate electrical springs to form one or more adaptive power sources. One or more embodiments may be described in terms of an AC power source. Subsequently, an adaptive DC power supply based on one or more similar principles is described.

Fig. 3a shows a schematic diagram of a single-phase power system. It should be noted, however, that while the transformer symbol used in fig. 3a may indicate a single phase system, in embodiments a multi-phase power system may be employed, such as, for example, a three-phase power system. For simplicity, single phase systems are used for illustrative purposes only, and claimed subject matter is not limited in this respect. In fig. 3a, terminal "L" may refer to a "live" terminal and N may refer to a neutral terminal. The standard AC mains, charged to neutral voltage, may refer to the phase voltages, which may typically be in the range of 220.0V-240.0V for a power system of about 50.0Hz and 100.0V-110.0V for a power system of about 60 Hz. In many countries, electric utilities may regulate AC mains voltage within tight tolerances of a certain percentage (e.g., +/-6% of the nominal AC mains voltage in hong kong). The tolerance for a standard AC mains is labelled X% in figure 3.

As shown in FIG. 3b, embodiments may include the use of an electrical spring circuit that electrically springsThe circuit may be based at least in part on an AC-to-AC power inverter for the AC voltage output, and may be used to form an adaptive AC power source. The "live" terminal of the adaptive AC power supply is called L_adapt。

For single phase systems, the electrical spring may comprise the half bridge power inverter circuit shown in fig. 4. In other embodiments, a full bridge power inverter or other type of power inverter (such as, for example, a multi-stage power inverter) may be used. The output voltage of the power inverter may be a sinusoidal Pulse Width Modulation (PWM) signal that may be filtered using a low pass filter to generate a controllable sinusoidal voltage as the electrical spring voltage. The power inverter of the electric spring can be adapted to reactive power and/or real power. DC support (DC link) capacitors of the power inverter may provide stored energy, which may provide reactive power compensation for regulating node voltage, for example, on the AC mains. For reactive power control, the current vector flowing into the load of the adaptive power supply may be at least approximately perpendicular to the voltage vector of the electrical spring. Examples of control methods for an electric spring for voltage regulation using pure reactive power control can be described in [13] to [16 ].

If real and reactive power control is determined to be advantageous, a DC power source (such as a battery) may be connected in parallel with one or more capacitors or may be used in place of capacitors as a whole, for example. The use of an active power source has already been discussed in [13 ]. In this example, for example, the current vector of the load in the adaptive power supply may not be approximately perpendicular to the voltage vector of the electrical spring. The mode of operation of such an electric spring with both real and reactive power control has been reported by the inventors in [17 ].

For a three-phase system, for example, a single-phase electrical spring (such as that shown in fig. 4) may be used for one or more phases. In an embodiment, for example, a single phase electrical spring may be used for each phase of a three-phase system. An embodiment of a three-phase electric spring circuit is shown in fig. 5. A three-phase power inverter with a DC link capacitor and/or an active DC voltage source (such as a battery) and a low pass filter (including inductors and capacitors) form the basic unit of a three-phase electric spring circuit. The filtered electric spring voltage may be coupled to three secondary windings having terminals X2, Y2 and Z2 through the primary windings of a three-phase transformer X-Y-Z having terminals X1, Y1 and Z1. The output terminals XX, YY and ZZ may thus form the three-phase line voltage output terminals of the three-phase adaptive power supply. Both star-connected and delta-connected loads may be connected to a three-phase adaptive power supply (such as shown, for example, in fig. 5). It should be noted that the three-phase transformer may also be replaced by, for example, three single-phase transformers, provided that the connections of the three single-phase transformers are equivalent or at least similar to those shown in fig. 5.

Adaptive power supplies based at least in part on the electric spring concept are not limited to, for example, low voltage power distribution networks, and may be applied, at least in principle, to medium and high voltage power networks. For medium and high voltage applications, for example, a multi-stage power inverter for use at higher voltages (e.g., higher voltage ratings) may replace at least part of the two-stage power inverter shown in fig. 5, for example.

Fig. 6 illustrates an adaptive power supply for a single-phase system according to an embodiment. The electrical springs and the input and output control loops are implemented on the low voltage side of the distribution line. Similar principles may be applied to a three-phase power system as shown in fig. 7. If desired, the electrical spring may be mounted on the high voltage side of the step-down transformer as shown in FIG. 8.

The examples differ from the previous concepts of electric springs reported in [13] - [16] in at least three respects.

Regardless of the load type, the electrical spring circuit may be incorporated (as part of the power supply infrastructure) into the power supply side. In previous reports, the electrical spring may be a separate circuit external to the power source and/or embedded in the appliance.

The adaptive power supply can employ both input voltage control and input frequency control (for regulating the standard AC mains voltage and reducing frequency instability in the traditional sense of the electrical spring reported in [13] - [16 ]). Output voltage control (for limiting the maximum and minimum voltage values of the adaptive AC mains voltage and allowing the output AC voltage to vary within the maximum and minimum voltage levels according to the input voltage control and the input frequency control) as illustrated in fig. 3 b.

The use of an active DC power source (such as a battery) may enable both a voltage control loop and a frequency control loop to be included in an adaptive power supply system as shown in fig. 9.

As shown in the embodiment of fig. 9, there may be four primary control blocks in the control scheme, for example. The control block 1 can perform an adaptive voltage regulation function based on input frequency control. The control block 2 may perform an adaptive voltage regulation function based on input voltage control. The control block 3 may perform a reactive power compensation function based at least in part on the input power displacement angle control. The control block 4 may perform an over-current protection function based at least in part on the output current detection.

In an embodiment, the control block 1 may comprise a voltage detector for detecting the input voltage V_SFrequency f of_SCircuit or other device of the method of. The detected frequency may be compared to a desired frequency f for the input voltage_{S（preset）}And (6) comparing. Difference E between these two frequencies_fsBy a factor K_fScaled and then passed through a limiter and input into an adder Sum. In the control block 2, the RMS value (e.g. V) of the sensed input voltage is assumed_S,rms) A circuit or method of. The detected RMS voltage is compared to a predetermined and/or desired RMS voltage V_{S,rms（preset）}And (6) comparing. Difference E between these two voltages_VS,rmsCan be passed through a factor K_VScaled and passed through a limiter and input into an adder labeled "Sum". At the adder "Sum", the signals from the control block 1 and the control block 2 can be compared with the desired reference value V of the output voltage_{O（preset）}Add to provide V_{O（preset）}And the adaptive output voltage reference value is +/-delta V. The output of Sum may be passed through, for example, a limiter, which may, for example, output one or more limits | V of a voltage reference point_Oref| is set to be not less than V_minAnd do notGreater than V_maxSo that V is_min≤|V_Oref|≤V_max。V_maxAnd V_minMay be set and/or may be programmable. The control blocks 1 and 2 may perform functions such as automatic load shedding or load boosting. When f is detected_SRatio f_{S（preset）}When high, which may indicate, for example, that the power bus (e.g., bus) is under-loaded, the output voltage reference is adaptively adjusted to a higher value such that at L_adaptThe regulated output voltage is higher. In some embodiments, for passive loads, a higher L_adaptMay result in greater power being drawn from the mains. This for the ratio f_{S（preset）}Low f_SThe opposite may be true. At the same time, when V is detected_S,rmsRatio V_{S,rms（preset）}When high, which may also indicate that the power bus is under-loaded, the output voltage reference may be adaptively adjusted to a higher value such that at L_adaptThe regulated output voltage is higher and vice versa.

For example, by detecting the input voltage V_S（LF）And an input current I_S（LF）The reactive power compensation can be performed at the control block 3. For example, the input voltage V_SAnd an input current I_SMay be passed through a low pass filter to preserve their fundamental frequency components (e.g., V)_S（LF）And I_S（LF）). The signal may be passed through a phase angle detection circuit/method to obtain the phase angle displacement θ. A positive angle of + θ may indicate that the input current is leading the input voltage, which may be equivalent to or at least similar to the behavior exhibited by the capacitive circuit. The negative angle (- θ) may for example indicate that the input current may lag behind the input voltage, which may for example exhibit a behavior similar to that of an inductive circuit.

Theta may then be related to the desired displacement angle theta_（preset）By comparison, the difference E between the two_θMay be passed through a compensator and/or limiter to change the sine signal sin2 π ft to sin (2 π ft + θ ft) before being fed into the phase delay circuit_com). By varying the angle theta_comDifferent reactive power compensation may be performed. For power factor correction, the desired phase angle is set to θ_（preset）And = 0. In the case of + theta, theta_comWill be negative, which should result in the electric spring generating a voltage that creates an inductive power to compensate for the capacitive effect of the load. In the case of-theta, theta_comMay be positive, which should result in the electric spring generating a voltage that creates a capacitive power to compensate for the inductive effect of the load.

Sine signal-to-input voltage V varying in sin2 pi ft_SAnd its use V_S（LF）Obtained by a frequency synchronization circuit. The output (e.g., including signal | V) from the adder/Limiter (Sum/Limiter) may be used_OrefI) modulation includes a signal sin (2 π ft + θ)_com) The output of the phase delay circuit of (1). This gives V_OrefCan be used for L_adaptAdaptive output voltage V of_OReal-time control of. For voltage feedback control, V_OCan be reacted with V_OrefIn comparison, the difference can be compensated and limited before being passed to the gated mode generator for controlling one or more switching actions of the electrical spring.

In the control block 4, at least in some embodiments, for example, the load current I_OCan be sensed and compared with the maximum allowable current I through the comparator_O（lim）The values of (a) are compared. For example, if an overcurrent or short circuit occurs at the output load such that I_O＞I_O（lim）In response, the comparator may trigger a high output signal to reset the flip-flop, thereby turning off the gated mode generator. The reset may restart the electrical spring.

There are at least three differences between the standard AC mains and the adaptive AC mains embodiments:

conventional AC mains often adopt a tight tolerance of X% for voltage fluctuations. However, the adaptive AC mains may exhibit an output voltage that can be regulated within a wider tolerance with a maximum value (+ n% of the nominal value) and a minimum value (m% of the nominal value).

Standard AC mains can be regulated by the utility company to fulfill commitments to maintain a good regulated power supply within tight tolerances. However, when using an adaptive power supply, the output voltage can be regulated over a wider voltage to vary the load power consumption for the load being supplied with power.

There is no longer a need for embodiments of the electrical spring to distinguish between critical and non-critical loads. The adaptive power supply may be based on electric spring technology, which is now part of the power supply infrastructure. A variable and/or constant electrical load may be connected to the adaptive power supply provided that the load can accommodate varying voltages within the maximum voltage level and the minimum voltage level of the adaptive power supply.

In essence, with an embodiment of an adaptive power supply, the intermittent nature of the renewable power generation can be matched by load demand changes. This may allow for balancing of the power generation by load demand. If such power balance is achieved, the voltage of the standard power supply may be adjusted to a nominal value.

If the total power generation at one instant is below the load demand, the voltage of the adaptive power supply may be dynamically reduced in order to reduce the power consumption of the electrical loads (other than those of the constant power type). If the amount of power generated is less than the load demand, such that the voltage of the adaptive power supply reaches its minimum, some of the load power may come from the energy storage of the adaptive power supply (such as a battery) via the power inverter of the electrical spring. By using input voltage control to regulate the AC mains voltage (e.g. the voltage of a standard power supply), the voltage of the adaptive power supply can be varied in such a way that: the total power consumption of the load using the adaptive power supply may be varied in order to achieve a power balance between the supplied power and the power loading.

If the amount of power generated at any time is greater than the load demand, the adaptive power supply may increase the voltage in such a way that: the total power consumption may be increased in order to balance the power generation or at least reduce the imbalance of the power generation. When the maximum value of the adaptive power supply voltage level is reached, additional power generation may be shunted to the battery for storage. In this way, a balance between power generation and load demand can still be maintained.

The embodiment of the adaptive AC power supply can be extended to an adaptive DC power supply for a DC electrical load as shown in fig. 10. Similar to the AC counterpart, the DC voltage output has maximum and minimum levels that can be set and programmed. For example, for a nominal DC voltage of about 48.0V, the maximum level may be n% higher than about 48V and the minimum level may be m% lower than about 48V. The DC voltage variation can be controlled in such a way: the DC load power consumption will balance or reduce the imbalance of the power generation and load demand. The adaptive DC power supply may be set up with a standard power outlet as shown in fig. 11.

Embodiments such as adaptive AC and/or DC power supplies may form part of the voltage infrastructure as shown in fig. 12. The AC and DC power sources fed by a standard AC mains can be adapted to the intermittent nature of future power grids with high penetration of dynamically changing renewable energy sources. Embodiments provide an adaptive power infrastructure that can meet control paradigms in which load demand follows power generation — which may be desirable for future smart grids. FIG. 13 illustrates a single phase example of a standard power supply and an adaptive power supply based at least in part on certain embodiments. An electrical spring circuit with substantial power consumption typically requires installation of a DC energy storage system, such as a battery storage system. Using certain embodiments, the battery storage system may optionally be replaced by a DC bus power supply, as shown in fig. 13.

Fig. 14 illustrates one embodiment of the invention with respect to the setting of future power supplies. It shows that the adaptive AC power supply may be derived from a standard AC mains supply. It is also demonstrated that the adaptive high voltage DC power supply and the low voltage power supply can also be derived from the same standard AC mains supply.

The description of the adaptive power supply so far based on the use of an electric spring assumes that the electric spring is always operating as an individual unit. It should be noted, however, that these electrical springs may also incorporate droop control into the input voltage control loop so that these electrical springs may help the adaptive voltage source to regulate the rail voltage in a coordinated manner, as described in patent application [16 ].

Furthermore, it is proposed to provide an accessible mechanism so that the utility or authority can control the reference mains voltage in the control loop of the electric spring, in order to provide a new mechanism to control the mains voltage level in different parts of the grid. Voltage control enables a power company to control the mains voltage in different parts of the grid for various purposes. An example is to change the voltage level in order to reduce unnecessary current flow in the power distribution network in order to reduce conduction losses. Such an accessible mechanism for changing an input voltage reference by an external subject (such as a power company or authority) is illustrated in fig. 15. The voltage reference provided by the external body may be transmitted by a wired or wireless mechanism.

Furthermore, it is also proposed to provide a load setting control mechanism with an output signal so that power consumers can use it for automatically controlling the amount of power used in their smart appliances or smart loads. Such a mechanism that may optionally be employed in an adaptive power supply for directly varying the load power is illustrated in fig. 15. The control mechanism detects the input frequency and voltage level and determines whether the grid is overloaded or underloaded. It provides an output signal R_setWhich contains information about the loading level available in the grid. Future smart appliances may be designed based on the R_setThe information provided to adjust its power consumption. As an example, the load setting control may be integrated with an adaptive power supply with ground to form a four pin power outlet, as shown in fig. 13. Such integration may extend to all adaptive power supplies.

Similar to fig. 9, there are four main control blocks in the control scheme in fig. 15. Here, an optional load setting control block is introduced for performing load power control in the smart appliance. Override control of the voltage reference is included in control block 1 and control block 2. The control block 1 performs an adaptive voltage adjusting function based on input frequency control. The control block 2 performs an adaptive voltage regulation function based on input voltage level control. The control block 3 performs a reactive power compensation function based on the input power displacement angle control. The control block 4 performs an overcurrent protection function based on output current detection.

In the control block 1, the input voltage V is detected_SFrequency f of_SA circuit or method of. The detected frequency may be compared to a reference frequency f for the input voltage_SrefAnd (6) comparing. Difference E between these two frequencies_fsBy a factor K_fScaled and then passed through a limiter and input into an adder Sum. Here, the reference frequency f_SrefTypically an internally preset desired frequency f_{S（preset）}Which is the default frequency of the grid. An override function is included so that if the power office wishes to change the transmission frequency, it can be checked by referencing the "true" signal with the new desired frequency f_S（ext）Feed to override block, which will then assume f_SrefAs f_S（ext）。

In the control block 2, the RMS value (e.g. V) of the sensed input voltage is assumed_S,rms) A circuit or method of. The detected RMS voltage is compared to a reference RMS voltage V_S,refAnd (6) comparing. Difference E between these two voltages_VS,rmsBy a factor K_VScaled, then passed through a limiter and input into an adder Sum. Here, the reference RMS voltage V_S,refTypically an internally preset desired RMS voltage V_{S（preset）}Which is the default frequency of the grid. An override function is included so that if the power utility wishes to change the transmission voltage, it can pass the true signal and the new desired RMS voltage reference V_S（ext）Feed to the override block which will then assume V_SrefAs V_S（ext）。

In the load setting control block, the frequency error E_fsAnd RMS voltage error E_VS.rmsBoth are respectively passed through factor K_yAnd K_xScaled and then passed through a limiter and input into an adder. The output is a signal ± Δ Ρ, with positive values corresponding to surplus of grid power production and negative values corresponding to shortages of grid power production.± Δ Ρ are fed to a quantizer that converts ± Δ Ρ into an output signal R of discrete values (e.g. in the range-2, -1, 0, 1, 2)_setThe discrete value has an implicit meaning to the smart appliance connected to the power supply. For example, R_set= -2 may indicate that the smart appliance is operating at its lowest power because there is a shortage of power generation. R_set= 1 means lower power operation of the smart appliance. R_set=0 means normal operation. R_set= 1 means higher power operation and R_set= 2 means that the appliance is operated at maximum power.

In the foregoing description, various aspects of the claimed subject matter have been described. For purposes of explanation, specific numbers, systems or configurations were set forth to provide a thorough understanding of claimed subject matter. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that the claimed subject matter may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the claimed subject matter. While certain features have been illustrated or described herein, many modifications, substitutions, changes, or equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications or changes as fall within the spirit of the claimed subject matter.

Reference to the literature

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Claims (10)

1. An adaptive power supply infrastructure comprising a power receptacle and an adaptive power supply fed by an initial AC bus, wherein the adaptive power supply comprises an electrical spring controlled with an input voltage and/or an output voltage, wherein the electrical spring comprises an energy storage system and a power inverter configured to provide power compensation in order to regulate the input voltage and/or the output voltage, wherein the electrical spring is incorporated between the AC initial AC bus and a single power receptacle.

2. The adaptive power supply infrastructure of claim 1, wherein the power inverter is a half-bridge power inverter, a full-bridge power inverter, or a multi-stage power inverter.

3. The adaptive power supply infrastructure of claim 1, wherein the power inverter is capable of generating a sinusoidal pulse width modulated signal.

4. The adaptive power infrastructure of claim 1, wherein the electrical spring is a single phase electrical spring for one or more phases.

5. The adaptive power supply infrastructure of claim 1, wherein the electrical spring is a three-phase electrical spring.

6. The adaptive power supply infrastructure of claim 5, wherein the three-phase electric springs comprise a three-phase power inverter comprising:

one or more DC support capacitors;

an input for receiving a DC voltage; and

a low pass filter.

7. The adaptive power supply infrastructure of claim 5, wherein the three-phase electrical springs are capable of accommodating one or more DC-connected loads or one or more AC-connected loads.

8. The adaptive power infrastructure of claim 1 further comprising an adaptive voltage regulator comprising an input control device and an output control device, wherein the input control device can be used for adaptive voltage regulation and reactive power compensation and the output control device can be used for over current protection.

9. The adaptive power infrastructure of claim 8, wherein said input control means is accessible to control mains voltage level by an external reference, said external reference being transmittable by wired or wireless means.

10. The adaptive power infrastructure of claim 8 wherein said input control means can detect a phase angle displacement between an input voltage and an input current.

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