POWER CONVERSION DEVICE

Abstract

A power conversion device is provided that supplies energy to a power system via a filter comprising an inductor and a capacitor, wherein the power conversion device comprises: a first subtraction unit that calculates a first difference between the measured value of a first current flowing in the inductor and a current command value for the first current, the current command value being used to adjust the voltage of the capacitor to a target voltage; an adder unit that adds a value corresponding to the first difference and a voltage command value for the voltage of the capacitor; and a voltage output unit that outputs a voltage corresponding to the addition result of the adder unit to the filter.

Description

Technical area

[0001] The present disclosure relates to a power conversion device. State of the art

[0002] A synchronous generator helps maintain the frequency of a power system through the inertia of a rotor. In recent years, a pseudo-synchronous generator has been known that controls the output from an inverter while performing processing to simulate a rotor included in the synchronous generator (for example, Patent Literature 1). Citation listPatent literature

[0003] Patent Literature 1: Japanese Patent No. JP7023430 Summary of the inventionTechnical problem

[0004] A pseudosynchronous generator is generally provided to a power system via a filter to remove harmonic components of a current. In such a case, the interposition of the filter can cause the actual voltage output to the power system to deviate significantly from a voltage command value in some cases.

[0005] The pseudo-synchronous generator described in Japanese Patent No. JP 7023430 does not disclose any measures for suppressing such a deviation from the voltage command value.

[0006] The present disclosure relates to a power converter capable of preventing the actual voltage output to a power system from deviating from a voltage command value. Solution to the task

[0007] One aspect of the present disclosure is a power converter that supplies power to a power system via a filter including a reactor and a capacitor, the power converter comprising: a first subtraction unit configured to calculate a first difference between a measured value of a first current flowing through the reactor and a current command value of the first current to cause a voltage across the capacitor to reach a target voltage; an addition unit configured to add a value corresponding to the first difference and a voltage command value of the voltage across the capacitor; and a voltage output unit configured to output an output voltage corresponding to a result of the addition of the addition unit to the filter.

[0008] Another aspect of the present disclosure is a power converter that supplies power to a power system via a filter including a choke coil and a capacitor, the power converter comprising: a first subtraction unit configured to calculate a difference between a voltage command value of a voltage across the capacitor and a measured value of the voltage across the capacitor;a current command value output unit configured to output a current command value of a current flowing through the reactor to cause the voltage across the capacitor to reach a target voltage, based on a target value of a first current flowing through the capacitor when the voltage across the capacitor reaches the voltage command value, a measured value of a second current flowing from a node where the reactor and the capacitor are connected to the power system, and a first value corresponding to a subtraction result of the first subtraction unit; a second subtraction unit configured to calculate a difference between the current command value and a measured value of the current flowing through the reactor; an adding unit configured to add a second value corresponding to a subtraction result of the second subtraction unit and the measured value of the voltage across the capacitor;and a voltage output unit configured to output an output voltage corresponding to a result of addition of the adding unit to the filter.;

[0009] Other features of the present disclosure will become apparent from what is described in this specification. Advantageous effects of the invention

[0010] According to the present disclosure, it is possible to provide a power supply device capable of preventing the voltage actually output to a power system from deviating from a voltage command value. Brief description of the drawings Fig. 1 is a diagram illustrating an example of a power system 1 having a power converter 2 (5 to 7). Fig. 2 is a diagram illustrating an example of functional blocks of a controller 20 in a general power converter 2. Fig. 3 is a diagram illustrating an example of functional blocks of a controller 50 in a power converter 5 of an embodiment. Fig. 4 is a diagram illustrating an example of functional blocks of a controller 60 in a power converter 6 of an embodiment. Fig. 5 is a diagram illustrating an example of functional blocks of a controller 70 in a power converter 7 of an embodiment. Fig. 6A is a diagram illustrating simulation results with respect to a power converter 6 and a power converter 7. Fig. 6B is a diagram illustrating simulation results with respect to a power converter 6 and a power converter 7. Fig. 6C is a diagram illustrating simulation results with respect to a power converter 6 and a power converter 7. Description of the embodiments<<VERWEIS AUF VERWANDTE PATENTANMELDUNG> >

[0011] This application claims priority to Japanese Patent Application No. 2023-022160, filed on February 16, 2023, the entire contents of which are hereby incorporated by reference. {General Power Converter}

[0012] Before describing a power converter of an embodiment, a general power converter 2 will first be described to clarify a problem of the general power converter 2.

[0013] Fig. 1 is a diagram illustrating an example of the general power converter 2 provided to a power system 1. The power system is a system that supplies alternating current (AC) power generated at a power plant to a customer's facilities via a distribution line 10.

[0014] The power converter 2 is supplied to the power system 1 via a filter 3. A switch 4 is arranged between the filter 3 and the power system 1. The filter 3, the power converter 2, and the switch 4 are described below in this order. <Filter 3> >

[0015] The filter 3 is provided to remove harmonic components of a current flowing from the power converter 2 to the power system 1. A current I s , which is output by the power converter 2, is input to the filter 3. The filter 3 then outputs a current I b , which is obtained by removing harmonic components from the current I s obtained to the energy system 1.

[0016] The choke coil L has one end connected to the output of the power converter 2 and the other end connected to the power system 1. The capacitor C has one end connected between the choke coil L and the power system 1.

[0017] In the following description, a point where one end of the capacitor C is connected between the reactor L and the power system 1 is referred to as “node N”. <<Leistungswandler 2> >

[0018] The power converter 2 is a so-called pseudo-synchronous generator that simulates a synchronous generator comprising a rotor. The power converter 2 comprises a control device 20 and a power conversion unit 23. These are described individually below. <Steuereinrichtung 20>

[0019] In the following, a hardware configuration of the control device 20 is first described and then functional blocks of the control device 20 are described. - Hardware configuration of the control device 20

[0020] The control device 20 comprises a digital signal processor (DSP) 200 and a memory device 201 ( Fig. 1). (DSP 200)

[0021] The DSP 200 executes a predetermined program stored in the memory device 201 to thereby implement various functions of the control device 20. (Storage device 201)

[0022] The storage device 201 comprises a non-temporary (e.g., non-volatile) storage device that stores various types of data to be executed or processed by the DSP 200.

[0023] The storage device 201 further includes, for example, a random access memory (RAM) and / or the like and is used as a temporary storage area for various programs, data, and the like. - Function blocks of the control device 20

[0024] Fig. Figure 2 is a diagram illustrating the functional blocks of the controller 20. The controller 20 includes an amplitude calculation unit 210, a voltage command value output unit 211, and a PWM pulse generation unit 212. These will be described individually below. (Amplitude calculation unit 210)

[0025] The amplitude calculation unit 210 calculates an amplitude V amp ** a target voltage at node N. A so-called automatic voltage regulator can be used as the amplitude calculation unit 210.

[0026] In particular, the amplitude V amp** based on the difference between a target value V amp * the amplitude of the target voltage at node N and an actual measured value V amp the amplitude of the voltage across the capacitor.

[0027] The amplitude calculation unit 210 includes a subtraction unit 210a and a calculation unit 210b. The subtraction unit 210a calculates the difference between the target value V amp * the amplitude of the target voltage at node N and the actual measured value V amp the amplitude of the voltage across the capacitor. The computing unit 210b calculates the amplitude V amp ** the target voltage such that the result of the subtraction of the subtraction unit 210a approaches 0 (zero). (Voltage command value output unit 211)

[0028] The voltage command value output unit 211 outputs a voltage command value V C * based on the amplitude V amp** the target voltage of the capacitor C, a frequency f* and a phase 2πf*t.

[0029] In particular, the voltage command value V C * calculated according to the following expression: VC*=Vamp**sin(2πf*t) where f* is a command value of a frequency of the voltage V C at node N and t is the time. (PWM pulse generation unit 212)

[0030] The PWM pulse generation unit 212 detects a node between a carrier wave and a sine wave serving as the fundamental wave, where the carrier wave is implemented, for example, by a triangular wave. This causes the PWM pulse generation unit 212 to determine the duty cycle of a PWM pulse and generate a PWM pulse signal V PWM with the specified duty cycle.

[0031] The PWM pulse V PWMis output to the power converter unit 23 to thereby drive an inverter circuit of the power converter unit 23. <Leistungswandlereinheit 23>

[0032] The power converter unit 23 includes a direct current (DC) power supply and the inverter circuit (not shown), which includes a plurality of switching elements. The inverter circuit converts a direct current (DC) voltage from the DC power supply into an alternating current (AC) voltage to output the AC voltage to the power system 1 via the filter 3.

[0033] In this case, the inverter circuit outputs a voltage based on the PWM pulse signal V PWM which is an output from the PWM pulse generation unit 212. The voltage output here corresponds to a voltage command value V at node N. <Schalter 4> >

[0034] Switch 4 is connected between the energy system 1 and the power converter 2. Switch 4 is, for example, a circuit breaker.

[0035] When the power system 1 is in a normal state, the switch is turned on, and the power converter 2 can exchange power with the power system 1. When an abnormality, such as a fault, occurs in the power system 1, the switch is turned off, and the power converter 2 is disconnected from the power system 1.

[0036] The general power converter 2 controls the output voltage V of the power converter unit 23. However, since the power converter 2 is supplied to the power system via the filter, the voltage V C at node N deviates from a target value. Therefore, in some cases, power converter 2 may not be able to exchange desired energy with power system 1.

[0037] The power converters 5 to 7 of the embodiments described below are each a device capable of suppressing a deviation of the voltage at node N from the voltage command value. First embodiment<<Leistungswandler 5> >

[0038] As described above, the general power converter 2 has a problem that the voltage at node N deviates from the voltage command value. The power converter 5 according to an embodiment of the present application is a device capable of suppressing a deviation of the voltage at node N from the voltage command value.

[0039] Fig. 3 is a diagram illustrating an example of the power converter 5 of an embodiment of the present application, and more specifically, is the diagram illustrating an example of functional blocks of a controller 50 therein.

[0040] The controller 50 includes the amplitude calculation unit 210, a block B1, a block B2, an adding unit 217, and the PWM pulse generation unit 212, and details thereof will be described below.

[0041] Here, block B1 is a block that generates a signal to control the voltage output by power converter 5. Block B2 is a block that generates a signal to control the current output by power converter 5.

[0042] In one embodiment of the present application, block B1 includes the above-described voltage command value output unit 211 of the general power converter 2. Thus, control device 50 differs from control device 20 of the general power converter 2 in that control device 50 further includes block B2.

[0043] By further including block B2, the power converter 5 can suppress a deviation of the voltage at node N. Details will be described below.

[0044] It should be noted that the power converter unit 23 and the filter 3 are the same as those described in the general power converter 2, and thus a description thereof is omitted below. <Steuereinrichtung 50>

[0045] The control device 50 comprises the amplitude calculation unit 210, the block B1, the block B2, the adding unit 217 and the PWM pulse generation unit 212 ( Fig. 3).

[0046] The amplitude calculation unit 210 and the PWM pulse generation unit 212 are the same as those described in the general power converter 2, and thus, a description thereof is omitted. Furthermore, in block B1, the voltage command value output unit 211 constituting block B1 is the same as that described in the general power converter 2, and thus, a description thereof is omitted. - Block B2

[0047] The block B2 includes a calculation unit 213, a current command value output unit 214, a subtraction unit 215, and an output unit 216. These are described individually below. (Arithmetic unit 213)

[0048] The arithmetic unit 213 calculates a target value I C * of current I C , which flows through the capacitor C. The target value I C * is based on the amplitude V amp**, the frequency f*, the phase 2πf*t of a result of differentiation of the target voltage and a capacitance C of the capacitor C.

[0049] In particular, the target value I C * of current I C calculated according to the following expression: IC*=CdVC*dt=2πf*CVamp**cos(2πf*t) where formula 1 is used for the second same sign. (Current command value output unit 214)

[0050] The current command value output unit 214 outputs a current command value I s * of the current flowing through the choke coil L. The current command value I s * corresponds to the current flowing through the choke coil L when the voltage V C at node N the voltage command value V C * reached.

[0051] The current command value I s * is based on the target value I C * of current I C and the measured value I bof the current flowing from node N, where the inductor L and the capacitor C are connected, to the power system.

[0052] The current command value I s * is in particular an added value of the measured value I b of the current and the target value I C * of the current. (Subtraction unit 215)

[0053] The subtraction unit 215 calculates the difference between the measured value I s the current flowing through the choke coil L and the current command value I s * output from the current command value output unit 214. (Output unit 216)

[0054] The output unit 216 multiplies the result of the subtraction of the subtraction unit 215 by a predetermined constant G to thereby output an output value V*.

[0055] In particular, the output value V* is calculated according to the following expression: V*=G(IC*+Ib−Is). (Adding unit 217)

[0056] The adding unit 217 adds a value corresponding to the difference calculated by the subtracting unit 215 and the voltage command value V C * the voltage across capacitor C output from the voltage command value output unit 211.

[0057] Here, it is assumed that the “value corresponding to the difference calculated by the subtraction unit 215” is the output value V* from the output unit 216, which is expressed by Formula 3 in an embodiment of the present application.

[0058] A result V** of the addition or the adding unit 217 is obtained by adding V C * to V* obtained from formula 3 and given by the following expression. V**=G(IC*+Ib−Is)+VC*

[0059] The result V** of the addition (Formula 3) of the adding unit 217 is input to the PWM pulse generation unit 212. The processing of the controller 50 following the above is the same as the processing of the controller 20 described above.

[0060] According to the power converter 5 described above, it is possible to adjust the voltage V C at node N so that it reaches the voltage command value V C * reached.

[0061] This is because block B2 supplies the current I s , which flows through the choke coil L, so that it controls the current command value I s * is reached. In response to the current I s flowing through the choke coil L, the current command value I s * reaches, the voltage reaches V C at node N the voltage command value V C *.

[0062] If the voltage V C at node N the voltage command value VC *, the voltage actually output to the power system 1 reaches the voltage command value V C *.

[0063] Although the amplitude calculation unit 210 is assumed to be included in the controller 50 of an embodiment of the present application, this is a given configuration, and the amplitude calculation unit 210 may not be included in the controller 50. < <korrespondenzbeziehungen>

[0064] Here, correspondence relationships of the power converter 5 according to an embodiment of the present application are summarized. First, it should be noted that in the power converter 5 of an embodiment of the present application, the voltage command value V C * is added to the output value V* output by the output unit 216 in the adding unit 217.

[0065] In contrast, in the power converters 6 and 7 of other embodiments, the measured value V C the voltage across capacitor C is added to the output value V* output by output unit 216, which is described in detail below.

[0066] In such a power converter, where the voltage command value V c * is added in the adding unit 217 as in an embodiment of the present application, it is assumed to follow the following correspondence relationships.

[0067] The subtraction unit 215 corresponds to a "first subtraction unit". The current flowing through the choke coil L corresponds to a "first current". The current I C , which flows through the capacitor C, corresponds to a "second current". The current flowing from node N to the power system corresponds to a "third current".

[0068] The difference between the measured value I s the current flowing through the choke coil L and the current command value I s * of the current to cause the voltage across capacitor C to reach the target voltage corresponds to a "first difference". The difference between the target value V amp * the amplitude of the target voltage at node N and the actual measured value V amp the amplitude of the voltage across the capacitor corresponds to a "second difference". The output value V* of the output unit 216 corresponds to a "first value".

[0069] A combination of the PWM pulse generation unit 212 and the power conversion unit 23 corresponds to a "voltage output unit." In other words, the voltage output unit outputs an output voltage corresponding to the addition result of the addition unit 217 to the filter 3. Second embodiment

[0070] Fig. 4 is a diagram illustrating an example of the power converter 6 of an embodiment of the present application, and more particularly, is the diagram illustrating an example of functional blocks of a controller 60 therein.

[0071] Although the functional blocks of the control device 60 differ from the functional blocks of the control device 50 of the first embodiment, the control device 60 outputs the same PWM pulse signal as in the control device 50 when the power system 1 is in the same state. In other words, the control device 60 is a device equivalent to the control device 50.

[0072] The control device 60 further includes a subtraction unit 218 and an output unit 219 compared to the control device 50 of the first embodiment. The control device 60 differs in the configuration of the current command value output unit 220. The control device 60 differs in the signal input to the addition unit 217. (Subtraction unit 218)

[0073] The subtraction unit 218 calculates the difference between the voltage command value V C * the voltage across the capacitor C and the measured value V C the voltage across capacitor C. (Output unit 219)

[0074] The output unit 219 multiplies the subtraction result of the subtraction unit 218 by the inverse of the predetermined constant G to thereby output an output value I*. Here, the constant G is a constant by which the subtraction result of the subtraction unit 215 is multiplied in the output unit 216. (Current command value output unit 220)

[0075] The current command value output unit 220 outputs the current command value I s * of the current flowing in the choke coil L. The current command value I s * corresponds to the current flowing through the choke coil L to cause the voltage V C on the capacitor C the target voltage V C * reached.

[0076] The current command value I s * is based on the target value I C * of current I C , the measured value I b of the current and a value corresponding to the result of the subtraction of the subtraction unit 218.

[0077] Here is the current I C the current flowing through the capacitor C when the voltage V C on the capacitor C the voltage command value V C * reached. The measured value I b of the current is a measured value of the current flowing from node N, where the reactor L and the capacitor C are connected, to the power system 1. The "value corresponding to the result of subtraction of the subtraction unit 218" is the output value I* from the output unit 219 in one embodiment of the present application.

[0078] The current command value I s * is in particular an added value of the measured value I b of the current, the target value I C * of current I C and the output value I*. (Adding unit 217)

[0079] In one embodiment of the present application, the adding unit 217 adds a value corresponding to the result of the subtraction of the subtracting unit 215 and the measured value V C the voltage across capacitor C.

[0080] Here, the "value corresponding to the result of subtraction of the subtraction unit 215" is the output value V* from the output unit 216 in one embodiment of the present application.

[0081] In particular, the output value V* is given by the following expression: V*=G(IC*+VC*−VCG+Ib−Is)

[0082] Accordingly, the result V** of the addition of the adding unit 217 is obtained by adding V C to V* obtained from formula 5 and given by the following expression: V**=G(IC*+Ib−Is)+VC*.

[0083] The addition result V** in one embodiment of the present application is equal to the addition result V** in the first embodiment (Formula 4). In other words, the control device 60 is shown to be equivalent to the control device 50 of the first embodiment.

[0084] The addition result V** (Formula 5) of the adding unit 217 is input to the PWM pulse generating unit 212. The processing of the controller 60 following the above is the same as the processing of the controller 50 described above.

[0085] According to the power converter 6 described above, as in the power converter 5, it is possible to adjust the voltage V C at node N so that it reaches the voltage command value V C * reached.

[0086] Furthermore, the control device 60 of an embodiment of the present application receives the measured value V C the voltage across the capacitor C. This indicates that the voltage command value V is output after the measured value V C in the power converter 6 of an embodiment of the present application.

[0087] It should be noted that, in one embodiment of the present application, the constant (G) by which an input value is multiplied in the output unit 216 and the constant (1 / G) by which an input value is multiplied in the output unit 219 have a relationship in which they are reciprocal to each other. With such a relationship, the controller 60 is equivalent to the controller 50.

[0088] However, the relationship between the constant by which the input value is multiplied in the output unit 216 and the constant by which the input value is multiplied in the output unit 219 is not limited thereto, and any preferable value can be set appropriately. < <korrespondenzbeziehungen>

[0089] Here, correspondence relationships of the power converter 6 according to an embodiment of the present application are summarized. First, it should be noted that in the power converter 6 according to an embodiment of the present application, the measured value V C the voltage across capacitor C is added to the output value V* from output unit 216 in adding unit 217.

[0090] In contrast, as described above, in the power converter 5 of the first embodiment, the voltage command value V C * added to the output value V* from the output unit 216 in the adding unit 217 ( Fig. 3).

[0091] In such a power converter, in which the measured value V C the voltage across the capacitor C in the adding unit 217 as in an embodiment of the present application, it is assumed to follow the following correspondence relationships.

[0092] The subtraction unit 215 corresponds to a "second subtraction unit." The subtraction unit 218 corresponds to a "first subtraction unit." The output unit 219 corresponds to a "first output unit." The output unit 216 corresponds to a "second output unit."

[0093] The Stream I C corresponds to a "first current". The current I b , which flows from node N, where the inductor L and the capacitor C are connected, to the energy system 1, corresponds to a "second current". The current I s flowing through the choke coil L corresponds to a "third current".

[0094] The "value corresponding to the result of subtraction by subtraction unit 218" corresponds to a "first value." The "value corresponding to the result of subtraction by subtraction unit 215" corresponds to a "second value."

[0095] Note that a third embodiment described below has the same correspondence relationships as those in an embodiment of the present application. Third embodiment

[0096] Fig. 5 is a diagram illustrating an example of the power converter 7 of one embodiment of the present application, and more specifically, it is the diagram illustrating an example of functional blocks of a control device 70 therein. The power converter 7 of one embodiment of the present application is a device capable of suppressing the occurrence of an overcurrent.

[0097] The power converter 7 differs from the second embodiment in that the control device 70 further includes a throttle unit 221. The configuration other than this is similar or the same as the second embodiment, and thus, its description is omitted. Note that the power converter 7 of one embodiment of the present application also has the same correspondence relationships as those in the power converter 6 of the second embodiment. (Throttle unit 221)

[0098] The throttle unit 221 throttles the current command value I s * output from the current command value output unit 220 within a predetermined range and outputs a throttled current command value I s ** to the subtraction unit 215.

[0099] Here, “within a specified range” may be a specified range within the range of the rated current of the power converter 7.

[0100] According to the power converter 7 described above, as in the power converter 6, it is possible to adjust the voltage V C at node N so that it reaches the voltage command value V C * to suppress the occurrence of an overcurrent. <Ergebnisse einer numerischen Simulation>

[0101] Results of a numerical simulation in which the power converter 7 of one embodiment of the present application and the power converter 6 of the second embodiment are adopted will be described.

[0102] Fig. 6A to Fig. 6C are diagrams illustrating simulation results assuming power converters 6 and 7. In these drawings, Fig. 6A Frequencies on a time series assumed in energy system 1, illustrated Fig. 6B shows a calculation result of the output current of the power converter 6 in the second embodiment and illustrates Fig. 6C shows a calculation result of the output current of the power converter 7 in an embodiment of the present application.

[0103] In this calculation, step-like frequency variations are assumed ( Fig. 6A). Before time t = 10.0 [s] and after time t = 10.06 [s], 50 [Hz] is assumed to be the frequency in a normal state. Between time t = 10.00 [s] and time t = 10.06 [s], 50.8 [Hz] is assumed.

[0104] In Fig. 6B and Fig. In Figure 6C, the vertical axis represents an output current and is normalized so that the rated current of power converters 6 and 7 equals 1. These diagrams illustrate the respective AC currents of the three phases.

[0105] From these results, it can be seen that the output current according to the power converter 7 of an embodiment of the present application varies without exceeding the rated current after the occurrence of frequency variations in the power system 1. Thus, according to the power converter 7 of an embodiment of the present application, it is possible to prevent the occurrence of an overcurrent. {Summary}

[0106] As described above, the power converter 5 of the first embodiment is a power converter that supplies power to the power system 1 via the filter 3 including the reactor L and the capacitor C. The power converter 5 includes: the subtraction unit 215 configured to calculate the first difference between the measured value of the first current flowing through the reactor L and the current command value of the first current to cause the voltage across the capacitor C to reach the target voltage; the addition unit 217 configured to add the value corresponding to the first difference and the voltage command value of the voltage across the capacitor C; and the voltage output unit configured to output the output voltage corresponding to the addition result of the addition unit 217 to the filter.

[0107] According to such a configuration, when the power converter 5 is supplied to the power system 1 via the filter 3, a deviation in the voltage actually output to the power system 1 can be suppressed by the filter 3. In other words, the voltage actually output to the power system 1 can be controlled to a desired value.

[0108] The power converter 5 of the first embodiment further includes: the voltage command value output unit 211 configured to output the voltage command value based on the amplitude, frequency, and phase of the target voltage at the capacitor C; the calculation unit 213 configured to calculate the second current flowing through the capacitor C based on the amplitude, frequency, and phase of the result of differentiating the target voltage and the capacitance of the capacitor C; and the current command value output unit 214 configured to output the current command value of the first current based on the target value of the second current and the measured value of the third current flowing from the node N to which the reactor L and the capacitor C are connected to the power system 1.According to such a configuration, it is possible to accurately calculate the command value of the current of the reactor, thereby improving the accuracy of the voltage output to the power system 1.

[0109] The power converter 5 of the first embodiment further includes the amplitude calculation unit 210 configured to calculate the amplitude of the target voltage based on the second difference between the target value of the amplitude of the target voltage and the amplitude of the voltage across the capacitor C. According to such a configuration, it is possible to accurately calculate the voltage command value of the capacitor C, thereby further improving the accuracy of the voltage output to the power system 1.

[0110] Each of the power converters 6 and 7 of the second and third embodiments is a power converter that supplies power to the power system 1 via the filter 3 including the reactor L and the capacitor C, the power converter 6, 7 including: the subtraction unit 218 configured to calculate the difference between the voltage command value of the voltage across the capacitor C and the measured value of the voltage across the capacitor C;the current command value output unit 220 configured to output the current command value of the third current flowing through the reactor L to cause the voltage across the capacitor C to reach the target voltage, based on the target value of the first current flowing through the capacitor C when the voltage across the capacitor C reaches the voltage command value, the measured value of the second current flowing from the node N where the reactor L and the capacitor C are connected to the power system 1, and the first value corresponding to the subtraction result of the subtraction unit 218; the subtraction unit 215 configured to calculate the difference between the current command value and the measured value of the third current; the addition unit 217 configured to add the second value corresponding to the subtraction result of the subtraction unit 215 and the measured value of the voltage across the capacitor C;and the voltage output unit configured to output the output voltage corresponding to the addition result of the adding unit 217 to the filter 3;

[0111] According to such a configuration, when the power converter 6 or 7 is supplied to the power system 1 via the filter 3, a deviation in the voltage actually output to the power system 1 can be suppressed by the filter 3. In other words, the voltage actually output to the power system 1 can be controlled to the desired value.

[0112] The power converter 7 of the third embodiment further includes the throttling unit 221 configured to throttle the current command value output by the current command value output unit 220 within a predetermined range and output a result to the subtraction unit 215. According to such a configuration, it is possible to prevent the occurrence of an overcurrent.

[0113] Each of the power converters 6 and 7 of the second and third embodiments further includes: the voltage command value output unit 211 configured to output the voltage command value based on the amplitude, frequency, and phase of the target voltage of the capacitor; and the calculation unit 213 configured to calculate the first current flowing through the capacitor based on the amplitude, frequency, and phase of the result of differentiating the target voltage and the capacitance of the capacitor. According to such a configuration, it is possible to accurately calculate the command value of the current of the reactor L, thereby improving the accuracy of the voltage output to the power system 1.

[0114] Each of the power converters 6 and 7 of the second and third embodiments further includes: the output unit 219 configured to multiply the subtraction result of the subtraction unit 218 by the inverse of the predetermined constant to thereby output the first value; and the output unit 216 configured to multiply the subtraction result of the subtraction unit 215 by the constant to thereby output the second value. According to such a configuration, the power converters 6 and 7 are equivalent to the power converter of the first embodiment.

[0115] Each of the power converters 6 and 7 of the second and third embodiments further includes the amplitude calculation unit 210 configured to calculate the amplitude of the target voltage based on the difference between the target value of the amplitude of the target voltage and the amplitude of the voltage across the capacitor C. According to such a configuration, it is possible to accurately calculate the voltage command value of the capacitor C, thereby further improving the accuracy of the voltage output to the power system 1. List of reference symbols 1 Energy system 2 Power conversion device 20 Control device 200 DSP 201 Storage device 210 Amplitude calculation unit 211 Voltage command value output unit 212 PWM pulse generation unit 213 computing unit 214 Current command value output unit 215 Subtraction unit 216 Output unit 217 Adding unit 218 Subtraction unit 219 Output unit 220 Current command value output unit 221 throttle unit 5 power converters 50 Control device 6 Power conversion device 60 control unit 7 power converters 70 Control device 3 filters 4 switches QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 7023430 [0003, 0005] JP 2023-022160

[0011] < / korrespondenzbeziehungen> < / korrespondenzbeziehungen>

Claims

[1] A power converter that supplies power to a power system through a filter comprising a choke coil and a capacitor, the power converter comprising: a first subtraction unit configured to calculate a first difference between a measured value of a first current flowing through the reactor and a current command value of the first current to cause a voltage across the capacitor to reach a target voltage; an adding unit configured to add a value corresponding to the first difference and a voltage command value of the voltage across the capacitor; and a voltage output unit configured to output an output voltage corresponding to a result of addition of the adding unit to the filter. [2] The power converter of claim 1, further comprising: a voltage command value output unit configured to output the voltage command value based on an amplitude, a frequency, and a phase of the target voltage of the capacitor; a computing unit configured to calculate a second current flowing through the capacitor based on an amplitude, a frequency, and a phase of a result of differentiating the target voltage and a capacitance of the capacitor; and a current command value output unit configured to output the current command value of the first current based on a target value of the second current and a measured value of a third current flowing from a node where the reactor and the capacitor are connected to the power system. [3] The power converter of claim 1, further comprising: an amplitude calculation unit configured to calculate an amplitude of the target voltage based on a second difference between a target value of the amplitude of the target voltage and an amplitude of the voltage across the capacitor. [4] A power converter that supplies power to a power system through a filter comprising a choke coil and a capacitor, the power converter comprising: a first subtraction unit configured to calculate a difference between a voltage command value of a voltage across the capacitor and a measured value of the voltage across the capacitor; a current command value output unit configured to output a current command value of a current flowing through the reactor to cause the voltage across the capacitor to reach a target voltage based on a target value of a first current flowing through the capacitor when the voltage across the capacitor reaches the voltage command value, a measured value of a second current flowing from a node where the inductor and the capacitor are connected to the power system, and a first value corresponding to a result of the subtraction of the first subtraction unit; a second subtraction unit configured to calculate a difference between the current command value and a measured value of the current flowing through the reactor; an adding unit configured to add a second value corresponding to a result of the subtraction of the second subtracting unit and the measured value of the voltage across the capacitor; and a voltage output unit configured to output an output voltage corresponding to a result of addition of the adding unit to the filter. [5] The power converter of claim 4, further comprising: a throttling unit configured to throttle the current command value output from the current command value output unit within a predetermined range and output a result to the second subtraction unit. [6] The power converter of claim 5, further comprising: a voltage command value output unit configured to output the voltage command value based on an amplitude, a frequency, and a phase of the target voltage of the capacitor; and a computing unit configured to calculate the first current flowing through the capacitor based on an amplitude, a frequency, and a phase of a result of differentiating the target voltage and a capacitance of the capacitor. [7] The power converter of claim 6, further comprising: a first output unit configured to multiply a result of the subtraction of the first subtraction unit by an inverse of a constant to thereby output the first value; and a second output unit configured to multiply a result of the subtraction of the second subtraction unit by the constant to thereby output the second value. [8] Power converter according to one of claims 4 to 7, further comprising: an amplitude calculation unit configured to calculate an amplitude of the target voltage based on a difference between a target value of the amplitude of the target voltage and an amplitude of the voltage across the capacitor.

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