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US 10,530,282 B2Granted
Current capability limiting of DC machines
AssigneeSteering Solutions IP Holding Corporation
InventorsPrerit Pramod, Krishna Mohan Pavan Namburi, Julie Ann Kleinau
Life of this patent
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Abstract
An embodiment of a control system includes a current command module configured to receive a torque command and output a current command for controlling a direct current (DC) motor, and a current capability limiting module configured to receive the current command and a current limit indicating a maximum motor current, limit the current command based on the current limit, and actively further limit the current command based on a capability limit value.
Claims17
A control system, comprising:
- a current command module configured to receive a torque command and output a current command;
- and
- a current capability limiting module configured to receive the current command and a current limit indicating a maximum motor current, limit the current command based on the current limit, and actively further limit the current command based on a capability limit value, and output a limited current command to control a brushed direct current (DC) motor;
- wherein the capability limit value is determined based on a non-linear function and is distinct from the maximum motor current.
1 more element
A control system, comprising:
- a current command module configured to receive a torque command and output a current command;
- and
- a current capability limiting module configured to receive the current command and a current limit indicating a maximum motor current, limit the current command based on the current limit, actively further limit the current command based on a capability limit value, and output a limited current command to control a direct current (DC) motor,
- wherein the capability limit value is calculated based on a DC bus voltage, the capability limit value includes a non-linear maximum motor current value (icp) based on a positive value of the DC bus voltage and a non-linear minimum motor current value (icn) based on a negative value of the DC bus voltage, wherein the capability limit value is distinct from the maximum motor current, and
- the maximum motor current value (icp) is calculated by solving a function ƒ(icp) represented by:
- f
-
- (
- i
- cp
- )
- =
- i
- cp
-
- R
- +
- K
- e
-
- ω
- m
- +
- σ
-
- (
- i
- cp
- )
-
- V
- 0
-
- (
- 1
- -
- e
-
- i
- cp
-
- I
- 0
- )
- -
- V
- DC
- =
- 0
- wherein R is a resistance of the DC motor, Ke is a motor voltage or torque constant, ωm is a rotational speed of the DC motor, V0 is a voltage variable, I0 is a motor current, VDC is the DC bus voltage, and
- σ
-
- (
- i
- cp
- )
-
- V
- 0
-
- (
- 1
- -
- e
-
- i
- cp
-
- I
- 0
- )
- is a brush drop voltage.
69 more elements
A control system, comprising:
- a current command module configured to receive a torque command and output a current command;
- and
- a current capability limiting module configured to receive the current command and a current limit indicating a maximum motor current, limit the current command based on the current limit, actively further limit the current command based on a capability limit value, and output a limited current command to control a direct current (DC) motor,
- wherein the capability limit value is calculated based on a DC bus voltage, the capability limit value includes a nonlinear maximum motor current value (icp) based on a positive value of the DC bus voltage and a non-linear minimum motor current value (icn) based on a negative value of the DC bus voltage, wherein the capability limit value is distinct from the maximum motor current, and
- the minimum motor current value (icn) is calculated by solving a function ƒ(icn) represented by:
- f
-
- (
- i
- cn
- )
- =
- i
- cn
-
- R
- +
- K
- e
-
- ω
- m
- +
- σ
-
- (
- i
- cn
- )
-
- V
- 0
-
- (
- 1
- -
- e
-
- i
- cn
-
- I
- 0
- )
- +
- V
- DC
- =
- 0
- wherein R is a resistance of the DC motor, Ke is a motor voltage or torque constant, ωm is a rotational speed of the DC motor, V0 is a voltage variable, I0 is a motor current, VDC is the DC bus voltage, and
- σ
-
- (
- i
- cn
- )
-
- V
- 0
-
- (
- 1
- -
- e
-
- i
- cn
-
- I
- 0
- )
- is a brush drop voltage.
69 more elements
A method of controlling a brushed direct current (DC) motor, comprising:
- receiving a torque command and generating a current command by a current command module;
- receiving the current command and a current limit at a current capability limiting module, the current limit indicating a maximum electrical current;
- actively further limiting the current command based on a capability limit value determined based on a non-linear function, wherein the capability limit value is distinct from the maximum motor current;
- and
- applying a voltage to the brushed DC motor based on the limited current command.
2 more elements
Dependencies are inferred from the claim text.