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CN-116235406-B - Power conversion device and heat pump system comprising same

CN116235406BCN 116235406 BCN116235406 BCN 116235406BCN-116235406-B

Abstract

When the carrier frequency used for generating the drive signal (Sd) is set to fsw (kHz), the maximum input power of the power conversion unit (10) is set to Pmax (kW), and the dead time of the drive signal (Sd) is set to Td (μs), the expression Td is not more than (34.00/fsw-0.145) (1.55-0.055×Pmax) is established.

Inventors

  • KAWASAKI RYOJI
  • KONO MASAKI
  • Fujiwara masahide

Assignees

  • 大金工业株式会社

Dates

Publication Date
20260512
Application Date
20210929
Priority Date
20200929

Claims (14)

  1. 1. A power conversion device including a power conversion unit (10) that converts power of three-phase ac output from an ac power supply (2), and a current compensation unit (20) that causes a compensation current (Ia (uvw)) to flow into the ac power supply (2), characterized in that: The current compensation unit (20) has a current compensation unit inverter (21), a current compensation unit capacitor (22), a current compensation unit reactor (23), a compensation control unit (26), and a drive signal generation unit (27), The current compensation part inverter (21) has a plurality of switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), The capacitor (22) for the current compensation unit is connected between the DC side nodes (21 a, 21 b) of the inverter (21) for the current compensation unit, The current compensation part reactor (23) is connected between the AC side of the current compensation part inverter (21) and the AC power source (2), The compensation control unit (26) obtains output voltage command values (Vid, viq) so as to reduce harmonic components contained in a power supply current (Is (uvw)) supplied from the AC power supply (2) to the power conversion device (100) by using the compensation current (Ia (uvw)), The drive signal generation section (27) generates a drive signal (Sd) for driving the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) by a three-phase modulation scheme based on the output voltage command values (Vid, viq), The current compensation part inverter (21) causes the compensation current (Ia (uvw)) to flow into the AC power supply (2) through the current compensation part reactor (23) by the switching operation of the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), When the carrier frequency used for generating the drive signal (Sd) is fsw (kHz), the maximum input power of the power conversion unit (10) is Pmax (kW), and the dead time of the drive signal (Sd) is Td (μs), the following expression (1) holds: Td≤(34.00/fsw-0.145)(1.55-0.055*Pmax) ......(1)。
  2. 2. A power conversion device including a power conversion unit (10) that converts power of three-phase ac output from an ac power supply (2), and a current compensation unit (20) that causes a compensation current (Ia (uvw)) to flow into the ac power supply (2), characterized in that: The current compensation unit (20) has a current compensation unit inverter (21), a current compensation unit capacitor (22), a current compensation unit reactor (23), a compensation control unit (26), and a drive signal generation unit (27), The current compensation part inverter (21) has a plurality of switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), The capacitor (22) for the current compensation unit is connected between the DC side nodes (21 a, 21 b) of the inverter (21) for the current compensation unit, The current compensation part reactor (23) is connected between the AC side of the current compensation part inverter (21) and the AC power source (2), The compensation control unit (26) obtains output voltage command values (Vid, viq) so as to reduce harmonic components contained in a power supply current (Is (uvw)) supplied from the AC power supply (2) to the power conversion device (100) by using the compensation current (Ia (uvw)), The drive signal generation section (27) generates a drive signal (Sd) for driving the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) by a two-phase modulation method based on the output voltage command values (Vid, viq), The current compensation part inverter (21) causes the compensation current (Ia (uvw)) to flow into the AC power supply (2) through the current compensation part reactor (23) by the switching operation of the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), When the carrier frequency used for generating the drive signal (Sd) is fsw (kHz), the maximum input power of the power conversion unit (10) is Pmax (kW), and the dead time of the drive signal (Sd) is Td (μs), the following expression (2) holds: Td≤(45.23/fsw-0.135)(1.48-0.048*Pmax) ......(2)。
  3. 3. A power conversion device including a power conversion unit (10) that converts power of three-phase ac output from an ac power supply (2), and a current compensation unit (20) that causes a compensation current (Ia (uvw)) to flow into the ac power supply (2), characterized in that: The current compensation unit (20) has a current compensation unit inverter (21), a current compensation unit capacitor (22), a current compensation unit reactor (23), a compensation control unit (26), and a drive signal generation unit (27), The current compensation part inverter (21) has a plurality of switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), The capacitor (22) for the current compensation unit is connected between the DC side nodes (21 a, 21 b) of the inverter (21) for the current compensation unit, The current compensation part reactor (23) is connected between the AC side of the current compensation part inverter (21) and the AC power source (2), The compensation control unit (26) obtains output voltage command values (Vid, viq) so as to reduce harmonic components contained in a power supply current (Is (uvw)) supplied from the AC power supply (2) to the power conversion device (100) by using the compensation current (Ia (uvw)), The drive signal generation section (27) generates a drive signal (Sd) for driving the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) by a three-phase modulation scheme based on the output voltage command values (Vid, viq), The current compensation part inverter (21) causes the compensation current (Ia (uvw)) to flow into the AC power supply (2) through the current compensation part reactor (23) by the switching operation of the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), When the carrier frequency used for generating the drive signal (Sd) is fsw (kHz), the maximum input power of the power conversion unit (10) is Pmax (kW), the dead time of the drive signal (Sd) is Td (μs), and the inductance of the current compensation unit reactor (23) when the current flowing to the current compensation unit reactor (23) is 0A is Lac (mH), the following equations (3) and (4) are satisfied: Lac≤16/Pmax ......(3) Td≤(34.00/fsw-0.145) ......(4)。
  4. 4. A power conversion device including a power conversion unit (10) that converts power of three-phase ac output from an ac power supply (2), and a current compensation unit (20) that causes a compensation current (Ia (uvw)) to flow into the ac power supply (2), characterized in that: The current compensation unit (20) has a current compensation unit inverter (21), a current compensation unit capacitor (22), a current compensation unit reactor (23), a compensation control unit (26), and a drive signal generation unit (27), The current compensation part inverter (21) has a plurality of switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), The capacitor (22) for the current compensation unit is connected between the DC side nodes (21 a, 21 b) of the inverter (21) for the current compensation unit, The current compensation part reactor (23) is connected between the AC side of the current compensation part inverter (21) and the AC power source (2), The compensation control unit (26) obtains output voltage command values (Vid, viq) so as to reduce harmonic components contained in a power supply current (Is (uvw)) supplied from the AC power supply (2) to the power conversion device (100) by using the compensation current (Ia (uvw)), The drive signal generation section (27) generates a drive signal (Sd) for driving the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) by a two-phase modulation method based on the output voltage command values (Vid, viq), The current compensation part inverter (21) causes the compensation current (Ia (uvw)) to flow into the AC power supply (2) through the current compensation part reactor (23) by the switching operation of the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), When the carrier frequency used for generating the drive signal (Sd) is fsw (kHz), the maximum input power of the power conversion unit (10) is Pmax (kW), the dead time of the drive signal (Sd) is Td (μs), and the inductance of the current compensation unit reactor (23) when the current flowing to the current compensation unit reactor (23) is 0A is Lac (mH), the following equations (5) and (6) are satisfied: Lac≤16/Pmax ......(5) Td≤(45.23/fsw-0.135) ......(6)。
  5. 5. The power conversion device according to claim 3 or 4, characterized in that: The ratio of the inductance of the current compensation unit reactor (23) when the current flowing in the current compensation unit reactor (23) is the peak current to the inductance of the current compensation unit reactor (23) when the current flowing in the current compensation unit reactor (23) is 0A is set to 1/3 or more.
  6. 6. The power conversion apparatus according to any one of claims 1 to 4, characterized in that: A filter (24) is provided between the AC power supply (2) and the current compensation unit reactor (23), the filter (24) having a filter reactor (24 a) having a smaller inductance than the current compensation unit reactor (23), and a filter capacitor (24 b), and the resonance frequency of the filter (24) being set to 4kHz or more.
  7. 7. The power conversion device according to claim 2 or 4, characterized in that: The drive signal generation unit (27) generates the drive signal (Sd) on the basis of the output voltage command values (Vid, viq) such that the ratio of the amplitude of the line-to-line voltage on the AC side of the current compensation unit inverter (21) to the DC voltage (Vdc) between the DC side nodes (21 a, 21 b) is 70% or more.
  8. 8. The power conversion device according to claim 2 or 4, characterized in that: The compensation control unit (26) includes a voltage command value calculation unit (29) and a DC voltage command value calculation unit (28), the voltage command value calculation unit (29) calculates the output voltage command values (Vid, viq) based on a DC voltage (Vdc) and a DC voltage command value (Vdc) between DC side nodes (21 a, 21 b) of the current compensation unit inverter (21), The DC voltage command value calculation unit (28) calculates a DC voltage command value (Vdc) based on the output voltage command values (Vid, viq) such that the DC voltage command value (Vdc) is equal to or less than twice the average value of the line-to-line voltages on the AC side of the current compensation unit inverter (21) or equal to or less than twice the fundamental frequency component.
  9. 9. The power conversion apparatus according to any one of claims 1 to 4, characterized in that: The power conversion unit (10) includes a rectifier circuit (11), a power conversion unit inverter (12), a power conversion unit capacitor (14), and a power conversion unit reactor (13), The rectifying circuit (11) rectifies the three-phase alternating current into direct current, The power conversion unit converts the direct current into alternating current by using an inverter (12), The power conversion unit capacitor (14) is connected between DC side nodes (12 a, 12 b) of the power conversion unit inverter (12) to allow the output voltage of the rectifier circuit (11) to vary, The reactor (13) for the power conversion unit is connected between the AC power source (2) and one end of the capacitor (14) for the power conversion unit.
  10. 10. The power conversion device of claim 9, wherein: The capacitance of the current compensation unit capacitor (22) is larger than the capacitance of the power conversion unit capacitor (14).
  11. 11. The power conversion apparatus according to any one of claims 1 to 4, characterized in that: The current compensation portion inverter (21) includes six unipolar transistors as the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2), the six unipolar transistors constituting three legs, The drive signal generation unit (27) generates the drive signal (Sd) so that the current compensation unit performs synchronous rectification operation with the inverter (21).
  12. 12. The power conversion device of claim 11, wherein: The switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) are elements which are mainly made of wide-bandgap semiconductors, The on-resistances of the switching elements (Sr 1, sr2, ss1, ss2, st1, st 2) are 100mΩ or less.
  13. 13. The power conversion apparatus according to any one of claims 1 to 4, characterized in that: the carrier frequency is below 100 kHz.
  14. 14. A heat pump system comprising the power conversion apparatus of any one of claims 1 to 13, characterized in that: The three-phase alternating current is input to the power conversion section (10) via three conductors (601, 602, 603), The heat pump system (1) further includes a higher harmonic generation source (300, 400), the higher harmonic generation source (300, 400) generating higher harmonics for a current of at least one wire (601, 602) of the three wires (601, 602, 603).

Description

Power conversion device and heat pump system comprising same Technical Field The present disclosure relates to a power conversion device including a power conversion unit that converts power of three-phase alternating current output from an alternating current power supply, and a current compensation unit that causes compensation current to flow into the alternating current power supply, and a heat pump system including the power conversion device. Background Patent document 1 discloses a power conversion device including a power conversion unit that converts power of three-phase ac output from an ac power supply, and a current compensation unit that causes a compensation current to flow into the ac power supply. In the power conversion device, the current compensation unit includes a current compensation unit inverter, a current compensation unit capacitor, a current compensation unit reactor, a compensation control unit, and a drive signal generation unit. The current compensation unit inverter includes a plurality of switching elements, the current compensation unit capacitor is connected between dc side nodes of the current compensation unit inverter, the current compensation unit reactor is connected between an ac side of the current compensation unit inverter and the ac power supply, the compensation control unit obtains an output voltage command value so as to reduce harmonic components included in a power supply current supplied from the ac power supply to the power conversion device by the compensation current, and the drive signal generation unit generates a drive signal by a three-phase modulation method based on the output voltage command value, the drive signal being used to drive the switching elements. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2015-92813 Disclosure of Invention Technical problem to be solved by the invention In the power conversion device including the current compensation unit as in patent document 1, if the proportion of the dead time in the carrier period of the current compensation unit converter is increased, the harmonic component included in the load current may not be sufficiently compensated. The purpose of the present disclosure is to more effectively compensate for higher harmonic components contained in a load current in a power conversion device that includes a current compensation unit. Technical solution for solving the technical problems A first aspect of the present disclosure Is a power conversion device including a power conversion unit 10 that converts power of three-phase ac output from an ac power supply 2, and a current compensation unit 20 that causes a compensation current Ia (uvw) to flow into the ac power supply 2, characterized in that: the current compensation unit 20 includes a current compensation unit inverter 21, a current compensation unit capacitor 22, a current compensation unit reactor 23, a compensation control unit 26, and a drive signal generation unit 27, the current compensation unit inverter 21 includes a plurality of switching elements Sr1, sr2, ss1, ss2, st1, st2, the current compensation unit capacitor 22 Is connected between dc side nodes 21a, 21b of the current compensation unit inverter 21, the current compensation unit reactor 23 Is connected between an ac side of the current compensation unit inverter 21 and the ac power source 2, the compensation control unit 26 obtains output voltage command values Vid, viq, in order to reduce the harmonic component included in the power supply current Is (uvw) supplied from the ac power supply 2 to the power conversion device 100 by the compensation current Ia (uvw), the drive signal generation unit 27 generates a drive signal Sd for driving the switching elements Sr1, sr2, ss1, ss2, st1, st2 by a three-phase modulation scheme based on the output voltage command values Vid, viq, the current compensation unit 21 causes the compensation current Ia (uvw) to flow into the ac power supply 2 via the current compensation unit reactor 23 by switching operations of the switching elements Sr1, sr2, ss1, ss2, st1, st2, and the carrier frequency employed for generating the drive signal Sd Is set to fsw (kHz), when the maximum input power of the power conversion unit 10 is Pmax (kW) and the dead time of the drive signal Sd is Td (μs), the following expression (1) holds: Td≤(34.00/fsw-0.145)(1.55-0.055*Pmax)......(1)。 in the first aspect, the higher harmonic component included in the power supply current Is (uvw) can be effectively reduced as compared with the case where the expression (1) Is not established. Therefore, the power supply current Is (uvw) Is easily matched with the higher harmonic standard (IEC 61000-3-2) formulated by IEC (International Electrotechnical Commission ). The second aspect of the present disclosure is a power conversion device including a power conversion unit 10 that converts three-phase ac output from an ac power supp