Control device, power conditioner, and heat pump system

Abstract

[PROBLEM] To suppress interference between two or more devices connected to a DC bus in voltage control of the DC bus in a device that receives and supplies DC power to the DC bus. [SOLUTION] A control device that is connected to a DC link unit including a capacitor and controls devices transmitting and receiving power to and from the DC link unit comprises: a first current value acquisition unit that acquires, from the capacitor, a detection value of a first current flowing through a device other than the device connected to the DC link unit; a voltage value acquisition unit that acquires a detection value of the voltage of the capacitor; and an adjustment unit that uses the detection value of the voltage and the detection value of the first current to adjust a second current that the device transmits and receives to and from the DC link unit.

Description

Control devices, power conditioners, and heat pump systems

[0001] This disclosure relates to a control device, a power conditioner, and a heat pump system.

[0002] Patent Document 1 discloses a DC power supply device configured by connecting multiple devices in parallel to a DC power supply, each device being configured by connecting an inductive element and a capacitive element in series, and the capacitive element and a load in parallel, wherein each device includes an electrical quantity detection means for detecting one or more of the following: load current flowing through the load, current flowing through the inductive element, voltage applied to the inductive element, voltage applied to the capacitive element, and current flowing through the capacitive element; and a control means for controlling each load based on the output of the electrical quantity detection means so as to reduce the inductive current component due to interference between each device.

[0003] Japanese Patent Publication No. 2013-187945

[0004] When controlling the voltage of a DC bus (DC link section) to which multiple devices are connected, high-precision control is required because the power state of each device connected to the DC bus changes sequentially. If each device controls the voltage of the DC bus individually, the system becomes redundant and may cause mutual interference. This disclosure aims to suppress interference between two or more devices in the voltage control of a DC bus to which two or more devices are connected, in a device that receives and supplies DC power to a DC bus to which two or more devices are connected.

[0005] The control device in the first aspect is a control device connected to a DC link section equipped with a capacitor, and controls equipment that transmits and receives power to and from the DC link section, the control device comprising: a first current value acquisition unit that acquires a detected value of a first current flowing from the capacitor to equipment other than the equipment connected to the DC link section; a voltage value acquisition unit that acquires a detected value of the voltage of the capacitor; and an adjustment unit that adjusts a second current to which the equipment transmits and receives power to and from the DC link section using the detected voltage value and the detected first current value. In this case, in equipment that receives and supplies DC power to a DC bus to which two or more devices are connected, interference between two or more devices in the voltage control of the DC bus can be suppressed. The control device in the second aspect is the control device in the first aspect, wherein the adjustment unit calculates a target value of the first current using the detected voltage value, and adjusts the second current to which the equipment transmits and receives power to and from the DC link section using the difference between the target value of the first current and the detected value of the first current. In this case, interference between devices can be suppressed without using information from other devices. The control device according to the third aspect is a control device according to the first or second aspect, wherein the device comprises a power conversion circuit, the control device comprises a second current value acquisition unit for acquiring a detected value of the second current, the adjustment unit outputs a control command for controlling the power conversion circuit, calculates the high-frequency component of the second current using the detected value of the second current, calculates the high-frequency component of the voltage using the detected value of the voltage, calculates the low-frequency component of the control command using the control command, calculates a first manipulated variable using the high-frequency component of the second current, calculates an interference amount using the high-frequency component of the voltage, and calculates a new control command using the first manipulated variable, the interference amount, and the low-frequency component of the control command. In this case, interference via the DC link unit can be canceled out with simple calculations. The power conditioner in the fourth aspect comprises a control device according to any of the first, third, or fourth aspects; a DC link section equipped with a capacitor; a converter connected to the DC link section and controlled by the control device; and a grid-connected inverter configured to be connectable to a grid power supply and connected to the DC link section.In this case, in a device that receives and supplies DC power to a DC bus to which two or more devices are connected, interference between the two or more devices in the voltage control of the DC bus can be suppressed. The heat pump system in the fifth aspect comprises a control device according to any of the first, third, or fourth aspects, a DC link section equipped with a capacitor, a converter connected to the DC link section, a refrigeration device connected to the DC link section, and a grid-connected inverter configured to be connectable to a grid power supply and connected to the DC link section, wherein the control device is configured to control the converter or the refrigeration device. In this case, in a device that receives and supplies DC power to a DC bus to which two or more devices are connected, interference between the two or more devices in the voltage control of the DC bus can be suppressed.

[0006] This is a diagram showing the circuit configuration of the power optimization system according to the first embodiment. This is a control block diagram of the control device of the first embodiment. This is a simplified diagram of the control block diagram of Figure 2. This is a diagram showing the circuit configuration of the power optimization system according to the second embodiment. This is a control block diagram of the control device of the second embodiment. This is a simplified diagram of the control block diagram of Figure 5. This is a control block diagram of the control device of modified example 1 of the second embodiment. This is a simplified diagram of the control block diagram of Figure 7. This is a diagram showing the circuit configuration of the power optimization system according to modified example 2 of the second embodiment. This is a control block diagram of the control device of the second embodiment. This is a diagram showing the circuit configuration of the power optimization system according to the third embodiment. This is a diagram showing the circuit configuration of the power optimization system according to the fourth embodiment. This is a control block diagram of the control device of the fourth embodiment. This is a control block diagram of the control device of modified example 1 of the fourth embodiment. This is a control block diagram of the control device of modified example 2 of the fourth embodiment. This is a diagram showing the circuit configuration of the power optimization system according to the fifth embodiment. This is a control block diagram of the control device of the fifth embodiment. This is a flowchart of the current command distribution process in the fifth embodiment. This is a diagram showing modified example 1 of the fifth embodiment. This is a control block diagram of modified example 1 of the fifth embodiment. This is a diagram showing modified example 2 of the fifth embodiment. This is a control block diagram of modified example 2 of the fifth embodiment. This is a diagram showing the system configuration of the sixth embodiment.

[0007] The embodiments will be described in detail below with reference to the attached drawings. <First Embodiment> [Overall Configuration] Figure 1 is a diagram of the circuit of the power optimization system 1 according to the first embodiment. In the first embodiment, a power optimization system 1 is described that suppresses interference in the voltage control of the DC link section by two or more devices when one of the devices is a converter in a system that controls a DC link section to which two or more devices are connected. The power optimization system 1 comprises a DC link section 20, a converter 30, a power supply 40, other devices 50, and a control device 101.

[0008] The converter 30 transmits and receives power to the DC link section 20. The power supply 40 supplies DC power to the converter 30. The power supply 40 is not particularly limited, but examples include solar cells and storage batteries. Other equipment 50 is connected to the DC link section 20 and transmits and receives power to the DC link section 20. Other equipment 50 is not particularly limited, but examples include electrical appliances such as refrigeration equipment, air conditioners, and water heaters. The control device 101 controls the DC link section 20 and the converter 30.

[0009] The DC link section 20 includes a capacitor 35. The capacitor 35 smooths the output of the converter 30. Let C be the capacitance value of this capacitor 35. The converter 30 includes a switch section 31, a reactor 32, and a resistor 33. In the converter 30, the switch section 31, reactor 32, and resistor 33 are arranged in that order from the upstream side in the direction of current flow. The reactance value of the reactor 32 is L. １ The resistance value of resistor 33 is set to r １ The switch unit 31 comprises two switch elements 31a and 32b. The DC current from the power supply 40 is stepped down by the synchronous operation of the switch elements 31a and 31b.

[0010] The control device 101 includes a device that processes various types of information. The control device 101 can be configured using a microcomputer and a memory device or the like in which software for operating the microcomputer is stored. The control device 101 also includes a first ammeter 71, a second ammeter 72, a first voltmeter 73, and a second voltmeter 74. The first ammeter 71 measures the current flowing from the capacitor 35 to the other device 50. The second ammeter 72 measures the current transmitted and received between the converter 30 and the DC link section 20. The first voltmeter 73 measures the voltage of the capacitor 35. The second voltmeter 74 measures the voltage of the power supply 40. The first ammeter 71, the second ammeter 72, the first voltmeter 73, and the second voltmeter 74 transmit the measured values to the control device 101. The transmission of the measured values to the control device 100 may be performed by wire or wirelessly. Also, let the current value measured by the first ammeter 71 be i ｅ and let the current value measured by the second ammeter 72 be i １ . Also, let the voltage value measured by the first voltmeter 73 be v ＬＩＮＫ and let the value measured by the second voltmeter 74 be the voltage value v １ . Also, at this time, let the output current of the converter be i ｏｕｔ . The control target 11 of the control device 101 includes the DC link section 20 and the converter 30. The control device 101 transmits the duty ratio d １ to the converter 30 as information for controlling the converter 30.

[0011] [Construction of Control Means] In the power optimization system 1 shown in FIG. 1, from the voltage of the power supply 40, the voltage of the converter 30, the voltage of the reactor 32, the voltage of the resistor 33, and the voltage of the capacitor 35, Equation (1-1) holds as a differential equation.

[0012]

[0013] Linearize Equation (1-1) near the equilibrium point. Here, let the equilibrium points of i １ , d １ , v ＬＩＮＫ be I １ , D １ , V ＬＩＮＫ and let the amount of variation around the equilibrium point be Δi １ , Δd１ , Δv ＬＩＮＫ i １ = I １ +Δi １、 d １ = D １ +Δd １ , v ＬＩＮＫ = V ＬＩＮＫ +Δv ＬＩＮＫ Then, we get equation (1-2).

[0014]

[0015] At the equilibrium point, equation (1-3) holds true.

[0016] Applying equation (1-3) to equation (1-2), we obtain equation (1-4) as a differential equation near the equilibrium point.

[0017]

[0018] Furthermore, equation (1-5) holds true as a differential equation relating to the current in capacitor 35.

[0019]

[0020] Similarly, equation (1-5) is linearized near the equilibrium point. ｅ The equilibrium point is I ｅ Let Δi be the amount of variation around the equilibrium point. ｅ Then, i ｅ = I ｅ +Δi ｅ This results in equation (1-6).

[0021]

[0022] At the equilibrium point, equation (1-7) holds true.

[0023]

[0024] Applying equation (1-7) to equation (1-6), we obtain equation (1-8) as a differential equation near the equilibrium point.

[0025]

[0026] As described in equation (1-8), Δv ＬＩＮＫ is, Δi １and Δi ｅ Since it includes Δi ｅ It is subjected to interference by Δv. Therefore, the interference component is Δv L1 Decoherence is performed by defining it as shown in equation (1-9).

[0027]

[0028] Applying equation (1-9) to equation (1-4) results in equation (1-4) becoming equation (1-10).

[0029]

[0030] Transforming equation (1-10) yields equation (1-11).

[0031]

[0032] According to equation (1-11), Δv L1 From Δi １ The transfer function up to this point is shown.

[0033] [Control System Configuration] Figure 2 is a control block diagram of the control device 101 of the first embodiment. Based on equations (1-5) and (1-11) described above, v ＬＩＮＫ and i １ We will construct a control system to control the following. Here, v ＬＩＮＫ By using feedback control, Δi １ ＊ Compensator G that outputs ｖ (s) 112 and Δi １ By using feedback control, Δv Ｌ１ ＊ Compensator G that outputs １ (s) 122 and a control system using the above were used. The control device 101 controls the converter 30 included in the controlled object 11 with a duty cycle d １ Calculate.

[0034] The control block of the control device 101 includes a voltage control unit 110, a current control unit 120, a non-interference control unit 130, a control command output unit 140, a first current high frequency unit 141, a second current high frequency unit 142, a voltage high frequency unit 143, and a command low frequency unit 144.

[0035] [First current high frequency section] The first current high frequency section 141 controls the first current i ｅ This is fed back, and the first current i ｅ The high-frequency component Δi ｅ The first current high-frequency unit 141 outputs the first current i by, for example, the following method. ｅ The high-frequency components are calculated.

[0036] As the first method, the first current high-frequency unit 141 detects the first current i ｅ The input is used, and the first current is detected i through a filter that removes low-frequency components. ｅ The high frequency is detected, and this high frequency is converted to Δi ｅ Here, examples of filters that remove low-frequency components include high-pass filters and band-pass filters. As a second method, the detected value i of the first current ｅ The input is the high-frequency component Δi １ The low-frequency component of the second current is detected through a filter that removes the unwanted noise. Then, the detected value i of the first current is... ｅ Subtracting the low-frequency component of the first current from this gives the high-frequency component Δi of the first current. ｅ In other words, the detected value i of the first current. ｅ The difference between the low-frequency component of the first current and the high-frequency component Δi of the first current is the difference between the low-frequency component and the high-frequency component of the first current. ｅ Here, examples of filters that remove high-frequency components include low-pass filters and moving average filters. As a third method, the detected i ｅ and command value i ｅ ＊ The deviation i ｅ -i ｅ ＊ Δi ｅ This can be illustrated as an example.

[0037] [Second current high frequency section] The second current high frequency section 142 detects the second current i １ This is fed back, and the second current i １ The high-frequency component Δi １ The second current high-frequency unit 142 outputs the second current i by, for example, the method illustrated below. １ The high-frequency component Δi １ Calculate.

[0038] As a first method, the second current high-frequency section 142 uses the detected value i of the second current １ as an input, detects the high frequency of the detected value i of the second current through a filter that removes low-frequency components, and sets this high frequency as Δi １ Here, examples of the filter that removes low-frequency components include a high-pass filter and a band-pass filter. As a second method, the second current high-frequency section 142 uses the detected value i of the second current １ as an input, and detects the low-frequency component of the second current through a filter that removes high-frequency components Δi １ Then, the high-frequency component Δi of the second current is obtained by subtracting the low-frequency component of the second current from the detected value i of the second current １ That is to say, the difference between the detected value i of the second current and the low-frequency component of the second current is set as the high-frequency component Δi of the second current １ Here, examples of the filter that removes high-frequency components include a low-pass filter and a moving average filter. As a third method, it can be exemplified that the deviation i between the detected i １ and the command value i １ is set as Δi １ １ and the command value i １ ＊ is set as Δi １ - i １ ＊ １

[0039] [Voltage High-Frequency Section] The voltage high-frequency section 143 feeds back the voltage v of the capacitor 35 ＬＩＮＫ and outputs the high-frequency component Δv of the voltage v ＬＩＮＫ The voltage high-frequency section 143 calculates the high-frequency component Δv ＬＩＮＫ by, for example, the methods exemplified below. ＬＩＮＫ

[0040] As a first method, the voltage high-frequency section 143 uses the detected value v of the voltage of the capacitor 35 ＬＩＮＫ as an input, and through a filter that removes low-frequency components, the high-frequency component Δv of v ＬＩＮＫ ＬＩＮＫThe low-frequency component is detected. Here, examples of filters that remove low-frequency components include high-pass filters and band-pass filters. As a second method, the high-frequency voltage section 143 detects the capacitor voltage v ＬＩＮＫ The input is used, and the low-frequency component detected is passed through a filter that removes the high-frequency component. Then, the detected value v of the voltage across capacitor 35 is used. ＬＩＮＫ Subtracting the low-frequency component of the voltage across capacitor 35 from this value gives v ＬＩＮＫ The high-frequency component Δv ＬＩＮＫ In other words, the detected value v of the voltage across capacitor 35. ＬＩＮＫ The difference between the low-frequency component of the voltage across capacitor 35 and the high-frequency component Δv of the capacitor voltage is the difference between the low-frequency component and the high-frequency component of the capacitor voltage. ＬＩＮＫ Here, examples of filters that remove high-frequency components include low-pass filters and moving average filters. As a third method, the detected v ＬＩＮＫ and command value v ＬＩＮＫ ＊ The deviation from ＬＩＮＫ -v ＬＩＮＫ ＊ Δv ＬＩＮＫ This can be illustrated as an example.

[0041] [Control Command Low Frequency Unit] The command low frequency unit 144 controls the control command value d １ ＊ The control command value d is used as input. １ ＊ Low-frequency component D １ ＊ The command low-frequency unit 144 outputs the low-frequency component D, for example, by the method illustrated below. １ ＊ To calculate this, firstly, the command value d １ ＊ The input is passed through a filter that removes high-frequency components, and the command value d １ ＊ Low-frequency component D １ ＊ This is detected. Here, examples of filters that remove high-frequency components include low-pass filters and moving average filters. As a second method, the command value d １ ＊The input is D, and the low-frequency component is obtained by delaying this input by one control cycle. １ ＊ For example, the command value d. １ One example of this configuration is using a delay circuit that delays the signal by one control cycle.

[0042] [Voltage Control Unit] The voltage control unit 110 controls v ＬＩＮＫ Command value v ＬＩＮＫ ＊ And, v ＬＩＮＫ The measured value and Δi output from the first current high-frequency section 141 ｅ Obtain the variation Δi of the converter current command value. １ ＊ It outputs the command value v. The voltage control unit 110 comprises a subtractor 111, a compensator Gv(s) 112, and an adder 113. The subtractor 111 outputs the command value v. ＬＩＮＫ ＊ From the measured value v ＬＩＮＫ Subtract the command value v. The compensator Gv(s) 112 is used to subtract the command value v. ＬＩＮＫ ＊ and measured value v ＬＩＮＫ The variation Δi of the command value of the second current to compensate for the difference. １ ＊ The adder 113 adds the high-frequency component Δi output from the first current high-frequency section 141 to the output from the compensator Gv(s) 112. ｅ Adding this, the variation Δi of the command value of the second current １ ＊ Output as follows.

[0043] [Current Control Unit] The current control unit 120 controls the second current i output by the voltage control unit 110. １ The amount of variation Δi of the command value １ ＊ The high-frequency component Δi output by the second current high-frequency section 142 １ Using as input, non-interference control v L1 The amount of variation Δv in the command value L1 ＊ The output is generated by the current control unit 120, which consists of a subtractor 121 and a compensator G １ (s) 122 and the subtractor 121 is the amount of change Δi output by the voltage control unit 110. １ ＊Therefore, the high-frequency component Δi output by the second current high-frequency section 142 １ Subtract it. Then, compensator G １ (s) 122 is (Δi １ ＊ -Δi １ ) based on non-interference control v L1 The amount of variation Δv in the command value L1 ＊ Outputs.

[0044] [Non-interference control unit] The non-interference control unit 130 performs non-interference control to compensate for the amount of variation in the interference component. The non-interference control unit 130 includes an adder 131 and a divider 132. Here, the duty cycle d to the converter １ The variation Δd in the command value １ ＊ This can be calculated using the following formula.

[0045]

[0046] The adder 131 is connected to the output of the current control unit 120, Δv Ｌ１ ＊ And the output of the voltage high-frequency section 143 is Δv ＬＩＮＫ The two are added together. Then, the divider 132 uses the output from the adder 131 as the numerator and the voltage v of the power supply 40. １ Divide by the denominator and calculate the variation Δd of the command value of the duty cycle. １ ＊ Outputs.

[0047] [Control Command Output Unit] The control command output unit 140 outputs the control command variation Δd １ ＊ And the control command value d １ ＊ Low-frequency component D １ ＊ Therefore, the control command value d １ ＊ Outputs the control command value d. １ ＊ It can be calculated using the following formula.

[0048]

[0049] The control command output unit 140 is composed of an adder, and the variation Δd of the control command １ ＊And the control command value d １ ＊ Low-frequency component D １ ＊ Adding these together, we get the control command value d １ ＊ Outputs.

[0050] Furthermore, the controlled device 11 includes an adder 161, four subtractors 171 to 174, and a multiplier 181. The subtractor 171 receives a control command value d from the control device 101. １ ＊ From equilibrium point D １ Subtracting Δd １ It outputs as follows. Then, the multiplier 181 is Δd １ and v １ Multiply by and. Also, subtractor 172 is v ＬＩＮＫ From equilibrium point V ＬＩＮＫ Subtract Δd from the multiplier 181. Here, the subtractor 173 subtracts Δd from the multiplier 181. １ ×v １ Therefore, subtractor 172 subtracted (v ＬＩＮＫ -V ＬＩＮＫ Subtracting ) gives Δv Ｌ１ Output as follows.

[0051] Here, from equation (1-11) above, Δv Ｌ１ From Δi １ The transfer function G1 up to is 1 / (L １ S+r １ ) And the adder 161 is Δi １ Equilibrium point I １ Add i １ It outputs as i. Furthermore, the subtractor 174 is i １ From the measured value of the first current i ｅ This is subtracted. Also, from equation (1-5) above, i １ -i ｅ From v ＬＩＮＫ The transfer function G2 up to this point is (1 / Cs).

[0052] Figure 3 is a modified version of the control block diagram in Figure 2. Next, the control block diagram in Figure 3 will be explained with reference to Figure 2. Figure 3 shows the equilibrium point D in Figure 2. １ The control command value d output by the command low-frequency unit 144 １＊ Low-frequency component D １ ＊ We consider and to be identical, Δv ＬＩＮＫ and (v ＬＩＮＫ -V ＬＩＮＫ This is a modified control block diagram, assuming that ) and are identical. Equilibrium point D １ The control command value d output by the command low-frequency unit 144 １ ＊ Low-frequency component D １ ＊ If they are the same, the control command output unit 140 outputs the control command value d １ ＊ Low-frequency component D １ ＊ The process of adding and subtracting is performed by the subtractor 171 to reach equilibrium point D １ The subtraction operation cancels out. In this case, the divider 132 performs v １ The process involves dividing with the denominator and multiplier 181 by v １ The multiplication process cancels out. Furthermore, Δv is added by adder 131. ＬＩＮＫ Then, subtracted by subtractor 173 (v ＬＩＮＫ -V ＬＩＮＫ When these are considered identical, they cancel each other out. If these canceling parts are removed from Figure 2, the current control unit 120 outputs Δv L1 ＊ From the input Δv of the transfer function L1 The process up to this point can be omitted and shown. The process of the adder 161 and subtractor 174 in Figure 2 is shown in Figure 3 as i ｅ = I ｅ +Δi ｅ The processing is carried out using subtractors 175 and 176. As shown in Figure 3, in the decoupling control block diagram, v ＬＩＮＫ And, Δi ｅ This has been fed back into the system.

[0053] [Features of the First Embodiment] A feature of this control is the compensation means (current control compensator G) that outputs the amount of fluctuation. １ (s) 112) is subjected to non-interference control (Δv) which compensates for the amount of variation in the interference component. ＬＩＮＫ (Addition process) and the variation Δd of the command value １ ＊After determining the command value d by adding the equilibrium point, １ ＊ The point is to calculate this. By configuring it in this way, for example, the following effects can be obtained. First, interference via the DC link section 20 can be canceled with a simple calculation. Second, the compensator G １ (s) Output Δv of 112 L1 ＊ Therefore, the output Δd of the non-interference control unit 130 １ ＊ The calculations up to this point only calculate the amount of fluctuation, so even if the amount of fluctuation is small compared to the equilibrium point, control can be performed without being affected by overflow, underflow, rounding errors, etc. Thirdly, interference in the DC link section 20 is suppressed and unnecessary inputs and outputs are reduced, so the ripple to the capacitor 35 can be reduced and the capacitance of the capacitor 35 can be reduced.

[0054] Fourthly, compensator G １ (s) compensates for the error due to the variability of the detector, reducing the impact of overflow, underflow, rounding errors, etc. resulting from the compensation of errors. Detectors have variations due to manufacturing tolerances, operating temperature, etc. These variations can be modeled as variations related to gain and variations related to offset, for example v ＬＩＮＫ The detector can be modeled by equation (1-14).

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] [Second Embodiment] Figure 4 shows the circuit configuration of the second embodiment. The second embodiment differs from the first embodiment in that it is a boost converter. The same reference numerals are used for functions similar to those in the first embodiment, and their explanation is omitted here. The power optimization system 2 comprises a DC link unit 20, a converter 330, a power supply 40, other equipment 50, and a control device 102.

[0061] The converter 330 comprises a switch unit 31, a reactor 32, and a resistor 33. Compared to the converter 30 of the first embodiment, the configuration of the converter 330 is such that the reactor 32, resistor 33, and switch unit 31 are arranged in that order from upstream to downstream in the direction of current flow. In the second embodiment, the reactance value of the reactor 32 is L ２ The resistance value of resistor 33 is set to r ２ Let's assume that.

[0062] Furthermore, the control device 102 includes a first ammeter 71, a second ammeter 75, a first voltmeter 73, and a second voltmeter 74. The second ammeter 75 measures the current flowing between the resistor 33 and the switch unit 31. The current value measured by the second ammeter 75 is i ２ The second ammeter 75 transmits the measured value to the control device 102. In the second embodiment, the value measured by the second voltmeter 74 is v ２ Let's assume that.

[0063] [Construction of Control Means] In the power optimization system 2 shown in Figure 4, the voltage of the power supply 40, the voltage of the converter 30, the voltage of the reactor 32, the voltage of the resistor 33, and the voltage of the capacitor 35 give rise to the differential equation (2-1).

[0064]

[0065] Similar to the first embodiment, linearizing equation (2-1) near the equilibrium point results in equation (2-2) as the differential equation near the equilibrium point.

[0066]

[0067] Also, as a differential equation regarding the current flowing through the capacitor 35, Equation (2-3) holds.

[0068]

[0069] Similarly, for Equation (2-3), when linearized near the equilibrium point, the differential equation near the equilibrium point becomes Equation (2-4).

[0070]

[0071] Here, the interference component is defined as Δv L２ as shown in Equation (2-5) to perform non-interference processing.

[0072]

[0073] When Equation (2-5) is applied to Equation (2-2), Equation (2-2) becomes Equation (2-6).

[0074]

[0075] When Equation (2-6) is transformed, it becomes Equation (2-7), and the transfer function from Δv L2 to Δi2 is shown.

[0076]

[0077] [Configuration of Control System] Figure 5 is a control block diagram of the control device 102 of the second embodiment. Based on the above-mentioned Equation (2-3) and Equation (2-5), a control system is adopted that performs feedback control on v ＬＩＮＫ to output i out ＊ using a compensator G ｖ (s)212, and performs feedback control on i ２ to output the variation Δv Ｌ２ ＊ using a compensator G １ (s)222.

[0078] The control block of the control device 102 includes a voltage control unit 210, a current control unit 220, a non-interference control unit 230, a control command output unit 140, a voltage high-frequency unit 143, a command low-frequency unit 144, and a conversion unit 150.

[0079] [Voltage Control Unit] The voltage control unit 210 includes a subtractor 111, a compensator Gv(s) 212, and an adder 113. The subtractor 111 subtracts the measured value v ＬＩＮＫ ＊ from the command value v ＬＩＮＫ . The compensator Gv(s) 212 calculates the command value i ＬＩＮＫ ＊ of the current i ＬＩＮＫ to compensate for the difference between the command value v ｏｕｔ and the measured value v ｏｕｔ ＊ . The adder 113 adds i ｅ to the output from the compensator Gv(s) 212 and outputs it as the command value i ｏｕｔ ＊ of the variation of the second current .

[0080] [Conversion Unit] The conversion unit 150 converts the command value i ｏｕｔ ＊ to i ２ ＊ . Specifically, the divider 151 performs division with the command value i ｏｕｔ ＊ as the numerator and d ２ ＊ １ as the denominator .

[0081] [Current Control Unit] The current control unit 220 includes a subtractor 121 and a compensator G ２ (s) 222. The subtractor 121 subtracts the value i ＊ ２ of the second current from the i ２ converted by the conversion unit 150. Then, the compensator G ２ (s) 222 outputs the variation amount Δv ＊ ２ -i<o000305>of the command value of the non-interference control v L２ based on (i ＊ ２ ).<00009o6>

[0082] [Non-Interference Control Unit] The non-interference control unit 230 includes an adder 131, a multiplier 232, and a divider 132. Here, the variation amount Δd ２ ＊ ２ of the command value of the duty ratio d ＊ to the converter 330 is obtained by the following equation (2-8).

[0083]

[0084] According to equation (2-8), the multiplier 232 multiplies the low-frequency component D output by the command low-frequency unit 144. ２ ＊ And the voltage high-frequency unit 143 output Δv ＬＩＮＫ The two are multiplied. Then, the adder 131 receives the command value Δv of the fluctuation amount output by the current control unit 220. Ｌ２ ＊ The output from the multiplier 232 and are added together. Furthermore, the divider 132 uses the output from the adder 231 as the numerator and the output from the voltage high-frequency unit 143 as the V ＬＩＮＫ Perform division with Δd as the denominator. ２ ＊ Outputs.

[0085] [Control Command Output Unit] The control command output unit 140 outputs the control command variation Δd ２ ＊ And the control command value d ２ ＊ Low-frequency component D ２ ＊ Therefore, the control command value d ２ ＊ Outputs the control command value d. ２ ＊ The answer is given by equation (2-9) below.

[0086]

[0087] According to equation (2-9), the control command output unit 140 is configured with an adder, and the variation Δd of the control command １ ＊ And the control command value d １ ＊ Low-frequency component D １ ＊ Add and output.

[0088] Figure 6 is a simplified diagram of the control block diagram in Figure 5. Next, the control block diagram in Figure 6 will be explained with reference to Figure 5. Figure 6 shows the equilibrium point D in Figure 5. ２ The control command value d output by the command low-frequency unit 144 ２ ＊ Low-frequency component D ２＊ We consider them to be the same, Δv ＬＩＮＫ and (v ＬＩＮＫ -V ＬＩＮＫ This is a modified control block diagram, assuming that ) and are identical. Equilibrium point D ２ The control command value d output by the control command output unit 140 ２ ＊ Low-frequency component D ２ ＊ If they are the same, the control command output unit 140 outputs the control command value d ２ ＊ Low-frequency component D ２ ＊ The process involves adding and subtracting to the equilibrium point D using the subtractor 171. ２ The subtraction process cancels out. Furthermore, in this case, the divider 233 reaches equilibrium point V ＬＩＮＫ The process involves dividing with the denominator, and multiplier 181 calculates the equilibrium point V ＬＩＮＫ The multiplication process cancels out. Furthermore, D is added by adder 231. ２ ＊ ×Δv ＬＩＮＫ Then, D is subtracted by the subtractor 173. ２ (v ＬＩＮＫ -V ＬＩＮＫ ) and cancel each other out. When these canceling parts are removed from Figure 5, the output Δv of the current control unit 220 is obtained. L２ ＊ Input Δv from transfer function G3 L２ The process up to this point can be omitted to show the result.

[0089] <Modification 1 of the second embodiment> Modification 1 of the second embodiment is that in the second embodiment, the output from the voltage control unit 210 is i ｏｕｔ ＊ In contrast, the output from the voltage control unit 210 was changed to a fluctuation amount Δi ｏｕｔ ＊ This is a block diagram of the configuration described above.

[0090] Figure 7 is a control block diagram of the control device 102-1 of a modified example 1 of the second embodiment. The control device 102-1 includes a voltage control unit 210, a current control unit 220, a non-interference control unit 230, a control command output unit 140, a conversion unit 250, a first current high frequency unit 141, a second current high frequency unit 142, a voltage high frequency unit 143, and a command low frequency unit 144.

[0091] The conversion unit 250 calculates the command value Δi ｏｕｔ ＊ Δi ２ ＊ Convert to . The conversion unit 250 comprises a multiplier 251, a subtractor 252, and a divider 253. The multiplier 251 converts to equilibrium point I ２ and Δd ２ ＊ Multiply by . Then, subtractor 252 outputs Δi from voltage control unit 210. ｏｕｔ ＊ From I ２ Δd ２ ＊ Subtracts from it. Furthermore, the divider 253 takes the output from the subtractor 252 as the numerator and calculates D ２ ＊ The output is obtained by dividing with as the denominator. The processing in the conversion unit 250 is based on equation (2-4). Also, the subtractor 121 of the current control unit 220 is Δi ２ ＊ From, Δi ２ Subtracting this value gives the compensator G of the current control unit 220. ２ This is the input to (s)222.

[0092] Figure 8 is a simplified diagram of the control block diagram in Figure 7. Next, the control block diagram in Figure 8 will be explained with reference to Figure 7. Figure 8 shows the equilibrium point D in Figure 7. ２ The control command value d output by the command low-frequency unit 144 ２ ＊ Low-frequency component D ２ ＊ We consider them to be the same, Δv ＬＩＮＫ and (v ＬＩＮＫ -V ＬＩＮＫ This is a modified control block diagram, assuming that ) and are identical. Equilibrium point D ２ The control command value d output by the control command output unit 140２ ＊ Low-frequency component D ２ ＊ If they are the same, the control command output unit 140 outputs the control command value d ２ ＊ Low-frequency component D ２ ＊ The process involves adding and subtracting to the equilibrium point D using the subtractor 171. ２ The subtraction process cancels out. Furthermore, in this case, the divider 233 reaches equilibrium point V ＬＩＮＫ The process involves dividing with the denominator, and multiplier 181 calculates the equilibrium point V ＬＩＮＫ The multiplication process cancels out. Furthermore, D is added by adder 231. ２ ＊ ×Δv ＬＩＮＫ Then, D is subtracted by the subtractor 173. ２ ×Δv ＬＩＮＫ These cancel each other out. If we omit these canceling parts in Figure 7, the current control unit 120 outputs Δv L２ ＊ Input Δv from transfer function G3 L２ The process up to this point can be omitted to show the result.

[0093] [Differences between the second embodiment and a modified example of the second embodiment] As described above, i ２ ＊ and i ｏｕｔ ＊ The conversion formula is, in the second embodiment, i ２ ＊ = i ｏｕｔ ＊ / d ２ ＊ In contrast, in modified example 1, Δi ２ ＊ = (Δi ｏｕｔ -I ２ Δd ２ ＊ ) / D ２ The difference lies in this point. Also, G ２ As input to (s), in the second embodiment, i ２ ＊ -i ２ In contrast, in modified example 1, Δi ２ ＊ -Δi ２It differs in that respect. As a result, in Modification 1 of the second embodiment, the dynamic range can be increased because it is controlled by the amount of change. Compared to the second embodiment, Modification 1 of the second embodiment can distinguish minute signals more finely and the control accuracy is improved. On the other hand, compared to the second embodiment, Modification 1 of the second embodiment is more susceptible to noise because it is controlled by the amount of change.

[0094] <Modification 2 of the Second Embodiment> Figure 9 is a diagram of the circuit of the power optimization system 2-2 according to Modification 2 of the second embodiment. The power optimization system 2-2 differs from the power optimization system 2 of the second embodiment in that the position of the current measured by the second ammeter 76 is different. The second ammeter 76 of the power optimization system 2-2 measures the current flowing from the converter 330 to the DC link section 20. In the modification of the second embodiment, the value of the current measured by the second ammeter 76 is i ２ ′ Let's assume that i ２ ′ In the second embodiment, the second ammeter 75 (see Figure 4) was measuring i ２ i ２ ′ = d ２ i ２ Since the above holds true, equations (2-1) to (2-9) in the second embodiment can be modified as follows.

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Figure 10 is a control block diagram of the control device 102-2 of a modified example 2 of the second embodiment. The control device 102-2 comprises a voltage control unit 210, a current control unit 220, a non-interference control unit 230-2, a high-frequency voltage unit 143, and a low-frequency command unit 144.

[0105] [Voltage Control Unit] The voltage control unit 210 comprises a subtractor 111, a compensator Gv(s) 212, and an adder 113. The subtractor 111 controls the command value v ＬＩＮＫ ＊ From the measured value v ＬＩＮＫ Subtract the command value v. The compensator Gv(s)212 is used to subtract the command value v. ＬＩＮＫ ＊ and measured value v ＬＩＮＫ Current i to compensate for the difference ｏｕｔ Command value i ｏｕｔ ＊ The adder 113 calculates i from the output of the compensator Gv(s) 212. ｅ Add this to the command value i of the fluctuation in the second current. ｏｕｔ ＊ Output as follows.

[0106] [Current Control Unit] The current control unit 220 consists of a subtractor 121 and a compensator G １ (s) 222 and, are provided. As is clear from Figure 9, i ｏｕｔ and i' ２ Since it is the same, the current control unit 220 outputs i from the voltage control unit 210. ｏｕｔ ＊ to i ２ ´ ＊ It is treated as such. The subtractor 121 takes the i output by the voltage control unit 210. ２ ´ ＊ From the value of the second current i ２ Subtract '. Then, compensator G １ (s) 122 is (i ２ ＊ -i ２ ) based on non-interference control v L２ The amount of variation Δv in the command value L２ ＊ Outputs.

[0107] [Non-interference control unit] The non-interference control unit 230-2 includes three multipliers 232, 235, 236, a doubler 237, an adder 238, a subtractor 239, and a divider 240. Here, the duty ratio d ２ of the command value variation Δd ２ ＊ is obtained by the following equation (2-17). According to equation (2-17), the multiplier 236 squares the D ２ ＊ output by the command low-frequency section 144. The multiplier 235 multiplies the V ＬＩＮＫ output by the voltage high-frequency section 143 and the D ２ ＊ output by the command low-frequency section 144. The multiplier 232 multiplies the (D ２ ＊ ) ２ output by the multiplier 236 and the Δv ＬＩＮＫ output by the voltage high-frequency section 143. The subtractor 239 subtracts both the Δv １ output by the compensator G L２ ＊ and the (D ２ ＊ ) ２ Δv ＬＩＮＫ output by the multiplier 232. The doubler 237 doubles the V ＬＩＮＫ D ２ ＊ output by 235. The subtractor 238 subtracts v ＬＩＮＫ D ２ ＊ from 2V ２ output by the doubler 237. The divider 240 divides the (–Δv L２ ＊ –(D ２ ＊ )) ２ Δv ＬＩＮＫ output by the subtractor 239 as the numerator and divides it by the (2V ＬＩＮＫ D ２ ＊ – v2) output by the subtractor 238 as the denominator.

[0108] [Control command output unit] The control command output unit 140 is composed of an adder and is the variation Δd １ ＊And the control command value d １ ＊ Low-frequency component D １ ＊ Add and output.

[0109] [Features of the control system of modified example 2 of the second embodiment] The difference between the second embodiment and modified example 2 of the second embodiment is that the current to be controlled is different. This second embodiment is i ２ i ２ Current control is performed on it. The output of the voltage control is i ２ ′ Therefore, i ２ ′ from i ２ Conversion process to (i ２ = i ２ ′ / d ２ ＊ ) is required, and the characteristics of the voltage control may deteriorate due to the delay and variation caused by the conversion process. Modification 2 of the second embodiment is i ２ ′ i ２ ′ Current control is performed on it. Voltage control output i ２ ′ Since it handles this, no conversion processing is required, and because it is not affected by delays or variations caused by conversion processing, there is no risk of degrading the characteristics of voltage control. On the other hand, i ２ This will indirectly control i ２ The control characteristics may be degraded compared to the second embodiment. Depending on the system requirements, either the second embodiment or the second modified embodiment may be selected.

[0110] [Third Embodiment] Figure 11 is a diagram of the circuit of the power optimization system 3 according to the third embodiment. In the third embodiment, three or more devices 50-1, 50-2, ..., 50-N are connected to the DC link section 20. Examples of devices 50-1 and 50-2 in Figure 11 include, for example, a solar power generation system, an energy storage system, a grid-connected inverter, a refrigeration unit, and an air conditioner. In this embodiment, voltage control is performed only by device 50-1, and not by device 50-2. A feature of this configuration is that the sum of the currents flowing from the capacitor 35 of the DC link section 20 to all devices other than device 50-1 is set to current i ｅ The point is to detect it as such. With this configuration, the voltage control characteristics of device 50-1 can be maintained even if the number of connected devices increases or decreases. Furthermore, all devices, including device 50-1, can employ the current control and non-interference control related to the amount of fluctuation described in the first embodiment and the second embodiment, including modified versions. By employing these controls, the effect of suppressing interference from other devices with simple control can be obtained.

[0111] [Fourth Embodiment] Figure 12 is a diagram of the circuit of the power optimization system 4 according to the fourth embodiment. The power optimization system 4 according to the fourth embodiment comprises a DC link section 20, a control device 104, a circuit 14-1, a circuit 14-2, ... a circuit 50-N, and equipment 50-(N+1) ... equipment 50-(N+M). Here, N is an integer of 3 or more, and M is an integer of 2 or more.

[0112] The control device 104 controls the voltage v of the capacitor 35 of the DC link section 20. ＬＩＮＫ The control device 104 controls circuits 14-1, 14-2, ..., 50-N. The DC link section 20 and circuits 14-1, 14-2, ..., 14-N are shown in Figure 12 as the control targets 14 of the control device 104. The control device 104 includes a first ammeter 71 and a first voltmeter 73. The first ammeter 71 measures the current i flowing from the capacitor 35 to the other device 50. ｅ The voltage v of capacitor 35 is measured. The first voltmeter 73 measures the voltage v ＬＩＮＫThe measurement is taken. The measured value may be transmitted to the control device 104 by wire or by wireless connection.

[0113] Circuit 14-1 is the circuit for device 50-1 (not shown) and functions as device 50-1 when controlled by the control device 104. Similarly, circuit 14-N is the circuit for device 50-N (not shown) and functions as device 50-N when controlled by the control device 104. In this embodiment, voltage control is performed on one or more devices from device 50-1 to device 50-N, but not on devices 50-(N+1) to device (N+M). Current i flowing from capacitor 35 ｅ However, the current is configured to be the sum of the currents flowing through all devices N+1 to (N+M) that do not undergo current control.

[0114] Figure 13 is a schematic diagram of the control block of the control device 104 according to the fourth embodiment. Command value i ｏｕｔ ＊ The current command i of each device ｋ ` ＊ The difference from the first to third embodiments is that a distributor 80 is provided to divide the signal into multiple outputs.

[0115] The controller 104 comprises a voltage control unit 210, a distributor 80, controller 104-1, controller 104-2, and controller 104-N. The voltage control unit 210 controls the current i measured by the first ammeter 71 (see Figure 12). ｅ And the voltage v measured by the first voltmeter 73 (see Figure 12) ＬＩＮＫ The command i of the current flowing through the DC link section 20 (see Figure 12) is fed back to the DC link section 20. ｏｕｔ ＊ The distributor 80 calculates the current command i. ｏｕｔ ＊ The current command i for each circuit 14-1, 14-2, ... 14-N １ ` ＊ i ２ ` ＊ , , i N ` ＊ Distribute.

[0116] The controller 104-1 controls the circuit 14-1 using the command value i distributed by the distributor 80.１ ` ＊ Controller 104-1 is controlled using the voltage v of the power supply of circuit 14-1. １ And the second current i １ The voltage v is obtained from circuit 14-1. Controller 104-1 controls the obtained voltage v １ And the second current i １ Based on this, control command d controls circuit 14-1. １ Similarly, controller 104-N transmits the command value i distributed by distributor 80 to control circuit 14-N. Ｎ ` ＊ Controller 104-N is controlled using the voltage v of the power supply for circuit 14-N. Ｎ And the second current i Ｎ The voltage v is obtained from circuit 14-N. The controller 104-N receives the obtained voltage v Ｎ And the second current i Ｎ Based on this, control command d controls circuit 14-N. Ｎ Send.

[0117] Figure 14 is a control block diagram of the control device 104 of the fourth embodiment. Controller 104-1 comprises a conversion unit 150, a current control unit 120, a non-interference control unit 230, a control command output unit 140, and a command low-frequency unit 144. Controller 104-1 differs from the control unit 102 of the second embodiment (see Figure 5) in that the voltage control unit 210 is located upstream of the distributor 80. Controller 104-1 receives i output from the distributor 80 １ ` ＊ Based on this, control command d for controlling circuit 14-1 １ It outputs the following. Furthermore, the controller 104-1 differs from the control unit 102 of the second embodiment (see Figure 5) in that the voltage high-frequency unit 143 is located outside the controller 104-1. The voltage high-frequency unit 143 outputs the calculated Δv ＬＩＮＫ This is output to the non-interference control units 230 of each controller 104-1, controller 104-2, ... controller 104-N.

[0118] [Modification 1 of the fourth embodiment] In the fourth embodiment, the command value i ｏｕｔ ＊The current command i for each circuit 14-1, 14-2, ... 14-N １ ` ＊ i ２ ` ＊ , , i N ` ＊ The current is distributed and controlled for each circuit 14-1, 14-2, ..., 14-N. Therefore, due to the influence of variations in the current detectors in each circuit 14-1, 14-2, ..., 14-N, i ｏｕｔ The control characteristics may deteriorate. In this modified example, i ｏｕｔ A current detector is provided, and the current of circuit 14-1 is controlled based on the current value calculated by equation (4-1).

[0119]

[0120] Here, i ｋ ' (where k is an integer from 2 to N) is the current value flowing from each circuit 14-1, 14-2, ... 14-N into the DC link section 20 (see Figure 12), and the current detection value i for each circuit 14-1, 14-2, ... 14-N １ i ２ ,...i Ｎ These are values ​​converted appropriately from ,

[0121] Figure 15 is a control block diagram of Modification 1 of the fourth embodiment. Compared to Modification 1 of the fourth embodiment, it differs in that it includes converters 450-2, ..., converter 450-N and subtractor 177. Converter 450-2 receives the current detection value i detected by the current detector provided in circuit 14-2. ２ The current value i flows from circuit 14-2 into the DC link section 20 (see Figure 12). ２ Convert to '. Similarly, the converter 450-N converts the current detection value i detected by the current detector provided in circuit 14-N. Ｎ The current value i flows from circuit 14-N into the DC link section (see Figure 12). Ｎ Convert to '. Subtractor 177 performs subtraction according to equation (4-1). Specifically, subtractor 177 performs the detected i ｏｕｔ From there, the current value i output by the converters 450-2 to 450-N ２ '...i NThe subtractor 177 performs a subtraction operation on each of the ''. The subtractor 177 outputs the result of the subtraction operation to the current control unit 120. In the modified example 2 of the fourth embodiment, the current control of circuit 14-1 is i ｏｕｔ Since current control is performed based on the detected value, the i value is affected by variations in the current detectors of each device. ｏｕｔ This can suppress the deterioration of the control characteristics.

[0122] [Fifth Embodiment] Figure 16 shows the circuit configuration of the power optimization system 5 according to the fifth embodiment. The power optimization system 5 comprises a solar power generation system 51, an energy storage system 52, a grid-connected inverter 53, and a connector 54. The solar power generation system 51 comprises a power conditioner (PCS) circuit 15-1 and a solar cell 41. The solar power generation system 51 is a power generation device in which the amount of power generated by the solar cell 41 is not constant but fluctuates depending on the operating environment. Here, the solar power generation system 51 may be, for example, a wind power generator or an AC / DC converter. The energy storage system 52 comprises a converter circuit 15-2 and a storage battery 42. The energy storage system 52 can control the amount of power generated by the storage battery 42. The connector 54 is a component for detachably connecting and conducting equipment to the DC link section 20. For example, refrigeration equipment and air conditioners are connected to the connector 54. In the example shown in Figure 16, the connector 54 is located on the opposite side of the photovoltaic power generation system 51, with the DC link section 20 in between. However, the connector 54 may also be located between the DC link section 20 and the photovoltaic power generation system 51. Also, in the example shown in Figure 16, there is one connector 54, but there may be multiple connectors 54. Note that the equipment may be connected directly to the DC bus without going through the connector 54. In this embodiment, the photovoltaic power generation system 51 and the energy storage system 52 control the DC voltage of the DC link section 20, i ｏｕｔ ＊ The current command value i of the solar power generation system 51 １ ´ ＊ and the current command value i of the energy storage system 52 ２ ´ ＊ It calculates and controls it.

[0123] Figure 17 is a control block diagram of the control device 105 of the fifth embodiment. The photovoltaic power generation system 51 (see Figure 16) is controlled by MPPT (Maximum Power Point Tracking). Here, MPPT control is a control that can automatically determine the optimal current × voltage value (maximum power point, or optimal operating point) that maximizes the output when the solar cell 41 is generating power. In addition, the energy storage system 52 (see Figure 16) is controlled by battery control and is controlled to make the most efficient use of the power generated by the photovoltaic power generation system 51. The distributor 80 receives command values ​​i from the photovoltaic power generation system 51 and the energy storage system 52. １ ＊＊ and command value i ２Lo ´ ＊ and command value i ２Ｈｉ ´ ＊ It obtains i. ｏｕｔ ＊ The distributor 80 obtains the obtained command value i. １ ＊＊ and command value i ２Lo ´ ＊ and command value i ２Ｈｉ ´ ＊ Based on this, the command value i ｏｕｔ ＊ current command value i １ ´ ＊ and current command value i ２ ´ ＊ Distribute it to them.

[0124] Figure 18 is a flowchart of the current command distribution in the fifth embodiment. The flowchart in Figure 18 shows that in step 1001 i ｏｕｔ ＊ ≧i １ ´ ＊＊ +i ２Ｈｉ ´ ＊ Determine whether or not. If the answer in step 1001 is YES, proceed to step 1002, i ｏｕｔ ＊ to i １ ´ ＊＊ +i ２Ｈｉ ´ ＊ toshi, i １ ´ ＊ to i １ ´＊＊ toshi, i ２ ´ ＊ to i ２Ｈｉ ´ ＊ The process is then terminated. Note that if the answer in step 1001 is YES, then PV is at maximum generated power, and the battery is supplying maximum discharge power. The voltage control input exceeds the supplyable current value.

[0125] If the answer in step 1001 is NO, proceed to step 1003, i ｏｕｔ ＊ ≧i １ ´ ＊＊ +i ２Ｌｏ ´ ＊ Determine whether or not. If the answer in step 1003 is YES, proceed to step 1004, i １ ´ ＊ to i １ ´ ＊＊ toshi, i ２ ´ ＊ to i ｏｕｔ ´-i １ ´ ＊＊ The process is then terminated. Note that if the answer in step 1003 is YES, the PV is at maximum power generation, and the battery is charging and discharging to make up for the power deficit.

[0126] If the answer in step 1003 is NO, proceed to step 1005, i ｏｕｔ ＊ >i ２Ｌｏ Determine whether it is '' or not. If the answer in step 1005 is YES, proceed to step 1006 i １ ´ ＊ to i ｏｕｔ ＊ -i ２Ｌｏ ´ ＊ toshi, i ２ ´ ＊ to i ２Ｌｏ ´ ＊ The process is then terminated. Note that if the answer in step 1005 is YES, the PV is below maximum power (output limit), and the battery is receiving and supplying maximum charging power.

[0127] If the answer in step 1005 is NO, proceed to step 1007, i ｏｕｔ ＊ to i２Ｌｏ ´ ＊ toshi, i １ ´ ＊ Let i be 0. ２ ´ ＊ to i ２Ｌｏ ´ ＊ The process is then terminated. Note that if the answer is NO in step 1005, the PV has stopped generating power (output is limited), and the battery is receiving maximum charge power.

[0128] [Modification 1 of the Fifth Embodiment] Figure 19 shows Modification 1 of the fifth embodiment. Modification 1 is configured to control the voltage of the DC link section 20 with a solar power generation system 51, an energy storage system 52, and a grid-connected inverter 53.

[0129] Figure 20 is a control block diagram of a modified example 1 of the fifth embodiment. In the fifth embodiment, the current i ｅ In the previous method, the current supplied to the grid-connected inverter 53 and other equipment was detected, whereas in the modified example 1, the current i ｅ The difference is that it detects the current supplied to other devices. In Example 5, i ｅ This includes AC components originating from the grid-connected inverter 53, and if the grid power supply connected to the grid-connected inverter 53 is single-phase, it is necessary to constantly detect AC components with a frequency twice that of the power supply frequency. In modified example 1, i ｅ Since it does not include the current from the solar power generation system 51, the energy storage system 52, or the grid-connected inverter 53, it is not affected by the AC component originating from the solar power generation system 51, the energy storage system 52, or the grid-connected inverter 53, making current detection easier.

[0130] [Modification 2 of the Fifth Embodiment] Figure 21 shows Modification 2 of the fifth embodiment. Modification 2 is configured to control the voltage of the DC link section 20 using a solar power generation system 51, an energy storage system 52, a grid-connected inverter 53, and a refrigeration device 55.

[0131] Figure 22 is a control block diagram of a modified example 2 of the fifth embodiment. In the modified example 2 of the fifth embodiment, the voltage of the DC link section 20 is controlled by the refrigeration equipment 55, i ｅSince the current does not include the currents from the solar power generation system 51, the energy storage system 52, the grid-connected inverter 53, or the refrigeration equipment 55, it is not affected by the AC component originating from the solar power generation system 51, the energy storage system 52, the grid-connected inverter 53, or the refrigeration equipment 55, making current detection easy. Although the refrigeration equipment 55 is shown as an example in Figures 21 and 22, the connected equipment is not limited to the refrigeration equipment 55, and for example, an air conditioner may be connected.

[0132] [Sixth Embodiment] Figure 23 is a diagram showing the system configuration of the sixth embodiment. The sixth embodiment shows an example of a system configuration in an actual embodiment. The configuration in which the solar power generation system 51 and the grid-connected inverter 53 are connected by a DC bus and current detection is also contained in a single power conditioner (PCR) 57. Voltage control within the DC bus is performed within the PCR. In this embodiment, the power conditioner 57 includes the solar power generation system 51 and the grid-connected inverter 53, but the power conditioner 57 may also include the energy storage system 52.

[0133] [Effects] The control device 101 of this embodiment is connected to a DC link section 20 equipped with a capacitor 35, and is a control device 101 that controls a converter 30 that transmits and receives power to the DC link section 20. The control device 101 detects the value i of the first current flowing from the capacitor 35 to other equipment 50 other than the converter 30 connected to the DC link section 20. ｅ A first ammeter 71 for obtaining the voltage v, a first voltmeter 73 for detecting the voltage of the capacitor 35, and ＬＩＮＫ The detected value of and the detected value of the first current i ｅ The control device 101 includes a voltage control unit 110 that adjusts the second current that the converter 30 transmits and receives power from the DC link section 20. In this case, in a device that receives and supplies DC power to a DC link section 20 to which two or more devices are connected, interference between the two or more devices in the voltage control of the DC link section 20 can be suppressed. In this embodiment, the control device 101, the voltage control unit 110 uses the detected voltage value of the DC link section 20 to set the command value i of the first current. ｅ ＊ The command value i of the first current is calculated. ｅ＊ and the detected value i of the first current ｅ Using the difference between the two, the converter 30 transmits and receives a second current i with the DC link section 20. １ This adjusts the settings. In this case, interference between devices can be suppressed without using information from other devices. The control device 101 of this embodiment includes a converter 30 with a switch unit 31, a second ammeter 72, and a control command d that controls the switch unit 31. １ ＊ The output is generated, and the second current i is calculated using the detected value of the second ammeter 72. １ The high-frequency component Δi １ The high-frequency component Δv of the voltage is calculated and the detected value of the first voltmeter 73 is used. ＬＩＮＫ Calculate and control command d １ ＊ Using this, the low-frequency component D of the control command １ ＊ Calculate the second current i １ The high-frequency component Δi １ Using this, the first manipulated variable Δv Ｌ１ ＊ The high-frequency component of the voltage is used to calculate the interference amount Δv ＬＩＮＫ The first manipulated variable Δv is calculated and Ｌ１ ＊ And the interference amount Δv ＬＩＮＫ And the low-frequency component D of the control command １ ＊ Using this, a new control command d １ ＊The following is calculated. In this case, interference via the DC link section 20 can be canceled out with a simple calculation. The power conditioner of this embodiment comprises a DC link section 20 equipped with a capacitor 35, a photovoltaic power generation system 51 connected to the DC link section 20 and equipped with a converter controlled by a control device, and a grid-connected inverter 53 configured to be connectable to a grid power supply 43 and connected to the DC link section 20. In this case, in equipment that receives and supplies DC power to a DC link section 20 to which two or more devices are connected, interference between two or more devices in the voltage control of the DC bus can be suppressed. The heat pump system of this embodiment comprises a DC link section 20 equipped with a capacitor 35, a photovoltaic power generation system 51 equipped with a converter connected to the DC link section 20, a refrigeration device 55 connected to the DC link section 20, and a grid-connected inverter 53 configured to be connectable to a grid power supply 43 and connected to the DC link section 20, and the control device is configured to control the converter or the refrigeration device 55. In this case, in equipment that receives and supplies DC power to a DC bus to which two or more devices are connected, interference between the two or more devices in the voltage control of the DC bus can be suppressed. Furthermore, the control device 101 of this embodiment can control not only power conditioners and heat pump systems, but also equipment connected via a common DC bus. The control device 101 can be applied, for example, to electric vehicles (EVs), uninterruptible power supply (UPS) devices in data centers, and energy management systems.

[0134] 1...Power optimization system, 20...DC link section, 11...Controlled object, 30...Converter, 31...Switch section, 32...Reactor, 33...Resistor, 35...Capacitor, 40...Power supply, 50...Equipment, 61...Converter circuit, 71...First ammeter, 72...Second ammeter, 73...First voltmeter, 74...Second voltmeter, 75...Second ammeter, 80...Distributor, 100...Control device, 101...Control device, 110...Voltage control section, 130...Non-interference control section, 140...Control command output section, 141...First current high frequency section, 142...Second current high frequency section, 143...Voltage high frequency section, 144...Control command low frequency section, 150...Conversion section

Claims

1. A control device connected to a DC link section equipped with a capacitor, for controlling equipment that transmits and receives power to and from the DC link section, the control device comprising: a first current value acquisition unit that acquires a detected value of a first current flowing from the capacitor to equipment other than the equipment connected to the DC link section; a voltage value acquisition unit that acquires a detected value of the voltage of the capacitor; and an adjustment unit that adjusts a second current to which the equipment transmits and receives power to and from the DC link section using the detected voltage value and the detected value of the first current.

2. The control device according to claim 1, wherein the adjustment unit calculates a target value for the first current using the detected voltage value, and adjusts the second current that the device transmits and receives power from the DC link unit using the difference between the target value for the first current and the detected value of the first current.

3. The control device according to claim 1 or 2, wherein the device comprises a power conversion circuit, the control device comprises a second current value acquisition unit for acquiring a detected value of the second current, the adjustment unit outputs a control command for controlling the power conversion circuit, calculates the high-frequency component of the second current using the detected value of the second current, calculates the high-frequency component of the voltage using the detected value of the voltage, calculates the low-frequency component of the control command using the control command, calculates a first manipulated variable using the high-frequency component of the second current, calculates an interference amount using the high-frequency component of the voltage, and calculates a new control command using the first manipulated variable, the interference amount, and the low-frequency component of the control command.

4. A power conditioner comprising: a control device according to any one of claims 1 to 3; a DC link section equipped with a capacitor; a converter connected to the DC link section and controlled by the control device; and a grid-connected inverter configured to be connectable to a grid power supply and connected to the DC link section.

5. A heat pump system comprising: a control device according to any one of claims 1 to 3; a DC link section equipped with a capacitor; a converter connected to the DC link section; a refrigeration device connected to the DC link section; and a grid-connected inverter configured to be connectable to a grid power supply and connected to the DC link section, wherein the control device is configured to control the converter or the refrigeration device.

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