Snubber circuit and power conversion system using same
View Patent ↗A snubber circuit includes a clamp circuit and a voltage conversion circuit. The clamp circuit is configured to absorb electrical energy of a main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a secondary-side voltage. The main circuit is of insulating type and is configured to perform electric power conversion. The voltage conversion circuit which is of insulating type is electrically connected to a pair of primary-side voltage points on a primary side of the main circuit and is configured to subject, to direct-current conversion, the direct-current voltage generated by the clamp circuit and output the direct-current voltage to the pair of primary-side voltage points. The voltage conversion circuit includes a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer.
1. A snubber circuit, comprising:
a clamp circuit configured to absorb electrical energy of a main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a voltage between the pair of secondary-side voltage points, the main circuit being of insulating type, the main circuit being configured to perform electric power conversion; and
a voltage conversion circuit electrically connected to the clamp circuit and a pair of primary-side voltage points on a primary side of the main circuit, the voltage conversion circuit being of insulating type, the voltage conversion circuit being configured to subject, to direct-current conversion, a direct-current voltage generated by the clamp circuit absorbing the electrical energy to obtain converted direct-current voltage and output the converted direct-current voltage to the pair of primary-side voltage points,
the voltage conversion circuit including a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer, and
the voltage conversion circuit being configured such that a secondary conversion value of an excitation current flowing through the primary winding wire of the transformer is larger than a load current supplied via the pair of primary-side voltage points to the main circuit.
2. The snubber circuit of claim 1 , wherein
the voltage conversion circuit includes a half-bridge connection of a first switch and a second switch, and
the first switch and the second switch are electrically connected to the primary winding wire of the transformer.
3. The snubber circuit of claim 1 , wherein the first capacitance component is electrically connected in parallel to the primary winding wire of the transformer.
4. The snubber circuit of claim 1 , wherein
the voltage conversion circuit includes a rectifier circuit configured to rectify a voltage across the secondary winding wire of the transformer, and
the second capacitance component is electrically connected between output ends of the rectifier circuit.
5. The snubber circuit of claim 1 , wherein the voltage conversion circuit includes an inductor electrically connected between the second capacitance component and at least one of the pair of primary-side voltage points.
6. The snubber circuit of claim 1 , wherein
the pair of secondary-side voltage points is a connection point of:
a secondary side of a high-frequency isolation transformer included in the main circuit, and
an inverter circuit configured to subject, to alternating-current conversion, an alternating-current voltage on the secondary side of the high-frequency isolation transformer, and
the clamp circuit is configured to absorb the electrical energy of a ringing component between the pair of secondary-side voltage points.
7. The snubber circuit of claim 1 , wherein the voltage conversion circuit is configured to operate at a drive frequency higher than a drive frequency of the main circuit.
8. The snubber circuit of claim 1 , wherein
the voltage conversion circuit includes a half-bridge connection of a first switch and a second switch, and
the first switch and the second switch are electrically connected to the primary winding wire of the transformer.
9. A snubber circuit, comprising:
a clamp circuit configured to absorb electrical energy of a main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a voltage between the pair of secondary-side voltage points, the main circuit being of insulating type, the main circuit being configured to perform electric power conversion; and
a voltage conversion circuit electrically connected to the clamp circuit and a pair of primary-side voltage points on a primary side of the main circuit, the voltage conversion circuit being of insulating type, the voltage conversion circuit being configured to subject, to direct-current conversion, a direct-current voltage generated by the clamp circuit absorbing the electrical energy to obtain converted direct-current voltage and output the converted direct-current voltage to the pair of primary-side voltage points,
the voltage conversion circuit including a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer, and
the voltage conversion circuit being configured to operate at a drive frequency higher than a drive frequency of the main circuit.
10. The snubber circuit of claim 9 , wherein
the voltage conversion circuit includes a half-bridge connection of a first switch and a second switch, and
the first switch and the second switch are electrically connected to the primary winding wire of the transformer.
11. A electric power conversion system, comprising:
a snubber circuit; and
a main circuit,
the snubber circuit including:
a clamp circuit configured to absorb electrical energy of the main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a voltage between the pair of secondary-side voltage points, the main circuit being of insulating type, the main circuit being configured to perform electric power conversion; and
a voltage conversion circuit electrically connected to the clamp circuit and a pair of primary-side voltage points on a primary side of the main circuit, the voltage conversion circuit being of insulating type, the voltage conversion circuit being configured to subject, to direct-current conversion, a direct-current voltage generated by the clamp circuit absorbing the electrical energy to obtain converted direct-current voltage and output the converted direct-current voltage to the pair of primary-side voltage points,
the voltage conversion circuit including a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer, and
the voltage conversion circuit being configured such that a secondary conversion value of an excitation current flowing through the primary winding wire of the transformer is larger than a load current supplied via the pair of primary-side voltage points to the main circuit.
12. The electric power conversion system of claim 11 , wherein the main circuit includes:
at least two primary-side terminals,
at least two secondary-side terminals, and
a high-frequency isolation transformer electrically connected between the at least two primary-side terminals and the at least two secondary-side terminals,
the main circuit being configured to convert electric power between the at least two primary-side terminals and the at least two secondary-side terminals via the high-frequency isolation transformer.