Interconnected inverter system and method of manufacturing interconnected inverter system

Abstract

An interconnection inverter system (10) includes an inverter circuit (120) that converts DC power from a DC power source into AC power and supplies the AC power to an AC power line, a voltage sensor (151) that detects a voltage of the DC power on a DC power source side of the inverter circuit, a DC current sensor (161) that detects a current of the DC power on the DC power source side of the inverter circuit, and a motor ECU (100) that controls the inverter circuit. The motor ECU calculates actual power of the AC power supplied from the inverter circuit by using a product of a voltage value detected by the voltage sensor and a current value detected by the DC current sensor, and controls the inverter circuit so that the calculated actual power follows a power command value from outside of the interconnection inverter system.

Description

Technical Field

[0001] This disclosure relates to interconnected inverter systems and methods of manufacturing interconnected inverter systems, and more particularly to interconnected inverter systems suitable for interconnecting direct-current (DC) power to power lines for alternating-current (AC) power, and methods of manufacturing such interconnected inverter systems. Background Technology

[0002] Conventionally, a device has been available comprising a measurement value acquisition unit that acquires a measurement value relating to the power flowing through the power line between the power grid and the load, an instruction value acquisition unit that acquires an instruction value representing the power to be supplied from the energy storage device to the power line, and a calculator that calculates a correction coefficient for correcting the instruction value, such that when the power supplied from the energy storage device is controlled and the controlled power is supplied to the power line or the controlled power is supplied from the power line according to the instruction value, the measurement value is set to the corresponding instruction value (see, for example, Japanese Patent Application Publication No. 2017-212861). Summary of the Invention

[0003] In the device disclosed in Japanese Patent Application Publication No. 2017-212861, a sensor for measuring the grid voltage value is provided. The device controls the power supply by calculating the power supplied from the power line and the current supplied to the power line using the voltage, the value of the current supplied from the power line, and the value of the current supplied to the power line. The conversion of an inverter system mounted in a vehicle to grid connection is considered. Since the vehicle-mounted inverter system is used to control the torque of the motor, it includes a three-phase current sensor; however, it does not include a three-phase voltage sensor. Therefore, when the vehicle-mounted inverter system is used for grid connection, additional circuit components such as a three-phase voltage sensor are required, which disadvantageously increases the cost.

[0004] This disclosure is made to address the aforementioned problems, and its purpose is to provide an interconnected inverter system that can be diverted from an on-board inverter system while suppressing cost increases, as well as a method for manufacturing such an interconnected inverter system.

[0005] The interconnected inverter system according to this disclosure includes: an inverter circuit that converts DC power from a DC power source into AC power and provides the AC power to an AC power line; a voltage sensor that detects the voltage of the DC power on the DC power source side of the inverter circuit; a DC current sensor that detects the current of the DC power on the DC power source side of the inverter circuit; and a control unit that controls the inverter circuit. The control unit calculates the actual power of the AC power supplied from the inverter circuit by multiplying the voltage value detected by the voltage sensor and the current value detected by the DC current sensor, and controls the inverter circuit such that the calculated actual power conforms to a power command value from outside the interconnected inverter system.

[0006] Voltage sensors are integrated into the on-board inverter system, and in some cases, DC current sensors are also integrated into the on-board inverter system. With this configuration, the actual power consumption can be calculated using these sensors. Therefore, when switching from an on-board inverter system, it is not necessary to add a three-phase voltage sensor for calculating the actual power consumption. Thus, an interconnected inverter system that can be switched from an on-board inverter system can be provided while suppressing cost increases.

[0007] The control unit can also take into account compensation for component losses in the inverter circuit to control the inverter circuit.

[0008] Because of component losses in the inverter circuit, a difference arises between the power calculated using the voltage value on the input side of the inverter circuit and the power supplied by the inverter circuit. With this configuration, by compensating for the component losses in the inverter circuit, power can be controlled more precisely.

[0009] An AC current sensor can be further provided, which detects the current in at least two of the three phases of the AC power on the AC power line side of the inverter circuit. The control unit can calculate at least some of the compensations using the current values ​​detected by the AC current sensor.

[0010] Component losses in an inverter circuit can be estimated based on the voltage supplied to the input side of the inverter circuit and the current flowing through it. The current flowing through the inverter circuit is related to the three-phase current from the output side of the inverter circuit. Knowing the current values ​​of two of the three phases allows us to determine the current value of the remaining phase. With this configuration, component losses in the inverter circuit can be estimated and compensated.

[0011] A boost circuit can be further configured to boost the DC power from the DC power supply. The control unit can calculate compensation for component losses in the boost circuit as at least some of the compensation using the current value detected by a DC current sensor.

[0012] With this configuration, when the inverter circuit includes a boost circuit, the component losses in the boost circuit can be compensated.

[0013] According to another aspect of this disclosure, a method of manufacturing an interconnected inverter system is a method of converting a system comprising: an inverter circuit that converts DC power from a DC power source into AC power; a voltage sensor that detects the voltage of the DC power on the DC power source side of the inverter circuit; a DC current sensor that detects the current of the DC power on the DC power source side of the inverter circuit; a motor that generates driving force using AC power from the inverter circuit; and a control unit that controls the inverter circuit.

[0014] A method of manufacturing an interconnected inverter system includes: providing terminals for input of DC power to the inverter circuit as a DC power supply connection; providing terminals for output of AC power from the inverter circuit as an AC power line connection; and modifying the control method of the control unit to calculate the actual power of the AC power supplied from the inverter circuit by multiplying a voltage value detected by a voltage sensor by a current value detected by a DC current sensor, and controlling the inverter circuit such that the calculated actual power conforms to a power command value from outside the interconnected inverter system.

[0015] Based on this configuration, a method can be provided to manufacture interconnected inverter systems that can be converted from on-board inverter systems while suppressing cost increases.

[0016] The foregoing and other objects, features, aspects and advantages of this disclosure will become more apparent from the following detailed description of this disclosure when taken in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a diagram showing a summary of the configuration of the inverter system mounted on the vehicle in this embodiment.

[0018] Figure 2 This is a block diagram illustrating the conventional process for obtaining current commands for controlling an inverter system connected to the grid.

[0019] Figure 3 This is a block diagram illustrating the conventional process for obtaining actual power from an inverter system used for grid connection.

[0020] Figure 4 This is a block diagram illustrating the process for obtaining current commands for controlling an inverter system connected to the grid in embodiments of this disclosure.

[0021] Figure 5 This is a schematic diagram showing the configuration of an inverter system that transitions from an in-vehicle application to a grid-connected application in the first embodiment.

[0022] Figure 6 This is a diagram illustrating a schematic of the configuration of an inverter system that transitions from an in-vehicle application to a grid-connected application in the second embodiment.

[0023] Figure 7 This is a schematic diagram showing the configuration of an inverter system that transitions from an in-vehicle application to a grid-connected application in the third embodiment. Detailed Implementation

[0024] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. In the following description, the same elements are labeled with the same reference numerals, and their designations and functions are identical. Therefore, their detailed description will not be repeated.

[0025] [First Embodiment]

[0026] Figure 1 This is a diagram illustrating a general configuration of the inverter system mounted on the vehicle in this embodiment. (Refer to...) Figure 1 Vehicle 1 includes an energy storage device 20, a motor generator 30, a resolver 31, current sensors 32U and 32W, LC filters for each phase of the three-phase circuit implemented by coils 60U, 60V and 60W and capacitors 70U, 70V and 70W, a motor ECU 100, an inverter circuit 120, a boost converter circuit 130, a resolver digital converter (hereinafter referred to as "RDC") 140, a smoothing capacitor 150, a voltage sensor 151, a DC current sensor 161, and an HV-ECU 200.

[0027] Both the motor ECU 100 and HV-ECU 200 have a central processing unit (CPU) and memory. The motor ECU 100 controls the inverter circuit 120 and the boost converter circuit 130. The HV-ECU 200 controls the overall system of vehicle 1, including the motor ECU 100.

[0028] The energy storage device 20 includes a battery assembly containing multiple individual cells. Each individual cell is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The energy storage device 20 supplies electricity to the motor generator 30 to generate the driving force for the vehicle 1, and the electricity generated by the motor generator 30 is stored in the energy storage device 20.

[0029] The boost converter circuit 130 includes a reactor 162 and switching units 131 and 132, and boosts the voltage on the energy storage device 20 side to supply the inverter circuit 120. Switching units 131 and 132 each include a power semiconductor switching element (hereinafter referred to as a "switching element") and an anti-parallel diode. The switching element is implemented, for example, by an insulated-gate bipolar transistor (IGBT), a power metal-oxide-semiconductor (MOS) transistor, or a power bipolar transistor. The switching of the switching element is controlled by a control signal from the motor ECU 100.

[0030] DC current sensor 161 detects the current supplied to the DC power converter circuit 130 and provides a signal representing the detected current value to motor ECU 100. Smoothing capacitor 150 smooths the voltage between its opposite terminals. Voltage sensor 151 detects the voltage between the opposite terminals of smoothing capacitor 150 and provides a signal representing the detected voltage value to motor ECU 100.

[0031] Inverter circuit 120 includes an upper U-phase arm 121, an upper V-phase arm 122, an upper W-phase arm 123, a lower U-phase arm 126, a lower V-phase arm 127, and a lower W-phase arm 128. Inverter circuit 120 converts DC power from boost converter circuit 130 into three-phase AC power and provides the resulting three-phase AC power to motor generator 30. Each of the upper U-phase arm 121, upper V-phase arm 122, upper W-phase arm 123, lower U-phase arm 126, lower V-phase arm 127, and lower W-phase arm 128 includes a power semiconductor switching element (hereinafter also referred to as a "switching element") and an anti-parallel diode. The switching element is implemented, for example, by an IGBT, a power MOS transistor, or a power bipolar transistor. HV-ECU 200 sends a signal indicating the required torque to motor ECU 100. The switching of the switching element is controlled by a control signal from motor ECU 100 based on the signal from HV-ECU 200.

[0032] Current sensors 32V and 32W detect the current in the V and W phases of the three-phase AC power supplied from inverter circuit 120 and provide signals representing the detected current values ​​to motor ECU 100, respectively.

[0033] The motor generator 30 drives the wheels of the vehicle 1 by rotating, using AC power supplied from the inverter circuit 120, and supplies three-phase AC power regenerated through the deceleration force from the wheels to the inverter circuit 120. The inverter circuit 120 converts the three-phase AC power into DC power and supplies the resulting DC power to the boost converter circuit 130. The boost converter circuit 130 reduces the regenerated DC power from the inverter circuit 120 and uses the resulting DC power to charge the energy storage device 20.

[0034] The rotary transformer 31 is an angle sensor that provides the rotation angle of the rotor as a two-phase AC voltage (analog signal), and includes an excitation coil, a rotor including a repeating coil, and two-phase output coils configured to form an angle of 90 degrees with respect to each other with the rotor's rotation axis defined as the center. Thus, the rotor of the rotary transformer 31 is connected to the rotation axis of the motor generator 30, and therefore the rotary transformer 31 functions as an angle sensor for the motor generator 30.

[0035] When an excitation signal is applied to the primary excitation coil in the rotary transformer 31, the rotor, which is connected to the shaft of the motor generator 30, rotates. The excitation signal generates an induced electromotive force (EMF) in the repeating coil of the rotating rotor. The induced EMF in the repeating coil generates an induced EMF in the output coil, so that the two-phase output coils on the secondary side provide sin and cos signals corresponding to the rotor angle.

[0036] RDC 140 is an integrated circuit (IC) that calculates the rotation angle of the rotor of the resolver 31 (hereinafter referred to as "resolver angle") using signals provided from the resolver 31 and provides a digital signal representing the rotation angle to the ECU 100. Since the rotor of the resolver 31 is connected to the rotating shaft of the motor generator 30 in this embodiment, RDC 140 calculates the rotation angle of the motor generator 30.

[0037] The conversion of the inverter system installed in vehicle 1 to the grid connection was considered. Figure 2 This is a block diagram illustrating the conventional flow for obtaining current commands for controlling an inverter system connected to the power grid. (Refer to...) Figure 2 Voltage-type inverter systems typically control the output current. When controlling the output power in an inverter system used for grid connection, current commands are used instead of power commands. Specifically, such as... Figure 2As shown, the current command is obtained by multiplying the result of subtracting the actual power from the power command by a gain. The motor ECU 100 controls the inverter circuit 120 according to this current command using known methods. The actual power supplied from the inverter circuit 120 therefore follows the power command from outside the interconnected inverter system.

[0038] Figure 3 This is a block diagram illustrating the conventional process for obtaining actual power from an inverter system used for grid connection. (See reference...) Figure 3 The actual power of phase U is calculated based on the voltage value obtained from the voltage sensor and the current value obtained from the current sensor for phase U, which is the power output from the inverter system to the grid. Similarly, the actual power of phase V and phase W is calculated based on the voltage values ​​obtained from the voltage sensor and the current values ​​obtained from the current sensor for the corresponding phase V and phase W, respectively, which are the power output from the inverter system to the grid. Based on the calculated actual power of phases U, V, and W, the actual power of the three-phase power supplied to the grid is then calculated.

[0039] The on-board inverter system is used to control the torque of the motor generator 30. Therefore, it includes a current sensor for three-phase AC power but not a voltage sensor for three-phase AC power. Consequently, when the on-board inverter system is used for grid connection, additional circuitry components such as a voltage sensor for three-phase AC power are required, resulting in a detrimental increase in cost.

[0040] In this disclosure, the inverter system 10 for grid connection includes: an inverter circuit 120 that converts DC power from an energy storage device 20 (which is a DC power source) into AC power and supplies the AC power to an AC power line; a voltage sensor 151 that detects the voltage of the DC power on the DC power supply side of the inverter circuit 120; a DC current sensor 161 that detects the current of the DC power on the DC power supply side of the inverter circuit 120; and a motor ECU 100 that controls the inverter circuit 120. The motor ECU 100 calculates the actual power of the AC power supplied from the inverter circuit 120 by multiplying the voltage value detected by the voltage sensor 151 and the current value detected by the DC current sensor 161, and controls the inverter circuit 120 such that the calculated actual power follows a power command value from outside the interconnected inverter system.

[0041] A voltage sensor 151 is mounted on the vehicle inverter system, and in some cases, a DC current sensor 161 is also mounted on the vehicle inverter system. Since the actual power can be calculated using these sensors, it is not necessary to add a voltage sensor for the three-phase AC power used to calculate the actual power when switching from a vehicle inverter system. Therefore, an inverter system 10 for interconnection can be provided that allows for switching from a vehicle inverter system while suppressing cost increases.

[0042] Refer again Figure 1 In order to convert it, firstly, in the vehicle inverter system, the steps of setting terminals 51P and 51M in the wires on the energy storage device 20 side of the boost converter circuit 130, and setting terminals 61U, 61V and 61W in the three-phase wires on the output side of the inverter circuit 120 are performed.

[0043] Then, the program for obtaining the current command stored in the memory of the motor ECU 100 is executed from... Figure 2 The program used for calculation shown has been changed to Figure 4 The steps of the procedure for calculation are shown. Through these steps, an inverter system 10 for the power grid is obtained.

[0044] Figure 4 This is a block diagram illustrating the process for obtaining current commands for controlling the inverter system 10 connected to the grid in embodiments of this disclosure. (Refer to...) Figure 4 ,and Figure 2 Unlike the conventional method shown, the current command is obtained by multiplying the result of subtracting the actual power from the power command that compensates for power losses in circuits such as inverter circuit 120 and boost converter circuit 130 by a gain. The actual power is calculated by multiplying the voltage value VH, which is detected by voltage sensor 151 and supplied to inverter circuit 120, by the current value IL, which is detected by DC current sensor 161 and supplied to inverter circuit 120.

[0045] Table 1

[0046] IL(A) -100 -50 0 50 100 Loss (W) 500 300 0 200 400

[0047] Table 1 shows an exemplary mapping for calculating component losses in boost converter circuit 130. Referring to Table 1, by using such a mapping, the conduction losses (W) of the upper components of boost converter circuit 130 can be specified when the current value IL (A) of the DC power detected by DC current sensor 161 is defined as a parameter. For example, when IL is 50 (A), the loss is 200 (W). The figures in Table 1 are hypothetical values.

[0048] Table 2

[0049]

[0050] Table 2 shows an exemplary mapping for calculating component losses in inverter circuit 120. Referring to Table 2, by using such a mapping, the losses (W) of the upper and lower components of phase V can be specified by defining the DC power voltage VH detected by voltage sensor 151 and the DC-converted value Iv (Arms (root mean square)) of the three-phase AC power current value of phase V detected by current sensor 32V as parameters. Component losses can be determined by the voltage value VH and the current flowing through the component. The current flowing through the component is related to the current Iv on the opposite side of the LC filter component. Therefore, the component losses of the upper and lower components of phase V can be calculated using the voltage value VH and the current Iv. For example, when VH is 400 (V) and Iv is 75 (Arms), the losses of the upper and lower components of phase V are 1600 (W). The figures in Table 2 are hypothetical values.

[0051] Similarly, by using the mapping shown in Table 2, with the DC conversion value Iw(Arms) of the DC power detected by voltage sensor 151 and the current value of phase W of the three-phase AC power detected by current sensor 32W defined as parameters, it is possible to specify the losses (W) of the upper and lower components of phase W.

[0052] Based on the DC conversion values ​​Iv and Iw of the V-phase and W-phase current values ​​of the three-phase AC power detected by current sensors 32V and 32W respectively, the DC conversion value Iu(Arms) of the U-phase current value of the three-phase AC power can be calculated. By using the mapping shown in Table 2, with the voltage value VH of the DC power detected by voltage sensor 151 and the DC conversion value Iu(Arms) of the U-phase current value of the three-phase AC power defined as parameters, the losses (W) of the upper and lower components of the U-phase can be specified.

[0053] Figure 5 This is a diagram illustrating a schematic of the configuration of the inverter system 10 in the first embodiment, which is transitioned from an in-vehicle application to a grid-connected application. (Refer to...) Figure 5 Due to the circuitry between terminals 51P, 51M and terminals 61U, 61V and 61W of the inverter system 10 used for grid connection applications, and the motor ECU 100, compared with reference... Figure 1 The vehicle-mounted inverter systems described are similar, so repeated descriptions are omitted.

[0054] The field controller 300 is a device for controlling the power grid 90 in a building such as a residence or building, and includes a CPU and memory. In this embodiment, in transitioning the system from an in-vehicle application to a grid-connected application, the field controller 300 is connected to the motor ECU 100 via a Local Area Network (LAN). The field controller 300 provides power commands to the motor ECU 100 via the LAN.

[0055] During conversion, battery 50 is connected to terminals 51P and 51M, and three-phase AC power grid 90 is connected to terminals 61U, 61V, and 61W. Battery 50 can be any type of battery, such as a primary battery, secondary battery, solar cell, or fuel cell. The upper switching unit 131 of the boost converter circuit 130 is turned on, and the lower switching unit 132 is turned off.

[0056] [Second Embodiment]

[0057] In the first embodiment, the conversion of an inverter system for automotive applications, including a boost converter circuit 130, to an inverter system 10 for grid-connected applications is described. In the second embodiment, the conversion of an inverter system for automotive applications, excluding the boost converter circuit 130, to an inverter system 10A for grid-connected applications will be described.

[0058] Figure 6 This is a schematic diagram showing the configuration of the inverter system 10A, which is transitioned from an in-vehicle application to a grid-connected application in the second embodiment. (Refer to...) Figure 6 Since the DC current sensor 161 included in the boost converter circuit 130 of the first embodiment is not provided, a new DC current sensor 161A is provided.

[0059] DC current sensor 161A detects the current supplied to the inverter circuit 120A with DC power and provides a signal representing the detected current value IH to the motor ECU 100. Thus, as in the first embodiment, the actual power supplied from the inverter circuit 120A is calculated by multiplying the voltage value VH of the DC power supplied to the inverter circuit 120A, detected by voltage sensor 151A, by the current value IH of the DC power supplied to the inverter circuit 120A, detected by DC current sensor 161A.

[0060] The power loss in the inverter circuit 120A can be calculated as described with reference to Table 2 in the first embodiment. Since no boost converter circuit is provided, the power loss in the boost converter circuit need not be considered.

[0061] When the DC current sensor 161A is configured as in this second embodiment, the cost can be lower compared to the example in which a voltage sensor for three-phase AC power is newly configured as in the conventional example.

[0062] [Third Embodiment]

[0063] In the first embodiment, the conversion of an inverter system for automotive applications, including a relatively new type of boost converter circuit 130 containing a DC current sensor 161, to an inverter system for grid-connected applications is described. In the third embodiment, the conversion of an inverter system for automotive applications, including a relatively old type of boost converter circuit 130B without a DC current sensor 161, to an inverter system 10B for grid-connected applications is described.

[0064] Figure 7 This is a schematic diagram showing the configuration of the inverter system 10B, which is transitioned from an in-vehicle application to a grid-connected application in the third embodiment. (Refer to...) Figure 7 The DC current sensor 161 included in the boost converter circuit 130 in the first embodiment is not provided, and therefore a new DC current sensor 161B is provided.

[0065] DC current sensor 161B detects the current supplied to the inverter circuit 120B with DC power and provides a signal representing the detected current value IH to the motor ECU 100. Thus, as in the first embodiment, the actual power supplied from the inverter circuit 120B is calculated by multiplying the voltage value VH of the DC power supplied to the inverter circuit 120B, detected by voltage sensor 151B, by the current value IH of the DC power supplied to the inverter circuit 120B, detected by DC current sensor 161B.

[0066] The power loss in inverter circuit 120B can be calculated as described with reference to Table 2 in the first embodiment. Although boost converter circuit 130B is provided, it is bypassed. Therefore, the power loss in boost converter circuit 130B need not be considered.

[0067] When the DC current sensor 161B is provided as in this third embodiment, the cost can be lower compared to the example in which a voltage sensor for three-phase AC power is newly provided as in the conventional example.

[0068] [Other variations]

[0069] (1) In the previously described embodiments, as referred to Figure 4 The description refers to compensating for power loss. Without such a limitation, it is not necessary to compensate for power loss.

[0070] (2) In the previously described embodiments, as referred to Figure 4 and Figure 5 As described, power loss in both inverter circuit 120 and boost converter circuit 130 is compensated. Without such limitation, power loss in either inverter circuit 120 or boost converter circuit 130 can be compensated.

[0071] (3) In the previously described embodiments, such as Figure 1 and Figures 5 to 7 As shown, the current sensors 32V and 32W for phases V and W are configured as current sensors for AC power. However, this is not a limitation; only current sensors for AC power that detect the current in two of the three phases should be provided. For example, current sensors for phases U and V, or current sensors for phases U and W, can be provided.

[0072] (4) In the previously described embodiments, such as Figure 1 and Figures 4 to 7 The diagram illustrates the sensors necessary for calculating the actual power output from inverter circuit 120 and the power losses in inverter circuit 120 and boost converter circuit 130. Without such limitation, another sensor can be provided. For example, a sensor can be provided to detect the voltage of any phase of a three-phase alternating current synchronized with the frequency or phase of the grid voltage.

[0073] (5) In the previously described embodiments, such as Figure 5 The diagram illustrates the conversion of an inverter system for vehicle applications to an inverter system 10 for grid connection applications within buildings. Without this limitation, the vehicle inverter system can be converted for grid connection to a power company's power grid. In this case, instead of the field controller 300, the motor ECU 100 can be connected to the power company's server.

[0074] (6) In the previously described embodiments, such as Figure 5 The diagram illustrates the interconnection with power grid 90. Without such limitations, interconnection with AC power lines independent of the power grid can be achieved.

[0075] (7) In the previously described embodiments, such as Figure 5 As shown, the inverter system 10 is used to convert DC power in battery 50 to AC power and to supply the AC power to the AC power line of power grid 90. However, the AC power in power grid 90 can be converted to DC power by inverter system 10, and battery 50 can be charged using the obtained DC power.

[0076] (8) The previously described embodiments can be understood as being used for Figures 5 to 7The disclosure of inverter systems 10, 10A, or 10B for interconnection applications shown is to be understood as a disclosure of a method for manufacturing inverter systems 10, 10A, or 10B for interconnection applications by converting inverter systems for vehicle applications into inverter systems 10, 10A, or 10B for interconnection applications; it is to be understood as a disclosure of a method for converting inverter systems for vehicle applications into inverter systems 10, 10A, or 10B for interconnection applications; or it is to be understood as a disclosure of a method for interconnecting inverter systems 10, 10A, or 10B for interconnection applications to a power grid or independent power line.

[0077] [Overview]

[0078] (1) As Figure 1 and Figures 5 to 7 As shown, an interconnected inverter system (e.g., interconnected inverter system 10, 10A, or 10B) includes: an inverter circuit (e.g., inverter circuit 120, 120A, or 120B) that converts DC power from a DC power source into AC power and supplies the AC power to an AC power line; a voltage sensor (e.g., voltage sensor 151, 151A, or 151B) that detects the voltage of the DC power on the DC power source side of the inverter circuit; a DC current sensor (e.g., DC current sensor 161, 161A, or 161B) that detects the current of the DC power on the DC power source side of the inverter circuit; and a control unit (e.g., motor ECU 100, 100A, or 100B) that controls the inverter circuit. See reference... Figure 4 As described, the control unit calculates the actual power of the AC power supplied from the inverter circuit by using the product of the voltage value detected by the voltage sensor and the current value detected by the DC current sensor, and controls the inverter circuit such that the calculated actual power follows the power command value from outside the interconnected inverter system.

[0079] Voltage sensors are integrated into the on-board inverter system, and in some cases, DC current sensors are also integrated into the on-board inverter system. Therefore, the actual power consumption can be calculated using these sensors. Consequently, when switching from an on-board inverter system, it is not necessary to add a three-phase voltage sensor for calculating the actual power consumption. Therefore, an interconnected inverter system that can be switched from an on-board inverter system can be provided while suppressing cost increases.

[0080] (2) Figure 4 As shown in Table 2, the control unit also considers compensation for component losses in the inverter circuit when controlling the inverter circuit.

[0081] Because of component losses in the inverter circuit, a difference arises between the power calculated using the voltage value on the input side of the inverter circuit and the power supplied by the inverter circuit. Therefore, by compensating for component losses in the inverter circuit, power can be controlled more precisely.

[0082] (3) Figure 1 and Figures 5 to 7 As shown, the interconnected inverter system also includes AC current sensors (e.g., current sensors 32V and 32W) that detect the current in at least two of the three phases of the AC power on the AC power line side of the inverter circuit. Figure 4 As shown in Table 2, the control unit calculates at least some of the compensations by using the current values ​​detected by the AC current sensor.

[0083] Component losses in an inverter circuit can be estimated based on the voltage supplied to the input side of the inverter circuit and the current flowing through it. The current flowing through the inverter circuit is related to the three-phase current flowing from the output side of the inverter circuit. Knowing the current values ​​of two of the three phases allows us to determine the current value of the remaining phase. Therefore, component losses in the inverter circuit can be estimated and compensated.

[0084] (4) Figure 1 and 5 As shown, the interconnected inverter system also includes a boost circuit (e.g., boost converter circuit 130 or 130B) that boosts the DC power from the DC power source. Figure 4 As shown in Table 1, the control unit calculates compensation for component losses in the boost circuit as at least some of the compensations by using the current value detected by the DC current sensor.

[0085] Therefore, when the inverter circuit includes a boost circuit, the component losses in the boost circuit can be compensated.

[0086] (5) Figure 1 and Figures 5 to 7 As shown, the method for manufacturing an interconnected inverter system is a method for converting the system, which includes: an inverter circuit that converts DC power from a DC power source into AC power; a voltage sensor that detects the voltage of the DC power on the DC power source side of the inverter circuit; a DC current sensor that detects the current of the DC power on the DC power source side of the inverter circuit; a motor that uses AC power from the inverter circuit to generate driving force; and a control unit that controls the inverter circuit.

[0087] For reference Figure 1 , 4As described in section 5, the method of manufacturing an interconnected inverter system includes: providing terminals for DC power supply connection (e.g., terminals 51P and 51M, 51PA and 51MA, or 51PB and 51MB) for DC power input to the inverter circuit; providing terminals for AC power supply connection (e.g., terminals 61U, 61V, 61W, 61UA, 61VA, 61WA, or 61UB, 61VB, 61WB) for AC power output from the inverter circuit; and modifying the control method by the control unit (e.g., retrieving a program stored in the memory of the motor ECU 100 for obtaining current commands from...). Figure 2 The program used for calculation shown has been changed to Figure 4 The program shown is used to calculate the actual power of the AC power supplied from the inverter circuit by multiplying the voltage value detected by the voltage sensor by the current value detected by the DC current sensor, and to control the inverter circuit so that the calculated actual power follows the power command value from outside the interconnected inverter system.

[0088] Therefore, a method can be provided to manufacture interconnected inverter systems that can be converted from on-board inverter systems while suppressing cost increases.

[0089] Although embodiments of the invention have been described, it should be understood that the embodiments disclosed herein are illustrative and not restrictive in every respect. The scope of the invention is defined by the terminology of the claims and is intended to include any modifications within the scope and meaning of the equivalent terms of the claims.

Claims

1. Interconnected inverter systems, including: An inverter circuit converts DC power from a DC power source into AC power and supplies the AC power to the AC power line; A voltage sensor that detects the voltage of the DC power supply on the DC power supply side of the inverter circuit; A DC current sensor detects the current of the DC power supply on the DC power supply side of the inverter circuit. A boost circuit that boosts the DC power from the DC power source; as well as A control unit that controls the inverter circuit by taking into account compensation for component losses in the inverter circuit, wherein The control unit The actual power supplied by the inverter circuit from the AC power is calculated by multiplying the voltage value detected by the voltage sensor by the current value detected by the DC current sensor. The inverter circuit is controlled so that the calculated actual power follows a power command value from outside the interconnected inverter system, and The compensation for component losses in the boost circuit is calculated using the current value detected by the DC current sensor as at least some of the compensation.

2. The interconnected inverter system according to claim 1 further includes an AC current sensor that detects the current in at least two of the three phases of the AC power on the AC power line side of the inverter circuit, wherein... The control unit calculates at least some of the compensations by using the current value detected by the AC current sensor.

3. A method for manufacturing an interconnected inverter system, the method being a method for converting a system, the system comprising: An inverter circuit converts DC power from a DC power source into AC power. A voltage sensor detects the voltage of the DC power supply on the DC power supply side of the inverter circuit. A DC current sensor detects the current from the DC power supply side of the inverter circuit. A boost circuit that boosts the DC power from the DC power source. The motor generates driving force by using AC power from the inverter circuit, and The control unit controls the inverter circuit by taking into account compensation for component losses in the inverter circuit. The method includes: Provides a terminal for connecting to a DC power source for inputting DC power to the inverter circuit; Provides terminals for connecting AC power from the output of the inverter circuit to the AC power line; as well as The method controlled by the control unit is modified to (i) calculate the actual power of the AC power supplied from the inverter circuit by multiplying the voltage value detected by the voltage sensor with the current value detected by the DC current sensor, (ii) control the inverter circuit such that the calculated actual power follows a power command value from outside the interconnected inverter system, and (iii) calculate compensation for component losses in the boost circuit as at least some of the compensations by using the current value detected by the DC current sensor.

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