# US 11,114,860 B2 · Apparatus and method for controlling MPPT of photovoltaic system using active power control

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,114,860 B2
- Document ID: US11114860B2
- Status: Granted
- Kind: B2
- Application number: 16/903,826
- Filed: 2020-06-17
- Published: 2020-12-24
- Granted: 2021-09-07
- Earliest claimed: 2019-06-18
- Assignees: Industry-Academic Cooperation Foundation, Yonsei University
- Applicants: Industry-Academic Cooperation Foundation, Yonsei University
- Inventors: Yongcheol Kang; Jungwook Park; Hyoungkyu Yang
- Web page: https://patentgrep.com/patent/US11114860B2

## CPC

- H02J 3/381: {Dispersed generators}
- G05F 1/67: to the maximum power available from a generator, e.g. from solar cell
- H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
- H02M 7/5395: by pulse-width modulation
- H02J 2101/25: {involving maximum power point tracking control for photovoltaic sources}
- Y02E 10/56: Power conversion systems, e.g. maximum power point trackers
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Disclosed is an apparatus and method for controlling maximum power point tracking (MPPT) of a photovoltaic system using active power control. The apparatus includes a photovoltaic panel, a photovoltaic inverter unit which converts direct current (DC) power received from the photovoltaic panel into alternating current (AC) power and outputs the AC power used as commercial power, and an active power-based inverter control unit which determines a reference value (Pmpp) for output power (Pinv) of a photovoltaic inverter using a curve (Pmpp) connecting maximum power points according to a change in solar irradiance in a P-V curve showing a relationship between photovoltaic output power and a terminal voltage and measures a terminal voltage (Vpv) of the photovoltaic panel to allow the photovoltaic inverter to perform an operation according to MPPT control for tracking a value of the terminal voltage changed according to the solar irradiance.

## Claims

### Claim 1

An apparatus for controlling maximum power point tracking (MPPT) of a photovoltaic system using active power control, the apparatus comprising:
a photovoltaic panel;
a photovoltaic inverter unit which converts direct current (DC) power received from the photovoltaic panel into alternating current (AC) power and outputs the AC power used as commercial power; and
an active power-based inverter control unit which determines a reference value (Pmpp) for output power (Pinv) of a photovoltaic inverter using a curve (Pmpp) connecting maximum power points according to a change in solar irradiance in a P-V curve showing a relationship between photovoltaic output power and a terminal voltage and measures a terminal voltage (Vpv) of the photovoltaic panel to allow the photovoltaic inverter to perform an operation according to MPPT control for tracking a value of the terminal voltage changed according to the solar irradiance,
wherein the active power-based inverter control unit includes:
an inverter power control signal output unit which receives a value of a terminal voltage (Vpv) of a parallel capacitor and determines the reference value (Pmpp) for the output power (Pinv) of the photovoltaic inverter from the received value to output an inverter power control signal (P*inv);
a power controller which receives the inverter power control signal (P*inv) from the inverter power control signal output unit to output a grid current control signal (I*grid);
a phase locked loop (PLL) which receives a grid voltage (Vgrid) to output a phase angle (θ) for synchronizing the grid voltage;
a current controller which receives a grid current (igrid), the phase angle (θ) of the PLL, and the grid current control signal (I*grid) to output an output control signal (m) for controlling a pulse width modulation (PWM); and
a PWM control signal generator which receives the output control signal (m) of the current controller to output a PWM control signal for controlling an output of the photovoltaic inverter.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the photovoltaic inverter unit includes:
a parallel capacitor, which is positioned between the photovoltaic panel and the photovoltaic inverter, to maintain the terminal voltage in a predetermined range;
the photovoltaic inverter which converts the DC power received from the photovoltaic panel into the AC power and outputs the AC power used as the commercial power;
a filter which removes noise included in AC power output from the photovoltaic inverter; and
a utility grid connected to an output terminal of the filter.

### Claim 3

A method of controlling maximum power point tracking (MPPT) of a photovoltaic system using active power control, the method comprising:
inputting a terminal voltage (Vpv) of a parallel capacitor to an active power-based inverter control unit;
receiving, by an inverter power control signal output unit of the active power-based inverter control unit, a value of the terminal voltage (Vpv) and determining a reference value (Pmpp) for output power (Pinv) of a photovoltaic inverter from the received value to output an inverter power control signal (P*inv);
receiving, by a power controller, the inverter power control signal (P*inv) from the inverter power control signal output unit to output a grid current control signal (I*grid);
receiving, by a current controller, a grid current (igrid), a phase angle (θ) of a phase locked loop (PLL), and the grid current control signal (I*grid) to output an output control signal (m) for controlling a pulse width modulation (PWM);
receiving, by a PWM control signal generator, the output control signal (m) of the current controller to output a PWM control signal for controlling an output of the photovoltaic inverter; and
performing, by the photovoltaic inverter, an operation according to MPPT control for tracking the value of the terminal voltage changed according to a solar irradiance.

### Claim 4 (depends on 3)

The method of claim 3, wherein, in the determining of the reference value (Pmpp) for the output power (Pinv) of the photovoltaic inverter to output the inverter power control signal (P*inv), the reference value (Pmpp) for the output power (Pinv) of the photovoltaic inverter is determined using a curve (Pmpp) connecting maximum power points according to a change in solar irradiance in a P-V curve showing a relationship between photovoltaic output power and the terminal voltage.

### Claim 5 (depends on 3)

The method of claim 3, wherein power (PCpv) supplied to the parallel capacitor is a difference between output power (Ppv) of a photovoltaic panel and the output power (Pinv) of the photovoltaic inverter and is defined by an Equation below:
C
pv
⁢
⁢
V
pv
⁢
dV
pv
dt
=
P
pv
-
P
inv
,
,
,
wherein Cpv refers to capacitance of the parallel capacitor, Vpv refers to a terminal voltage of the photovoltaic panel, Ppv is determined by the solar irradiance, a temperature, and Vpv, and Pinv is controlled by controlling active power of the photovoltaic inverter.

### Claim 6 (depends on 5)

The method of claim 5, wherein, when the solar irradiance is changed from a first value to a second value greater than the first value,
the output power (Ppv) of the photovoltaic panel is changed from output (A) of the photovoltaic panel with respect to the first value of the solar irradiance to output (A′) of the photovoltaic panel with respect to the second value of the solar irradiance, and
the output power (Pinv) of the photovoltaic inverter is not changed so that the output power (Ppv) of the photovoltaic panel has a value greater than that of the output power (Pinv) of photovoltaic inverter.

### Claim 7 (depends on 6)

The method of claim 6, wherein the output power (Ppv) of the photovoltaic panel having the value greater than that of the output power (Pinv) of the photovoltaic inverter means that a right side of the Equation has a positive value, and
when the solar irradiance is increased, the terminal voltage (Vpv) of the photovoltaic panel is increased.

### Claim 8 (depends on 7)

The method of claim 7, wherein, when the terminal voltage (Vpv) of the photovoltaic panel is increased,
an operating point of the output power (Ppv) of the photovoltaic panel moves from a position (A′) to another position (B′) in a P-V curve showing a relationship between photovoltaic output power and the terminal voltage,
an operating point of the output power (Pinv) of the photovoltaic inverter moves from a position (A) to another position (B) in a curve (Pmpp) connecting maximum power points, and
even in this case, the output power (Ppv) of the photovoltaic panel has a value greater than that of the output power (Pinv) of the photovoltaic inverter so that the terminal voltage (Vpv) of the photovoltaic panel is further increased.

### Claim 9 (depends on 8)

The method of claim 8, wherein, when the terminal voltage (Vpv) of the photovoltaic panel is further increased, the operating point of the output power (Ppv) of the photovoltaic panel moves to an intersection of two curves along the P-V curve showing the relationship between the photovoltaic output power and the terminal voltage, and the operating point of the output power (Pinv) of the photovoltaic inverter moves to the intersection along the curve (Pmpp) connecting the maximum power points so that the output power (Ppv) of the photovoltaic panel has the same value as that of the output power (Pinv) of the photovoltaic inverter, the terminal voltage (Vpv) of the photovoltaic panel converges, and the output power (Pinv) of the photovoltaic inverter also has a constant value.