Power converter for outputting power to a system
View Patent ↗A power converter includes a booster circuit, an inverter circuit, a hysteresis control circuit, and a proportional-integral control circuit. The booster circuit boosts DC power of a DC power source. The inverter circuit converts the DC power outputted from the booster circuit into AC power and outputs the AC power to a system. The hysteresis control circuit controls the inverter circuit by hysteresis control so that the AC power can be outputted to the system when an AC voltage of the system is less than a DC voltage of the power source. The proportional-integral control circuit controls the booster circuit by proportional-integral control so that the AC power can be outputted to the system when the AC voltage of the system is larger than the DC voltage of the power source.
1. A power converter comprising:
a booster circuit configured to boost DC power of a DC power source;
an inverter circuit configured to convert the DC power outputted from the booster circuit into AC power and output the AC power to a system;
a hysteresis control circuit configured to control the inverter circuit by hysteresis control so that the AC power is outputted to the system when an AC voltage of the system is less than a DC voltage of the power source; and
a proportional-integral control circuit configured to control the booster circuit by proportional-integral control so that the AC power is outputted to the system when the AC voltage of the system is larger than the DC voltage of the power source; wherein:
the inverter circuit includes a bridge circuit and a normal coil connected between the bridge circuit and the system;
the hysteresis control and the proportional-integral control are performed based on a current flowing through the normal coil; and
the power converter further comprises a control gain reduction circuit configured to reduce a control gain for a predetermined period from when the proportional-integral control circuit starts to control the booster circuit.
2. The power converter according to claim 1 , wherein
the control gain reduction circuit reduces the control gain over a resonance frequency between a capacitive component and an inductive component of the booster circuit.
3. The power converter according to claim 1 , further comprising: a prevention circuit configured to prevent the booster circuit to boost the DC power when the AC voltage is less than the DC voltage.
4. The power converter according to claim 1 , further comprising:
a polarity control circuit configured to cause the inverter circuit to convert the DC power boosted by the booster circuit into the AC power when the AC voltage is larger than the DC voltage.
5. The power converter according to claim 1 , wherein
the proportional-integral control circuit includes an average value calculator configured to calculate a moving average of the current flowing through the normal coil and performs the proportional-integral control of the booster circuit based on the moving average.
6. A power converter comprising:
a booster circuit configured to boost DC power of a DC power source;
an inverter circuit configured to convert the DC power outputted from the booster circuit into AC power and output the AC power to a system;
a hysteresis control circuit configured to control the inverter circuit by hysteresis control so that the AC power is outputted to the system when an AC voltage of the system is less than a DC voltage of the power source;
a proportional-integral control circuit configured to control the booster circuit by proportional-integral control so that the AC power is outputted to the system when the AC voltage of the system is larger than the DC voltage of the power source; wherein:
the inverter circuit includes a bridge circuit and a normal coil connected between the bridge circuit and the system;
the hysteresis control and the proportional-integral control are performed based on a current flowing through the normal coil; and
the power converter further comprises: a delay circuit configured to stop the proportional-integral control of the booster circuit a predetermined delay time after the AC voltage decreases below the DC voltage.
7. A power converter comprising:
a booster circuit configured to boost DC power of a DC power source;
an inverter circuit configured to convert the DC power outputted from the booster circuit into AC power and output the AC power to a system;
a hysteresis control circuit configured to control the inverter circuit by hysteresis control so that the AC power is outputted to the system when an AC voltage of the system is less than a DC voltage of the power source;
a proportional-integral control circuit configured to control the booster circuit by proportional-integral control so that the AC power is outputted to the system when the AC voltage of the system is larger than the DC voltage of the power source: wherein:
the inverter circuit includes a bridge circuit and a normal coil connected between the bridge circuit and the system;
the hysteresis control and the proportional-integral control are performed based on a current flowing through the normal coil; and
the power converter further comprises: an advance circuit configured to start the proportional-integral control of the booster circuit a predetermined advance time before the AC voltage increases above the DC voltage.
8. The power converter according to claim 7 , wherein
the advance time is equal to or larger than one-tenth of a resonance frequency between a capacitive component and an inductive component of the booster circuit and equal to or less than the resonance frequency.