US 12,334,845 B2
Power tool
Aihua Xie, Nanjing (CN); Yanqing Xu, Nanjing (CN); Guang Li, Nanjing (CN); and Shuang Li, Nanjing (CN)
Assigned to Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed by Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed on Mar. 24, 2023, as Appl. No. 18/189,507.
Application 18/189,507 is a continuation of application No. PCT/CN2021/119601, filed on Sep. 22, 2021.
Claims priority of application No. 202011121013.6 (CN), filed on Oct. 20, 2020; and application No. 202011122569.7 (CN), filed on Oct. 20, 2020.
Prior Publication US 2023/0231503 A1, Jul. 20, 2023
Int. Cl. H02P 21/22 (2016.01); H02P 21/18 (2016.01); H02P 27/08 (2006.01)
CPC H02P 21/22 (2016.02) [H02P 21/18 (2016.02); H02P 27/085 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A power tool, comprising:
a motor comprising a stator winding and a rotor rotating around a stator;
a speed regulation mechanism at least used for setting a target rotational speed of the motor;
a driver circuit for delivering electrical energy provided by a power supply device from a direct current bus to the motor, wherein the driver circuit comprises a plurality of electronic switches connected between the power supply device and the motor; and
a control module;
wherein the control module is configured to calculate a voltage vector according to a measured rotational speed of the motor, a phase current of the stator winding, and the target rotational speed and overmodulate the voltage vector to obtain a modulated voltage vector to output a pulse-width modulation (PWM) signal to the driver circuit and a per-unit value of an amplitude of the modulated voltage vector ranges from 0 to 1.15,
wherein the control module comprises a first rotational speed loop for generating a target current of the motor according to the target rotational speed of the motor and an actual rotational speed of the motor,
wherein the control module comprises:
a current distribution unit for distributing a direct-axis target current and a quadrature-axis target current according to the target current of the motor generated by the first rotational speed loop;
a current conversion unit for generating a direct-axis actual current and a quadrature-axis actual current according to an actual current of the motor;
a first current loop for generating a first regulation voltage according to the direct-axis target current and the direct-axis actual current;
a second current loop for generating a second regulation voltage according to the quadrature-axis target current and the quadrature-axis actual current;
a voltage conversion unit for generating a first voltage control quantity and a second voltage control quantity according to the first regulation voltage and the second regulation voltage;
an overmodulation unit configured to perform overmodulation according to the first voltage control quantity and the second voltage control quantity to output a first overmodulated voltage and a second overmodulated voltage; and
a control signal unit for generating control signals according to the first overmodulated voltage and the second overmodulated voltage, and
wherein the control signals are used for controlling switching operations of the plurality of electronic switches of the driver circuit.